Presentation on theme: "SMS 501 Biological Oceanography 4 November 2009 Mary Jane Perry Lecture 17 Zooplankton III: Gelatinous Zooplankton AKA Gelly or Jelly Plankton, or Gelata."— Presentation transcript:
SMS 501 Biological Oceanography 4 November 2009 Mary Jane Perry Lecture 17 Zooplankton III: Gelatinous Zooplankton AKA Gelly or Jelly Plankton, or Gelata
House keeping Highpoints from Marine Waters Conference? Oral final exam schedule – week of finals (in Orono or at the DMC)
1 st Law of Thermodynamics – you can’t get something for nothing (photosynthesis uses extraterrestrial energy – from outside earth/ocean system). 2 nd Law of Thermodynamics – you can’t break even While zooplankton are secondary ‘producers’, there is a cost; efficiency of transfer of consumed POC (phytoplankton or protozoa or other organic particle) to new zooplankton body mass or eggs is ~ %.
Copepods dominate zooplankton biomass in many places. Zooplankton have ‘behaviors’ – response to chemical or mechanical cues (food or mate or predator); functional response curves for food ingestion as a function of food concentration; heterotrophs are ‘richer’ food. Life scales of months to year +. Time to sexual maturity weeks to months. Growth rate related to temperature and food concentrations. Different strategies of egg production but all related to quantity and quality of food (diatoms & aldehyde production). Swimming speed is scaled to body size; diel migrate vertically. Zooplankton are patchy – aggregation in response to food patches at fronts or thin layers or as predation minimization strategy. Zooplankton control phytoplankton blooms dP = P (growth – loss) dt
Historical treatment of jellies: jellies clogged my nets!” Zooplankton are typically categorized as crustaceans or gelatinous.
Commerical treatment of jellies 2008 Nobel Prize for Green Fluorescent Protein from Aequorea
Organisms from 8 phyla are included among the gelata: a) Nemertean. b) Phaeodarian radiolarian. c) Salp w/ parasitic copepod. d) Lobate ctenophore. e) Narcomedusan hydrozoan. f) Nudibranch mollusc. g) Chaetognath. h) Physonect siphonophore. i) Coronate scyphozoan. j) Polychaete. From Haddock Hydrobiologia 530/531: 549
Gelantinous plankton AKA jelly or gelly plankton; gelata taxonomically very diverse; unified by gelatinous, watery body; transparent (Biol. Bull. 201:113) and fragile; complex life cycles (sexual and asexual reproduction); rapid growth “blooms” with large interannual variability; abundance may be increasing ? diverse feeding patterns: small-particle filter feeders; raptorial predators; sweeping encounter predators
Complete transparency only in euphotic zone (not deep sea); note that many gelata are completely transparent. Johnsen, Biol. Bull. 201: 301
Difficult to sample with nets or acoustics. One labor-intensive way is through in situ studies of jellies by divers or observers in submarines
Gelatinous bodies mostly transparent (although many deep sea species are bioluminescent); high water content; low nutritional value (low nutritional value and refuge from predation?) *many successful at low food concentrations able to “sweep” or “clear” large volumes of water with low food concentrations at low energy costs (have been called “fake” giants -large filter surface relative to C) can also ‘degrow’ or shrink at very low food conc. (survival) * efficient feeders – compete with zooplankton * high growth rates –> may be responsible for ‘swarms’ * tunicates (salps, doliolids, larvaceans) waste products have high sinking rates (material flux) * medusa-like predators not visual predators (compete with fish larvae? do well in regions of turbidity) Salp volume Salp volume, scaled to crustacean C/vol
3 primary pathways for material & energy flow: * food web(s) leading to large metazoans (i.e., fish) * microbial loop * gelatinous zooplankton – 2 pathways: 1) alternative to microbial loop (small phytoplankton) 2) feed on macrozooplankton, but not necessarily a food web leading to fish (can be either raptorial predators or sweeping encounter predators)
Urochordates Filter feeders on small particles ; tremendous ability to “clear” the water (short circuit microbial loop). Clearance rates comparable to phytoplankton growth rates. Pelagic tunicates Appendicularians or larvaceans – collect particles externally, in a ‘house’ Thaliace – filter internally Salps Doliolids They “bloom” but onset of blooms poorly understood
Appendicularians (larvacean): Body form of a “tadpole” with tail containing a notochord; hermaphrodites. Forms mucous house which usually surrounds the animal and collects microscopic planktonic particles for consumption. The larvacean can be seen inside or beside the much larger mucous house as it beats its tail to create feeding currents. Vacant houses ––> carbon flux Oikopleura
