plankton ecology Flashcards
whats the Eulerian & Lagrangian Perspectives
- Eulerian = Remaining in a fixed location - observe flow of water at a fixed location
- Lagrangian = Traveling with the water - follow the movement of a water parcel
how far does light penetrate the ocean
100m
Photosynthesis is restricted to this depth
biggest limiting factor in the ocean for phytoplankton
nutrients (e.g. nitrogen and phosphorus)
- they are dissolved in the ocean at very low-concentration
what does phytoplankton growth depend on
their SA:V ratio
- phytoplankton can only take up nutrients
proportional to their surface area (SA)
why is being small an advantage to phytoplankton
Nutrient-limited growth will be inversely related to size - bigger surface area
3 implications of being small
Short life-span
Slow movement
Abundance
explain the implications of a short life span
Phytoplankton can double every day
explain the implications of a slow movement
will take a phytoplankton ~1 day to
move 1 meter - But that’s basically the lifetime of a phytoplankton
explain the implications of abundance
- If each individual is miniscule there must be a lot of individuals to make up significant biomass
- allows incredible diversity amongst the plankton on small scales
- Populations can exist at incredibly low concentrations
- Population persistence under poor conditions
what 2 major domains of life are phytoplankton found within
- Bacteria (cyanobacteria) - PROKARYOTE
- Protists (diatoms, dinoflagellates,
coccolithophores, cryptophytes, pelagophytes,
rhodophytes, chlorophytes…) - EUKARYOTE
Prokaryotic Phytoplankton
cyanobacteria
- Prochlorococcus
- Synechococcus
- Trichodesmium
Prochlorococcus characteristics
- most abundant photosynthetic organism on earth
- Particularly important in the oligotrophic ocean - Small size, and therefore large surface-to-volume ratio, gives them an advantage in nutrient poor water
Synechococcus characteristics
- Contains chlorophyll a + phycoerythrin
– More abundant in nutrient rich environments than in the oligotrophic ocean - cells prefer the upper well-lit portion of the euphotic zone
– Many different clades with distinct ecological niches
Trichodesmium characteristics
- Colonial
– Common in open ocean
– Capable of nitrogen-fixation: contains nitrogenase
– Can short-circuit pelagic nutrient limitation
eukaryotic Phytoplankton
Diatoms
Coccolithophores
Dinoflagellates
diatom characteristics
- can be as large as 2mm
– Responsible for 20 – 25% of all marine carbon fixation
– Unicellular or colonies (often form chains) - contained within a silica cell wall
(frustule), comprised of two separate shells that overlap - can reproduce by binary fission AND sexual repro
coccolithophores characteristics
- Typically unicellular
- have amoeboid, coccoid, and palmelloid stages
– Produce shell of calcium carbonate plates (“coccoliths”)
phytoplankton Dinoflagellates characteristics
- diverse lineage
- Have 2 unequal flagella
– Some are armored (“thecate”)
– Can be photosynthetic, heterotrophic, or mixotrophic - can be phytoplankton, zooplankton or mixotrophs
- some produce red tides
Key factors affecting phytoplankton growth
Light
- they are adapted to use different wavelengths of light depending on depth
Dissolved nutrients - N, P, Si (some), Fe (micronutrient)
- Monod Kinetics
Temperature
- Warming = decrease in growth rates as nutrients were depleted (ambient nutrient conditions)
- warming = increase in growth rates (nutrient replete conditions)
2 groups of zooplankton
Protistan
Metazoan (animals)
types of Protistan zooplankton
Ciliates
Dinoflagellates
Heterotrophic nanoflagellates
Ciliates characteristics
- very common (and important)
- free-living bacterivores, herbivores, and predators of other protists
– Typically members of the microzooplankton
– Use cilia for motility
– Cannot generate their own chloroplasts - some engage in kleptoplasty
zooplankton Dinoflagellates characteristics
- huge neclei and genome
- often mixotrophs
- Some can consume cells even larger than themselves
- Often feed on large, chain-forming diatoms
- Pallium feeding – use an extruded pseudopod-
like membrane
Heterotrophic nanoflagellates characteristics
- hard to tell apart without using genetic approaches
- Dominant grazers of heterotrophic bacteria and all of those cyanobacteria
- don’t yet know their ecological roles
