Zooplankton

Question 1

What are pelagic environments and list them in order from the surface to the bottom

Answer 1

Open ocean part of the water column. Neritic/Oceanic Province: Epipelagic (0-200m), Mesopelagic (200-1000m), Bathypelagic (1000-4000m), Abyssopelagic (>4000m)

Question 2

What are benthic environments and list them in order from the surface to the bottom?

Answer 2

The region at the lowest level of a water column (bottom). Supralitoral (shore), Subneritic (Littoral (High/low tide), Sublittoral (0-200m), Bathyal (200-4000m), Abyssal (4000-6000m), Hadal (>6000m)

Question 3

What are the characteristics of plankton? What are the types of plankton?

Answer 3

Floaters (drift with ocean currents)

Bacterioplankton (planktonic bacteria), Phytoplankton (planktonic microalgae), Zooplankton (protozoa and other animals)

Question 4

What are the size classifications of phytoplankton from large to small?

Answer 4

Megaplankton, Macroplankton, Mesoplankton, Microplankton, Nanoplankton, Picoplankton,Femtoplankto

Question 5

What are nekton?

Answer 5

Swimmers (move independently of ocean currents), some capable of long migrations, distribution controlled by S,T,D,P, food availability

Question 6

What are some examples of nekton?

Answer 6

Adult fish, squid, marine mammals

Question 7

What are benthos?

Answer 7

Bottom dwellers. Number and biomass decrease with depth

Question 8

What are the types of benthos?

Answer 8

Epifauna: seafloor surface (attached/moving)
Infauna: buried
Nektobenthos: on bottom but capable of swimming over seafloor

Question 9

What are zooplankton?

Answer 9

Planktonic animals that cannot swim against a current. May range from <1mm to >1m. Heterotrophic (Herbivore, carnivore, omnivore).

Question 10

What are the rolls of zooplankton in marine food webs?

Answer 10

Primary consumers of phytoplankton, primary link in energy transfer between the base of the food web and higher trophic levels.

Question 11

What are the 2 types of life cycles zooplankton can live?

Answer 11

Holoplankton (spend their whole life as plankton), Meroplankton (benthic and nektonic species with planktonic larval stages for days to months)

Question 12

Why do meroplankton exist?

Answer 12

Provide sessile species with a means of dispersal. Main reason marine populations are more connected than terrestrial populations.

Question 13

What are planktonic protozoans?

Answer 13

Single celled, eukaryotic organisms, usually solitary, taxonomically diverse group, key components of microbial loop, feed on bacteria, detritus, small phytoplankton, important prey source for larger zooplankton

Question 14

What are the most important groups of planktonic protozoans?

Answer 14

Ciliates, foraminiferans, radiolarians

Question 15

What are the characteristics of ciliates?

Answer 15

Some of the largest free-living protists, cell surface covered with cilia to propel organism through water/draw in food particles

Question 16

What are the characteristics of foraminifera?

Answer 16

Encased in CaCO3 test, common in colder waters. Form sediment layers in the deep sea. Used in dating of marine sediments/determine ancient oceanic conditions

Question 17

What are the characteristics of radiolaria?

Answer 17

Surrounded by SiO2, common in tropical, subtropical waters. Use pseudopodia to capture bacteria, phytoplankton and detritus. Form sediment layers in the deep sea

Question 18

What are the different groups of jellies?

Answer 18

Cnidarians (true jellyfish), Ctenophores (comb jellies), Salphs, Appendicularians

Question 19

What are the characteristics of cnidarians?

Answer 19

Specialized cells known as nematocysts, barbed stinging cells to subdue their prey

Question 20

What are the characteristics of ctenophores?

Answer 20

Tentacles have sticky cells (colloblasts), feed on zooplankton or ctenophores

Question 21

What are the characteristics of salphs?

Answer 21

May be asexual or sexual (aggregate generation), cilindrical, gelatinous body with openings at each end, muscular pumping for locomotion and feeding, catch food particles by internal net of mucus, can form large swarms, unusual life cycle

Question 22

What are the characteristics of appendicularians?

Answer 22

Look like small tadpoles? Secrete mucous house that pumps water and sieves food particles. Gets new house if old is clogged, which become food source for other zooplankton and substrate for bacteria and protozoans

Question 23

What are the characteristics of chaetognaths (arrow worms)?

Answer 23

Small phylum, elongated body, transparent, carnivorous raptorial feeders, significant diel vertical migrations, hermaphroditic (both sexual organs)

Question 24

What are the characteristics of molluscs?

Answer 24

Most benthic, all have veliger larvae with hrs/months in plankton stage. Most are pteropods (small planktonic snails, temperate/cold waters, foot=wings for swimming), also thecosomes (thin, coiled calcareous shell, secretes sticky mucus web), gymnosomes (naked, elongate, feed on thecosomes)

Question 25

What are the characteristics of arthropods?

Answer 25

Most diverse eukaryotes, segmentation, paired, jointed appendages, hard, external exoskeleton, most important are crustaceans, benthic forms usually have meroplanktonic larvae (nauplius)

Question 26

What are the main groups of arthropods?

Answer 26

Euphausiids, amphipods, copepoda

Question 27

What are the characteristics of euphausiids?

Answer 27

Largest zooplankton (1-10cm), shrimp-like appearance, stalked eyes, omnivorous (filter phytoplankton and smaller zooplankton), multi-year life-cycles, some harvested commercially, most have diel vertical migrations each night, major food source for many fish and baleen whales.

Question 28

What is diel vertical migration?

Answer 28

When zooplankton feed at the surface during the night, descent at dawn, reside near the bottom by day, and ascents at dusk

Question 29

What are the characteristics of amphipods?

Answer 29

Laterally compressed, usually carnivorous, live commensally with large jellyfish, direct development (no nauplius)

Question 30

What are the characteristics of copepods?

Answer 30

Most abundant zooplankton. Main grazers of phytoplankton (esp. diatoms), may be carnivorous/omnivorous, migrate vertically, 100um-10mm, major prey of young fish and key link from plankton to higher tropic levels in most marine food webs

Question 31

What is the life cycle of a copepod?

Answer 31

Winter: Adult’s reproduce to form nauplii at depth (400-700m)
Spring-early summer: nauplii grow closer to the surface (0-50m)
Late summer to autumn: Migrate back to depth (400-700m) as they reach adult stage. Diapause.