1. Plankton

2. Marine life 3 categories: 1.Benthos: bottom dwellers; sponges, crabs 2.Nekton: strong swimmers- whales, fish, squid 3.Plankton: animal/plants that drift in water. The have little control over their movement. Includes: diatoms, dinoflagellates, larvae, jellyfish, bacteria.

3. What physical factors are plankton subject to? 1.Waves 2.Tides 3.Currents

4. Plankton classified by: Size Habitat Taxonomy

5. Size: Picoplankton (.2-2 µm) bacterioplankton Nanoplankton (2 - 20 µm) protozoans Microplankton (20-200 µm) diatoms, eggs, larvae Macroplankton (200-2,000 µm) some eggs, juvenile fish Megaplankton (> 2,000 µm) includes jellyfish, ctenophores, Mola mola

6. Holoplankton- spends entire lifecycle as plankton Ex. Jellyfish, diatoms, copepods Meroplankton- spend part of lifecycle as plankton Ex. fish and crab larvae, eggs Habitat: snail lobster fish

7. Life cycle of a squid Squid experience benthic, planktonic, and nektonic stages Squid are considered meroplankton (opposite = holoplankton)

8. Taxonomy Zooplankton Phytoplankton

9. Importance of Phytoplankton Phytoplankton population decline causes zooplankton and apex predators to decline. Phytoplankton is the base of the food chain.

10. Phytoplankton- restricted to the euphotic zone where light is available for photosynthesis. Blooms: High nutrients Upwelling Seasonal conditions

11. Diatoms: temperate and polar waters, silica case or shell Dinoflagellates: tropical and subtropical waters.... also summer in temperate Coccolithophores: tropical, calcium carbonate shells or "tests" Silicoflagellates: silica internal skeleton... found world wide, particularly in Antarctic Cyanobacteria (blue-green algae): not true algae, often in brackish nearshore waters and warm water gyres Green Algae: not common except in lagoons and estuaries Some important types of phytoplankton

12. Crustaceans: Copepods Krill Cladocera Mysids Ostracods Jellies Cniderian (True jellies, Man-of-wars, By-the-wind-sailors) Ctenophores (comb jellies) Urochordates (salps and larvacea) Worms (Arrow worms, polychaetes) Pteropods (planktonic snails) Some important types of zooplankton

13. Marine Snow Base of Florida Escarpment covered with marine snow. Octocorals attach to steep sides and under ledges to avoid burial. A major component of marine snow is fecal pellets

14. Nutritional modes of zooplankton: Herbivores: feed primarily on phytoplankton Carnivores: feed primarily on other zooplankton (animals) Detrivores: feed primarily on dead organic matter (detritus) Omnivores: feed on mixed diet of plants and animals and detritus

15. Diurnal vertical migration Organisms within the deep scattering layer undertake a daily migration to hide in deep, darker waters during daytime

16. 1.Nocturnal Migration single daily ascent near sunset 2.Twilight migration (crepuscular period) two ascents and two descents 3.Reverse migration rise during day and descend at night Diurnal Vertical Migration Each species has its own preferred day and night depth range, which may vary with lifecycle.

17. Advantages for Diurnal vertical migration 1.An antipredator strategy; less visual to predators Zooplankton migrate to the surface at night and below during the day to the mesopelagic zone. Copepods avoid euphasiids which avoid chaetognaths.

18. Energy conservation Encounter new feeding areas Get genetic mixing of populations Hastens transfer of organic material produced in the euphotic zone to the deep sea Advantages for DVM

19. Plankton Patchiness Zooplankton not distributed uniformly or randomly Aggregated into patches of variable size Difficult to detect with plankton nets - Nets “average” the catch over the length of the tow May explain enormous variability in catches from net tows at close distances apart

20. Causes of Patchiness Aggregations around phytoplankton - If phytoplankton occurs in patches, grazers will be drawn to food - Similar process that led to phytoplankton patches will form zooplankton patches Grazing “holes” Physical process - Langmuir Cells - Internal waves