Cyanobacteria Ecological Strategies: Initiation, Development & Termination

of a Bloom

Barry H. Rosen, Ph. D.Florida Gulf Coast University

brosen@fgcu.edu

407-353-1541

Cyanobacteria

(aka blue-green algae; cyanoHABs)

•gram negative bacteria

•pigments in thylakoids

Ecological Strategy: Staying in the light (photic zone), but much more

Gas Vesicles: Buoyancy regulation and vertical migration

(C6H12O6)n

Low light

Nutrients scavenged whilst near

lake sediments or thermocline

Select genera

Ecological Strategy: gas vesicles

Ecological Strategies: morphology for staying in the water column

rarerare

Depiction of the primary producers (algae and cyanobacteria)

rarerare

Depiction of the primary producers (algae and cyanobacteria)

• Slow-growing nutrient specialist• Fast-growing nutrient

opportunist

• Variety of organisms, some common, some rare (why?) (how are some “holding on”?)

• At any given time, they experience approximately the same nutrient environment (although microhabitats exist)

• Daily, weekly, monthly, seasonal forcing functions (temp., light quantity and quality, rainfall)

• Each organism has an optimum rate of nutrient uptake; and optima for all other factors

• Each organism has a concentration threshold efficiency to take up that nutrient

Add a limiting factor

before afterrarerare

rarecommon

rarecommon

rarecommon

rarecommon

rarecommon

rarecommon

Some cells simply

increase in size

rare

• quiescent (subsistent) species stimulated

• rare species stimulated; more common species become rare (relatively)

Ecological Strategies: members of the community can overcome a limiting factor, like nitrogen limitation

• Lipid layer around cell wall• Loss of oxygenic-photosystem II• Visible pigment difference

Ecological Strategies: fix your own nitrogen from the atmosphere (the heterocyte)

Lake Okeechobee: (730 sq. miles) June progression of harmful algae bloom (NOAA)

Q: Where in the Lake Okeechobee do we see the blooms develop (monthly) and what are the suite of organisms that allow bloom formation? Do the current physical and chemical parameters explain the dynamics of these blooms?

Caloosahatchee-USGS S-79-monthly; intensified during a bloom

St. Lucie at S-308 , SFWMD/FDEP-monthly

SFWMD-collected 17 open water lake-monthly• whole water shipping to USGS • extensive water chemistry/physical

parameters by SFWMD

Caloosahatchee-SFWMD/FDEP at S-77-monthly

USGS Orlando

a. quantification and ID

b. culturingc. toxin gene screening d. toxin screening

Whole water shipping to USGS

USGS to CESU for metagenomics and 16s.

USGS to CESU for metagenomics and 16s.

USGS Orlando

a. quantification and ID

b. culturingc. toxin gene screening d. toxin screening

Partners: USGS (Ft. Myers, Orlando and KS), USACE, SFWMD, FDEP, universities

Testing: chemical and physical parameters, metagenomics, cyanotoxins-genes and toxins, and species ID and quantification

S-77

S-79S-80

S-308

Whole water shipping to USGS

St. Lucie at S-80 USGS-monthly

Cutting-edge approach with genetics

USGS installation

of mescosms

S-79

Q: Are macronutrients the maindriver in starting a bloom? Q: Do we see a response in the organisms: are toxin genes upregulated with these treatments? Q: Besides the bloom organism, how important are the other organisms in the water?

Partners: USACE, USGS, SFWMD, FDEP & universities

Testing: chemical and physical parameters, metagenomics, metatranscriptomics, proteomics, cyanotoxins, species, nutrient uptake, etc.

Year 2/3: refine experiment to focus on what was found in year one. May need to test other nutrients and elements like iron or other factors found from the complementary spatial survey.

Meta-transcriptomic and Proteomic Approach

Mesocosms1) pre-bloom “jumpstart” (using nitrate, ammonia or phosphorus)2) mid-bloom stimulation (same treatments)3) post-bloom “re-initiation”(same treatments)

Too much of a good thing?

Low dissolved oxygenleads to fish kills

Termination

“healthy colony”

Termination

Low dissolved oxygenleads to fish kills

Bacteria, predators, leaking cells, cell death, etc.

“healthy colony”

Termination

Low dissolved oxygenleads to fish kills

Bacteria, predators, leaking cells, cell death, etc.

DNA staining

showing interior

cells are protected

TerminationBacteria, predators, leaking cells, cell death, etc.

disaggregation consumers? Limiting factors

• Key nutrient (macro or trace element)

• Physical factor(s): light, temperature

• Natural succession

• Bacteria’s “hidden role”?

Termination

23

24

25

26

27

28

29

30

(5,000)

-

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

45,000

50,000

4/27 5/17 6/6 6/26 7/16 8/5 8/25

Num

ber

of

fila

men

ts/m

L

Tem

peratu

re (oC

)

Dolichospermum

Temp.

Copper sulfate treatments

Termination

phycoerythrinphycocyanin

Thank You!

brosen@fgcu.edu407-353-1541

Ecological Strategies: cyanobacterial art