Golden AlgaeAn Invading Toxic Protist

Karen Glenn Bluestem Chapter – Texas Master Naturalist

Austin College – Department of ChemistryScientist III - University of Oklahoma Biological Station (2007 – 2011)

Texas Master Naturalist Annual MeetingOctober 19, 2019 – Rockwall, Texas

What exactly is Golden Alga?• Golden algae is not considered a “true” alga. There are approximately 1000 species of Chrysophytes that are

collectively referred to as “golden algae” due to the coloring of the water during an active bloom events.

• Kingdom Protista (Five Kingdom System) or Chromista (Seven Kingdom System) – simple eukaryotic organisms Not a plant, animal, or fungi

Usually found in an aquatic environment

Usually single celled organisms, but may sometimes be multicellular

Often have flagella or cilia for movement

May be heterotrophs (saprotrophy and phagotrophy) or autotrophs (photosynthesis)

Historically grouped with Protozoa, Slime Molds, Sporozoans such as Giardia and Plasmodia, and Amoebas

May have the ability to form cysts and/or practice allelopathy when conditions are unfavorable

The Five Kingdom System

Illustration by Robert G. Howells, TPWD

Golden Alga – Prymnesium parvum

Characteristics:

Single-celled marine species – prefers a saline environment

Haptophyta – prominent haptonema, a microtubular appendage

Two uneven flagella – provides locomotion

Photosynthetic – two prominent chloroplasts

Submicroscopic organic scales – requires an electron microscope

The Scandinavian Culture Collection of Algae and Protozoa at the University of Copenhagen

A microscopic picture of a golden alga cell (1000X magnification).

Photo by Greg Southard, TPWD

Golden Algae cannot be detected without magnification due to its size!

Cells average ~ 10 micrometers (range from 8 to 15 micrometers).(For comparison the thickness of a human hair averages around 90 micrometers.)

P. parvum was first identified by Liebert and Deerns during a 1920 fish kill in the Netherlands.

Liebert F, Deerns WM. Onderzoek naar de oorzak van een Vischsterfte in den Polder Workumer Nieuwland, nabij Workum.Verhandungen en Rapporten uitgegeven door Rijkinstituten voor Visscherijonderzoek. 1920;1:81–93.

P. parvum was confirmed in 5 separate water sheds within Texas in the 1980’s.

Note: not all watersheds have experienced fish kills.

First confirmed appearance in 1985 in the Pecos River watershed, although earlier fish kills may havebeen caused by P. parvum.

Responsible for an estimated 30-50 million dollar loss to recreation and aquaculture industries in affected areas.

Dundee State Fish Hatchery’s striped bass production wiped out in 2001 due to using contaminated lake water.

Since the first confirmed arrival of P. parvum, it has been reported in 20 states, and has recently been confirmed in the Rio Grande, San Jacinto and Wichita river watersheds.

Alabama, Arizona, Arkansas, California, Florida, Georgia, Hawaii, Louisiana, Maine, Mississippi, Nevada, New Mexico, North Carolina, Oklahoma, Pennsylvania, South

Carolina, Texas, Washington, West Virginia and Wyoming.

Texas Parks and Wildlife

States Reporting P. parvum

Where Did Golden Algae Come From?

“Everything is everywhere, but, the environment selects” – Baas Becking hypothesis (1934)

• P. parvum has always been here in very small numbers until environmental factors favoredan increase in its number to detectable (and harmful) limits.

• Bilge water from transport ships

• Bird guano and possibly feathers

• Transfer of resting cysts in sediment

• Boats and live wells

• Bottom line: no one knows how it first got here, but it is probably a mixture of all the above

Confirmed P. Parvum Fish Kills in Lake Texoma

Image: David Hambright, Lebanon Pool Fish Kill, 2004.

First fish kill in Lake Texoma occurred in Jan – Mar of 2004. Density was approximately 144,000 cells mL-1.

Bloom was sporadic with fish kills mostly observed inLebanon Pool and the mouth of the Big Mineral arm.