‘House is a complex set of channels and filters made of mucous fibers and sheets; seawater is pumped by tail to inflate house. Water is pumped into the house by the oscillation of the larvacean's tail. Particles are sieved from the flow as they pass through the internal filter – fine mucus; they accumulate and are aspirated at intervals into the pharynx of the larvacean via a mucous tube. Houses become clogged with particulates and fecal pellets, and are then jettisoned (maybe several times per day). The larvacean expands a new house (there may be several house rudiments on its body, awaiting expansion) and resumes filter feeding. The abandoned houses can be an important source of marine snow and serve as food for various planktonic omnivores. Also can fall to sea floor.’ Madin and Harbison (2001) Encyclopedia of Ocean Sciences, pp
Abandoned houses sink 800 m/d New houses produced w/in a few to 24 hr Sizes from mm to 3 m Larvacean video earch?q=larvacean&emb=0&a q=f#\
Giant larvacean houses: more abandoned houses, more carbon flux. Monterey bay ~ 4 houses/m 2 seafloor/day
flagellatesbacteria ciliates copepodsfish large phytoplankton (diatoms) sinking particles picophytoplankton microbial loop and linear food web to fish
flagellatesbacteria ciliates copepodsfish large phytoplankton (diatoms) sinking particles picophytoplankton larvaceans, salps, doliolids larvaceans, etc. short circuit microbial loop particle export
Doliolids: Barrel shaped. Relatively small, transparent body with complete bands of circumferential muscles (8 or 9). Anterior and posterior openings. Feeds on small plankton using currents created by cilia rather than pulsing of body. Hangs motionless until disturbed, and then exhibits characteristic jumpy motion Complex alternation of five asexual and one sexual generations; can occur together as parts of large colonies of thousands of zooids. Colonies may >1m. Fragile, so not collected by nets. Undersampled by acoustics. Madin and Harbison (2001) Encycl. Ocean Sc., pf. 1120
Salps: Body with incomplete circular bands of muscles (various numbers depending on the species). Anterior and a posterior opening. Size is mm to cm. Muscular pulsing of body wall pumps water through an internal mucous net that gathers small plankton. Locomotion by jet propulsion, contraction of body muscles. Alternate between two forms – asexually budding solitary (oozooid) stage and a sexually reproducing aggregate (blastozooid) stage. The latter remain connected together in chains or whorls (right figure, chain is 10 m). Growth rates of 0.25 /d. Consume 0.5 body weight / day. Asexuality and rapid growth – important for blooming! Ephemeral, patchy blooms ---- very tough to study ! Madin and Harbison (2001) Encycl. Ocean Sc., pf. 1120
A mature solitary stage (oozooid) of salp, Cyclosalpa affinis. Body is oriented so that the oral siphon (i.e. the mouth) is to left. Stolon projects forward from a point just in front of the digestive organs. Files of blastozooids are budded (asexually) and develop along either side of the stolon, the distal ones being more advanced. Lacalli Biol. Rev. 74: 177
Groups (aggregates) of mature blastozooids then separate to begin an independent life in the plankton. They reproduce sexually (younger chains are female; older colonies are male) to complete the cycle. Each blastozooid in the chain acts as a `nurse' zooid, supporting the growth of a single embryo inside its atrium (left figure). The embryo, when mature, is releases as a solitary stage (oozooid). Growth rates ~ day (similar to phytoplankton). (photo: Gulf of the Farallones NMS) pgcordell/living/living_26.html
Thought to be associated with warm water intrusions from Slope Water south of Georges Bank. Absent in 1996, 1997, 1998 (no intrusions? paper does not say).
Other regions with documented swarms of salps; up to 100,000 km 2 (hot spots?) Don’t find swarms in – very low productivity regions (not enough prey for blooms) or – very high productivity regions (clog mucus nets; stop feeding; Harbison et al. 1986) Estimate bloom concentrations to be ~ 1,000 mL biovolume m -2 Madin et al. 2006, DSR I 53: 804
Salps graze on wide range of particles, < 2 µm – 1 mm including microzooplankton that are not fast enough to escape! Can alter community structure (remove both phyto and zooplankton). Biovolume of Salpa asera of 1,000 mL/m^2 would remove 25% of small particles per night. If phytoplankton double once per day, estimate that salps could remove ~35% of primary production. Sinking rate of fecal pellets up to 2,700 m d -1 (freight-train to the sea floor)!
