1. Marine Classification Notes

2. Overview ›250,000 identified marine species
Most live in sunlit surface seawater
Species success depends on ability to:
Find food
Avoid predation
Reproduce
Cope w/ physical barriers to movement

3. Classification by Habitat & Mobility
Plankton - Aquatic organisms w/ limited or
no swimming ability. Transported by currents & tides. “planktos” means “drifting.”
Nekton - Aquatic organisms that can swim
through the water against the currents. Most are vertebrates. Ex. Sharks, squid, etc…
Benthic - Aquatic organisms that dwell on
the bottom of the ocean or are permanently attached to something.
Ex. Mussels, clams, snails

5. Plankton Most biomass on Earth consists of plankton Phytoplankton
Microscopic plants & bacteria. “Fix” carbon through photosynthesis, making it available for higher trophic levels.

6. Zooplankton
Microscopic animal plankton. Heterotrophic. Can indicate future fisheries’ health b/c they are a food source for organisms at higher trophic levels, such as finfish.

8. Sea Foam in Saint-Guenole, France

9. Plankton Holoplankton Entire lives as plankton. Meroplankton
Part of it’s life as plankton; egg or larval stage of an animal that will become benthic or nektonic.
Macroplankton
Larger animal plankton from 2cm – 20cm in size. Ex – jellyfish or Sargassum

10. Nekton Independent swimmers Most adult fish & squid Marine mammals
Marine reptiles
Fig. 12.3

11. Benthos Epifaunal live on surface of sea floor.
Infaunal live buried in sediments.
Nektobenthos swim or crawl through
water above seafloor
Most abundant in shallower water.