Phytoplankton Flashcards
what is phytoplankton’s biomass versus their photosynthetic production percentage
1% of total biomass, 50% of global photosynthetic production
how can we classify phytoplankton?
taxonomically
functionally based on ecological roles
size
what are the two major groups of phytoplankton?
eukaryotic (photosynthetic protists)
prokaryotic (photosynthetic bacteria)
which phytoplankton are eukaryotic
diatoms, dinoflagellates, coccolithophores, phaeocystis
what phytoplankton are prokaryotic?
synechococcus, prochlorococcus, trichodesmium
what different colours of algae can we identify
green (chlorophyta)
brown (chromophyta)
red (rhodophyta)
all that we discuss are brown
autotrophic definition
organism that creates its own energy, primary produce
heterotrophic definition
secondary producers that seeks their energy from other sources (zooplankton)
mixotrophic definition
organisms that are autotrophic and heterotrophic
what is the range of sizes for phytoplankton
less than to micrometers to 200 micrometers
which phytoplankton are the high resource requirement type?
diatoms
which phytoplankton are the resource efficient group?
cyanobacteria
how does resource efficiency affect when in the spring season a phytoplankton will appear?
high resource requirement ones show early in the season, once nutrients diminish more resource efficient phytoplankton show up
how do diatoms present themselves
principally solitary cells, also in large chains
what is the glass covering on diatoms called?
siliceous cell
frustule
how much of a diatoms weight does the frustule take up?
4%-50%
what kind of symmetry does a centric diatom have?
radial symmetry
what kind of symmetry does a pennate diatom have?
bilateral symmetry
effects of having a frustule:
diatoms need silicate in their environment
increases their density therefore sink faster
what are diatoms roles in the biological pump?
promote sinking of organic carbon to the sediments where it will be buried and stored
what is the role of the huge vacuole found in diatoms?
exploit presence of high nutrients to store for later, allow cell divisions in low nutrient environments
what is the toxic acid found in some diatoms?
domoic acid
neurotoxin
what is an example of a diatom with domoic acid?
Pseudo-nitzschia
where are diatoms mostly found?
temperate high latitudes
high nutrient areas
what is the cellulose wall on some Dinoflagellates called?
Theca
what kind of nutritional modes to dinoflagellates use
all three, most are mixotrophs
what is the feeding process of dinoflagellates called?
phagocytosis
how do dinoflagellates reroduce?
mostly asexually
what is the function of “cysts” for dinoflagellates
created during periods of stress, can remain dormant until they are triggered and reintroduced genetic material
what allows dinoflagellates to be more mobile?
flagella (tail)
what is the name of the enzyme that causes bioluminescence in dinoflagellates
luciferase
what are HABs?
harmful algae blooms
toxic algae bloom associated with poisonous compounds
what causes a red tide?
HABs
what diseases can HABs cause
Diarrheic/Paralytic Shellfish Poisoning (DSP, PSP)
what toxin causes PSP?
saxitoxin
how does saxitoxin work?
sodium channel inhibitor in nerve cells
example of a symbiotic relationship involving dinoflagellates
dinoflagellates and corals
receive nutrients, exchange photo energy
what regions are dinoflagellates found in?
tropical/subtropical waters
low nutrient concentrations
in same areas as diatoms after the diatom blooms
what does a dinoflagellate do in the day time versus the night time?
day; photosynthesis at the surface
night: take up nutrients at deeper ocean
what kind of species are considered haptophytes?
coccolithphorids
phaeocystis
isochrysis
prymnesium
what are coccoliths covered in?
calcareous plates (calcium carbonate)
where are coccoliths generally found?
globally
what is the calcification equation for coccoliths?
calcium + bicarbonate -> calcium carbonate + water + CO2
why are coccoliths visible from space?
their liths scatter light
how do coccoliths perform calcification
vesicle in the cell concentrates calcium and bicarbonate to favour CaCO3 formation
how does calcification benefit phytoplankton
increases CO2 concentration for photosynthesis
why do coccoliths sink to the ocean floor?
calcium carbonate is denser than seawater
how do coccoliths affect the global carbon cycle?
photosynthesis on biological carbon pump
carbonate counter pump while creating cell wall
where are phaeocystis usually found
open and coastal ocean
high latitudes
what causes phaeocystis’ mucus texure
carbohydrate rich polymers surrounding it
what is DMSP
dimethyl sulphonium propionate
what species produces high levels of DMSP
phaeocystis
what happens to DMSP in seawater
degrades to DMS (dimethyl sulphide)
oxidizes to sulfate aerosols
acts as cloud condensation nuclei
what does cloud formation because of DMS cause?
promotes cooling because of cloud energy reflectance
influences acidity of rain
what kind of haptophyte is phaeocystis?
naked, no CaCO3 shell
what is a consequence of phaeocystis’ stickyness
promotes aggregation of things, sinks easily
where are cyanobacteria most abundant?
low nutrient, low biomass waters
what is the most abundant phytoplankton?
cyanobacteria
what are the major groups of cyanobacteria?
synechococcus
prochlorococcus
trichodesmium
what are the characteristics of cyanobacteria
unicellular
filamentous/colony forming
what phytoplankton is responsible for oxygenating the atmsphere?
cyanobacteria
where are trichodesmium found?
above 25 degrees celsius water (tropical and subtropical)
why do trichodesmium need to be in nitrate poor regions?
to favour N-fixing reaction
what are the requirements for N-fixing
low O2
low NH4
ATP
1 atm pressure
20 degrees celsius
what enzyme fixes nitrogen
nitrogenase (contains iron)
what phytoplankton can fic nitrogen?
richelia symbiot in diatoms
synechococcus, crocosphaera
which is the oldest photosynthetic organism?
synechococcus
which is the smallest phytoplankton
prochlorococcus
is Pro or Syn more abundant?
prochlorococcus
does Pro or Syn inhabit a wider range of ocean?
synechococcus
does Pro or Syn inhabit a deeper range of ocean?
prochlorococcus
