千奇百怪的浮游生物

1、Zooplankton,.uk,Planktos: “drifts” in greek,Their distribution depends on currents and gyres Certain zooplankton can swim well, but distribution controlled by current patterns Zooplankton: all heterotrophic plankton except bacteria and viruses; size range from 2 m (heterot

2、rophic flagellates, protists) up to several meters (jellyfish),Herbivorous zooplankton: Grazers,Nutritional modes in zooplankton,Herbivores: feed primarily on phytoplankton Carnivores: feed primarily on other zooplankton (animals) Detrivores: feed primarily on dead organic matter (detritus) Omnivore

3、s: feed on mixed diet of plants and animals and detritus,Feeding modes in Zooplankton,Filter feeders Predators catch individual particles,Filter Feeder,Copepod,Filter Feeder,Ctenophore,Predator,Chaetognath Arrow Worm,Life cycles in Zooplankton,Holoplankton: spend entire life in the water column (pel

4、agic) Meroplankton: spend only part of their life in the pelagic environment, mostly larval forms of invertebrates and fish Ichthyoplankton: fish eggs and fish larvae,Holoplankton,Copepods Planktonic crustaceans,Barnacles: benthic sessile crustacean,/labs/pinedalab/,Meroplankto

5、n,Nauplius larva,.uk,Meroplankton,.uk,Cypris larva,/labs/pinedalab/,Cypris larva and metamorphosed juveniles,/labs/pinedalab/,Barnacle population regulation,/labs/pinedalab/,Gadida

6、e Gadus morhua,Ichthyoplankton,Gadidae Gadus morhua,Ichthyoplankton,Gadidae Gadus morhua,Ichthyoplankton,Gadidae Atlantic cod Gadus morhua,Demersal Adult,Protists: Protozooplankton,Dinoflagellates: heterotrophic relatives to the phototrophic Dinophyceae; naked and thecate forms. Noctiluca miliaris u

7、p to 1 mm or bigger, bioluminescence, prey on fish egg most abundant 40N 40S,Dinoflagellates Noctiluca miliaris,/pubs/1999/nsf98106/98106htm/ht-015.gif,Colonial choanoflagellates Bacteriofages (Ross Sea),Foraminifera (calcareous all latitudes),Radiolaria: spherical, amoeboid cells w

8、ith silica capsule; 50 m to several mm; contribute to silica ooze sediments, feed on bacteria, small phyto- and zooplankton; cold water and deep-sea Ciliates: feed on bacteria, phytoplankton, HNF; naked forms more abundant but hard to study (delicate!); tintinnids: sub-group of ciliates with vase-li

9、ke external shell made of protein; herbivores,Protists: Protozooplankton,Figure 3.21b,Radiolarians (siliceous low latitudes),http:/www.jochemnet.de/fiu/,/public/life/199/radiolaria.jpg,Live Radiolarian,Cnidaria: primitive group of metazoans; some holoplanktonic, others have ben

10、this stages; carnivorous (crustaceans, fish); long tentacles carry nematocysts used to inject venoms into prey; box jellyfish of Australia kills humans within minutes Medusae: single organisms, few mm to several meters Siphonophores: colonies of animals with specialization: feeding polyps, reproduct

11、ive polyps, swimming polyps; Physalia physalis (Portuguese man-of-war), common in tropical waters, Gulf of Mexico, drifted by the wind and belong to the pleuston (live on top of water surface),Invertebrate Holoplankton,Cnidaria (medusae),Cnidaria (medusae),Cnidaria (siphonophora),Ctenophores: separa

12、te phylum, do not belong to Cnidaria; transparent organisms, swimm with fused cilia; no nematocysts; prey on zooplankton, fish eggs, sometimes small fish; important to fisheries due to grazing on fish eggs and competition for fish food Chaetognaths: arrow worms, carnivorous, 4 cm Polychaets: Tomopte

