Lecture9Zooplankton

Lecture9Zooplankton - Zooplankton The Heterotrophs...

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Unformatted text preview: Zooplankton: The Heterotrophs Zooplankton are the animals of the plankton Copepods Are carried passively by the ocean currents (by definition!) Cannot swim against currents Zooplankton can be.... herbivores - feed on phytoplankton carnivores - feed on other zooplankton omnivores - feed on both phytoplankton and zooplankton Sizes can range from micrometers to tens of meters (jellyfish) Usually grow very fast and growth is dependent on the food supply Arrowworm krill All of these are examples of zooplankton Pteropods Ctenophores Jellies (“Jellyfish”) More Zooplankton Groups Salps Shrimp Copepods Ciliates Larvae Images are NOT to scale!! http://www.livescience.com/php/multimedia/imagegallery/igviewer.php?p=10&gid=46 http://photography.nationalgeographic.com/photography/photogalleries?nav=TOPNAV http://jellieszone.com/gelatinousid.htm http://articles.uwphoto.no/oversikter/Marine_Sea_Squirts.htm http://www.exploretheabyss.com Sizes of Zooplankton Sizes Microzooplankton: 20-200 µm zooplankton: Mesozooplankton: ~200 to 2000 µm zooplankton: Macroplankton (big!) (text says larger than Macroplankton a cm) cm) A typical copepod is ~ 0.5 cm or less Copepods account for ~70% of all zooplankton biomass Plagiopyla frontata, a marine ciliated protozoan Ciliates Ciliates One of the most important groups One in the Kingdom Protista Kingdom Single-celled Common almost everywhere there Common is water – lakes, ponds, oceans, rivers, and soils rivers, The tintinnids Microzooplankton Important heterotrophic feeders on phytoplankton Dictyocysta mitra Ciliates continued Ciliates Name comes from presence of hair-like Name organelles called cilia, which are identical in cilia which structure to flagella, but shorter and present in flagella but much larger numbers with a different pattern of movement of Paramecium, the well-known ciliate http://www.liv.ac.uk/ciliate/intro.htm http://www.microscopy-uk.org.uk/mag/indexmag.html Importance of Zooplanktonic Ciliates Importance Important in the transfer of Important material through food webs – link between small phytoplankton and larger zooplankton larger 30 - 50 % of primary production 30 grazing by microzooplankton in temperate coastal waters is by ciliates Very diverse: different ciliate species may be autotrophic, mixotrophic, or primary and/or secondary consumers Foraminifera Foraminifera Single-celled, amoeba-like protists (Kingdom Protista) Single-celled, (Kingdom Produce CaCO3 “shell” called a test Planktonic and benthic forms Feed by cytoplasm streaming out of shell along spines, Feed collecting algae and bacteria, pulling back into test collecting Globigerinoides ruber Globigerinoides sacculifer Kingdom: Animalia Phylum: Arthropoda Subphylum: Crustacea Class: Maxillopoda The Copepods The Greatest biomass in the oceans (~70%) Greatest …some call them the insects of the sea insects At least one third of all species live as associates, At commensals, or parasites on invertebrates and fishes. Are particle feeders – mouth appendages produce a water current from anterior to posterior Importance in the food web: Importance Take in energy from phytoplankton and 'repackage' it for Take consumption by higher trophic level predators Produce fecal pellets – significant contributor to marine snow, Produce marine accelerates sinking of nutrients and minerals Most of the economically important fishes depend on copepods. Most http://www.uni-oldenburg.de/zoomorphology/Biologyintro.html Copepod Anatomy (Swimming legs) Pereopods Cephalothorax Pereon Telson Belong to Phylum Belong Arthropoda : Arthropoda Jointed appendages, exoskeleton, segmentation segmentation Note antennae, legs, feeding appendages (maxillipeds) (maxillipeds) Copepod Anatomy Mandibles & Maxillae Pereopods Krill Euphausia superba Keystone species in Antarctic ecosystems (krill graze diatoms, are then eaten by seabirds, squid, fish and whales) 500 to 750 million metric tons Crustacean - Phylum Arthropoda Krill swarm Water flea Other Crustaceans in the Zooplankton the Ostracod Amphipod Lobster larva Crab larva Shrimp larva “Jellies” Includes numerous diverse groups: jellyfish, pteropods, salps and ctenophores jellyfish, Most jelly images from http://www.jellieszone.com