No kills were observed in 2005, but subsequent kills observed 2006 and 2007 (and beyond). Most of the latter kills have been in Lebanon Pool.

Full time monitoring program began in Feb 2006 at the University of Oklahoma Biological Station, funded by the Oklahoma Department of Wildlife Conservation.

Plankton Ecology and Limnology Lab (PELL) – University of Oklahoma Biological Station

Detecting and Monitoring P. parvum (PELL)

Direct cell counts – requires ability to visually detect and count cells under a microscope• Very labor intensive!• Limits of approximately 333-1000 cells/ mL

Cell counts with a Flow Cytometer – uses cell’s ability to self-fluoresce vs. size to count cells.• Fast, relatively easy.• Possibility of other cells being counted as target. • Can sometimes be difficult with mobile species (migrate away from “sipper”)

Cell counts with qPCR – using specific DNA sequences to detect and quantify algal cells in water samples.• Specific, depending on primers used• Ability to detect very low concentrations (~ 6 - 22 cells/mL, depending on volume of water sampled)• Quick and repeatable• Early detection of low densities• Requires knowledge of copy number for sequence used (how many copies of the sequence are in each cell)

Zamor,R.M.; Glenn, K.L.; Hambright, K.D.. 2012. Incorporating molecular tools into routine HAB monitoring programs: Using qPCR to track invasive Prymnesium. Harmful Algae 15, 1-7.

Lake Texoma Monitoring (PELL)Nitrogen and Phosphorus Concentrations• Nutrient loads are critical in understanding water quality. • Common ratio of Nitrogen:Phosphorus (N:P) is ~ 16:1 in nature.• N:P ratio varies across sample sites in Lake Texoma.

Conductivity • Specific conductivity ranged from 887.6 µS/cm to 3,062 µS/cm, indicating high levels of current

conducting ions (chlorides and salts) in the system. • These values are highest within the upper reservoir arms, notability the Red River, and generally decline

moving towards the dam. Washita Arm has low conductivity.

Salinity• Values ranged from 0.30 ppt in the Washita River arm to 1.70 ppt in the Red River arm. • Texoma has much higher salt content compared to other Oklahoma reservoirs.

Chlorophyll • Total chlorophyll can give an idea of algal concentrations, although it is a general measure and cannot

give information about species.

Hambright, K.D., R.M. Zamor, J.D. Easton, K.G. Looper, E.J. Remmel, & A.C. Easton. 2010. Dynamics of an invasive toxigenic protist in a subtropical reservoir. Harmful Algae 9:568–577.

What Causes Golden Algae to Bloom?Nutrient loads – Blooms are associated with changes in the nutrient levels in the water. There have beendifferences among studies, but generally the ratio of Nitrogen (N) to Phosphorus (P) plays a role.

• P. parvum tends to bloom under high N and high P conditions.

• When the environment becomes P-limited, P. Parvum becomes more toxic.

• Upper Red River ratio of N:P is ~ 11:1, Washita Arm is ~17:1.

• Texoma is classified as a P-limited, eutrophic lake. (Washita Arm is mesotrophic)

pH – P. parvum growth is optimized at ~ pH 8

• Lake Texoma pH ranges from ~ 7.4 to 8.5, depending on inflow and conditions.

What Causes Golden Algae to Bloom?

Salinity – P. parvum can tolerate a wide range of salinities from 1 – 15 ppt

• Ranges on Texoma vary from ~ 0.5 – 1.8 ppt. Lebanon Pool can reach ~ 2.00 ppt when isolated.

Temperature – Historically, blooms happen in the Winter or early Spring.

• Blooms on Texoma have shifted from early in the year (Jan – Mar) to early summer (June – July of 2017) • Is this a change or an isolated incident?

Sunlight – Some studies have found that UV light reduces toxicity of P. parvum blooms.

• Winter blooms may be a response from shifting from an autotroph to an heterotroph?• Less competition from other algal species in winter?

How Does Golden Algae Kill Fish?P. Parvum releases several toxic compounds into the water column during a bloom (usually ≥ 50,000 cells/mL).

