Marine Classification Notes

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

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

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

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.

Sea Foam in Saint-Guenole, France

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

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

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.