Zooplankton of the Phylum Cnidaria Phylum All Cnidarians have radial symmetry and nematocysts All radial nematocysts Scyphozoans – the true jellyfish – alternate between medusa and polyp stages medusa Hydrozoans – usually colonial cnidarians with either medusa Hydrozoans (hydromedusa) or polyp (hydroid) stage dominant, depending on species depending Scyphozoa – sea nettle swarm Hydromedusa Aequorea Not all Jellies are “Plankton”: Not Echizen – Nomura’s Giant Jellyfish Echizen Invasive species in Japan Invasive 6 feet diameter, 120 pounds pounds Form massive swarms Form Ctenophores or Comb jellies Comb Coeloplana Pleurobrachia Sea gooseberry Have 8 ciliated comb rows or Have ctenes ctenes Are NOT Cnidarians (Phylum Phylum Ctenophora?) Ctenophora Predatory, carnivorous, extend Predatory, tentacles to feed tentacles Hermaphroditic Ctenes (comb rows) Beroe eating Mnemiopsis Cestum – Venus’ girdle Beroe Cavolinia sp. Limacina inflata Clio pyramidata Pteropods – “Sea Butterflies” Phylum Mollusca Phylum Foot is modified into “wings” Foot Some have calcareous tests – aragonite, dissolve easily aragonite, Feed using mucus nets Feed Atlanta sp. Cuvierina sp. Larvaceans, Salps, and Tunicates Larvaceans, Members of the Phylum Chordata Members Phylum possess a notochord, dorsal nerve cord, possess and pharyngeal gill slits at some point gill Suspension feeders Most begin life in a mobile larval stage Most and remain pelagic (salps, larvaceans), others later develop into a barrel-like adult forms (tunicates), both pelagic & benthic benthic Important contributors to organic Important carbon, marine snow: gill slits secrete extensive mucus nets or webs extensive Salps Salps Salps are filter feeders, Salps continuously filtering water through a mucus net as it swims. swims. Pegea Salpa Chain forming salps – individual forms smaller chained whorls of offspring Cyclosalpa Larvaceans Larvaceans (sometimes called “Appendicularians”) Tunicates Thalia Oikopleura Doliolum Builds a new house every day! Dolioletta solitary stage Oikopleura in its mucus house Dolioletta “nurse” stage Phylum Chaetognatha Phylum Chaetognath Anatomy Every arrow worm develops both male and female sexual organs (hermaphroditic). The male organs develop first, but they seldom fertilize themselves although they carry sperm and eggs at the same time. Arrowworms (Chaetognaths) (Chaetognaths) Uncolored, transparent with black eye spots Sagitta is a common genus Found from the surface to a depth of several hundred meters Are fast swimmers and effective predators; can kill prey as big as themselves Eat krill, jellies, copepods, other arrowworms Puncture prey with bristles, some inject tetrodotoxin poison Meroplankton Meroplankton Meroplankton are marine organisms that spend some portion of their life as plankton (vs. holoplankton—whole life as plankton) Eggs, larvae, and juvenile stages of many marine species are planktonic Adults live as free swimmers (nekton) or bottom-dwellers (benthos) Advantages of meroplanktonic larvae: Transport over large distances - population is dispersed Allow for production of large numbers of offspring Abundant food source (phytoplankton) Safety in numbers Meroplankton are also an important food source for some organisms Many major animal groups have meroplankton larvae: Mollusks: snails, clams, oysters Echinoderms Crustaceans: barnacles, crabs Polychaete worms Fish Meroplankton, young and old young Brittle star Polychaete worm Chiton Barnacle Sea squirt Turban snail Octopus Gumboot chiton Plankton Samplers Plankton Hardy Continuous Plankton Recorder Plankton net with cod end Video Plankton Recorders Towed box moves water past a video camera, recording images either continually or at pre-determined times. Can be set to different resolutions to record a variety of planktonic organisms as small as some diatoms, Better for imaging larger zooplankton such as copepods and planktonic larvae VPRs can be towed by research vessels or commercial cargo ships that cross large areas of the ocean. For maximum effectiveness, they can be attached to trawls and other sampling instruments ...
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This note was uploaded on 02/22/2012 for the course MSCI 102 taught by Professor Benner during the Spring '10 term at South Carolina.

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