Scenario 1 Flashcards
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
brevotoxin
saxitoxin
may be produced by dinoflagella
- from Alexandrium sp.
- depresses sodium ion transport, impacting nervous system
- kills filter-feeding bivalves, and potentially humans that feed on them
brevotoxin
may be produced by dinoflagella
- 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
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
Zooxanthellae is a colloquial term for single-celled dinoflagellates that are symbiotic with invertebrates like demosponges, corals, jellyfish, and nudibranchs
- NOT free-living- within host tissue
phytoplankton
photosynthesizing plankton
2 main classes of phytoplankton
- diatoms
- dinoflagellates
Zooplankton
DIFFERENT FROM ZOOXANTHELLAE
Not photosynthesizers- heterotrophs
- next level of food chain above phytoplankton or a bit higher- important parts of lower levels
Describe the major drivers of patchiness in plankton distribution
horiz. changes in physical/chem conditions
depth gradients
grazing - zooplankton feeding or phytoplankton, for ex.
reproductive behaviors
feeding behaviors
swimming capabilities (eg. flagella in dinoflagellates, jellyfish, pteropods)
Analyze the connections between abiotic factors, phytoplankton blooms and zooplankton dynamics, and explain their role in carbon sequestration in the world’s oceans.
water motion + mixing depth- mixing depth lower in winter bc density gradient is less extreme- summer surface water is MUCH hotter than deep water
Explain how nutrients like Nitrogen and Phosphorus influence phytoplankton dynamics.
P is a limiting factor for phytoplankton photosynthesis
Use your understanding of phytoplankton biology, and the factors that influence phytoplankton distribution and abundance, to describe how and why Harmful Algal Blooms (HABs) form
stable water column, input of nutrients, + input of resting stages (grow in good conditions)
