Marine Biological Hotspots: Ecosystem Services and …€¦ · the coastal Beaufort Sea has now been revised upwards. • Benthic bivalve assemblages differ greatly between fjords,

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Marine Ecosystem ServicesJ.-É. Tremblay, M. Gosselin and P. Archambault

ArcticNet Annual Research Compendium (2013-14)

Marine Biological Hotspots: Ecosystem Services and Susceptibility to Climate Change

Project LeadersMichel Gosselin, Philippe Archambault (Université du Québec à Rimouski); Jean-Éric Tremblay (Université Laval)

Network InvestigatorsYves Gratton (Institut national de la recherche scientifique - Eau, Terre et Environnement); Simon Bélanger, Pierre Larouche, Christian Nozais, Michel Poulin, Yvan Simard (Université du Québec à Rimouski); Connie Lovejoy (Université Laval); Kim Juniper (University of Victoria)

CollaboratorsDerek Mueller (Carleton University); Nicolas Cassar (Duke University); Leah Braithwaite (Environment Canada - Canadian Ice Service); Peter Galbraith (Fisheries and Oceans Canada - Maurice Lamontagne Institute); Daniel Bourgault, Sylvie Lessard, Laure de Montety, Michel Starr, Lisa Treau de Coeli (Institut des sciences de la mer de Rimouski); Frédéric Olivier (National Museum of Natural History of France); Steve Blasco (Natural Resources Canada - Geological Survey of Canada (Atlantic)); Pascal Guillot, Maurice Levasseur (Québec-Océan); Kevin Arrigo (Stanford University); Marjolaine Blais, Cindy Grant, Mike Hammill, Marie-France Lavoie, CJ (Christopher John) Mundy, Huixiang Xie (Université du Québec à Rimouski); Jacques Gagné, Jonathan Gagnon, Pierre Galand, Marianne Potvin, Warwick Vincent (Université Laval); Andrew Hamilton, Bernard Laval (University of British Columbia); Julie Granger (University of Connecticut); David G. Barber, Steven Ferguson, Gary A. Stern (University of Manitoba); John Hughes Clarke (University of New Brunswick); Simon T. Belt, Guillaume Massé (University of Plymouth); Jody Deming (University of Washington)

Post-Doctoral FellowsHongyan Xi (Fisheries and Oceans Canada - Maurice Lamontagne Institute); Delphine Benoit, André Comeau, Pierre Coupel, Adam Monier, Chiaki Motegi, Ramon Terrado (Université Laval)

PhD StudentsSélima Ben Mustapha (Fisheries and Oceans Canada - Maurice Lamontagne Institute); Heike Link, Virginie Roy (Institut des sciences de la mer de Rimouski); Caroline Sévigny (Institut national de la recherche scientifique - Eau, Terre et Environnement); Blandine Gaillard, Christian Marchese, Armelle Simo, Nassim Taalba (Université du Québec à Rimouski); Nathalie Jolie, Johannie Martin, Emmanuelle Medrinal, Deo Florence Onda, Nicolas Schiffrine, Mary Thaler (Université Laval)

MSc StudentsGabrièle Deslongchamps (Institut national de la recherche scientifique - Institut Armand-Frappier); Vincent Carrier (UNIS - The University Centre in Svalbard); Mariève Bouchard Marmen, Katrine Chalut, Clémence Fourier, Julien Laliberté (Université du Québec à Rimouski); Jean-Sébastien Côté, Robyn Edgar (Université Laval); Jessica Nephin (University of Victoria)

Undergraduate StudentsJoannie Charette, Sophia Elvire Thompson (Université du Québec à Rimouski); Marie-Amélie Blais, Isabelle Courchesne (Université Laval)

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Abstract

Living, harvestable resources in the upper Arctic Ocean ultimately depend on the production of marine microalgae. Microalgal production also mitigates global warming by fixing the greenhouse gas CO2 into biomass, of which a portion sinks to the seafloor. This process, called the ‘biological CO2 pump’, supplies food to the benthic organisms living at the bottom. Ongoing alterations of the physical environment will have profound impacts on the growth conditions of primary producers, affecting the timing, productivity and spatial extent of biological hotspots (i.e. areas of elevated food web productivity against the low background typical of the Canadian Arctic). This project investigates how changes in the dynamics of sea-ice and glacial ice (icebergs and ice islands), water temperature, ocean circulation and wind forcing affect primary production in the upper water column and the benthic ecosystem underneath. Specific objectives are to 1) locate biological hotspots (and coldspots) of pelagic and benthic activity, 2) assess how they function and interact, and 3) assess how their productivity and biodiversity is likely to respond to further perturbations of the environment. To do so, we are and have been developing and implementing cutting-edge observational and experimental approaches that exploit remote sensing from space, autonomous underwater vehicles as well as the sampling and laboratory facilities of the CCGS Amundsen. Our work is done in very close collaboration with several ArcticNet projects, collaborators and partners from government and the industry.

Key Messages

• Given the geographical location of the eastern Canadian Arctic, with respect to the large-scale oceanic circulation, it seems highly improbable at present that overall marine productivity will increase in the region.

• The relatively short seaward extent of eastern Canadian Arctic shelves, their low-productivity status and susceptibility to strong acidification makes it doubtful that this ecosystem could support a local boom of harvestable resources in the foreseeable future.

• Remote-sensing images of chlorophyll (an index of plant biomass) shows that the spring phytoplankton now happens earlier in most sub-regions of the Canadian Arctic.

• The under-ice bloom in the Amundsen Gulf begins 9 days after the upper mixed layer of the water column has reached its seasonal maximum depth.

• Northern Baffin Bay is a multivorous food-web system with a high potential for CO2 export to depth, whereas Davis Strait is dominated by a microbial food-web system with limited potential for vertical carbon export.

• Exceptionally high abundances of picocyanobacteria during the fall in Davis Strait indicate a substantial advection of Atlantic-influenced waters toward Baffin Bay.

• Benthic remineralization provides an essential service for marine productivity – it allows to recycle the nutrients that reach the bottom and to recirculate them. We found the temporal variability of this benthic remineralization function to be higher at biological hotspots than at coldspots.

• Frontal structures (i.e., ocean areas where two water masses collide) are usually associated with enhanced biological productivity (mini-hotspots). The number of frontal structures existing in the coastal Beaufort Sea has now been revised upwards.

• Benthic bivalve assemblages differ greatly between fjords, indicating that they are exposed to very different environmental conditions.

• The distribution of sub-clades of MAST-1 stramenopiles (planktonic microbes) is highly sensitive to ice conditions. It is thus expected

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the further changes in ice cover will have consequences on the function of the marine food web by altering cell size and grazing rates.

• Maximum concentrations of polar cod occur in the Amundsen Gulf, where total estimated biomass reached approximately 250 kt.

• Young and adult polar cod occupy distinct ecological niches, one is located in the epipelagic layer (near-surface), while the other occurs in the mesopelagic or benthopelagic layers.

• The load of total suspended matter (TSM) in surface waters plays an important role by altering water transparency and the penetration of light for primary producers and visual predators. The new algorithms we developed for the satellite estimation of TSM perform better than previous ones by as much as 31%.

• Turbulence is a critical processes allowing for the upward re-supply of nutrients from the deep ocean to the sunlit surface layers were phytoplankton photosynthesize and produce food. We have been able to characterize the distinct mixing regimes occurring in the Canadian Arctic and to identify different types of turbulence (classical, double-diffusion and differential mixing).

Objectives

• Determine where pelagic and benthic hotspots (or coldspots) of productivity and diversity occur, how they function and are likely to shift in the future.

• Adapt remote-sensing techniques for the estimation of phytoplankton biomass and suspended matter in the particular environment of the Arctic Ocean, with the aim of better characterizing the spatio-temporal variability of primary production at different spatial scales.

• Elucidate the oceanic, cryospheric and atmospheric drivers of microalgal primary production and microbial diversity in surface waters.

• Relate key indices of primary production to the biomass and diversity of consumers in the lower pelagic and benthic food web.

• Assemble decadal time-series to deconvolute the effect of different forcing mechanisms (inter-annual variability, climate oscillations, climate change) on productivity and biodiversity.

• Develop and/or implement cutting-edge approaches to augment the spatial and temporal coverage and resolution of observations on the productivity and biodiversity of the lower food web.

Introduction

Living, harvestable resources in the upper Arctic Ocean ultimately depend on the production of marine microalgae, which is recognized as a universal index of ecosystem richness and fisheries yield (Chassot et al., 2010; Conti and Scardi, 2010). Microalgal production also mitigates global warming by fixing the greenhouse gas CO2 into biomass, of which a portion sinks to the seafloor. This process, called the “biological CO2 pump”, supplies food to the benthic organisms living at the bottom.

Microalgae require light and the nutrients supplied from deep waters, rivers and currents (Tremblay and Gagnon, 2009). By blocking light and the wind-driven mixing or upwelling of nutrients from deep waters, sea ice continues to restrict photosynthesis and the yield of harvestable resources over much of the Arctic. Ongoing environmental alterations will have profound impacts on the growth conditions of primary producers, affecting the timing, productivity and spatial extent of biological hotspots (i.e. areas of elevated food web productivity against the low background typical of the Canadian Arctic). These changes may also favor harmful algal blooms, which disrupt food webs and human health at lower latitudes (e.g. Walsh et al., 2011).

Hotspots can be observed using in situ and remote sensing approaches, each with their strengths and

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limitations. We have been progressing on all these fronts and the results presented here show recent achievements and successes obtained by exploiting the complementary nature of those techniques. While essential knowledge on ecosystem function and processes will continue to be derived from scientific expeditions to the Arctic, the estimation of biological productivity through satellite remote sensing of ocean colour offers the only means to detect temporal and spatial trends in productivity at a variety of scales ranging from local, to regional and hemispheric (Arrigo and van Dijken, 201; Kahru et al., 2011; Perrette et al., 2011). These methods currently tend to overestimate surface chlorophyll a (Chl a) due to large riverine input of organic matter in the coastal Arctic (Bélanger et al., 2008; Matsuoka et al., 2009) and to overlook the occurrence of subsurface chlorophyll maximum (SCM; Martin et al., 2010). Moreover, ice and clouds continue to hamper the acquisition of ocean color data in the Arctic. We have thus been working toward the development of new remote sensing algorithms designed specifically for the Beaufort Sea/Amundsen Gulf region, which now allows a more rigorous estimation of chlorophyll concentration (Mustapha et al., 2012).

