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03a ZOOPLANKTON. I. Taxa common in zooplankton A.Crustaceans 1.Characteristics a.Two pairs of antennae b.Mandibles c.Member of Phylum Arthropoda (1)Paired,

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Presentation on theme: "03a ZOOPLANKTON. I. Taxa common in zooplankton A.Crustaceans 1.Characteristics a.Two pairs of antennae b.Mandibles c.Member of Phylum Arthropoda (1)Paired,"— Presentation transcript:

1 03a ZOOPLANKTON

2 I. Taxa common in zooplankton A.Crustaceans 1.Characteristics a.Two pairs of antennae b.Mandibles c.Member of Phylum Arthropoda (1)Paired, jointed appendages (2)Exoskeleton of chitin (3)Grow by molting

3 of chitin Jointed appendages

4 A.Crustaceans (continued) 2.Common examples a.Copepods (1)Most common zooplanktoner (2)Long antennae

5 Copepod with characteristic long antennae Purvis et al., 2001, Fig a

6 a.Copepods (continued) (3)Swim w/ characteristic jerky movements (4)Reynolds number  1 (5)Females often with 1 or 2 egg masses (6)Two major types in plankton (a)Cyclopoid

7 Cyclopoid copepod carrying two external egg masses Cyclops strenuus Purvis et al., 2001, Fig

8 (6)Two types of copepods (continued) (b)Calanoid

9 Group of Calanoid copepods (Calanus sp.) Purvis et al., 2001, Fig

10 a.Copepods (continued) (7)Acartia common in Mobile Bay

11 2.Examples of planktonic crustaceans (continued) b.Krill (1)Shrimp-like crustaceans that dominate plankton in Antarctic Ocean (2)Gills extend out of carapace (3)Major food source for baleen whales (4)Euphausia superba

12 Krill (Euphausia pacifica) Purvis et al., 2001, Fig gills

13 2.Examples of planktonic crustaceans (continued) c.Larvae (1)Naupliar larvae (= nauplius) (a)Shape iOval ii3 pairs of appendages iiiOne compound eye (b)1st stage larvae for... iCopepods iiShrimp iiiBarnacles

14 Naupliar Larva Purvis et al., 2001, Fig b

15 Sheldon Plankton Operator, Chum Bucket Restaurant in Bikini Bottoms

16 Pelagic “goose” or stalked barnacles Settle on flotsam and drift with plankton Fouling problem for ships, buoys and oil rigs. Lepas anatifera Purvis et al., 2001, Fig

17 Lepas pectinata Appendages used to grab prey from plankton Purvis et al., 2001, Fig d

18 c.Crustacean larvae (continued) (2)Crabs (a)Zoea (b)Megalopa

19 Crab Larvae Castro & Huber, 2003, p. 140

20 B.Examples of Meroplankton larvae 1.Annelids (= segmented worms) a.Polychaetes b.Initially a TROCHOPHORE larva (1)Ciliary band anterior to mouth (2)Apical tuft of cilia c.Segments added as larva grows and it begins to resemble a worm

21 TROCHOPHORE larva Found in Annelids and Mollusks Castro & Huber 2003, p. 332

22 B.Meroplankton examples (continued) 2.Mollusks a.Initially a trochophore larva b.Becomes a VELIGER larva (1)Two large ciliated lobes (2)May develop a foot, shell, & resemble an adult

23 VELIGER larval stage of mollusks Castro & Huber 2003, p. 332

24 B.Meroplankton examples (continued) 3.Echinoderms (= sea stars, sea urchins) a.PLUTEUS larva b.Numerous long arms

25 Pluteus larva Bipinnaria larva Echinoderm larval stages Castro & Huber 2003, p. 332

26 C.Gelatinous zooplankton 1.What are the selective advantages of being gelatinous? a.Evolved many times b.Building material (protein & long sugar = polysaccharides molecules) is physiologically “cheap” c.Grow or shrink in size quickly

27 1.Selective advantages of being gelatinous (continued) d.Reproduce quickly e.Easy to manipulate buoyancy f.Transparency provides protection against visual predators