Gelatinous Molluscs: heteropods and pteropod (thecosome and gymnosomes) Reduced shell (no shell in gymnosome pteropods ) made of aragonite (CaCO 3 ) – thermodynamically unstable and dissolves more readily than calcite (different crystaline structure) Pteropods are major contributors to global CaCO 3 flux. Difficult to sample; net avoidage – heavy and ‘drop’ ‘Poster’ organism of ocean acidification (ocean is undersaturated with regard to aragonite; decreased pH will drive reaction against formation of aragonite) Depending on species, mm in length. Generally, poor literature on this group.
Heteropod mollusc: Elongate body with single ventrally placed swimming fin, held upward. Light transparent shell (aragonite); some none; fossil record. Sculling motion of fin propels animal forward. Well developed pair of eyes on a snout-like head. Active predators on salps, doliolids, chaetognaths and other gelatinous zooplankton. Different species found at all depths. Difficult to sample. heteropod Oxygyrus
Thecosome pteropods: Body with large pair of lateral plate-like extensions of foot. Plate flap like wings for propulsion. Some with aragonite calcareous shell, others w/ soft pseudoconch; fossil record. Flux of pteropod shells in Sargasso responds to the annual cycle of primary production in the upper ocean. Jasper and Deuser (1993) DSR I, 40: 653. Cacavolinia thecosome pteropod (with shell) pH & aragonite
Limacina (shelled pteropod ) Herbivores with mucous web to passively collect plankton; it ingests the web (5 sec) and deploys a new one (20 sec). Can also ‘trap’ motile organism in the web, including small copepods. Feeding only observed in situ, by scuba. Web floats above animal, and contributes to buoyancy. Web is ~ 4 times diameter of the organism. Feeding pteropods; Lalli and Gilmer, redrawn in Denny’s (2008)
Clione gymnosome pteropod Gymnosome pteropods: Body with small pair of lateral muscular wings. Beats wings to swim rapidly. Body lacks any kind of shell. Head with two pairs of retractable antennae and buccal (oral) apparatus with a radula, specialized hook sacs and a jaw. Active predators on thecosome pteropods; juvenile veliger stages feed on phytoplantkon. Sometimes observed in swarms. Few references - Hunt et al. (2008) Prog. Oceanog. 78: 193
Clione captures Limacina w/ six buccal cones. Proboscis draws body out of shell. Based on Lalli and Gilmer (1989). Original source unknown; In the Southern Ocean, Clione limacina antarctica life cycle is strongly synchronized with it’s favorite prey, Limacina helicina antarctica
In Southern Ocean, pteropods are variable but significant part of zooplankton population (I believe data are based on # of individuals; diamonds are maxima observed). Both seasonal and interannual variability in abundances Hunt et al. (2008) Prog. Oceanog. 78: 193
Chaetognath (Arrow worms - important predator) Separate phylum 2nd in numerical dominance to copepods Slender transparent body, large caudal fin, anterior spines of either side of mouth. Carnivorous - catch large numbers of zooplankton and swallow them whole; ambush or raptorial feeders; sense hydrodynamic signals from prey. Mechanoreceptors to sense water movement and detect prey; behavior of prey will influence selectivity (active vs. passive prey). Can eat large copepods (major predator); capture efficiency related to prey escape; primarily feed on copepodites. Can be cannibals, particularly late in season (leads to rapid population decline).
head with spines -->> Chaetognath
Table shows % prey population removed per day – seasonally, big impact on prey populations Functional response curve: more prey -> more consumption; not satiated in this experiment. Voracious carnivores &um=1&ie=UTF-8&sa=N&tab=wv# Tonnesson and Tiselius 2005MEPS 289: 177
What is the role of predators like chaetognaths in regulating zooplankton populations (top-down control?) Central-West North Sea (5 mi from English coast) omnivore abundance predator abundance Clark et al ICES J. Mar. Science 60: 187 Note seasonal switch of dominant predator from ‘jelly fish’ (Hydroida / medusa) to Chaetognatha (gelata are major predator)s.
What is the role of predators like chaetognaths in regulating zooplankton populations (top-down control?) Central-West North Sea (5 mi from English coast) omnivore abundance predator abundance Clark et al ICES J. Mar. Science 60: 187 Is summer decrease in omniovores (mostly copepods) due to Chaetognatha?
