Dinoflagellates Flashcards
what are some characteristics of the intertidal zone
large fluctuations of humidity, temp, salinity and light twice a day posing as an extreme environment
how are some sea weeds exposed to extreme environments
1) polar sea weeds endure months of darkness under sea ice
2) prey to hosts of herbivores and microbial pathogens
3) physical and biological challenges
how can kelp forests made up from brown algae be used
- provide shelter for a diversity of fish and invertebrate animals
- large carnivores find food and refuge
- humans harvest kelps for food and industrial products
what keeps phytoplankton populations in check in unpolluted waters
- seasonal climate changes
- nutrient limitation
- predation
what are red/brown tides
when large numbers of algal cells containing red or brown accessory pigments bloom as a result of increased nutrients
how can algal blooms be harmful
- can produce toxic compounds to wildlife and humans causing massive die-offs of fish, birds and aquatic mammals
how can phytoplankton help with carbon cycling
they can transform co2 into carbohydrates by photosynthesis or into CaCO3 by calcification which is transported to the ocean bottom
how can CaCO3 produced by calcification be used
deposited as tiny scales covering phytoplankton where they sink to the sea floor
how did eukaryotic algae evolve membrane bound organelles
the ingestion of purple bacteria (mitochondria) and cyanobacteria (chloroplasts)
what classes di dinflagellates, diatoms, haptophytes and brown seaweeds belong to
dinflagellates = protozoa
everything else = chromista
what are the 6 divisions of algae which we will look at
1) rhodophyta = red alage
2) dinophyta = dinoflagellates
3) haptophyta = primnesiophytes
4) chlorophyta = green alage
5) phaeophyta - brown alage
6) heterokntophyta = diatoms
what are dinoflagellates
belong to the phylum dinophyta they are unicellular biflagellates with up to 2000 species and can be responsible for red time harmful algal blooms
outline the structure of dinoflagellates
stiff cellulose plates form the theca
in the open ocean they have sail like theca plates
what are the feeding stratergies of dinoflagellates
half lack photosynthetic apparatus
ingest solid food particles absorb dissolved organic compounds
outline the relationships between dinoflagellate zooxanthellae and coral
amino acids produced by polyps of coral stimulate dinoflagellate to produce glycerol which is used in coral respiration
what are dinoflagellate resting cysts
produced under unfavourable conditions such as low nutrients
they are non-motile and drift in lakes of ocean bottom
when conditions become favourable they will germinate
what is pfiesteria piscicida
a type of dinoflagelltae which produces deadly compounds for a hit and run feeding stratergy
how do dinoflagellates feed on fish
as they decay they extend peduncles and feed on fish flesh before returning to a benthic cyst stage
what are dinophysis actuta
armoured marine planktonic dinoflagellates found in cold and temperate waters
they are a toxic species associated with diarrhetic shelfish poisoning
what are other toxins which can be produced by dinoflagellates
1) brevetoxins- toxic to fish, marine mammals, birds and humans
2) saxitoxin- paralytic shellfish posioning
how do dinoflagellates bioluminescence
when disturbed a series of biochemical events cause a reaction
- luciferin and enzyme luciferase
why do some dinoflagellates bioluminescence
anti-predatory mechanisms againts species as they startle predators or the predators become visbale to other predatory species