28 Aurelia aurita or moon jelly seen from below Nat. Geog., 2000, 197(6): 95

29 Aurelia & floating glacier ice seen from deck of ship in College Fjord, Alaska Photo by J. O ’ Brien, June, 2014

30 C.Gelatinous zooplankton (continued) 2.Cnidaria a.Jellyfish (= Scyphozoa) (1)MEDUSA stage (= “bell”)

31 The Medusa's head central to a mosaic floor in a tepidarium of the Roman era. Museum of Sousse, Tunisia

32 Photo by J. O’Brien, 2012 Chrysoara “Sea Nettle” at the Monterey Bay Aquarium, CA

33 Photo by J. O’Brien, 2012 Aggregation of Sea Nettles on Display at the Monterey Bay Aquarium, CA

34 a.Jellyfish (= Cnidaria, Scyphozoa) continued (2)The sea nettle Chrysaora (a)Outbreaks (= blooms) occur in summer when salinities get between ‰ & temperatures 26-30°C

35 Salinity and sea-surface temperatures encompassing 95% of the sea nettle blooms in Chesapeake Bay

36 (2)The sea nettle, Chrysaora (continued) (b)Tentacles break off medusae, drift in water, difficult to see, still retain active nematocysts (c)Become painful nuisance to swimmers, but not life-threatening (field biologists will often wear wet suits when working in relatively warm water to protect themselves from sea nettles)

37 Welt from a sea nettle encounter on a marine biology field trip Photo; Jack O’Brien, 2012

38 a.Jellyfish (= Cnidaria, Scyphozoa) continued (3)Some scyphozoan species have medusae that are 2 meters wide

39 Nomura Jellyfish onalgeographic.com/news/200 9/07/photogalle ries/giant- jellyfish- invasion-japan- pictures/index. html

40 a.Jellyfish (= Cnidaria, Scyphozoa) continued (4)Outbreaks or “ blooms ” of scyphozoan medusae can be an economic nuisance

41 Recent outbreaks of Nomura jellyfish have destroyed nets & caused significant economic loss to the Japanese fishing industry invasion-japan-pictures/index.html

42 (4)Blooms can become an economic nuisance (continued) (a) Australian & Pacific species appeared in great numbers in GOM at turn of century (b) Unknown ecological impact (c)One (untested) hypothesis is that polyps were on oil/gas rigs transported across ocean

43 Mobile Register March 12, 2001

44 Science, 2001, 293, p. 29

45 a.Jellyfish (= Cnidaria, Scyphozoa) continued (5)Tentacles contain NEMATOCYSTS (a)Organelles w/ harpoon-like structures (b)Eject when in contact w/ prey (c)Contain venom (d)Prey upon zooplankton & small nekton

46 Purvis et al., 2001, Fig. 31.7

47 a.Jellyfish (continued) (6)Alternation of generations [Not seen in corals and sea anemones] (a)MEDUSA stage iPlanktonic iiSexual reproduction (b)POLYP stage iSessile iiAsexual

48 Alternation of generations within the Cnidaria Purvis et al., 2001, Fig Polyps

49 Adult medusa of the moon jelly Aurelia aurita

50 Polyps of Aurelia aurita developing and releasing immature medusae

51 2.Cnidaria (continued) b.Siphonophores (1)Colonies of specialized medusae that drift together (2)Venom of Physalia (the Portuguese man- o-war) can kill people

52 Float The siphonophore, Physalia Portuguese man-o-war Castro & Huber 2003, p. 122

53 Siphonophore: By-the-wind sailor Velella velella showing its upright "sail."

54 Colony of the siphonophore Praya dubia Stretching for more than 40 meters, it may be one of the longest animals on Earth. Photo was taken in the deep sea from an Remotely Operated Vehicle. It shows two nectophores and a long curtain of stinging dactylzooids trailing behind.

55 b.Siphonophores (continued) (3) BLUEWATER DIVING (a) Allows observations in planktonic animal’s natural open ocean environment (b)Technical problems are similar to astronaut “space walks” iAt depths > 100 ft divers cannot see surface nor ocean floor iiTethers prevent divers from drifting away from mother ship

56 BLUEWATER DIVING Collecting diver is tethered to a “down line” and monitored by a safety diver armed with a shark stick plorations/07philippines/backgro und/diving/media/divers_close_6 00.html

57 b.Siphonophores (continued) (4)Movement of dactylozooid tips (a)Jerk up & down (b)Mimic copepod swimming movements (c)Attract fish that feed on copepods

58 Dactylozooids and gastrozooids of the siphonophore Physalia


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