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Plankton http://www.dnr.sc.gov/marine/sertc/gallery.htm http://www.coralreeffish.com/larvae.htm
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Vertical divisions: Pelagic = open water Benthic = ocean bottom Horizontal divisions: Coastal (neritic) = on/over shelf (shallow) Oceanic = beyond continental shelf (deep) Ocean Zones
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Holoplankton Meroplankton
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Plankton or Nekton? How fast can you swim? Gulf Stream peak velocity = 5 knots = 2.5 m/sec Surface currents more typically <0.5 knot = 0.25 m/sec (=0.56 mph) http://oceancurrents.rsmas.miami.edu/atlantic/img_mgsva/gulf-stream-YYY.gif
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Plankton or Nekton? Swim faster than 25 cm/sec? Yes → Nekton: Dolphin = 170 cm/sec (up to 40 mph!) Tuna = 75 cm/sec (higher burst speeds) No → Plankton: Shrimp = 5 cm/sec Bacteria = 0.005 cm/sec
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Slow, but not necessarily small http://www.dnr.sc.gov/marine/sertc/gallery.htm Portuguese man-of-war float = 12 inches wide tentacles = over 150 ft. long (ouch!)
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Net Plankton
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Phytoplankton Cyanobacteria Unicellular microalgae Diatoms Dinoflagellates Coccolithophorids http://www.daviddarling.info/images/diatoms.jpghttp://www.microscopy-uk.org.uk/micropolitan/fresh/protozoa/ceratiumdic2.jpg c2004 Pearson Education, Inc., publishing as Benjamin Cummings
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Zooplankton Divided by life history: Holoplankton – spend whole life (larval and adult stages) living as plankton Meroplankton – spend only larval stage living as plankton, then grow up to be nekton or benthic as adults
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Zooplankton - Holoplankton Protozoans (unicellular): Foraminiferans Radiolarians Ciliates http://server1.fandm.edu/Departments/Biology/People/Shimeta/research/tin2.JPGhttp://www.anu.edu.au/EMU/Images/radiol.jpg
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Gelatinous: Jellyfish (medusa) Siphonophores http://life.bio.sunysb.edu/marinebio/plankton.html NOAA Zooplankton - Holoplankton
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Gelatinous: Comb jellies (ctenophores) Zooplankton - Holoplankton
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Gelatinous: Salps Larvaceans (invertebrate chordates) NOAA Zooplankton - Holoplankton
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Molluscs: Pteropods (gastropods), with and without shell Zooplankton - Holoplankton
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Crustaceans: Copepods Amphipods Ostracods Isopods Krill, shrimp http://www.oceanexplorer.noaa.gov/gallery/livingocean/livingocean.html Zooplankton - Holoplankton
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“Arrow worms” (Phylum Chaetognatha) http://pharyngula.org/images/chaetognathhead.jpghttp://www.microscopy-uk.org.uk/mag/imgjan00/CHAET2b.JPG Zooplankton - Holoplankton
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Mollusc larvae: Trochophore Veliger http://people.bu.edu/veliger/http://oceanlink.island.net/abaloneproject/growthanddevelopment/growth%20and%20development.htm Zooplankton - Meroplankton
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Crustacean larvae: Crab zoea Shrimp, barnacle nauplius Lobster phyllosoma http://www.dnr.sc.gov/marine/sertc/gallery.htm http://www.science-in-salamanca.tas.csiro.au/themes/larval/phyllosoma-early.htm NOAA Zooplankton - Meroplankton
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Other larvae: Starfish (bipinnaria) Brittle stars, urchins (pluteus) http://raven.zoology.washington.edu/embryos/ NOAA Zooplankton - Meroplankton
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More larvae: Polychaete worms (trochophore) http://www.microscopy-uk.org.uk/mag/imgmar99/poly3.jpg Zooplankton - Meroplankton
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Fish larvae http://www.coralreeffish.com/larvae.htm Zooplankton - Meroplankton
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That Sinking Feeling It’s a long way down – average ocean depth around 4000 m Phytoplankton – need to stay in the light surface layer (0-200 m) Zooplankton – eat the phytoplankton and/or other zooplankton, so need to be where the food is http://www.nerc.ac.uk/images/photos/lp-ocean-sunlight.jpg
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That Sinking Feeling Why am I sinking? Denser than water Densities (in g/cm 3 ): Seawater = 1.025 Air = 0.00125 Lipids = 0.9 Proteins = 1.3 Carbohydrates = 1.5 Cellulose = 1.5 Silica shell = 2.6 Calcareous shell = 2.8
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That Sinking Feeling How not to sink: Float – Lipids (less dense than water) Gas vacuoles, sacs, bubbles http://www-cyanosite.bio.purdue.edu/images/images.html
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That Sinking Feeling How not to sink: Stay neutral High water content (gelatinous) Reduced or no shell NOAA
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That Sinking Feeling How not to sink: Drag (high surface area) – Small size Flat shape Spines, long structures -------- Isopod
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That Sinking Feeling How not to sink: Upwelling (also good for nutrients) Southern Hemisphere – Ekman transport to the left
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That Sinking Feeling How not to sink: Actively swim – cilia, flagella, muscles, appendages http://www.coralreeffish.com/larvae.htm
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Nowhere to Hide Active predators can’t eat what they can’t see – so be invisible
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Nowhere to Hide Active predators can’t eat what they can’t see – so hide where it is dark
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Somewhere to Hide Floating mats of macroalgae and seagrasses form pelagic communities - camouflage http://www.bigelow.org/bacteria/teach/images/open_orgs/sargassum.jpghttp://www.naturalsciences.org/education/deepsea/images/sargassum_fish.jpg NOAA Sargassum
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Food Webs
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