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BIOL311 > Phytoplankton and Zooplankton > Flashcards

Phytoplankton and Zooplankton Flashcards

1
Q

Approximate size range of phytoplankton

A

<2um to 2mm
most are microscopic (<100m)

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2
Q

What is the purpose of accessory pigments?

A
  • allow for different wavelengths of light to be absorbed
  • rely on accessory pigments to utilize other PAR wavelengths
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3
Q

what is PAR?

A

“photosynthetically available radiation”

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4
Q

How deep do small wavelengths reach

A

only about 1m deep

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5
Q

Phytoplankton combine energy from sunlight with water and inorganic carbon to produce organic material through photosynthesis. They are __________

A

autotrophs

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6
Q

if primary production is low, production at higher trophic levels will be _____

A

low too

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7
Q

3 “big picture” reasons phytoplankton are important

A
  1. atmospheric O2 concentration (currently about 50% of oxygen produced on earth per year is by-product of phytoplanktonic synthesis)
  2. global climate dynamics: fluctuations of primary production have significant consequences for atmospheric CO2 concentration and earths climate
  3. fossil fuel production: most oil and natural gas deposits are formed by the “cooking” of dead phytoplankton
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8
Q

phytoplankton known species

A

4,000-5,000

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9
Q

3 main phytoplankton groups of major ecological importance

A
  1. diatoms
  2. dinoflagellates
  3. coccolithophorids
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10
Q

Diatom size

A

2um-2mm (most under 100um)

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11
Q

2 groupings of Diatoms

A

centrics (radially symmetric) & pennates (bilaterally symmetric)

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12
Q

external frustule is made of:

A

silica

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13
Q

two valves of Diatoms and function

A

larger: epitheca, smaller: hypotheca
- two different sized valves has implications during reproduction
- valves split and both become the epitheca (larger part) for next generation
- so one side is always getting smaller

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14
Q

Why do diatoms have ornamentation?

A

makes them smaller and lighter = easier to stay near surface

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15
Q

Adaptations for planktonic existence**

A
  • Weight reduced by pores/grooves in frustule
  • Spines may help increase drag by increasing surface area:volume ratio
  • Chain forming may reduce sinking rates
  • Ionic regulation of cell contents can make them lighter (use of lighter ions)
  • Many phytoplankton have lipid/oil droplets to increase buoyancy
  • Rely on turbulent mixing to help keep them in the surface waters
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16
Q

reproduction of diatoms is

A

asexual (via mitosis)

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17
Q

Key roles of diatoms in marine ecosystems:

A
  • Frequently the most abundant type of phytoplankton in coastal waters, particularly during the “spring bloom” (may account for 20% of all the C fixed per year -> more than all the worlds tropical rainforests!!!)
  • Also common in highly productive coastal upwelling ecosystems , where they are grazed directly by small fish
  • Key food source for herbivorous zooplankton, and hence represent one end of the “classic” marine food chain
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18
Q

Which type of phytoplankton is most productive?

A

diatoms because they are most abundant

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19
Q

Toxic diatom bloom effects

A
  • domoic acid: a compound that can be toxic to humans and other animals including fish and marine mammals
  • toxins amplified up the food chain in fisheries
  • resulted in shellfish harvest and fishery closures in 2015
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20
Q

Dinoflagellate number of species

A

2000

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21
Q

Dinoflagellate shape

A

tripod - have 2 flagella for locomotion (can swim against gravity)

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22
Q

Outer theca is made of

A

cellulose plates

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23
Q

Dinoflagellates nutritional mode(s)

A
  • Obligate autotrophs: strictly photosynthetic (majority)
  • Facultative heterotrophs (aka “mixotrophs”): photosynthesize and also feed on other plankton
  • Obligate heterotrophs: no chloroplasts, feed exclusively on other plankton (or organic material)
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24
Q

Adaptations for planktonic existence of dinoflagellates

A
  • Flagella provide locomotory power – enables them to move to depths with higher inorganic nutrient concentrations
  • Thecal plates are ornamented to increase surface area:volume ratio (lighter to float)
    • increase drag
    • larger surface area to take up nutrients (efficient growth)
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25
Q

Reproduction and cycts

A

generally asexual - when conditions are super unfavorable they can produce spores/cysts that can settle and remain in “resting stage” for many years

26
Q

Common in __________ water columns

A

stratified (dont need mixing like diatoms)

27
Q

Impact of dinoflagellates on humans?