The resource and services of an ecosystem depends largely on the relationship between the different levels of the food web, especially the link between primary producers and the benthic fauna, which plays a key role in the recycling of organic matter and channeling of food to higher trophic levels. It has been suggested that the shift in primary producers caused by global warming will impact on both the quantity and the quality of food exported towards the seabed (Forest et al., 2011; Link et al., 2011; Tremblay et al., 2011). Finally, apart from playing a fundamental role in marine food webs, planktonic and benthic communities have been recognized as bioindicators of climate changes since the variability in ice cover, temperature, stratification and ocean currents are reflected in their biomass, diversity, productivity and spatial distribution (Li et al., 2009; Comeau et al., 2011).

Activities

1. Dissemination of scientific results

• Dissemination of results to the scientific communities, public, partners and stakeholders in high-ranking articles, either submitted (3) or accepted/published (29), and 3 book chapters.

• Wide dissemination of scientific result via oral 20) and poster (35) presentations during national/international conferences : International Diatom Workshop, DOE-JGI users meeting, ArcticNet Annual Meeting, Québec Océan Annual Meeting, Chantier Arctique Français, International Sclerochronology Conference, 45th International Liège Colloquium.

• Six students graduated after defending their PhD theses (E. Alou-Font, M. Thaler, S. Nahavandian, J. Martin, C. Sévigny) or handing their MSc dissertations (B. Philippe). Note that Alou-Font, Nahavandian and Philippe are no longer part of the active member list.

• Students won 1st prizes for posters (2) and a talk (1) at the annual scientific meetings of Quebec-Océan and ArcticNet.

• Invited talk at the combined Phycological Society of America and International Society of Protozoologist meeting in Vancouver BC.

• Participation to a workshop on scientific communication (Québec-Océan Annual, Rivière-du-Loup (QC), Canada), on deep cold water soft corals identification (Institut des sciences de la mer de Rimouski at Université du Québec à Rimouski, Rimouski (QC), Canada), on boreal and cold ocean habitat mapping and surrogacy (CHONe workshop at Huntsman Marine Science Centre, St. Andrews (NB), Canada.

• Several NI’s will are presenting ArcticNet work at the Ocean Sciences Meeting, Hawaii (USA) from 23 to 28 February.

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2. Expeditions and laboratory work, instrumentation, analysis

A) Summary of CCGS Amundsen 2013 Expedition in the IRIS 1 (Western and Central Canadian Arctic), IRIS 2 (Eastern Canadian Arctic) and IRIS 4 (Eastern Canadian Subarctic) areas.

• Sampling of 4 stations in 2 Labrador fjords (IRIS 4), 18 stations in Baffin Bay and 8 stations in the eastern Canadian Arctic Archipelago (IRIS 2) from 29 July to 15 September 2013.

• Estimation of the depth of the euphotic zone with a Secchi disk and from a vertical light profile measured with a PNF-300 radiometer.

• Collection of water samples for the determination of dissolved organic carbon concentration (TOC- Shimadzu analyzer), particulate carbon and nitrogen concentration (CHN analyzer), cell abundance and identification (light microscopy and flow cytometry), pigment signature (HPLC method), chlorophyll a biomass (fluorometry) and primary production rates (14C-assimilation method).

• Dilution experiments were conducted at the 4 Labrador fjord stations to estimate the growth and mortality rates of phytoplankton.

• All samples that could not be processed directly onboard have been analyzed during fall 2013 except for HPLC samples and taxonomic samples that will be analyzed during winter-spring 2014.

• Sampling for DNA and RNA from Basic and Full stations and protein expression from Baffin Bay.

• We instigated two Lagrangian studies on the Greenland and Canadian sides of Baffin Bay to track metatranscriptomes at different times of the day.

• Radiometric measurements for the estimation of apparent optical properties (AOPs) and in situ measurements of the inherent optical properties (IOPs).

B) Participation to other expeditions extending the scope of our work within the Canadian Arctic.

• Preliminary study on the phytoplankton dynamics was conducted in summer 2013 in Cambridge Bay (CHARS) in collaboration with C.J. Mundy (IRIS 1).

• Study of the nitrogen balance and productivity of sea-ice near Resolute in spring 2013 in collaboration with C. Michel, DFO (IRIS 2)

• Participation to an expedition in the Beaufort Sea onboard the Frosti in August 2013 (IRIS 1).

• Participation in the JOIS-IOS expedition onboard the CCGS Louis St. Laurent in the Canada Basin. Samples were collected in the context of our long term Amundsen Gulf monitoring region (IRIS 1).

C) Several NI’s took part in international oceanographic expedition, with the goal of understanding how the Canadian Arctic connects with the larger Arctic system and waters inflowing through major remote oceanic gateways.

• Invited participation to the trans-Arctic expedition of TARA-OCEANS on board the Tara (France-led). Collection of nutrient samples from all sectors of the Arctic.

• Invited participation onboard the RV Mirai (Japan) in September 2013 from the Bering Strait and Chukchi Sea to collect RNA samples and carried out experiments.

• Invited participation on the RV Helmer Hansen in January 2014 to collect winter baseline data in the Barents Sea near Svalbard (Norwegian funded project Carbon Bridge).

3. Contributions to the IRIS process

During summer and fall 2013, the leaders of project 3.1 and other NI’s completed the drafts of two comprehensive chapters for the IRIS 2 report. These drafts are now being assessed by the steering committee :

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• Marine ecosystem productivity in the changing eastern Canadian Arctic (Jean-Éric Tremblay, Simon Bélanger, Michel Gosselin, Yves Gratton, Philippe Archambault and Dany Dumont).

• Marine Protected Areas and Biodiversity Conservation in the Eastern Arctic (A. Piot, P. Archambault , D. Berteaux, D. Blanchard D, L. Brown, E. Edinger, O. Jensen, V. Sahanatien).

4. Other activities :

• Creation of a dataset of incident irradiance (Ed) measurements collected during the NOW, CASES, Malina and ArcticNet expeditions. The goal is to validate various methods estimating Ed from satellite data and ultimately used in primary production models (Bélanger et al., 2013a).

• In preparation for the next synthesis of scientific knowledge on biological Arctic productivity, an extensive data set of biochemical variables has been assembled, regrouping data on primary production, biomass, nutrients and in-water light. This includes data from ArcticNet expeditions and other programs (Ardyna et al. in prep).

• Processing of the remote sensing reflectance measurements from the 2011 ArcticNet expedition (Leg 1).

Results

Foreword:

Partial syntheses of our activities are described in the draft IRIS chapters now being reviewed by the steering committee. The specific research results described below are less “synthetic” but illustrate the degree of advancement of the coordinated subprojects that coalesce into the syntheses. The main overall conclusion of our scientific chapter for the eastern Canadian Arctic IRIS (Tremblay et al., submitted) is the following:

“Given the geographical location of the eastern Canadian Arctic with respect to the large-scale oceanic

circulation, it seems highly improbable at present that overall marine productivity will increase in the region. The apparent shift of elevated productivity zones toward the north (Kane Basin) or the west (inner Lancaster Sound) implies that nutrients are stripped from surface waters before flowing into the once productive zones of Smith Sound and eastern Lancaster Sound. The seasonal timing of primary production in these zones may also continue to change, with added consequences on the structure and function of marine food webs. The current fisheries yield is low and might somewhat increase if fishing effort intensified with the greater incidence of icefree conditions (fishing vessels can spend more time offshore) and if new port facilities allowed fast turnover of the catch.However, the relatively short seaward extent of eastern Canadian Arctic shelves, their low-productivity status and susceptibility to strong acidification makes it doubtful that this ecosystem could support a local boom of harvestable resources in the foreseeable future.”

Detailed scientific results of sub-projects:

Detecting marine biological hotspots from space

1. Regional algorithms for remote-sensing estimates of total suspended matter in the Beaufort Sea (NI: Larouche, Coll.: S. Tang, A. Niemi, C. Michel)

We developed two regional algorithms for the estimation of total suspended matter (TSM) concentration using MERIS spectral bands, based on in situ optical and suspended particulate data collected during the Canadian Arctic Shelf Exchange Study (CASES) and the Arctic Coastal Ecosystem Study (ACES) in summers of 2004 and 2010, respectively. The remote sensing reflectance ratio Rrs560/Rrs490 was best correlated with seawater containing low TSM concentrations (<3.0 g m-3), whereas the Rrs681/Rrs560 ratio was well correlated with seawater containing higher TSM concentrations. Hence, an empirical piecewise algorithm is proposed with the switch between the two TSM conditions being triggered by the Rrs681/Rrs560 ratio at a threshold

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value of 0.6. The second algorithm made use of support vector machines (SVM) as a nonlinear transfer function between TSM concentrations and remote sensing reflectance ratios Rrs681/Rrs560, Rrs665/Rrs560 and Rrs560/Rrs490. Results show that both algorithms developed during this study perform better (31 and 25%, respectively) than other published TSM algorithms including the MERIS Case 2 water processor (C2R) neural network algorithm (Fig. 1).

2. Seasonal variability of light absorption properties in Hudson Bay (NI: Larouche, HQP: H. Xi)

The use of accurate light absorption coefficients by phytoplankton (ph), nonalgal particles (NAP) and colored dissolved organic matter (CDOM) could improve the quantification of the phytoplankton

biomass in the Canadian Arctic. Previous studies have shown that the optical properties of the water constituents in Hudson Bay are different from other Arctic regions (Brunelle et al., 2012). The analysis of the bio-optical data set collected in fall 2005 and in summer 2010 in Hudson Bay shows seasonal variability in light absorption coefficients by the different constituents. Indeed, the relative contribution of CDOM to total non-water absorption is higher during summer than during fall as a result of decreased phytoplankton absorption in summer (Fig. 2). The seasonal variability in light absorption coefficients is

Figure 1. Suspended sediment processed by SVM algorithm from MERIS satellite observation, showing the extent of the Mackenzie River plume in delta regions. a) Data acquired on 23 August 2007 at high runoff; b) Data acquired on 28 August 2004 at low runoff.

Figure 2. Ternary plots illustrating the relative contribution of phytoplankton (aph), nonalgal matter (aNAP) and CDOM (aCDOM) to total non-water absorption at five SeaWiFS wavelengths in summer and fall. Solid gray lines for aph(λ), dashed lines for aNAP(λ), and dotted lines for ag(λ).

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more pronounced near the coast than in central part of the Bay.

