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Biological Oceanography & Limnology > Marine Zooplankton > Flashcards

Marine Zooplankton Flashcards

1
Q

Holoplankton

A

organisms which spend their whole life as plankton

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2
Q

Meroplankton

A

organisms which have only part of their life cycle in the plankton. An example is larvae of barnacles or crabs. Many benthic organisms have part of their life cycle as meroplankton.

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3
Q

About——of benthic organisms have a planktonic stage

A

70%

Duration of the planktonic stage ranges from minutes to even years in some exceptional cases

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4
Q

trochophore larvae

A

small, translucent, free-swimming larva characteristic of marine annelids and most groups of mollusks. Trochophores are spherical or pear-shaped and are girdled by a ring of cilia (minute hairlike structures), the prototroch, that enables them to swim.

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5
Q

After the Trochophore stage, benthic snails and clams produce ……

A

shelled veliger larvae

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6
Q

Zooplankton size ranges

A

Picozooplankton 2-20µm
Microzooplankton 20-200 μm
Mesozooplankton 200 μm-2 mm
Macrozooplankton 2-20 mm

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7
Q

There are many diverse classes of zooplanktonic holoplankton….

A 
Crustacea (copepods, krill, many meroplankton
Cnidaria (siphonophores, medusa)
Molluscs (pteropods)
Appendicularians (salps & larvaceans)
Ctenophores (comb jellies)
Picozoa 2-3 µm heterotrophs
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8
Q

Picozoa

A

a new phylum — Originally called Picobiliphytes, they were found to contain phycobiliproteins (PB) and thought to be photosynthetic.
However, the PB came from cyanobacteria eaten by the organisms.
Very widespread!

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9
Q

Crustacea

A

are members of the phylum Arthropoda. Examples of Crustacea are: lobsters, shrimp, copepods and crabs. The arthropods include 80% of all animal species on Earth and include spiders, scorpions, insects, mites, millipedes, centipedes etc.

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10
Q

what supports and protects the exoskeleton of crustaceans?

A

chitin (a nitrogenous polysaccharide)

cellulose and starch are the three most abundant organic compounds in nature. Chitin is a polysaccharide with an amide (with N) group attache

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11
Q

Crustaceans Body Plan

A

have two pairs of antenna and limbs with 7 segments

All crustaceans have a nauplius (larval) stage in their life cycle

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12
Q

Crustacean larval called?

A

nauplius – molt about 6 times before developing into the next stage

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13
Q

If so many zooplankters are molting, why isn’t the ocean filling up with chitin?

A

Bacteria (Vibrio) detect the chitin, swim to it and synthesize enzymes to break it down

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14
Q

Chitosan-based DNA nanoparticle for gene delivery and transfection….

A

Chitosans, typically isolated from the shell of shrimp, has the ability to react with DNA and compact it to produce a nanoparticle. Such nanoparticles are more readily taken up by cells. In this way we can transfer novel genes into cells, either for therapeutic purposes (gene therapy)

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15
Q

Copepoda

A

subclass of Crustacean members of the zooplankton Most abundant group of animals on Earth. Picozoa probably more abundant!

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15
Q

Copepoda

A

subclass of Crustacean members of the zooplankton Most abundant group of animals on Earth. Picozoa probably more abundant!

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16
Q

In developing, copepods must

A

molt or shed their exoskeleton. This is because as they grow, their exoskeleton becomes too small for their body.

Usually go through 6 naupliar and 6 copepodite stages before becoming an adult

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17
Q

Copepods use their antenna for…

A

sensing the environment

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18
Q

Antenules (NOT antenna) in copepods are used for…

A

Antennules are used in swimming

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19
Q

Copepod life cycle

A

egg –> 6 nauplii stages –> 5 copepodid stages

egg, nauplius, copepodite, and adult

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20
Q

Why could C. finmarchicus (copepod) have a diapause stage?

A

winter goes into a diapause stage where metabolism slows, stops feeding, and it goes to deep water

like hibernation, not as much food available ?

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21
Q

it has been discovered that both diatoms and dinoflagellates can depress copepod reproduction, why?

A

When certain species are eaten, copepod egg and fecal pellet production and hatching success is depressed

Three different aldehydes were isolated from diatoms that are responsible

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22
Q

Euphausids

A

Euphausia superba is “Krill” of Southern Ocean.

