Dinoflagellates

Question 1

what are some characteristics of the intertidal zone

Answer 1

large fluctuations of humidity, temp, salinity and light twice a day posing as an extreme environment

Question 2

how are some sea weeds exposed to extreme environments

Answer 2

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

Question 3

how can kelp forests made up from brown algae be used

Answer 3

• provide shelter for a diversity of fish and invertebrate animals
• large carnivores find food and refuge
• humans harvest kelps for food and industrial products

Question 4

what keeps phytoplankton populations in check in unpolluted waters

Answer 4

• seasonal climate changes
• nutrient limitation
• predation

Question 5

what are red/brown tides

Answer 5

when large numbers of algal cells containing red or brown accessory pigments bloom as a result of increased nutrients

Question 6

how can algal blooms be harmful

Answer 6

• can produce toxic compounds to wildlife and humans causing massive die-offs of fish, birds and aquatic mammals

Question 7

how can phytoplankton help with carbon cycling

Answer 7

they can transform co2 into carbohydrates by photosynthesis or into CaCO3 by calcification which is transported to the ocean bottom

Question 8

how can CaCO3 produced by calcification be used

Answer 8

deposited as tiny scales covering phytoplankton where they sink to the sea floor

Question 9

how did eukaryotic algae evolve membrane bound organelles

Answer 9

the ingestion of purple bacteria (mitochondria) and cyanobacteria (chloroplasts)

Question 10

what classes di dinflagellates, diatoms, haptophytes and brown seaweeds belong to

Answer 10

dinflagellates = protozoa
everything else = chromista

Question 11

what are the 6 divisions of algae which we will look at

Answer 11

1) rhodophyta = red alage
2) dinophyta = dinoflagellates
3) haptophyta = primnesiophytes
4) chlorophyta = green alage
5) phaeophyta - brown alage
6) heterokntophyta = diatoms

Question 12

what are dinoflagellates

Answer 12

belong to the phylum dinophyta they are unicellular biflagellates with up to 2000 species and can be responsible for red time harmful algal blooms

Question 13

outline the structure of dinoflagellates

Answer 13

stiff cellulose plates form the theca
in the open ocean they have sail like theca plates

Question 14

what are the feeding stratergies of dinoflagellates

Answer 14

half lack photosynthetic apparatus
ingest solid food particles absorb dissolved organic compounds

Question 15

outline the relationships between dinoflagellate zooxanthellae and coral

Answer 15

amino acids produced by polyps of coral stimulate dinoflagellate to produce glycerol which is used in coral respiration

Question 16

what are dinoflagellate resting cysts

Answer 16

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

Question 17

what is pfiesteria piscicida

Answer 17

a type of dinoflagelltae which produces deadly compounds for a hit and run feeding stratergy

Question 18

how do dinoflagellates feed on fish

Answer 18

as they decay they extend peduncles and feed on fish flesh before returning to a benthic cyst stage

Question 19

what are dinophysis actuta

Answer 19

armoured marine planktonic dinoflagellates found in cold and temperate waters
they are a toxic species associated with diarrhetic shelfish poisoning

Question 20

what are other toxins which can be produced by dinoflagellates

Answer 20

1) brevetoxins- toxic to fish, marine mammals, birds and humans

2) saxitoxin- paralytic shellfish posioning

Question 21

how do dinoflagellates bioluminescence

Answer 21

when disturbed a series of biochemical events cause a reaction
- luciferin and enzyme luciferase

Question 22

why do some dinoflagellates bioluminescence

Answer 22

anti-predatory mechanisms againts species as they startle predators or the predators become visbale to other predatory species