The summertime chlorophyll-specific absorption coefficients by phytoplankton in Hudson Bay are among the lowest reported in the literature. These low values are attributed to the presence of large phytoplankton cells (microphytoplankton) and to high package effect. The contribution of accessory pigments to total pigments was smaller during summer than during fall, resulting in a lower blue-to-red phytoplankton absorption ratio. However, the slope of the exponential function describing nonalgal matter and CDOM spectral absorption shows little variability between summer and fall.

3. Phytoplankton phenology and primary production variability in the eastern Canadian Archipelago as assessed from satellite remote sensing (NI: Bélanger, HPQ: C. Marchese, J. Laliberté)

The North Water (NOW), located between Greenland and Ellesmere Island, is one of the largest and most productive polynyas in the Northern Hemisphere (Fig. 3). A satellite-based primary production (PP) model

was recently used to estimate PP in the NOW for the period 1998-2010 (Bélanger et al., 2013). PP time series revealed that productivity dropped dramatically after 2002 in the NOW, but increased in the Kane Basin where earlier ice breakup occurs in the recent years. More precisely, for the whole studied area and period a decrease of 25% in PP was observed. The monthly trends in PP suggest that the spring-summer phytoplankton bloom tend to occur earlier in season (Gaillard et al., submitted). In this regard, the seasonal-to-inter-annual variability of chlorophyll a (chl a) was monitored from 1998 to 2012 using satellite ocean color imagery. The seasonal variation in chl a was modeled for 8 sub-regions shown in Figure 3 using a Gaussian function from which a baseline of phenological characteristics was extracted.

The mean seasonal variability in chl a calculated over the 15 years of observation for each sub-region is shown on Figure 4. The seasonality is characterized by a main peak of production occurring between May and July, which varies spatially among the sub-regions. The earliest bloom occurs around Carey Island in the eastern part of the polynya, consistent with previously reported results (Klein et al., 2002). The latest bloom

Figure 3. a) Map of the Baffin Island and West Greenland Currents and b) the key sub-regions. The sub-regions approximate the distribution of the different water masses.

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occurs, as expected, in the Kane Basin, where landfast ice prevents light to penetrate the water column until July.

The timing of the maximum chl a concentration is subject to inter-annual variability (Fig. 5). Interestingly, the onset of the bloom tended to happen earlier in season in most sub-regions.

Environmental factors favoring the formation of marine biological hotspots

4. The spatial and temporal variation of the mixed layer depth in the Canadian Beaufort Sea (NI: Gratton, HQP: S. Nahavandian)

We studied the properties and seasonal evolution of the mixed layer depth (MLD) in the southeastern Beaufort Sea and Amundsen Gulf, using all the CTD profiles obtained between 2002 and 2009. Seasonal differences were found between sub-regions, except for the

Figure 4. Average seasonality of the phytoplankton bloom from 1998 to 2012 for the eight sub-regions shown in Figure 3.

Figure 5. Interannual variability in the date of the onset (blue), peak (red) and end (green) of the phytoplankton spring-summer bloom in two sub-regions: Ellesmere-Devon Island on the western side of the NOW (left) and the Carey Island sector on the eastern side (right).

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summer when all MLDs were similar. All MLDs were systematically deeper during the Circumpolar Flaw Lead Study (CFL) than during the Canadian Shelf Exchange Study (CASES). In addition, all MLDs were systematically deeper offshore (Fig. 6). The evolution of the mass budget of the mixed layer was modeled at the CASES overwintering station, using CTD profiles only. The MLD reacts immediately to vertical motions at the base of the layer, but it takes 21 days to integrate the effects of the atmospheric fluxes. Interestingly, based on CTD data only, we were able to estimate the evolution of the ice thickness and to show that the under-ice phytoplankton bloom begins 9 days after the MLD has reached its seasonal maximum (Fig. 7).

5. Frontal zone mixing in Canadian Arctic waters (NI: Gratton, HQP: C. Sévigny)

The study shows that frontal structures in the Amundsen Gulf are more numerous than reported in the literature until now. Figures 8 and 9 present the observed frontal structures and eddy in June 2004 during CASES and in September 2007 during CFL. Although mixing intensity is generally low, strong mixing events are observed in these frontal regions.

Figure 6. Monthly mean values of the mixed layer depth (MLD) during 2003-2004 (green) and 2007-2008 (red). The dash lines are uncertainty limits with 95% confidence interval. Monthly minimum (upward triangle) and maximum (downward triangle) MLDs during CASES (in green) and CFL (in red) are shown.

Figure 7. a) Comparison between estimated ice thickness and observed values; b) Mixed layer depth (MLD).

Figure 8. Surface potential density and currents at 16 m during the fall of 2007. Frontal zones are numerous. The eddy in central Amundsen Gulf is especially noticeable.

Figure 9. Noticeable structures in June 2004, superimposed on NOAA sea surface temperature observed between 17 and 24 June. CB-1 and CB-2 are fronts observed in the Cape Bathurst upwelling zone; PG is a frontal region near the ice bridge and, finally TA is an eddy.

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The most interesting result is the successful distinction between classical turbulence, double-diffusion and differential mixing throughout the Canadian Arctic. This allowed the production of tables presenting minimum and maximum values of mixing coefficients for northern Baffin Bay, Northwest Passage and Amundsen Gulf.

Pelagic and benthic marine hotspots

6. Distribution of phytoplankton and other protists in Baffin Bay and Davis Strait during early fall 2012 (NI: Gosselin, Poulin, Tremblay, HQP: M. Blais, S. Lessard, A. Lapoussière)

The predicted continuous warming trend of the ocean surface is expected to favor the growth of smaller phytoplankton cells (picophytoplankton replacing large diatoms) that in turn would also favor small-

sized zooplankton species (Li et al., 2009; Pomerleau et al., 2011). During early fall 2012, we had the opportunity to study the structure and function of the lower trophic levels of the food web along a latitudinal transect between Baffin Bay and Davis Strait. The eukaryotic phytoplankton community ≤20 µm in the surface waters was largely dominated by small cells (≤2 µm) in Baffin Bay/Davis Strait area, totaling, on average, 88% of the cell abundance (Fig. 10). The lowest and highest abundances were observed at the two northernmost stations and at three stations located in the central part of northern Davis Strait, respectively (Fig. 10).

The surface phytoplankton community (>2 µm) was mainly composed of diatoms and flagellates in Baffin Bay and of nanoflagellates and unidentified cells in Davis Strait (Fig. 11). However, the northernmost station in Davis Strait located offshore McBeth

Figure 10. Total abundance of pico- (≤2 µm) and nanoeukaryotic (2-20 µm) phytoplankton in the surface waters of Baffin Bay and Davis Strait during fall 2012.

Figure 11. Relative abundance of four protist groups (>2 µm) in the surface waters of Baffin Bay and Davis Strait during fall 2012. Diatom counts include spores and dinoflagellate counts include cysts, which are both in very low abundance.

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Fjord had a composition similar to Baffin Bay samples. Dinoflagellates generally made up <10% of the total phytoplankton community >2 µm with Gyrodinium spp. (10-20 µm) as the dominant genus. The most abundant diatom species were the centrics Leptocylindrus danicus, Chaetoceros contortus and Chaetoceros socialis. Unidentified cells ranging mainly from 2 to 5 µm were relatively abundant in Davis Strait (Fig. 11).

In the surface waters, the heterotrophic protist community was numerically dominated by choanoflagellates in Baffin Bay and at the southernmost station of Davis Strait and by other heterotrophic groups at 6 stations in Davis Strait (Fig. 12). Ciliates (cells ranging mainly from 10 to 20 µm) or choanoflagellates (cells ranging mainly from 5 to 10 µm) are the second most abundant heterotrophic group >2 µm in Davis Strait. In Davis Strait, the two

most abundant taxa belonging to the so-called “other heterotrophic groups” were Leucocryptos marina and Telonema sp.

In the surface waters, the picoplankton carbon biomass was dominated by heterotrophic bacteria in Baffin Bay, offshore McBeth Fjord and at most stations in southern Davis Strait and by picoeukaryotic phytoplankton in the central part of northern Davis Strait. Picocyanobacteria were mainly present in southern Davis Strait (Fig. 13).

Figure 12. Relative abundance of three heterotrophic protist groups (>2 µm) in the surface waters of Baffin Bay and Davis Strait during fall 2012.

Figure 13. Relative contribution of picocyanobacteria, picoeukaryotic phytoplankton and heterotrophic bacteria to the total picoplankton carbon biomass (≤2 µm) in the surface waters of the Baffin Bay and Davis Strait during fall 2012. Cell abundances were converted into carbon biomass using the equations of Buithenhuis et al. (2012) for picophytoplankton and the one of Lee and Fuhrman (1987) for heterotrophic bacteria.

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7. Environmental selection of marine stramenopile clades in the Arctic Ocean and coastal waters (NI: Lovejoy, HQP: M. Thaler)

Single celled bacterial grazers are key components of marine ecosystems, and at times represent the dominant eukaryotes in the Arctic Ocean. Among these are small, phylogenetically diverse stramenopiles, known almost exclusively from their 18S rRNA gene sequences. Marine Stramenopiles (MAST) have been found in the upper waters of the world oceans. In particular three sub-clades of MAST-1, MAST-1A, -1B and -1C, co-occur in Arctic waters, but details on their ecology and distribution are lacking. Here we have updated phylogenies of the MAST-

1 clade to test whether there are Arctic-specific MAST-1 ecotypes. In addition, taking advantage of samples collected over two years as part of several Arctic cruises leading up to and during the International Polar Year, we applied sub-clade specific probes and fluorescent in situ hybridization (FISH) to describe the distribution of the three sub-clades in the Canadian Arctic.

The three sub-clades of MAST-1 were found principally in the euphotic zone (Fig. 14); however, evidence of Arctic ecotypes remains elusive. Some environment-specific separation among sub-clades was detected, with MAST-1C reaching significantly greater concentrations near the marginal ice zone, while MAST-1A and MAST-1B were associated with ice-covered stations and open waters, respectively (Fig. 15). MAST-1B appeared to be able to persist at greater depths (Fig. 14b).

Figure 14. Concentration of: a) MAST-1A; b) MAST-1B; and c) MAST-1C in samples from water masses in different regions of the Arctic. d) Water masses referred to in text. Symbols: Beaufort Sea (square), Baffin Bay (circle), Canada Basin (triangle, point down), Labrador Sea (triangle, point up), Lancaster Sound (diamond). Open symbols indicate that no hybridized cells were observed. Water masses: Labrador Sea Water (LSW); Atlantic Water (AtW); Bottom Water (BW); Lower Halocline (LH); Arctic Water (AW); Pacific Water (PW); Winter Water (WW); Surface Water (SW). The dashed line indicates the freezing point of seawater at different salinities. Curved grey lines indicate density (sigma-theta).

