Algal EcologyAlgal Ecology

Harmful Algal Bloom WorkshopsHarmful Algal Bloom WorkshopsSauk Centre, Mankato, & St. PaulSauk Centre, Mankato, & St. Paul

March 4, 5, & 6, 2008March 4, 5, & 6, 2008

Howard Markus, Ph.D., P.E.Howard Markus, Ph.D., P.E.MPCAMPCA

Algal EcologyAlgal EcologyWhat are algae?What are algae?What kinds of algae are there?What kinds of algae are there?What are the nutrient requirements of What are the nutrient requirements of algae?algae?Plants Plants –– phytoplankton phytoplankton –– major habitatsmajor habitatsLiterature lake algal sequence vs Mn lake Literature lake algal sequence vs Mn lake algal sequencealgal sequenceMore on BGA and special attributes that More on BGA and special attributes that enable them to bloom so successfully? enable them to bloom so successfully? Examples of BGA and some recent Examples of BGA and some recent incidents incidents Why is BGA toxicity hard to predict Why is BGA toxicity hard to predict

What are algae?What are algae?

algae generally are small to microscopic algae generally are small to microscopic plants, but some marine brown algae plants, but some marine brown algae can grow very largecan grow very largealgae have a worldalgae have a world--wide distribution and wide distribution and can be found in water, soils, and the aircan be found in water, soils, and the airalgae photosynthesize during the day algae photosynthesize during the day and respire 24/7and respire 24/7

What kinds of algae are there?What kinds of algae are there?

most common types are most common types are diatoms, bluediatoms, blue--green algae, green green algae, green algae, dinoflagellates, and algae, dinoflagellates, and chrysophyteschrysophytes

Diatoms [Bacillariophyceae]Diatoms [Bacillariophyceae]

Bluegreen Algae [Cyanobacteria]Bluegreen Algae [Cyanobacteria]

Green Algae [Chlorophyta]Green Algae [Chlorophyta]

Dinoflagellates [Pyrrhophyta]Dinoflagellates [Pyrrhophyta]

YellowYellow--brown algae [Chrysophyta]brown algae [Chrysophyta]

Plants Plants –– phytoplankton phytoplankton –– major major habitatshabitats

AlgaeAlgae––Phytoplankton (float freely in the water)Phytoplankton (float freely in the water)––Periphyton (attached to aquatic vegetation, Periphyton (attached to aquatic vegetation,

rocks, wood and other substrates)rocks, wood and other substrates)––Benthic algae (grow on the lake Benthic algae (grow on the lake

bottom/sediments); also sometimes called bottom/sediments); also sometimes called periphytonperiphyton

What are the nutrient requirements of What are the nutrient requirements of algae?algae?

Algae are plants, so they need COAlgae are plants, so they need CO22 & H& H220, 0, plus nutrients like phosphorus and plus nutrients like phosphorus and nitrogennitrogendiatoms have an added requirement, diatoms have an added requirement, silica, because of their outer casesilica, because of their outer case

How do algae fit into the food web? How do algae fit into the food web?

LightFood Web

Literature lake algal sequence vs Mn Literature lake algal sequence vs Mn lake algal sequencelake algal sequence

The The ‘‘literatureliterature’’ refers to a classical refers to a classical lake algal seasonal sequence: lake algal seasonal sequence: diatoms to greens to bluediatoms to greens to blue--greens to greens to diatomsdiatoms

In Minnesota lakes, we have found In Minnesota lakes, we have found the green algae step to be very the green algae step to be very diminisheddiminished

Seasonal TrendsSeasonal Trends

Rapid Assessment of Algal Community Eden Lake

0%10%20%30%40%50%60%70%80%90%

100%

5/4/2004 6/8/2004 7/8/2004 8/3/2004 9/10/2004

Per

cent

of A

bund

ance

Blue Greens Greens Diatoms Yellow-Browns Yellow Greens Other

Washburn Lake Summer Algal Trend Site 103

0%10%20%30%40%50%60%70%80%90%

100%

June July Aug Sept

Blue Greens Diatoms Yellow-Browns Other

Blue GreensBlue GreensUnicellular, (nonUnicellular, (non--NN22 fixing) fixing) MicrocystisMicrocystis*, *, GomphosphaeriaGomphosphaeria

Filamentous, nonFilamentous, non--heterocystous heterocystous (mostly non(mostly non--NN22 fixing) fixing) LyngbyaLyngbya*, *, OscillatoriaOscillatoria**

Filamentous, heterocystous (NFilamentous, heterocystous (N22fixing) fixing) AnabaenaAnabaena*, *, AphanizomenonAphanizomenon*, *, CylindrospermopsisCylindrospermopsis*,*,NodulariaNodularia* *

* Contains Toxic strains* Contains Toxic strainsHans Paerl, UNC

What are the special attributes of BlueWhat are the special attributes of Blue--green green algae that enable them to bloom so algae that enable them to bloom so

successfully?successfully?

nitrogen fixationnitrogen fixationbuoyancybuoyancyiron fixationiron fixation

96

22

238

37 26 2920

5.2 3.1 4.9 40

50

100

150

200

250

May June July Early August Late August September

µg/L

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Chl-a Microcystin % Toxin Producers

8,400

Lake George 2006Lake George 2006

Complexity in predicting toxic conditions Complexity in predicting toxic conditions

Blue Green Examples Blue Green Examples

2007 Blue Green Incidents 2007 Blue Green Incidents examples examples

Crystal (Mankato)

Sand (Detroit Lakes )

Little Rock (St. Cloud)

Fountain (Wright Co.)

BlueBlue--green Algal toxicitygreen Algal toxicity

Cyanobacteria can produce a wide Cyanobacteria can produce a wide array of neurotoxins, liver toxins, cell array of neurotoxins, liver toxins, cell toxins and skin irritants. In addition, toxins and skin irritants. In addition, many genera, such as many genera, such as AnabaenaAnabaena, can , can produce multiple toxins.produce multiple toxins.The rest of the Workshop will discuss The rest of the Workshop will discuss this in greater detail this in greater detail