~85 species
~ 80 mm (3 inches) long

Spawn Jan-March in Antarctic waters. Eggs sink to ~ 1800 m. Naupliar stages slowly swim upward in time to feed on austral summer phyto blooms which start in October. Next 2 yrs grow to 6 cm in length and live in upper 200 m

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23
Q

Euphausid life cycle

A

Eggs sink & hatch in
Spring. Reach the
Furcilia stage by
winter

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24
Q

Appendicularians (LARVACEANS)

A

Chordates (Phylum Chordata) which are closely related to benthic tunicates (sea squirts)

Because they resemble larval stages of benthic species they are called larvaceans
Look like a tadpole
Builds a mucoid house and filter to collect food. Filter becomes clogged and is discarded (ca 10X/day).
Can have ~ 1000 discarded houses/m3
Contribute to “marine snow.”
Marine snow sinks relatively rapidly to the bottom and is food for deep sea benthos
~ 70 species

25
Q

Larvaceans have a

A

primitive “backbone” or notochord

26
Q

Salps

A

chordates
The large aggregates can be 15 m long

Aggregate stage has hermaphroditic (both sexes in one individual) salps which produce sperm & egg (at different times)
Fertilized eggs grow to be a solitary salp which then reproduces by budding until the large aggregate is formed
Have very rapid growth rates
Typically found in warm waters, not polar regions, but with global warming are invading polar areas

27
Q

what is the reproduction of salps like?

A

sexual and asexual reproduction

soliary stage (asexual) –> aggregated stage (sextual) —> aggregate with embryo –> embryo

28
Q

Pyrosomes

A

bioluminescent & are also tunicates, colonial filter feeders. Zooids are a few mm in size and embedded in a gelatinous tunic, tropical… the really big long tube things

29
Q

Phylum Cnidaria, name the classes?

A

Hydrozoa, Scyphozoa, Anthozoa

30
Q

Anthozoa

A

(sea anemone & stony corals)

31
Q

Scyphozoa

A

(large jellyfish)

32
Q

Hydrozoa

A

(small jellyfish, siphonophores & hydroids)

33
Q

Siphonophores

A

Siphonophores are colonial hydrozoan jellyfish that range from the surface to the deepest waters. The group is poorly known from conventional plankton net samples because the delicate colonies often are damaged beyond recognition during capture. Surface species often have small gas-filled floats and prey on zooplankton. They contain a complex of medusoid and polyploid members that function together as an organism. A primitive nervous system coordinates the individuals.

34
Q

Nematocysts

A

(stinging cells)

35
Q

Scyphomedusa

A

large jellies, have nematocysts,

36
Q

Ctenophores

A 
Do not move by pumping water
Use cilia to move 
Do not have nematocysts (stinging cells)
Very big predator on copepods
Can become very abundant
(NOT in the cnidarian phyulm)
37
Q

Phylum Mollusca

A 
Pteropods -- Planktonic molluscs
Foot is modified to be a wing like appendage
2-5 cm in size (1-2 in.)
Flap wings like a butterfly 
See prey with their eyes
38
Q

Pteropod

A

Pteropod (winged foot) is a term to cover two groups that aren’t closely related

Thecosomata are the shelled organisms called “sea butterflies”

Gymnosomata have no shell and they are called “sea angels”
The sea angels are predators on the sea butterflies and suck them right out of their shells

39
Q

sea gooseberries

A

Ctenophores

40
Q

Sea Butterflies

A

Mollusca (pteropod)

41
Q

Velella

A

cnidarian –> hydrozoan

42
Q

Nomura jellyfish

A

cnidarian –> scyphozan

43
Q

Platynereis dumerilii

A

Trochophore larvae vertically migrate.

Swim up to surface at
Night & down in day
Larvae produce 
melatonin only at night.
Melatonin causes the
neurons that control beating 
Hairs to stop beating, and the
Larvae sink at end of the 
daylight. Precursor to sleep?
44
Q

Oceanographic “Fronts”

A

areas where two water masses meet

Zooplankton typically have high populations in these frontal regions.

Recent research in the Red Sea (Genin et al. 2005, Science 308, 860) shows that zooplankton are able to aggregate into “patches” and hold their depth by swimming against these vertical currents.

45
Q

how are zooplankton distributed? (even if the environment is homogenous)

A

NOT homogeneously – patch or clumped

46
Q

what causes patchiness?

