L8-phytoplankton,diversity,size,taxa,alage blooms Flashcards
Where do phytoplankton live?
upper, sunlit layers of ocean
What is total biomass of phytoplankton?
outweighs that of all marine animals.
What proportion of world’s primary productivity is phytoplankton?
40-50%
Are phytoplankton monophyletic?
no many different groups
How much of phytoplankton is sequestered?
1%
How well known is phytoplankton diversity?
not at all very little research on them
What are the main phytoplankton phyla?
Cyanobacteria1
Diatoms
Haptophytes (include coccolithophorids)3
Dinoflagellates
Eukaryotic phytoplankton belong
to 5 evolutionary lineages
Alveolates
- Stramenopiles
- Rhodophyta
- Green Plants
- Other Protists
How are phytoplankton phyla characterised?
photosynthetic pigments chloroplast structure energy reserves cell wall chemistry flagella ultrastructure
What size is nanoplankton?
- 0 - 20 um
e. g. Emiliania huxleyi A coccolithophorid
What proportion is Nanoplankton?
55% of phytoplankton biomass
What size is Picoplankton?
[0.2 - 2.0 m
What size is Microplankton?
[20 - 200 m
How much of primary productivity are diatoms?
40% marine primary productivity
What are diatoms cell walls features?
complex
made of silica
biogeochemical cycling of silica
What is diatom Ooze?
When diatoms die they sink to the bottom of the ocean
where they accumulate (1-3 cm/1000 years).
•The slow dissolution of silica and high productivity of
some diatoms lead to the accumulation of oozes.
Coccolithophorids Characteristics?
flagella: 2 smooth
haptonema (food capture, attachment organelle)
cell covering of calcareousscales (CaCO3) ‘coccoliths’
Emiliania huxleyi (Ehux) features?
• most abundant coccolithophorid - globally
• extremely widespread - most oceans.
• usually outnumbers all other species
combined (can be 80-90%+ phytoplankton)
• many free-floating coccoliths (due to overproduction, death)
What forms chalk?
coccolithophorids
What are algal blooms?
refer to the overgrowth of macroalgae and/or phytoplankton in response to natural or human-induced changes to the environment.
What causes fish kills?
low oxygen due to bacteria feeding on dead algae from algae blooms
Why are blue green algae a problem?
massive bloms
Produces hepatotoxins can accumulate
What are the main organisms in harmful algae blooms?
Dinoflagellates
how much of a bloom are autotrophic?
50% autotrophic
When are Harmful algal blooms initiated?
higher temperatures (late summer) cause cysts in sediments to germinate
What favours population growth?
high irradiance
low salinity
excess nutrients (N & P)
vertical migrations optimise use of light & nutrients
toxins and growth inhibitors inhibit other species
stable water column
What will happen to blooming species with climate change?
increase as favoured by higher temp
more agricultural runoff
hard surface(eg. rodas) cause more runoff
How do dead zones form?
fresh water brings nutrient input algae bloom algae die and are eaten by bacteria oxygen depleted fish die
How common are dead zones?
number of Dead Zones in the world’s oceans is increasing dramatically
