Plankton

http://www.dnr.sc.gov/marine/sertc/gallery.htm http://www.coralreeffish.com/larvae.htm

Vertical divisions: Pelagic = open

water Benthic = ocean bottom

Horizontal divisions: Coastal (neritic) = on/over shelf (shallow) Oceanic = beyond continental shelf (deep)

Ocean Zones

Ocean ZonesHoloplanktonMeroplankton

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

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

Slow, but not necessarily small

http://www.dnr.sc.gov/marine/sertc/gallery.htm

Portuguese man-of-warfloat = 12 inches widetentacles = over 150 ft. long (ouch!)

Net Plankton

Phytoplankton

Cyanobacteria Unicellular microalgae

Diatoms Dinoflagellates Coccolithophorids

http://www.daviddarling.info/images/diatoms.jpg http://www.microscopy-uk.org.uk/micropolitan/fresh/protozoa/ceratiumdic2.jpg

c2004 Pearson Education, Inc., publishing as Benjamin Cummings

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

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

Gelatinous: Jellyfish (medusa) Siphonophores

http://life.bio.sunysb.edu/marinebio/plankton.html

NOAA

Zooplankton - Holoplankton

Gelatinous: Comb jellies (ctenophores)

Zooplankton - Holoplankton

Gelatinous: Salps Larvaceans (invertebrate chordates)

NOAA

Zooplankton - Holoplankton

Molluscs: Pteropods (gastropods),with and without shell

Zooplankton - Holoplankton

Crustaceans: Copepods Amphipods Ostracods Isopods Krill, shrimp

http://www.oceanexplorer.noaa.gov/gallery/livingocean/livingocean.html

Zooplankton - Holoplankton

“Arrow worms” (Phylum Chaetognatha)

http://pharyngula.org/images/chaetognathhead.jpg http://www.microscopy-uk.org.uk/mag/imgjan00/CHAET2b.JPG

Zooplankton - Holoplankton

Mollusc larvae: Trochophore Veliger

http://people.bu.edu/veliger/http://oceanlink.island.net/abaloneproject/growthanddevelopment/growth%20and%20development.htm

Zooplankton - Meroplankton

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

Other larvae: Starfish (bipinnaria) Brittle stars, urchins (pluteus)

http://raven.zoology.washington.edu/embryos/

NOAA

Zooplankton - Meroplankton

More larvae: Polychaete worms (trochophore)

http://www.microscopy-uk.org.uk/mag/imgmar99/poly3.jpg

Zooplankton - Meroplankton

Fish larvae

http://www.coralreeffish.com/larvae.htm

Zooplankton - Meroplankton

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

That Sinking Feeling Why am I sinking? Denser than water

Densities (in g/cm3): 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

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

That Sinking Feeling How not to sink:

Stay neutral High water content (gelatinous) Reduced or no shell

NOAA

That Sinking Feeling How not to sink:

Drag (high surface area) – Small size Flat shape Spines, long structures

--------Isopod

That Sinking Feeling How not to sink:

Upwelling (also good for nutrients)

Southern Hemisphere – Ekman transport to the left

That Sinking Feeling How not to sink:

Actively swim – cilia, flagella, muscles, appendages

http://www.coralreeffish.com/larvae.htm

Nowhere to Hide Active predators can’t eat what they can’t see – so be invisible

Nowhere to Hide Active predators can’t eat what they can’t see – so hide where it is dark

Somewhere to Hide Floating mats of macroalgae and seagrasses form pelagic communities - camouflage

http://www.bigelow.org/bacteria/teach/images/open_orgs/sargassum.jpg http://www.naturalsciences.org/education/deepsea/images/sargassum_fish.jpg

NOAA

Sargassum

Food Webs

Food Webs