A 
Langmuir circulation cells
Fronts
Grazing by groups
 of predators
their food is patchy too 
ext
47
Q

Calanus pacificus

A

copepod–

Spends the winter deep as Stage V copepodite
In Jan-March it molts to adult stage and goes to surface where phytoplankton are blooming.
In summer eggs hatch
In autumn Stage V migrates down to spend winter where it is cool
Thus its life cycle is tuned to be able to be ready to feed as adults on the spring phytoplankton bloom

48
Q

Calanus (copepod) fecal pellets

A

Adult females of C. finmarchicus feeding on diatom cultures produce a fecal pellet every 5-7 minutes.
Size is ca 0.2-0.6 mm.
Pellets this size sink a few hundred m/day
Those from Euphausids sink 100-800m/d
Nutritional value can vary
Bacteria colonize pellets rapidly
At 22oC 16% of C lost by bacterial decomposition in 1 d, 67% in 2 d
At 5oC loss was only 10% in 14 d, so if a pellet makes it into deep water fast enough its energy will make it to the bottom for benthic organisms to feed on

49
Q

Microzooplankton-

A

Microzooplankton-

Ciliates-cilia
Flagellates- 1 to many flagella
Amoeba-pseudopodia (rhizopods)

50
Q

Mesodinium

A

“red tide”

From Cryptomonad pigments (are a group of algae, most of which have plastids))

Phycoerythrin (any of a group of red photosynthetic pigments )

51
Q

Amoeboid Forms (Phylum Sarcodina)

A

Amoebae-usually attached to surfaces but a few are planktonic. Can cause diseases in lobster & crabs

Testaceans- Amoeba lives in a shell or “test” Most are freshwater

Foraminifera -Have a multi chambered shell. Put out long (15 mm) streamers called rhizopods

Heliozoa-Freshwater “sun animalcules”

Radiolaria- siliceous spines

Acantharia- 20 strontium sulfate spicules

52
Q

Testaceans

A

Amoeba lives in a test or shell. Most are freshwater.

53
Q

Foraminifera

A

benthic & planktonic amoeboid species. There are different shell types. (Sarcodina)

Have a multi chambered shell. Put out long (15 mm) streamers called rhizopods

54
Q

more about foraminifera

A

Foram shell (test) can be gelatinous, chitinous, calcareous or siliceous-shape varies a lot.

Chambers connected by pores going from oldest to newest

Ca 40 planktonic & 4000 benthic species

Have photosynthetic symbionts in test

Rhizopodia used in feeding

Paleontology-Water temp. affects distribution of a species and shape of the test. Larger tests from colder waters. Studies on species in sediments give clues to past climates.

Planktonic Forams very abundant between 40N & 40S

55
Q

Radiolaria-

A

have a central membrane separating granular endoplasm from frothy ectoplasm

Skeleton is of silica.

siliceous spines

56
Q

Chaetognaths

A

(Arrow worms). Abundant carnivorous group. Most < 4 cm long

57
Q

Copepod feeding is complex and feeding currents are established…

A

by the maxillae

they make feeding currents with antenna, setae catch food particles, feeding limbs creat the vortices (circle movement) around the body

58
Q

Copepod feeding (explained in human context)

A

Feeding is like trying to eat while suspended in molasses. Pretend you are in molasses and you want to grab a donut suspended in front of you.
If you reach for food particle it is pushed away from you (a) and if you try to clasp it (b) it squirts away.
You can try a zig zag (c) back and forth to grab it. This can work.
Basically (d) put your elbows against your waist and fling your arms open to draw in the donut, then open your elbows and this will pull the donut closer & next close your arms in then close your elbows in again.

59
Q

Copepod feeding (explained in human context)

A

Feeding is like trying to eat while suspended in molasses. Pretend you are in molasses and you want to grab a donut suspended in front of you.
If you reach for food particle it is pushed away from you (a) and if you try to clasp it (b) it squirts away.
You can try a zig zag (c) back and forth to grab it. This can work.
Basically (d) put your elbows against your waist and fling your arms open to draw in the donut, then open your elbows and this will pull the donut closer & next close your arms in then close your elbows in again.

60
Q

what is the microbial loop?

A

Bacteria are then eaten by microzooplankton.

Some microzooplankton are eaten by larger zooplankton but most release more DOM which is taken up by bacteria forming a loop

Biological Oceanography & Limnology (5 decks)

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