Figure 15. Ordination diagram of the first two axes of Canonical Correspondence Analysis (CCA) showing the relationship between MAST-1 sub-clades and environmental variables. Axes are constrained by abundance of MAST-1 clades and environmental variables. Distance to ice edge (squares) is included as a nominal variable.

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8. Patterns and drivers of mega- and macrobenthic diversity across the Canadian Arctic

(NI: Archambault, HQP: V. Roy)

Marine ecosystems of the Canadian Arctic are expected to experience profound modifications in response to climate changes; yet, a continental-scale baseline understanding of the mega-epibenthic seafloor communities and the environmental controls that drive them is still missing. The current project provided regional richness estimates and studied how mega-epibenthic community structure responds to several environmental factors. Faunal trawl samples were collected between 2007 and 2011 at 78 sites from 30 to 1000 m depth over a 70° longitudinal gradient (2000 km) from the Beaufort Sea to Baffin Bay. Mega-epibenthic taxonomic richness was high in all regions studied, but estimates were from <50% to 70% of expected richness (Fig. 16). Variations in univariate

Figure 16. Station-based rarefaction curves for the five geographical regions. RS9 represents the rarefied number of taxa expected to be recorded in each geographical region based on nine sites (999 permutations). E: Eastern; W: Western.

Figure 17. Location of mega-epibenthic community clusters. Site codes correspond to ArcticNet expedition labels; sampling years were not added for clarity. Main polynyas are indicated by dotted polygons and by capital italic letters (CB: Cape Bathurst Polynya, FS: Franklin Strait Polynya, LS-BI: Lancaster Sound-Bylot Island Polynya, NOW: North Water Polynya, VMS: Viscount-Melville Sound Polynya).

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biodiversity metrics (richness, Shannon-Wiener diversity) and multivariate taxonomic composition were mostly related to water mass properties (salinity, oxygen), revealing a depth zonation. Deep communities were likely limited by the supply or fresh organic matter. Clustering analysis based on biomass data resulted in six mega-epibenthic community clusters (Roy et al., submitted; Fig. 17). Dominant drivers of the spatial distribution of community clusters exhibited low temporal variability reflecting their long-term integration in benthic communities.

9. Benthic faunal diversity and community structure on the Beaufort shelf and slope (NI: Juniper, Archambault, HPQ: J. Nephrin)

This project is using data from recent (2007-2011) ArcticNet and BREA sampling expeditions to develop

an understanding of spatial and, to a lesser degree, temporal patterns in benthic faunal abundance, diversity and community structure on the shelf and slope of the Canadian sector of the Beaufort Sea. Infauna were principally comprised of polychaetes with Nephtyid polychaetes dominant on the shelf (<100 m) and Maldanid polychaetes (up to 92% in relative abundance/station) dominant on the slope. Epifauna were principally comprised of Ophiocten spp. (up to 90% in relative abundance/station) dominant on the shelf and Ophiopleura spp. Separate (infaunal and epifaunal) multivariate analyses revealed heterogeneous clusters of stations (Fig. 18a) that predominantly represent faunal turnover across the bathymetry gradient (Fig. 18b). For both faunal groups, functional differences between clusters were less prominent than compositional differences, as the majority of dominant taxa were deposit feeders. Our results suggest infauna variability may be greater across temporal scales while epifauna vary more rapidly across the bathymetric gradient. This work (Nephrin et al., submitted) contributes to the establishment of a baseline for future monitoring of the impact of ocean change and resources development on ecosystem health in the Beaufort Sea.

10. Impact of organic matter enrichment produced by two colonial seabird species (Fulmarus glacialis and Uria lomvia) on Arctic benthic communities of Lancaster Sound and Pond Inlet (NI: Archambault, HPQ: M. Bouchard Marmen, Coll.: E. Kenchington)

The Canadian Arctic shelters millions of seabirds each year during the breeding season. These biological vectors return important quantities of organic matter (guano, feathers) locally during the summer, potentially influencing the sessile, long-lived benthic species surrounding a bird colony.

The main objective of this project is to characterize the impact of seabird colonies on the benthos communities. We hypothesized that inputs of inorganic nutrients and organic matter from seabird colonies enhance the biodiversity, biomass, abundance and growth of the benthic communities. Sampling was carried out at control sites (without colonies) and at seabird-affected sites in Lancaster Sound and Pond Inlet, onboard the CFAV Quest and CCGS Henry

Figure 18. Geo-referenced a) infaunal and b) epifaunal clusters defined in dendrograms of taxonomic composition.

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Larsen in 2012. Benthic camera transects and samples collected by Van Veen grab allowed us to characterize benthic communities and to subsample sediments and organic matter.

In 2013, we analyzed nutrient samples and benthic photos. Preliminary results show no significant differences in the taxonomic composition or in the abundance of the benthos between controls and bird-affected sites (Fig. 19). The abundance of brittle stars, urchins and polychaete worms is similar between both sites. More photos and samples will be processed to support these conclusions.

11. Studying the functioning of benthic ‘hotspot’ vs ‘coldspot’ ecosystems in the Canadian Arctic (NI: Archambault, HQP: H. Link, Coll.: D. Piepenburg)

Recently, Link et al. (2013a) studied the temporal variability of benthic ecosystem functioning at hotspots (sites with high benthic boundary fluxes) and coldspots (sites with lower fluxes) across two years in the Canadian Arctic. They observed that temporal variability of benthic remineralization function at hotspots is higher than at coldspots and that taxonomic and functional macrobenthic diversity did not change significantly between years. Temporal

variability of food availability (i.e., sediment surface pigment concentration) seemed higher at coldspot than at hotspot areas. Sediment chlorophyll a (chl a) concentration, taxonomic richness, total abundance, water depth and abundance of the largest gallery-burrowing polychaete Lumbrineris tetraura together explained 42% of the total variation in fluxes (Fig. 20). Food supply proxies (i.e., sediment chl a and depth) split hot- from coldspot stations and explained variation on the axis of temporal variability, and macrofaunal community parameters explained variation mostly along the axis separating eastern from western sites with hot- or coldspot regimes.

We also studied benthic biogeochemical fluxes in the Arctic and the influence of short-term (seasonal to annual), long-term (annual to decadal) and other environmental variability on their spatial distribution to provide a baseline for estimates of the impact of future changes (Link et al., 2013b). We tested the influence of eight environmental parameters on single benthic fluxes. Short-term environmental parameters (sinking flux of particulate organic carbon above the bottom, sediment surface chl a) were most

Figure 20. Distance-based Redundancy Analysis (dbRDA) plot of the distLM model based on the five parameters fitted to the variation in benthic boundary fluxes. Vectors indicate direction of the parameter effect in the ordination plot. Chl a = Ln of sediment chl a concentration; N = abundance, Tax S = taxonomic richness. Red = hotspots, blue = coldspots; full symbols = 2008, open symbols = 2009; AG = Amundsen Gulf, MD = Mackenzie Delta, MS = Mackenzie Shelf/Slope; LS = Lancaster Sound; NW = North Water Polynya; BB = Baffin Bay; C, E, N, W = central, east, north, west.

Figure 19. Non-metric multidimensional scaling ordination based on Bray-Curtis similarity matrix calculated on a) untransformed data and b) presence-absence data from benthic photos taken at control sites (2, 5, 8) and at bird-affected sites (1, 3, 4a, 4b, 7).

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important for explaining oxygen, ammonium and nitrate fluxes. Long-term parameters (porosity, surface manganese and iron concentration, bottom water oxygen concentrations) together with δ13Corg signature explained most of the spatial variation in phosphate, nitrate and nitrite fluxes (Fig. 21). Variation in pigments at the sediment surface was most important to explain variation in fluxes of silicic acid. In a model including all fluxes synchronously, the overall spatial distribution could be best explained (57%) by the combination of sediment chl a, phaeopigments, δ13Corg, surficial manganese and bottom water oxygen concentration (Fig. 21).

12. The use of bivalves as proxies for climate change effects on Arctic benthic ecosystem (NI: Archambault, Bélanger, Gosselin, HPQ: B. Gaillard, Coll.: R. Tremblay, F. Olivier, L. Chauvaud, T. Meziane)

We used mollusk shells as bio-archives and fatty acids trophic markers to estimate the effects of the reduction of the sea ice cover on the benthos. A bathyal bivalve Astarte moerchi that lives at 600 m depth in northern Baffin Bay reveals strong positive shell growth anomalies over the past 10 years that we relate to a change in the food availability. Fatty acid trophic markers show that this species feeds mainly on microalgae exported from the euphotic zone to the seabed. These strong benthic-pelagic coupling suggested by Gaillard et al. (submitted) was also highlighted with the data collected in project 3 above.

13. Using the bivalve Portlandia arctica as an indicator of environmental variations within Nunatsiavut fjords (NI: Archambault, Nozais, HPQ: K. Chalut)

In this study, we investigated the impacts of environmental variations on fjordic bivalves’ annual growth dynamics using sclerochronology. We hypothesized that bivalves inhabiting northernmost fjord on the coast of Labrador provide evidences of greater environmental variability than those from southernmost fjord as a consequence of important hydrologic changes inferred by the proximity of a glacier in this region. To test this hypothesis, growth profiles of bivalve shells (Portlandia arctica) were determined from samples collected during the 2010 CCGS Amundsen expedition in the Canadian Arctic and geochemical analyses were performed to characterize the recorded disturbances.

Despite very similar environmental conditions within Nachvak and Saglek fjords, averaged increment width series showed statistically significant differences between the two sites, alike between the years (Fig. 22). Once the biological growth trend removed, it appeared that each fjord was locally affected by a specific set of predictors. However, since repeated measures ANOVA performed on standardized indices revealed no significant differences between either fjords or years, it seemed that Nunatsiavut fjords were mastered by a more regional factor.

Figure 21. Distance-based redundancy analysis (dbRDA) plot of the DistLM based on the environmental parameters fitted to the variation in biogeochemical fluxes. Vectors indicate direction of the parameter effect in the ordination plot. chl a = natural logarithm of sediment chl a concentration; dC13 = 13C signature; Phaeo = sediment phaeopigment concentration; MnHCl = sediment surface manganese oxide concentration; and O2 bottom = bottom water oxygen concentration. Brown and red triangles: shallow Mackenzie shelf and delta; green circles: Cape Bathurst and Amundsen Gulf region (east); blue squares: deeper Mackenzie slope.