Prymnesins – Hemolysin – Stearidonic acid – Neurotoxins?

Toxins tend to concentrate as the bloom subsides • triggered by inflow ( esp. after low water events)

Why are toxins released? • Competition for resources?• Stress?• Are toxins endogenous or exogenous?• Difficult to compare natural waters to lab samples.

Henrikson, J.C., M.S. Gharfeh, A.C. Easton, J.D. Easton, K.L. Glenn, S.L. Mooberry, K.D. Hambright, R.H. Cichewicz. 2010.Reassessing the ichthyotoxin profile of cultured Prymnesium parvum (Golden Algae) and comparing it to samples collected

from recent freshwater bloom and fish kill events in North America. Toxicon 55:1396-1404.

June 21 to 24, 2017 - Paradise Cove , Big Mineral arm.

• approximately 157,000 dead fish in the area• 90 percent were small (1 inch) threadfin shad

Other fish species significantly affected (estimates):

• 9,122 freshwater drum • 1,332 crappie• Small numbers of catfish and other game fish• No striped bass observed.

Texas Parks and Wildlife Department (press release)

Most Recent Lake Texoma Fish Kill

What does a Golden Algae Bloom look like?

Brazos River Authority and Texas Parks and Wildlife Department

During full bloom water takes on a golden color. Foam often forms along shoreline, especially in windy conditions.

Fish kills usually begin to appear as water becomes discolored. Birds and other animals are often observed eating dead fish and drinking discolored water with no ill effects.

Texas Parks and Wildlife Department University of Oklahoma Plankton Ecology and Limnology Lab

What does a P. parvum kill look like?

Texas Parks and Wildlife Department © 2006 (Greg Southard)

Fish may be spotted “gasping for air” at the surface of the water, even when DO is in the normal range.

Dead and dying fish have brightly colored gills, sometimes damage to tissue is obvious

Fins and skin areas between scales become bloody.

Threadfin shad and drum are usually the first to die off, followed by crappie, sunfish, and game fish.

Mussels, salamanders, and other thin-skinned species may be affected.

What are the Dangers to Humans, Livestock, and Pets?

Daniel L. Roelke • Aaron Barkoh • Bryan W. Brooks • James P. Grover • K. David Hambright • John W. LaClaire II • Peter D. R. Moeller • Reynaldo PatinoA chronicle of a killer alga in the west: ecology, assessment, and management of Prymnesium parvum blooms. 2015. Hydrobiologia, 764(1), 29-50.

Complete suite of toxins and allelopathic chemicals are currently unknown.

Toxins lethal to fish appear to be photolabile and degrade rapidly when exposed to sunlight.

Individual toxins are very difficult to obtain and/or reproduce in the laboratory.

Most studies to date focus on acute toxic effects and do not follow chronic exposure of birds, livestock, and humans to P. parvum toxins

One study suggested P. Parvum extracts may affect glutamate activity within an in vitro rat neurotransmitter model

Another study reported toxicity of some P. parvum compounds to a laboratory mammalian cell line

P parvum produce a complex mixture of neurotoxins, prymnesiums, cytotoxic compounds, and hemolyticfactors, often dependent on bloom conditions and nutrients.

So, now that is it here, what can be done? Factors controlling P. parvum blooms are quite difficult, if not impossible, to

control on a large reservoir like Lake Texoma. Most management practices can only be used in hatcheries and smaller bodies of water. P. parvum is almost impossible to eradicate out of an ecosystem, once it appears, without affecting numerous other species.

Best management practices involve lowering nutrient run offs due to agriculture and industry upstream.

Fish have been observed to move to refugia when subsequent blooms happen, which lowers losses to important species, and lake populations have recovered quickly after kill events.

Ongoing research efforts will be needed to better understand the implications of living with P. parvum, including long term effects of toxins, as well as changes in the local community structure of the lake.

What to do if you observe an active bloom event!

Contact TPWD:

To report fish kills or suspected golden alga at any timecall the Texas Parks and Wildlife Department

TPWD communications dispatch 512-389-4848 (Austin)

or call your local game warden.

Questions?