Phytoplankton functional groups

What are the 6 functional groups of phytoplankton (Taxon)

Cyanobacteria, Diatoms, Crysophytes, Dinoflagellates, Coccolithophores, Cryptophytes

Characteristics of cyanobacteria

Prokaryotes, most of them fix nitrogen, unicellular and colonial species, come toxic

Characteristics of diatoms

unicellular and chain forming species, silica frustule, marine and freshwater, global distribution, account for 40% of marine primary production, few toxic species

Characteristics of dinoflagellates

Mainly marine, some freshwater species, have two flagella, some bioluminescent, some toxic, autotrophic and mixotrophic, heterotrophic species

Characteristics of cryptophytes

Freshwater but also marine and brackish (small to medium in size), 2 flagella

Characteristics of crysophytes

Also called golden algae, mostly freshwater, 2 flagella

Characteristics of chlorophytes

Marine, freshwater, terrestrial, huge group, some members found in extreme environments

Characteristics of coccolithophores

Calcium carbonate scales, global importance

What are the three functional characteristics of phytoplankton

Nitrogen fixers, calcifiers, harmful

Size of picoplankton

0.2-2 μm

Size of nanoplankton

2-20 μm

Size of microplankton

>20 μm

Benefits of small size in phytoplankton

small cells have a larger surface to volume ratio, they can take up low nutrient concentration efficiently (small species dominate in low nutrient waters)

Benefit of large cell size in phytoplankton

They can store nutrients inside the cell

How does cell size play a role in predation dynamics with phytoplankton

some are too small or too big to be eaten

Characteristics of stormer growth strategies

Large, protection against grazing, low growth rate under low iron but rapidly dominate once iron is available

Characteristics of performer growth strategies

Small, highly efficient iron uptake, grows fast but gets eaten quickly

Under what conditions do cyanobacteria dominate

High light, warm, low N, high Fe areas

Ecological strategy of diatoms

High species diversity, clear annual cycle in temperature and polar regions, clear successional pattern, require high nutrients, can deal with turbulence and low light

Ecological strategy of dinoflagellates

Lower species diversity, unpredictable, short duration, shortened succession, swimming strategy, low nutrients, often mixotrophic

What is a resting spore

it is a specialized dormant cell that allows phytoplankton to survive prolonged periods of stress. cells undergo metabolic reprogramming, exhibit thickened cell walls, and accumulate energy reserves. these resting stages settle into sediments, forming extensive seed banks that can persist for very long times. Resting spores germinate when favorable conditions return

Old versus new understanding of microbial plankton

Used to believe that Phototrophs and Phagotrophs were distinctly different and did not overlap. Current understanding is that there is a spectrum between Phagotrophs and phototrophs and many plankton are mixotrophic

Kleptoplasty in Dinophysis example

Dinophysis needs chloroplasts to photosynthesize but the species that contains chloroplasts (Teleaulax sp.) is too small to eat directly. Teleaulax sp. is eaten by Mesidinium sp. which is large enough for Dinophysis to consume. Once Dinophysis gets chloroplasts it can photosynthesize.

Hatena Arenicola (part time algae) example

Develops a feeding apparatus and feeds on specific algae to steal chloroplasts, feeding apparatus disappears, the cell then divides but isn’t able to split the chloroplasts leaving one daughter cell with the chloroplast and the other without. The cell without the chloroplasts must dorm a feeding apparatus and repeat the cycle

Pallium feeding

When the plankton creates an external membrane around the food to digest it (enables large food to be consumed)

Prorocentrum balticum example

Is a plankton that is like a spider, forms a sticky membrane in the morning to catch prey, consumes what it wants and leaves the membrane to divide (in nutrient poor areas it can sexually reproduce) the membrane is heavy and sinks thus sequestering carbon

Phaeocystis polymorphous life cycle

Different life stages (motile and non-motile forms), different movement strategies (Motility/floating and sinking)

Importance of this figure

Everything in life is about the three main concepts at the top, Trait types are on the left. Even single cell organisms can fit all of the trait types