quiz 3- plankton Flashcards
Define plankton as a group
- organisms found generally floating in the water column- some types can swim but not strong enough to oppose currents
- functional group, not taxonomic
phytoplankton
photosynthesizing plankton
Describe the major ecological roles of marine viruses as plankton in the water column.
- nutrient cycling
- pathogens of plankton
Describe the major ecological roles of bacteria as plankton in the water column.
- decomposers- use up oxygen and contribute to oxygen minimum layer
Describe the major ecological roles of fungi as plankton in the water column.
- fungi- important decomposers, also parasites of plankton
Define cyanobacteria and describe their importance in nitrogen cycling.
- “blue-green algae” but actually bacteria
- fix n into ammonium, nitrates + nitrites
Describe similarities in ecological roles across viruses, bacteria, and marine fungi
- nutrient cycling
Diatoms: biological characteristics and ecology
- single-celled protists
- dominate phytoplankton communities in temperate to polar waters
- fit together like a pill box- shells made of silica
phylum and class of diatoms
P: Chrysophyta
C: Bacillariophyceae
Dinoflagellates: biological characteristics and ecology
- protists and single celled (same as diatoms
- dominate subtropical + tropical communities
- some bioluminescent
- can cause harmful algal blooms- cause “red tides”
- generally free-living
- Two flagella: one transverse wrapped around the cell in the groove, the other is perpendicular and runs to the back of the cell
- covered in THECA
- may produce different toxins-
examples of toxins that may be produced from dinoflagella
saxitoxin
- from Alexandrium sp.
- depresses sodium ion transport, impacting nervous system
- kills filter-feeding bivalves, and potentially humans that feed on them
brevotoxin
- Katerina Brevis species
- cause of TOXIC red tides
- also binds to sodium channels, but RARELY fatal to humans
Dinoflagellates Phylum and class
P: Pyrrophyta
C: Dinophyceae
Diatoms: life cycle
- sexual + asexual (binary fission) reproduction
- diatoms get smaller after each division- at a certain size, a gamete is produced
- auxospores- cell increases in size, casts of small valves and replaves them with larger valves
- asexual repro helps them form large blooms very quickly
- can also create ASEXUAL RESTING SPORES- fall to seabed and wait out poor envi conditions b4 developing
Dinoflagellates: life cycle + resting stages
- asexual (binary fission) and sexual repro
- temporary cysts- resting stages- sink to ocean floor until conditions are favorable and they can begin development
theca
series of CELLULOSE PLATES covering dinoflagellates, important for helping to identify them
what are zooxanthellae
dinoflagellates
NOT free-living- within host tissue
Coccolithophores Phylum
Chrysophyta
Coccolithophores- about
Phytoplankton
tropical open ocean
Massive bluish-white blooms- can be seen from space!
Coccolithophores- bio char.s
- spherical
- covered in coccoliths (but not all of them are- some “naked” coccolithophores)
what are coccoliths?
plates covering Coccolithophores
CALCIUM CARBONATE
make up 1/3 of total Ca Carbonate production in the ocean!