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14. Large scale 3D distribution and abundance of the keystone forage species in southeastern Beaufort Sea (NI: Simard, Fortier, HPQ: D. Benoit)

Multifrequency split-beam acoustic data collected in October–November 2003 revealed that polar cod is distributed in two distinct layers. Age-0 polar cods formed an epipelagic layer between 0 and ~60 m depth without any clear large-scale biomass trend. In contrast, adult polar cods tended to distribute into an offshore mesopelagic layer between ~200 and 400 m that shoaled into a denser (1–37 g m−2) benthopelagic layer on sloping bottoms (between 150 and 600 m isobaths) along the Mackenzie shelf and into the Amundsen Gulf basin (Fig. 23). Concentrations peaked in the Amundsen Gulf where estimated total biomass reached ~250 kt. Both age-0 and adult polar cod were distributed in the warmer waters (>−1.4°C).

Discussion

The discussion focuses on 1) the link between environmental parameters and the ecosystem structure and functions; 2) the interconnection between primary producers, benthic population and higher trophic levels; and 3) the monitoring of phytoplankton and benthic communities.

During early fall 2012, the structure and function of the lower trophic level of the food web in the surface waters of Baffin Bay and Davis Strait were investigated. We observed a striking difference between the two regions in terms of plankton dynamics. In Baffin Bay and offshore McBeth Fjord,

Figure 23. Spatial distribution of polar cod biomass (g m−2) in southeastern Beaufort Sea between 18 October and 20 November 2003 for a) the epipelagic layer (depth <60 m) and b) the mesopelagic (depth >60 m) layer. Dots area is proportional to biomass (From Benoit et al., 2014).

Figure 22. Within fjord averaged increment width series (raw measurements in mm) and a) associated standard errors and b) standardized growth indices obtained for each fjord from 1992 to 2010. In graph (a), different letters indicate significant differences between years based on a posteriori pair-wise tests.

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the large phytoplankton community was dominated by centric diatoms, which were in a declining stage, whereas the small plankton community was dominated by heterotrophic bacteria. The abundance of bioavailable carbon from diatom exudation and mortality is likely an important factor contributing to the growth and accumulation of heterotrophic bacteria in the surface waters. This high relative biomass of heterotrophic bacteria seems to favor the growth of choanoflagellates, the main grazers of bacteria. Hence, choanoflagellates may constitute an important link for the transfer of carbon to the microbial and metazoan food webs. This region is thus characterized by a multivorous food-web (Legendre and Rassoulzadegan, 1995), and is likely associated with a high potential for carbon export to depth. In contrast, in Davis Strait, nanoflagellates dominated the large phytoplankton community and were accompanied by a high abundance of picoeukaryotic phytoplankton. In addition, heterotrophic bacteria contributed to a large proportion of the picoplankton carbon biomass in this region. Since they graze on both small (<2 µm) autotrophic and heterotrophic plankton, heterotrophic flagellates (the main component of the “Other heterotrophic groups”) and ciliates generally dominated the phagotrophic community. The flagellate-dominated system present in Davis Strait is typically associated with a microbial food-web (Legendre and Rassoulzadegan, 1995) and limits the export of carbon to depth.

Another key feature of Davis Strait is the presence of picocyanobacteria in the surface waters of the southernmost stations. Picocyanobacteria are generally poorly represented in the Arctic seas (Murphy and Haugen, 1985; Booth and Horner, 1997; Mostajir et al., 2001; Sherr et al., 2003) since their two main sources are freshwater input from rivers and Atlantic waters, the latter likely being responsible for the occurrence of small cyanobacteria in Davis Strait. The highest abundance of picocyanobacteria (27 500 cells mL–1) retrieved in this area is similar to the upper range of abundance that has been found in the Atlantic influenced waters of the Barents Sea, which are characterized by high surface water

temperature (Not et al., 2005). It is actually the highest picocyanobacteria abundance observed so far during the whole ArcticNet program. This corroborates earlier studies that identified cyanobacteria as bioindicators for the advection of Atlantic-influenced waters into the Arctic seas (Murphy and Haugen, 1985; Gradinger and Lenz, 1995).

Molecular biology provides clues on the dominance of a group of phytoplankton on the others by identifying ecological traits. It was showed than some clades of the marine stramenopiles (MAST-1), a key component of Arctic Ocean ecosystem, are more specific of the marginal ice zone, others of the ice-free or ice-covered areas while others persist at greater depth. Because of their sensitivity to ice conditions, the concentrations and distributions of MAST-1 sub-clades are expected to be impacted by changing ice-cover and mixing regimes.

New findings on the mixing processes and mixed layer dynamics are providing critical information on which clades or group of protists would be favored in the future. We showed that different mixing processes occurred in the Canadian Arctic Archipelago (i.e., classical turbulence, double-diffusion and differential mixing) and that frontal structures in Amundsen Gulf are much more numerous than previously reported (Sévigny, 2014). Furthermore, the estimation of the evolution of the ice thickness revealed that the under-ice phytoplankton bloom begins 9 days after the mixed layer depth has reached its seasonal maximum (Nahavandian, 2014).

Environmental changes in the Arctic Ocean, such as the influence of Atlantic waters on cyanobacteria or ice-cover and mixing regimes on the stramenopiles, are expected to have repercussions on the marine food web because of previously studied differences in cell size and grazing rates. The current paradigm stipulates that in response to sea ice decrease, there would be a shift from a ‘sea-ice algae-benthos’ to a ‘phytoplankton-zooplankton’ dominance. An increase should impact key forage species. It is crucial to investigate the cascading effect of the “phytoplankton-

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zooplankton” system on higher trophic levels as key forage species. Here we reported the first large-scale estimate of the standing stock and distribution of polar cod in the southeastern Beaufort Sea. We hypothesize that concentration of adult polar cods over slopes is governed by the combined actions of (1) local currents concentrating both depth-keeping zooplankton and polar cod at the shelf-break and basin slopes and (2) trophic association with these predictable topographically-trapped aggregations of zooplankton prey. During freeze-up, these slope concentrations of polar cod are thought to constitute the main source of the observed dense under-ice winter aggregations at depth in the Amundsen Gulf. The hypothesis of active short-distance displacements interacting with prevailing mean currents is retained as the likely aggregation mechanism.

Change in the state of the pelagic system, from phytoplankton to fish, is expected to impact the benthos communities by controlling the food supply exported to the seabed. Contrary to our expectation, bathyal bivalves of the species Astarte moerchi that lives at a 600 m depth, were collected in northern Baffin Bay. This bivalve showed strong positive shell growth anomalies over the past 10 years that we relate to a change in the food availability. Fatty acid trophic markers show that this species feeds mainly on microalgae exported from the euphotic zone to the seabed at 600 m. We explain this strong pelagic-benthic coupling by either local sea ice dynamics through the bottom-up regulation exerted by ice on phytoplankton production, or by a temporal mismatch between phytoplankton bloom and zooplankton grazing. Either scenario allows an increased export of food to the seabed (Gaillard et al., submitted). Change in the benthic communities will have repercussions on the rates and pathways of carbon and nutrient cycling at sediments interface, as well as on biogeochemical fluxes. We noted that variability in benthic re-mineralization, food supply and diversity will react to climate change on different time scales, and that their interactive effects may hide the detection of progressive change, particularly at hotspots (Link

et al., 2013a). It is necessary to consider long-term environmental variability along with rapidly ongoing environmental changes to predict the flux of oxygen and nutrients across Arctic sediments even at short timescales (Link et al., 2013b).

Information about long-term environmental conditions can be conveyed by monitoring the benthic fauna, which is recognized as a key indicator of ocean health and changing conditions at the seafloor and in the water column overhead. Macrobenthic assemblages in general are particularly good integrators of change since they are long-lived and in most cases, sessile (Borja et al., 2008; Van Hoey et al., 2010). In this context, Nephrin et al. (submitted) and Roy et al. (submitted) used the data from recent ArcticNet and BREA sampling expeditions (2007-2011) to develop an understanding of spatial and, to a lesser degree, temporal patterns in benthic faunal abundance, diversity and community structure on the shelf and slope of the Canadian sector of the Beaufort Sea. This monitoring will provide a baseline for future field programs, helping to deconvolute the relative influence of change and spatial variability at various scales.

Long-term monitoring of the primary producers is also needed to understand the variability of benthic communities as well as the whole food chain. Satellite imagery offers an appropriate tool to investigate the long-term variability of the phytoplankton. A satellite-based primary production (PP) model revealed that productivity dropped dramatically after 2002 in the North Water (NOW polynya), but increased in the Kane Basin where earlier ice breakup occurs in the recent years. Monthly trends in PP suggest that the spring-summer phytoplankton bloom tends to occur earlier in season (Gaillard et al., submitted). Preliminary results imply that the timing and magnitude of blooms in the NOW are locally controlled by a succession of oceanic and climatic forcings. In this regard, future work will include an evaluation of the most robust method to describe phenology metrics of phytoplankton blooms and link those with changing environmental factors (e.g., atmospheric forcing, mixed-layer depth and sea ice variability).

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With the aim of improving the characterization of phytoplankton from space, we showed the importance of considering the seasonal variability of light absorption properties in Arctic waters. Studies in Hudson Bay suggest that seasonal variability of the light absorption coefficients by the different constituents is related to phytoplankton size structure and accessory pigments composition. The relatively large variability of phytoplankton absorption and chl a show that it would be adequate to use a seasonally varying coefficient rather than a mean value in the bio-optical models used in the remote-sensing derivation of inherent optical properties. Steadiness of NAP and CDOM absorption and their spectral slopes for both seasons should facilitate the simulation of NAP and CDOM absorption spectra in analytical/semianalytical algorithms. However, high contributions of CDOM absorption to total absorption must be considered in the development of regional relationships linking remote sensing reflectance to the concentrations of optical water constituents. As the results indicated, seasonal variability in the phytoplankton absorption coefficient is a key optical parameter to take into consideration in Hudson Bay. It is thus highly probable that spring optical properties, when the main phytoplankton bloom happens, will also differ from those of the summer and fall. It is therefore essential to characterize the full seasonal variability of optical properties in order to improve bio-optical models and derive reliable remote sensing.

Conclusion

The period 2013-2014 was highly productive in terms of scientific results with 29 published papers. The participation of our NIs and HQPs to national and international conferences has supported a large dissemination of our results as reflected by the annual ArcticNet meeting in Halifax in December 2013. The ArcticNet participants were involved in numerous collaborations and partnership, which will continue and diversify in the future.