A

harmful algal blooms

28
Q

Name some toxins associated with HABs

A

Brevetoxin → condition produced: neurotoxic shellfish poisoning → phytoplankton responsible: dinoflagellate → characteristics: nervous system; respiratory failure in fish and marine mammals; food poisoning symptoms in humans
Ciguatoxin → condition produced: ciguatera fish poisoning → phytoplankton responsible: dinoflagellate → characteristics: nervous system; variable human symptoms
Domoic acid → condition produced: domoic acid poisoning → phytoplankton responsible: diatom → characteristics: acts on vertebrate nervous system

29
Q

Bioluminescence

A
  • Dinos flash in response to mechanical stimulation
  • Chemical reaction involves the protein luciferan (produces light and heat)
30
Q

Why do dinoflagellates bioluminesce?

A

The ‘burglar alarm’ hypothesis → Many dinos are bioluminescent, but only flash when they encounter a strong current shear. It has been proposed that this could serve as a “burglar alarm”. It startles the predator, but also alerts the predator’s predator
****assumes predator is visual

31
Q

coccolithophorid species amount

A

<500

32
Q

coccolithophorid size and shape

A

<10um usually spherical with two flagella

33
Q

coccolithophorids outer covering composition and name

A

calcium carbonate - called coccoliths

34
Q

adaptations for coccolithophorids existence

A
  • Flagella for locomotion
  • Lipids for buoyancy
  • Porous CaCO3 coccoliths reduce weight
35
Q

Reproduction in cocc

A

largely asexual

36
Q

What are picoplankton?

A

prokaryotic phytoplankton (aka bacteria) discovered inthe 1980s

37
Q

picoplankton size and shape

A

approx. 1um in diameter and coccoid in shape
- related to cyanobacteria

38
Q

Why can picoplankton grow near the lower limit of the euphotic zone?

A

they have an accessory pigment called phycoerythrin which absorbs blue light

39
Q

how much primary production can picoplankton account for?

A

up to 50% especially in open ocean

40
Q

what are zooplankton?

A

planktonic animals that cannot swim against a current

41
Q

zooplankton are heterotrophic… what does that mean?

A

they are consumers not producers (omnivores, carnivores and omnivores)

42
Q

a single net tow often contains animals form ___ different phyla

A

6-8

43
Q

2 key roles of zooplankton in food webs:

A
  1. Primary Consumers: zooplankton (particularly copepods) are the main grazers of phytoplankton in marine ecosystems
  2. Main link in energy transfer between the base of the food web and higher trophic levels (can occupy various trophic levels)
44
Q

Holoplankton

A

Zooplankton that spend their whole life cycle in the plankton

45
Q

Meroplankton

A

many benthic and nektonic (i.e. free swimming) species also have planktonic larval stages that spends days to months in the plankton

46
Q

planktonic larvae advantages

A

disperse - genetics, crowding (overpopulation); individual larvae can spread and mix over hundreds of km
- main reason that marine populations are more open “connected”

47
Q

3 phyla of jellies

A

cnidarians (true jellyfish), ctenophores (comb jellies), salps (primitive chordates)

48
Q

nematocysts:

A

barbed stinging cells used by jellies to subdue prey

49
Q

Ctenophore tentacles have:

A

sticky cells called colloblasts

50
Q

Salps diet

A

filter feeders -> can consume particles down to 5um

51
Q

main holoplanktonic molluscs are called the

A

pteropods

52
Q

what do pteropods look like

A
  • small planktonic snails
  • most common in temperate/cold waters
  • foot has evolved into paired wings for swimming
53
Q

Thecosomes

A
  • thin, coiled calcareous shell
  • size: few mm → 30mm
  • feeds by secreting a sticky mucus web
54
Q

Gymnosomes

A
  • naked (no shell)
  • elongate in shape
  • feed almost exclusively on thecosomes (latch onto shel and pull them out)
55
Q

characterization of Arthropods

A
  • segmentation
  • paired, joint appendages
  • hard, external exoskeleton
56
Q

what are the most important marine arthropods

A

crustaceans

57
Q

copepoda species amount

A

13,000

58
Q

zooplankton abundance (%)

A

often 80%

59
Q

can copepods swim against a current?

A

NO! many migrate vertically (often 100’s of metres) each night

60
Q

copepoda size

A

100’s um - 10mm

61
Q

what is the key link between plankton and higher trophic levels?

A

copepoda

62
Q

copepoda reproduction

A

sexual reproduction
internal fertilization
eggs shed into water

BIOL311 (4 decks)

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