Planktonic Consumers OCN 201 Biology Lecture 5 Grieg Steward

Jean Marie Cavanihac http://forum.mikroscopia.com/index.php?showtopic=2503&mode=linearplus Consumer Types • Grazers Eat vegetation but typically do not kill it (Herbivore) • Predators Kill their prey (Herbivore or Carnivore, or Omnivore) • Parasites Intimate, prolonged interaction between two organisms where one feeds on the other without killing it • Scavengers Consume things already dead • Decomposers Final degraders of organic compounds Large Grazers Examples Manatee grazing on sea grass urchin eating kelp

http://www.ejfoundation.org/modules/PagEd/medipics/manatee-feeding-on-seagrass.jpg

Other examples from video: crabs and marine iguana feeding on macroalgae Small but Abundant Pelagic Predators

• Find large grazers nearshore where seagrasses and kelp grow, but… • Most primary production in the sea is by microscopic single-cell organisms • Therefore, most primary consumers in the ocean are also microscopic! Phytoplankton Predators

salps

copepods Diatoms & Dinoflagellates Predators Flagellates and Ciliates

Most abundant predators! Flagellates & Coccolithophores

Cyanobacteria & Picoeukaryotes Protistan Predators (protozooplankton) • Flagellates (1-10 µm) • Ciliates (100 µm) • Amoeboid • Radiolaria (0.5 mm) silica skeleton • Foraminifera (1 mm) calcium carbonate shell Protozoa

• No Mouth - Ingest particles mostly by phagocytosis. What do they eat? -bacteria -phytoplankton

• Digest particles in food vacuole inside the cell (in some cases, outside the cell)

Phagocytosis Heterotrophic Ciliates Flagellates

1 µm

1 µm

Pseudobobo tremulans

Monosiga sp. Amoeboid Protists

Radiolarians Silica skeleton Foraminifera Calcium carbonate shells Globigerinella

Bernd Walz

http://www.microscopyu.com/staticgallery/smallworld/2008/id2008-walz.html

Robert Brons Planktonic Animal Herbivores

• Crustaceans ✦ Copepods http://fishweb.ifas.ufl.edu/planktonweb/Cyclops.jpg ✦ Euphausiids (Krill)

Steven Haddock • Tunicates ✦ salps ✦ larvaceans ✦ pyrosomes

Laurence Madin Tunicates: Salps

• Gelatinous • Pelagic • Often colonial • Major consumers of phytoplankton Tunicates: Larvaceans

• Small larva-like • Secretes a mucus mesh “house” • Uses tail to create feeding current • Catches food on filter Tunicates: Pyrosomes

Colonial pelagic John P. Hoover http://www.hawaiisfishes.com/inverts/tunicates/neattunicates.htm tunciates

Filter feeders known for their brilliant bioluminescence Parasites Leeches (Segmented Worms) just a couple of examples

Arthropods (isopod) J. L. Justine et al. 2012, Aquat. Biosyt. 8: 22

Photo by Ronald Englund ©HBS Scavengers Some fish, sharks, molluscs, crustaceans, etc.

Illustration by Michael Rothman Decomposers

Bacteria Fungi

Osmotrophic: not phagotrophic – Cannot ingest particles or cells Osmotrophs

Material is digested outside the cell by enzymes and small molecules are transported through protein channels in the membrane

Flagellum Zoom in on membrane Bacterial Cell Autotrophs (primary producers) Heterotrophs (consumers) Phytoplankton Predators

Diatoms & Dinoflagellates Predators Symbiont Flagellates and Ciliates parasitic worms & Dissolved Organics isopods Mixotrophs & Detritus

Flagellates & Coccolithophores

Decomposers Bacteria and Fungi

Scavengers hagfish Cyanobacteria & Picoeukaryotes amphipod