The community has reached scientific objectives and opened new perspectives of work. The emphasis was in particular placed on the linkages between environmental parameters and the ecosystem diversity and function. A striking regional difference in the planktonic community composition was observed in the eastern Canadian Arctic in early fall: Baffin Bay was characterized by a multivorous food-web system whereas Davis Strait was dominated by a microbial food-web system. Also pointed out is the relationship between the ice conditions and the diversity of stramenopiles, a key component of the marine Arctic system. The implications of changing pelagic system for the diversity and function of the benthic communities were highlighted, especially the implications for the carbon and nitrogen cycle in the sediments. A important pelagic-benthic coupling was observed even for depth as great as 600 m. Methods and approaches for the monitoring of pelagic and benthic communities were developed and improved. Notably a new satellite algorithm taking into accounts the regional variations in the optical properties of Arctic waters and a deeper knowledge of the polar cod distribution. Finally, the use of bivalves as bio-archive of climate changes provided new insights of the past influence of sea ice on the benthos (better growth in specific areas over the last 10 years) and highlighted the strong coupling between the pelagic and the seafloor at greater depth than expected. A large panel of fieldwork, oceanographic cruises and collaborations were set up to continue this research in the coming years.

Acknowledgements

We thank Pierre Coupel, Jonathan Gagnon, Marjolaine Blais and Cindy Grant for their assistance in compiling and organizing the information presented in this report.

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Sévigny, C., 2014, Mélange et fronts océaniques dans la couche de surface du golfe d’Amundsen et de l’Arctique canadien, Ph.D. Thesis, INRS-ETE, December 2013.

Sherr, E.B., Sherr, B. F., Wheeler, P.A., and Thompson, K., 2003, Temporal and spatial variation in stocks of autotrophic and heterotrophic microbes in the upper water column of the central Arctic Ocean, Deep-Sea Research I, 50, 557–571.

Tremblay J.-É., S. Bélanger, D.G. Barber, M. Asplin, J. Martin, G. Darnis, L. Fortier, Y. Gratton, H. Link, P. Archambault, W. J. Williams, A. Sallon, C. Michel, B. Philippe, M. Gosselin. 2011. Climate forcing multiplies biological productivity in the coastal Arctic Ocean. Geophys. Res. Lett. 38:L18604, doi:10.1029/2011GL048825

Tremblay, J.-É. and Gagnon, J., 2009, The effects of irradiance and nutrient supply on the productivity of Arctic waters: a perspective on climate change, In: Influence of climate change on the changing Arctic and sub-Arctic conditions, J.C.J. Nihoul and A.G. Kostianoy (eds.), p. 73-93.

Tremblay, J. E., et al., 2011, Climate forcing multiplies biological productivity in the coastal Arctic Ocean, Geophysical Research Letters, 38, L18604, doi:10.1029/2011GL048825.

Van Hoey, G., Borja, A., Birchenough, S., Buhl-Mortensen, L., Degraer, S., Fleischer,D., Kerckhof, F., Magni, P., Muxika, I., Reiss, H., Schröder, A., and

Zettler, M.L., 2010, The use of benthic indicators in Europe: from the Water Framework Directive to the Marine Strategy Framework Directive, Marine Pollution Bulletin 60, 2187–2196.

Walsh, J.J. et al., 2011, Trophic cascades and future harmful algal blooms within ice-free Arctic Seas north of Bering Strait: A simulation analysis, Progress in Oceanography, 91, 312-343.

Publications

(All ArcticNet refereed publications are available on the ASTIS website (http://www.aina.ucalgary.ca/arcticnet/).

Alou, E., Mundy, C.-J., Roy, S., Gosselin, M. and Agusti, S., 2013, Snow Cover Affects Ice Algae Pigment Composition in The Coastal Arctic Ocean During Spring, Marine Ecology Progress Series, v474, 89-104

Alou-Font, E, 2014, Viabilité du phytoplancton et des algues de glace dans la mer de Beaufort (Arctique canadien)., Thèse (Ph. D.), Université du Québec à Rimouski, 156 p

Antoine, D., Hooker, S.B., Bélanger, S., Matsuoka A., and Babin M., 2013, Apparent Optical Properties of the Canadian Beaufort Sea, Part I: Observational Overview and Water Column Relationships, Biogeosciences, 4493-4509

Ardyna, M., Babin, M., Franks, P., Gosselin, M. and Tremblay, J.-É., 2014, Phytoplankton phenology in a changing Arctic Ocean, Ocean Sciences Meeting 2014, Honolulu, Hawaii, USA, Oral presentation

Ardyna, M., Babin, M., Franks, P., Gosselin, M. and Tremblay, J.-É., 2013, Physical control of subsurface chlorophyll maximum in the Arctic Ocean, 12th Annual General Meeting of Quebec-Ocean, Rivière-du-Loup, Quebec, Canada, Poster presentation

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Ardyna, M., Babin, M., Franks, P., Gosselin, M. and Tremblay, J.-É., 2013, Physical control of subsurface chlorophyll maximum in the Arctic Ocean, ArcticNet Annual Scientific Meeting, Halifax, Nova Scotia, Canada, Poster presentation

Ardyna, M., Babin, M., Gosselin, M., Devred, E., Bélanger, S., Matsuoka, A. and Tremblay, J.-É., 2013, Parameterization of Vertical Chlorophyll a in the Arctic Ocean: Impact of the Subsurface Chlorophyll Maximum on Regional, Seasonal and Annual Primary Production Estimates, Biogeosciences, v.10, 4383–4404

Bélanger S., Cizmeli, S.A., Ehn, J., Matsuoka, A., Doxaran, D., Hooker S. and Babin M., 2013, Light absorption and partitioning in Arctic Ocean surface waters: Impact of multi-year ice melting, Biogeosciences, 6433-6452

Bélanger, S., 2013, Major change in primary productivity of the North Water, Canadian Arctic, 48th CMOS Congress, Canada, Saskatchewan, Saskatoon, Oral presentation,

Bélanger, S., Babin M. and Tremblay J. E., 2013, Increasing cloudiness in Arctic damps the increase in phytoplankton primary production due to sea ice receding, Biogeosciences, v.10, 4087-4101.

Belt, S. T., Brown, T. A., Ringrose, A. E., Cabedo-Sanz, P., Mundy, C. J., Gosselin, M. and Poulin, M., 2013, Quantitative measurements of the sea ice diatom biomarker IP25 and sterols in Arctic sea ice and underlying sediments: Further considerations for palaeo sea ice reconstruction, Organic Geochemistry, v.62, 33-45

Benoit, D., Simard, Y. and Fortier, L., 2014, Pre-winter distribution and habitat characteristics of polar cod (Boreogadus saida) in southeastern Beaufort Sea., Polar Biology, v. 37, 149-163

Blais, M. and Gosselin, M., 2013, Opposite trends in phytoplankton biomass and production between

Beaufort Sea and Baffin Bay., ArcticNet Annual Scientific Meeting, Halifax, Nova Scotia, Canada, Poster presentation

Blais, M., Gosselin, M. and Dumont, D., 2013, Towards a green oasis in the Arctic Ocean? Trends in phytoplankton biomass and production over the Canadian Arctic Ocean, International Conference on Arctic Ocean Acidification, Bergen, Norwa, Poster presentation

Brown, K. A., Miller, L.A., Mundy, C.J., Carnat, G., Papakyriakou, T., Gosselin, M., Swystun, K., François, R. and Tortell, P., 2014, Inorganic carbon system dynamics in land-fast Arctic sea ice during the early-melt period: Observations using stable carbon isotopes, Ocean Sciences Meeting 2014, Honolulu, Hawaii, USA, Poster presentation

Burt, A., Wang, F., Pucko, M., Mundy, C.-J., Gosselin, M., Philippe, B., Poulin, M., Tremblay, J.-É. and Stern G.A., 2013, Mercury uptake within an ice algal community during the spring bloom in first-year Arctic sea ice, Journal of Geophysical Research: Oceans, v.118, 1-9

Campbell, K., Mundy, C.J., Barber, D. and Gosselin M., 2014, Response of remotely estimated ice algae biomass to the environmental conditions during spring melt, Arctic, In press

Campbell, K., Mundy, C.J., Barber, D. and Gosselin, M., 2014, Characterizing the ice algae chlorophyll a-snow depth relationship over Arctic spring melt using transmitted irradiance, Journal of Marine Systems, In Press

Campbell, K., Mundy, C.J., Barber, D. and Gosselin, M., 2013, Characterizing the ice algae biomass-snow depth relationship over spring melt using transmitted irradiance, The 45th International Liège Colloquium, Primary production in the ocean: from the synoptic to the global scale, Liège, Belgium, Poster presentation

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Chalut, K., Archambault, P., Nozais, C., Roy, V. and Olivier, F., 2013, Using the Bivalve Portlandia arctica as an Indicator of Environmental Variations within Fjords (Labrador, Canada), ICES Annual Science Conference, Reykjavik, Iceland, September 23-27, Poster

Chalut, K., Archambault, P., Nozais, C., Roy, V. and Olivier, F., 2013, Using the Bivalve Portlandia arctica as an Indicator of Environmental Variations within Fjords (Labrador, Canada), Québec-Océan Annual Meeting, Rivière-du-Loup, Canada, November 13-15. Poster

Chauvaud, L., Richard, J., Thébault, J., Clavier, J., Jolivet, A., David-Beausire, C., Amice, E., Olivier, F., Meziane, T., Tremblay, R., Archambault, P., Winkler, G., Gaillard, B., Martel, A., Ambrose, W., Rysgaard, S., Blicher, M., Carroll, M., Strand, Ø. and Strohmeier, T., 2013, Sclérochronologie des Mollusques Polaires pour l’Observation des Variables Environnementales, Colloque national du Chantier Arctique Français «Arctique: les grands enjeux scientifiques», Paris, France, June 3-6. Poster

Chauvaud, L., Richard, J., Thébault, J., Clavier, J., Jolivet, A., David-Beausire, C., Amice, E., Olivier, F., Meziane, T., Tremblay, R., Archambault, P., Winkler, G., Gaillard, B., Martel, A., Ambrose, W., Rysgaard, S., Blicher, M., Carroll, M., Strand, Ø., Strohmeier, T., Gaumy, J. and Paumelle, S., 2013, Bivalves Pan-Arctiques comme Bioarchives Polaires – Projet Scientifique B.B. Polar, Colloque national du Chantier Arctique Français «Arctique: les grands enjeux scientifiques», Paris, France, June 3-6. Poster