13、ris spp. only important planktonic genus,Invertebrate Holoplankton,Ctenophora (comb jellies),Ctenophora (comb jellies),Invertebrate Holoplankton,Mollusca: Heteropods: small group of pelagic relatives of snails, snail foot developed into a single “fin”; good eyes, visual predators Pteropods: snail fo

14、ot developed into paired “wings”; suspension feeder produce large mucous nets to capture prey; carbonate shells produce pteropod ooze on sea floor,Heteropod (Predates on Ctenophores),Pteropod,/expeditions/,Protochordate Holoplankton,Appendicularia: group of Chordata, live in gelat

15、inous balloons (house) that are periodically abandoned; empty houses provide valuable carbon source for bacteria and help to form marine snow; filter feeders of nanoplankton Salps or Tunicates: group of Chordata, mostly warm water; typically barrel-form, filter feeders; occur in swarms, which can wi

16、pe the water clean of nanoplankton; large fecal bands, transport of nano- and picoplankton to deep-sea; single or colonies,Appendicularia,Pelagic Salps,Arthropoda: crustacean zooplankton,Cladocera (water fleas): six marine species (Podon spp., Evadne spp.), one brackish water species in the Baltic S

17、ea; fast reproduction by parthenogenesis (without males and egg fertilization) and pedogenesis (young embryos initiate parthenogenetic reproduction before hatching) Amphipoda: less abundant in pelagic environment, common genus Themisto; frequently found on siphonophores, medusae, ctenophores, salps

18、Euphausiida: krill; 15-100 mm, pronounced vertical migration; not plankton sensu strictu; visual predators, fast swimmers, often undersampled because they escape plankton nets; important as prey for commercial fish (herring, mackerel, salmon, tuna) and whales (Antarctica),Amphipoda,Amphipoda (parasi

19、tes of gelatinous plankton),Euphasids (krill),Arthropoda: crustacean zooplankton,Copepoda: most abundant zooplankton in the oceans, “insects of the sea“; herbivorous, carnivorous and omnivorous species Calanoida: most of marine planktonic species Cyclopoida: most of freshwater planktonic species Har

20、pacticoida: mostly benthic/near-bottom species Copepod development: first six larval stages = nauplius (pl. nauplii), followed by six copepodit stages (CI to CVI) Tropical species distinct by their long antennae and setae on antennae and legs (podi),Copepods,http:/www.jochemnet.de/fiu/,Mollusca: cla

21、ms and snails produce shelled veliger larvae; ciliated velum serves for locomotion and food collection Cirripedia: barnacles produce nauplii, which turn to cypris Echinodermata: sea urchins, starfish and sea cucumber produce pluteus larvae of different shapes, which turn into brachiolaria larvae (st

22、arfish); metamorphosis to adult is very complex Polychaeta: brittle worms and other worms produce trochophora larvae, mostly barrel- shaped with several bands of cilia,Common Meroplankton,Decapoda: shrimps and crabs produce zoa larvae; they turn into megalopa larvae in crabs before settling to the s

23、ea floor Pisces: fish eggs and larvae referred to as ichthyoplankton; fish larvae retain part of the egg yolk in a sack below their body until mouth and stomach are fully developed,Common Meroplankton,Meroplankton,Meroplanktonic Larvae,Planktotrophic Feeding larvae Longer Planktonic Duration Times H

24、igh dispersal potential Lecithotrophic (non-feeding) Non-feeding larvae Shorter planktonic Duration Times Low dispersal potential,/wgbh/nova/sharks/island/images/veliger.jpeg,Molluscs: Meroplankonic Veliger larvae PLANKTOTROPHIC,Vertical Distribution,Epipelagic: upper 200-300 m wate

25、r column; high diversity, mostly small and transparent organisms; many herbivores Mesopelagic = 300 1000 m; larger than epipelagic relatives; large forms of gelatinous zooplankton (jellyfish, appendicularians) due to lack of wave action; some larger species (krill) partly herbivorous with nightly migration into epipelagic regimes Oxygen Minimum Zone: 400 800 m depth, accumulation of fecal material due to density gradient, attract high bacterial growth, which in turn attracts many bacterial and larger graze