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7/25/2019 Comparison Sampling Methods Zooplakcton Riverine 2011
1/1
2011 E. Schweizerbartsche Verlagsbuchhandlung, Stuttgart, Germany
DOI: 10.1127/1868-5749/2011/0048
www.schweizerbart.de
1868-5749/2011/0048 $ 5.40
A comparison of sampling methods for riverine zooplankton
Tamara D. Sluss1, Jeffrey D. Jack* and James H. Thorp2
with 5 figures and 1 table
Abstract:Research of zooplankton in large rivers is more recent and less common than lentic and marine studies
and over ten different sampling devices have been used to sample riverine zooplankton around the world to date.
The objectives of this study were to (i) demonstrate the need for standardizing collection methods for riverine zoo-
plankton; (ii) report the results of field tests on the relative effectiveness of three sampling devices (alpha bottle,
Schindler trap, and manual bilge pump) in collecting copepods, cladocerans, and rotifers from a large river during
low and high flow periods at two depths in the Ohio River; and (iii) discuss advantages and disadvantages of sam-
pling devices and provide sampling suggestions based on this field study and experience sampling riverine zoo-
plankton. Our results indicate that there is great variability in the densities of zooplankton captured by different
sampling devices and variability between replicate measurements of the same sampling device. The alpha bottle and
the pump collected significantly different densities of every taxa (excepting Bosmina) with significant differences
due to sampling device. All other taxa showed no significant differences between devices indicating that the Schind-
ler may be the least effective of the three devices. The Schindler captured less total zooplankton than the other de-
vices and those differences were driven by the capture of fewer Bosmina and Keratellaby the Schindler device.
Additionally, during the three sampling events, there were only significant differences between samples taken from
different depths for cyclopoid copepods indicating a relatively well-mixed sampling region both vertically and later-
ally, from shore to channel. Although this study was conducted in only one large river and across two sampling
seasons, the differences due to sampling device makes it clear that conclusions drawn from cross-study comparisons
when different sampling devices were used are precarious. It may be proper for river researchers to standardize col-
lection methods while also becoming aware of the consequences of using different methods in various riverine
habitats and during disparate seasonal and hydrologic conditions.
Keywords:Riverine zooplankton, sampling, comparative methods
River Systems Vol. 19/4, p. 315326published online November 2011
Addresses of the authors:1Division of Math and Sciences, Kentucky State University, Frankfort, KY 40601 (tamara.sluss@kysu.edu)2Kansas Biological Survey and Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66047-3759
USA (thorp@ku.edu)
*Deceased
Article
Introduction
The need for standardized collection methodsfor riverine zooplankton
Zooplankton are important consumers in many aquatichabitats (Williamson 1987) and can be vital conduits forenergy and material transfers from suspended algae anddetritus to higher trophic levels (Mallin & Paerl 1994).
Their crucial role in riverine food webs have only just re-
ceived attention in fundamental ecological research (e.g.,Thorp et al. 1994, Kobayashi 1997, Gosselain et al. 1998,Jack & Thorp 2002, Thorp & Mantovani 2005). Zoo-
plankton occur along the longitudinal dimension of rivers(headwaters to the mouth) in two broad areas: higher flow,main channel habitats and lower to zero flow, slackwaterhabitats (side channels, bays, near shore, etc.) (Lair,2006). Densities and growth rates are considerably greaterin slackwaters, probably primarily because of low turbu-
lence and greater water retention which affect recruit-
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