Chauvaud, L., Richard, J., Thébault, J., Clavier, J., Jolivet, A., David-Beausire, C., Amice, E., Olivier, F., Meziane, T., Tremblay, R., Archambault, P., Winkler, G., Gaillard, B., Martel, A., Ambrose, W., Rysgaard, S., Blicher, M., Carroll, M., Strand, Ø., Strohmeier, T., Gaumy, J. and Paumelle, S., 2013, Bivalves Pan-Arctiques comme Bioarchives Polaires – Projet Artistique B.B. Polar, Colloque national du Chantier Arctique Français «Arctique: les grands enjeux scientifiques», Paris, France, June 3-6. Poster

Comeau, A. M., Philippe, B., Thaler, M., Gosselin, M., Poulin, M. and Lovejoy, C., 2013, Protists in Arctic Drift and Land-Fast Sea Ice, Journal of Phycology, v.49, 229-240

Comeau, A.M., Philippe, B., Thaler, M., Gosselin, M., Poulin, M. and Lovejoy, C., 2013, Diatom communities from Arctic drift and land-fast ice as revealed by high-throughput pyrosequencing., XXII International Diatom Symposium, Ghent, Belgium, 26-31 August (Poster presentation), 0

Côté, J.-S., Tremblay, J.-É., Gagnon, G. and Michel, C., 2013, The nitrogen balance of sea ice in the Canadian Arctic Archipelago., Assemblée générale annuelle de Québec-Océan, Rivière-du-Loup, Poster Presentation

Côté, J.-S., Tremblay, J.-É., Gagnon, G. and Michel, C., 2013, The nitrogen balance of sea ice in the Canadian Arctic Archipelago, ArcticNet Annual Scientific Meeting 2013, Halifax, Poster Presentation

Coupel P., Matsuoka A., Ruiz-pino D., Gosselin M., Claustre H., Marie D., Babin M., Tremblay J.-É., 2013, Pigment signature of the phytoplankton communities in Beaufort Sea., 12e Assemblée générale annuelle, Rivière-du-Loup, Oral presentation

Coupel P., Ruiz-Pino D., Sicre M.-A., Gascard J.-C., 2013, The role of freshening on the phytoplankton production in the Pacific Arctic Ocean., The 45th International Liège Colloquium – Liège, Belgium, Poster

Coupel P., Ruiz-pino D., Sicre M.-A., Gascard J.-C., Chen J.F., Joo H.M., 2013, Impact de la fonte de la glace et de la désalinisation des eaux arctiques sur les communautés de phytoplancton., Chantier Arctique Français, Paris, Poster Presentation

Coupel, P., Matsuoka, A., Ruiz-Pino, D., Gosselin, M., Lessard, S., Claustre, H., Marie, D., Tremblay, J.-É. and Babin, M., 2013, Pigments signature of the

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phytoplankton communities in Beaufort Sea, ArcticNet Annual Scientific Meeting, Halifax, Nova Scotia, Canada, Oral presentation

Daniëls, F.J.A., Gillespie, L.J. and Poulin M., 2013, Plants, in: Arctic Biodiversity Assessment. Status and trends in Arctic biodiversity, 258-301

Deslongchamps, G., Tremblay, J.-É., Gagnon, J., Granger, J. and Treibergs, L., 2013, Impacts des conditions environnementales sur le cycle de l’azote dans l’océan Arctique canadien, AGA Québec-Océan, Rivière-du-loup, Oral Presentation

Deslongchamps, G., Tremblay, J.-É., Gagnon, J., Granger, J. and Treibergs, L., 2013, Impact of environmental conditions on the nitrogen cycle in the Canadian Arctic., ASA ArcticNet, Halifax, Oral Presentation

Duerksen, S.W., Thiemann, G.W., Budge, S.M., Poulin, M. and Michel, C., 2013, Under-ice pelagic production of essential fatty acids and the implications for Arctic food webs, ArcticNet 9th Annual Scientific Meeting, Halifax, Poster presentation

Edgar, R., Monier, A., Terrado, R., Lovejoy, C., 2013, Exploring Differential Gene Expression of Five Arctic Microbial Eukaryotes, ArcticNet 9th Annual Scientific Meeting, Halifax, Nova Scotia, Canada, Poster presentation, 0

Else, B. G. T., Galley R. J., Lansard B., Barber D. G., Brown K., Miller L. A., Mucci A., Papakyriakou T. N., Tremblay J. E. and Rysgaard S., 2013, Further observations of a decreasing atmospheric CO2 uptake capacity in the Canada Basin (Arctic Ocean) due to sea ice loss, Geophysical Research Letters, v.40, 1132-1137

Forest, A., Coupel P., Else B. , Nahavandian S. , Lansard B. , Raimbault P. , Papakyriakou T. , Gratton Y. , Fortier L. , Tremblay J.-É. and Babin M., 2013, Synoptic evaluation of carbon cycling in Beaufort Sea during summer: contrasting river inputs, ecosystem

metabolism and air-sea CO2 fluxes, Biogeosciences Discussions, 10: 15641-15710

Gaillard, B., Olivier, F., Meziane, T., Tremblay, R., Martel, A. and Archambault, P., 2013, Effets du Couplage Pélago-Benthique sur la Dynamique des Bivalves Filtreurs Bathyarca glacialis (Gray, 1824) d’Environnements Contrastés de l’Arctique Canadien, Colloque national du Chantier Arctique Français «Arctique: les grands enjeux scientifiques», Paris, France, June 3-6. Poster

Gaillard, B., Olivier, F., Thébault, J., Meziane, T., Tremblay, R., Dumont, D., Bélanger, S., Gosselin, M., Chauvaud, L., Martel, A. and Archambault, P., 2014, Bathyal Arctic Climate Change Fosters Bathyal Bivalve Astarte moerchi Shell Growth, Limnology and Oceanography,

Gaillard, B., Olivier, F., Thébault, J., Meziane, T., Tremblay, R., Dumont, D., Bélanger, S., Gosselin, M., Chauvaud, L., Martel, A. and Archambault, P., 2013, Sclerochronology of Bathyal Bivalves Suggests Major Trophic Shifts and Stronger Pelagic-Benthic Coupling in the Canadian Arctic, 3rd International Sclerochronology Conference, Caernarfon, North Wales, UK, May 18-22. Oral presentation

Galand, P.E., Alonso-Sàez, L., Bertilsson, S., Lovejoy, C., and Casamayor, E.O., 2013, Contrasting activity patterns determined by BrdU incorporation in bacterial ribotypes from the Arctic Ocean in winter, Frontiers in Microbiology, Doi 10.3389/fmicb.2013.00118.

Galindo, V., Levasseur, M., Mundy, C. J., Gosselin, M., Tremblay, J.-É., Scarratt, M., Gratton, Y., Papakiriakou, T., Lizotte, M. and Poulin M., 2014, Biological and physical processes influencing sea ice and under-ice algae and dimethylsulfoniopropionate during spring in the Canadian Arctic Archipelago, Journal of Geophysical Research, doi:2013JC009497R,

Galindo, V., Levasseur, M., Scarratt, M., Mundy, C.J., Gosselin, M., Kiene, R.P., Papakyriakou, T., Michaud,

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S. and Lizotte, M., 2013, Fate of sea ice DMSP during the spring melt period in Arctic, Gordon Research Conferences in Polar Marine Science, Ventura, California, USA, Poster presentation

Gosselin, M., 2013, Hudson Bay research activities on the lower trophic levels of the food web, 2003-2014, The Hudson Bay Integrated Regional Impact Study: Scoping a path 2014-2017, ArcticNet 9th Annual Scientific Meeting,Halifax, Nova Scotia, Oral presentation

Gosselin, M. and Levasseur, M., 2013, 2014 NETCARE Amundsen cruise: Ocean-atmosphere interactions., NETCARE Workshop, University of Toronto, Toronto, ON, Oral presentation

Gourdal, M., Levasseur, M., Galindo, V., Scarratt, M., Mundy, C.J., Gosselin, M., Babin, M. and Lizotte, M., 2013, Sea ice and melt ponds as sources of DMS in the Arctic, ArcticNet Annual Scientific Meeting, Halifax, Nova Scotia, Canada, Poster presentation

Hop, H., Bluhm, B.A., Daase, M., Gradinger, R. and Poulin, M., 2013, Arctic Report Card: Arctic sea ice biota. National Oceanic and Atmospheric Administration (NOAA) – Pacific Marine Environmental Laboratory, Seattle, Washington, Online from: http://www.arctic.noaa.gov/reportcard/sea_ice_biota.html

Joli, N., Babin, M., Lovejoy, C, 2013, Métagénomiques et métatranscriptomiques du plancton microbien Arctique, Colloque National “Arctique : les grands enjeux scientifique Paris France Poster Presentation, 0

Joli, N., Lovejoy, C., 2013, Strategie pour métagénomiques et métatranscriptomiques du plancton microbien Arctique, ArcticNet 9th Annual Scientific Meeting, Halifax, Nova Scotia Poster Presentation, 0

Kinda, G.B., Simard, Y., Gervaise, C., Mars, J.I. and Fortier, L., 2013, Under-ice ambient noise in Eastern

Beaufort Sea, Canadian Arctic, and its relation to environmental forcing, Journal of Acoustical Society of America, v. 134, 77-87

Laliberte, J., Belanger, S., 2013, Validation of a satellite-based approach to estimation incident irradiance reaching the sea surface in the Arctic, Arcticnet annual science meeting, Halifax, Canada,

Lapoussiere*, A., Michel C., Gosselin M., Poulin M., Martin* J. and Tremblay J. E., 2013, Primary production and sinking export during fall in the Hudson Bay system, Canada, Continental Shelf Research, 52: 62-72

Le Fouest*, V., Babin M. andTremblay J. E., 2013, The fate of riverine nutrients on Arctic shelves, Biogeosciences, 10: 3661-3677

Leu, E., Mundy, C.J., Juul-Pedersen, T., Gabrielsen, T. and Gosselin, M., 2013, Arctic spring awakening - a pan-Arctic view on processes controlling bottom ice algae blooms. Arctic Frontiers 2013, Geopolitics and Marine Production in a Changing Arctic, Tromsø, Norway, Oral presentation

Levasseur, M., Galindo, V., Gourdal, M., Mundy, C.J., Gosselin, M., Michel, C., Babin, M., Tremblay, J.-É., Scarratt, M.E. and Lizotte, M., 2014, Contribution of ice and under-ice blooms to the vernal production of dimethylsulfide in the Arctic., Ocean Sciences Meeting 2014, Honolulu, Hawaii, USA, Oral presentation

Link, H., Chaillou, G., Forest, A., Piepenburg, D. and Archambault, P., 2013, Multivariate Benthic Ecosystem Functioning in the Arctic – Benthic Fluxes Explained by Environmental Parameters in the Southeastern Beaufort Sea, Biogeosciences, 10: 5911-5929, doi: 10.5194/bg-10-5911-2013

Link, H., Piepenburg, D. and Archambault, P., 2013, Are Hotspots Always Hotspots? The Relationship Between Diversity, Resource and Ecosystem Functions in the Arctic, PLoS ONE 8(9): e74077, doi:10.1371/journal.pone.0074077

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Lovejoy, C., 2013, Microorganisms, chapter 11, Arctic Biodiversity Assessment, 372-382

Lovejoy, C., 2013, Changing views of Arctic protists (marine microbial eukaryotes) in a changing Arctic, Acta Protozoologica,

Lovejoy, C., 2013, Changing views of arctic protists in a changing Arctic, International Society of Protozoologist Meeting (invited talk), 0

Marchese, C., Albouy, C., Vissault, S., Tremblay, J.-É. and Bélanger, S., 2013, Variability of chlorophyll-a bloom timing in NOW polynya: a preliminary analysis, Arcticnet annual science meeting, Halifax, Canada, 9-13 December, Poster presentation, 0

Meltofte, H., Barry, T., Berteaux, D., Bültmann, H., Christiansen, J.S., Cook, J.A., Dalhberg, A., Daniëls, F.J.A., Ehrich, D., Fjeldså, J., Friöriksson, F., Ganter, B., Gaston, A.J., Gillespie, L.J., Grenoble, L., Hoberg, E.P., Hodkinson, I.D., Huntington, H.P., Ims, R.A., Josefson, A.B., Kutz, S.J., Kuzmin, S.L., Laidre, K.L., Lassuy, D.R., Lewis, P.N., Lovejoy, C., Michel, C., Mokievsky, V., Mustonen, T., Payer, D.C., Poulin, M., Reid, D.G., Reist, J.R., Tessler, D.F. and Wrona, F.J., 2013, Arctic Biodiversity Assessment. Status and trends in Arctic biodiversity. Synthesis., Conservation of Arctic Flora and Fauna, 124 p.

Monier, A., Forest, A., Matsuoka, A., Babin, M., Lovejoy, C., 2013, The phylogenetic basis of light and nutrient depletion effects on microbial communities from the Arctic Ocean, Colloque National “Arctique : les grands enjeux scientifique Paris, France, 0

Monier, A., Terrado, R., Thaler, M., Comeau, A., Médrinal, E., Lovejoy, C., 2013, Upper Arctic Ocean water masses harbor distinct communities of heterotrophic flagellates, Biogeosciences, 10: 4273-4286

Monier, A., Terrado, R., Worden, A.Z., Lovejoy, C., 2013, Rewiring of N-related metabolism by

alien genes innthe diatom Phaeodactylum and other eukaryotic algae, The Moleculr life of Diatoms, EMBO meetine 25-28 June 2013 Paris France, 0

Mundy, C.J., Ehn, J., Leu, E., Gosselin, M. and Campbell, K., 2013, Arctic spring: key processes influencing timing of primary producers in ice-covered waters., The 45th International Liège Colloquium, Primary production in the ocean: from the synoptic to the global scale, Liège, Belgium, Oral presentation

Mundy, C.J., Gosselin, M., Gratton, Y., Brown, K., Galindo, V., Campbell, K., Levasseur, M., Barber, D., Papakyriakou, T. and Bélanger, S., 2014, Role of environmental factors on phytoplankton bloom initiation under landfast sea ice in Resolute Passage, Canada., Marine Ecology Progress Series, v.497, 39-49

Nephin, J., 2013, Monitoring Soft-Bottom Arctic Benthos: Can Epifauna Predict Patterns of Infauna Diversity?, SEOS Grad Student Workshop, Victoria, BC, April 19. Oral presentation

Pedneault, E., Galland, P, Potvin M, Thaler, M., Tremblay J. -É., and C. Lovejoy, 2013, Co-occurance of active ammonia-oxidizing and predominantly dormant urea utilizing Archaea nitrifiers in the Arctic Ocean., Science Reports,

Philippe, B., 2013, Changements récents dans la dynamique des algues de glace dans le secteur canadien de la mer de Beaufort, Mémoire de maîtrise (M. Sc.), Université du Québec à Rimouski, -

Pineault, S., Tremblay, J.-É., Gosselin, M., Thomas, H. and Shadwick, E., 2013, The Isotopic Signature of Particulate Organic C and N in Bottom Ice: Controlling Factors and Applications for Tracing the Fate Of Ice Algae in the Arctic Ocean, Journal of Geophysical Research (Oceans), vol. 118, 1-14

Potvin, E., Rochon, A. and Lovejoy, C., 2013, Cyst-theca relationship of the Arctic dinoflagellate cyst Islandinium minutum (Dinophyceae) and phylogenetic

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position based on SSUrDNA and LSU rDNA, Journal of ¨Phycology, 49: 888-899

Poulin, M., Underwood, G.J.C. and C. Michel, 2014, Sub-ice colonial Melosira arctica in Arctic first-year ice, Diatom Research, In Press

Ringrose, A, 2013, Temporal and vertical distributions of IP25 and other lipid biomarkers in sea ice from Resolute Bay, Nunavut, Canada, MPhil thesis, University of Plymouth, UK, -

Roy, V., Archambault, P., Tremblay, J.-E., Gosselin, M., Bélanger, S. and Iken, K., 2013, Benthic Food-Web Responses to Marine Biological Productivity and Depth across the Canadian Arctic, Québec-Océan Annual Meeting, Rivière-du-Loup (QC) Canada. November 13-15. Oral presentation

Roy, V., Archambault, P., Tremblay, J.-É., Gosselin, M., Bélanger, S. and Iken, K., 2013, Réponses du réseau trophique benthique à la productivité biologique marine et à la profondeur dans l’Arctique canadien, 12e Assemblée générale annuelle de Québec-Océan, Rivière-du-Loup, Québec, Canada, Oral presentation

Roy, V., Iken, K., and Archambault, P., 2013, Environmental Drivers of the Canadian Arctic Mega-Epibenthic Communities, PLOS ONE,

Roy, V., Iken, K., Tremblay, J.-É., Gosselin, M., Bélanger, S. and Archambault, P., 2014, Benthic food-feeb responses to marine biological productivity and depth across the Canadian Arctic, Ocean Sciences Meeting 2014, Honolulu, Hawaii, USA, Oral presentation

Schiffrine, N., Tremblay, J.-E. and Babin M., 2013, Ecophysiology and nitrogen nutrition of key species phytoplankton species., Chantier Arctique Français, Paris, France, Poster Presentation

Schiffrine, N., Tremblay, J.-E. and Babin M., 2013, Ecophysiology and nitrogen nutrition of key species

phytoplankton species., AGA Québec ocean, Rivières-du-Loup, Qc, Canada, Poster Presentation

Schiffrine, N., Tremblay, J.-E. and Babin M., 2013, Ecophysiology and nitrogen uptake uptake of Chaetoceros socialis., Arctinet Annual Scientific Meeting (ASM2013), Halifax, NS, Canada, Poster Presentation

Simo, A., 2013, Le phytoplancton… Un géant microscopique!, Concours « Votre soutenance en 180 secondes », 81e Congrès de l’ACFAS, Université Laval, Québec, Canada, Oral presentation

Simo, A., Blais, M. and Gosselin, M., 2013, Which environmental factors determine the spatial and seasonal variability of phytoplankton dynamics in Labrador fjords (56–60°N)?, Gordon Research Conferences in Polar Marine Science, Ventura, California, USA, Poster presentation

Simo, A., Blais, M. and Gosselin, M., 2013, Contrôle environnemental de la structure et du fonctionnement des communautés phytoplanctoniques des fjords subarctiques de la côte est du Canada, 12e Assemblée générale annuelle de Québec-Océan, Rivière-du-Loup, Québec, Canada, Oral presentation

Simpson, K. G., Tremblay J. E. andPrice N. M., 2013, Nutrient dynamics in the Western Canadian Arctic. I. New production in spring inferred from nutrient draw-down in the Cape Bathurst Polynya, Marine Ecology Progress Series, v.484, 33-45

Simpson, K. G., Tremblay J. E., Brugel S. andPrice N. M., 2013, Nutrient dynamics in the western Canadian Arctic. II. Estimates of new and regenerated production over the Mackenzie Shelf and Cape Bathurst Polynya, Marine Ecology Progress Series, v.484, 47-62

Song, G., Xie, H., Bélanger, S., Leymarie, E., and Babin, M., 2013, Spectrally resolved efficiencies of carbon monoxide (CO) photoproduction in the

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western Canadian Arctic: particles versus solutes., Biogeosciences, v.10, 3731-3748

Taalba, N., Xie, H., Scarratt, M. G., Bélanger, S. and Levasseur, M, 2013, Photooxidation of Dimethylsulfide (DMS) in the Canadian Arctic, Biogeosciences, v.10, 6793-6806

Tang, S., Larouche, P., Niemi , A. and Michel, C., 2013, Regional Algorithms for Remote-Sensing Estimates of Total Suspended Matter in the Beaufort Sea, International J. of Remote Sensing, http://dx.doi.org/10.1080/01431161.2013.804222

Taylor, R. L., Semeniuk D. M., Payne C. D., Zhou J., Tremblay J. E., Cullen J. T. and Maldonado M. T., 2013, Colimitation by light, nitrate, and iron in the Beaufort Sea in late summer, Journal of Geophysical Research-Oceans, no.7, 3260-3277

Thaler, M. and Lovejoy, C., 2013, Environmental selection of marine stramenopiles clades in the Arctic Ocean and coastal waters., Polar Biology,

Tremblay, J.-É., Raimbault, P., Garcia, N., Lansard, B., Babin, M., Gagnon, J., 2013, Impact of river discharge, upwelling and vertical mixing on the nutrient loading and productivity of the Canadian Beaufort Shelf, Biogeosciences Discussions, 10, 16675-16712

Xi, H., Larouche, P., Tang, S., and Michel, C., 2013, Seasonal Variability in Light Absorption Properties and Water Color Parameters in Hudson Bay, Canada, Journal of Geophysical Research, v.118, 3087-3102

Documents

Marine Biological Hotspots: Ecosystem Services and …€¦ · the coastal Beaufort Sea has now been revised upwards. • Benthic bivalve assemblages differ greatly between fjords,