Ctenophores (sea gooseberries): Body with 8 rows of combs (ciliary plates), often seen as shimmering waves of color. Usually transparent (except for some of the deep-water forms). Predators on various types of zooplankton, fish eggs, planktonic larvae. Suspension feeders (of sorts), sweeping two contractile tentacles. No stinging cells; colloblasts on tentacles secrete a sticky substance to entangle prey. When contact a prey, tentacles contract and pass food to mouth. Bioluminescent – typically green light.
Ctenophore body shapes. Some exceed a meter and can only be collected by divers or submarines. Haddock Hydrobiologia 530:549: 549
Laurence P. Madin Bolinopsis vitrea, a lobate ctenophore
Unidentified Ctenophore Photo by MarshYoungbluth
Gellies are difficult to quantitatively sample; example of using fish as integrator – stomach content and frequency of occurrence of ctenophores; NW Atlantic (region, next slide) Link and Ford, 2006, MEPS 320: 153
Climate change? Climate oscillations? Is this a permanent change in distributional pattern? Or in prey preference?
Beroe ovata Later introduced into the Black Sea, in ballast water; predator on Mnemiopsis. Here with mouth open. al/news/blackseajellies/blackseajellies.htm Mnemiopsis leidyi Introduced into the Black Sea in 1982, presumably in ballast water; predator on zooplankton
Historical background of Blank Sea: By 1970, overfishing removed top pelagic predators. Went from 4 trophic levels to 3. Daskalov et al. (2007) PNAS 104: 10,518 Small planktivorous fish increased (large fish predation pressure was removed); fishery developed for small fish. By 1980’s, small fish were overfished. Zooplankton increased (small fish predation pressure was removed). In 1982, Mnemiopsis was introduced by ballast water into Black Sea. Abundant food (zooplankton) and no predator (small fish gone) ––> population explosion (at one time Mnemiopsis was 90% of animal biomass in Black Sea ! ). Phytoplankton increased (zooplankon predation pressure gone). Algal blooms w/o grazing ––> anoxia. Fertilizer runoff ‘helped’. W/o fishing, small fish ‘recovered’, exerting predation on zooplankton. Beroe, predator on Mnemiopsis introduced in ballast.
Mnemiopsis introduced species to Black Sea in 1982 Within 10 years, biomass was 1 billion tons! (~ 10+ animals m 3 ) Voracious predators on wide range of prey, including crustaceans and fish eggs (individual can consume 15 g DW/day); captured by contact w/ tentacles (capture success will vary w/ prey type; can remove ~30% copepods/d) Success due to simultaneous hermaphrodites rapid growth rate (~ 7 d): larvae hatch w/in 24 h; double weight daily; w/high food, adult can produce ~ 1,000 + eggs/day high eutrophication (agricultural run off), esp. northern Black Sea decreased freshwater flow (river diversion) overfishing less predation on zooplankton - hence high zoo biomass; few predators for the ctenophore Very sensitive to low temperature (not found <2ºC; Q 10 ~ 3.5). Appear tolerant of low O 2 (1 mg L -1 ). Purcell (2001) Hydrobiologia 451: 145
top predators small fish gellies other zooplankton phytoplanktonoxygen Data are standardized to mean; Daskalov et al. (2007) PNAS 104: 10,518 Not a stable ecosystem
Cnidaria hydromedusae, siphonophores, scyphomedusae all carnivores with tentacles and nematocysts Claudia Mills - good web site Fragile: difficult to sample them, without destroying them
Hydromedusae: Single radially symmetrical swimming bell. Tentacles with nematocysts. Small and relatively transparent. Predators on various types of zooplankton. Claudia Mills - good web site
Claudia Mills The trachymedusan jellyfish Benthocodon pedunculata
Laurence P. Madin _The anthomedusan Pandea conica, predator onn other gellies
Scyphomedusae: Single radial symmetrical swimming bell with tentacles with nematocysts. Often large, conspicuous, and with pigmentation. Predators on other zooplankton, including other medusae.
Hyperidean amphipod feeding on medusa
Siphonophores: Siphonophore tentacles can be 10 m long - sweeping the water for prey. Colony of polymorphic individuals in a chain, from inches to 100 ft: sting and capture prey (long tentacles with potent sting); reproductive cells; propulsion. Predators on zooplankton and fish larvae.
Voracious feeding by Aequorea victoria on Pacific herring larvae (no saturation here) Purcell Hydrobiologia 451: 27 Life cycle: sexual and asexual. Many have two life stages: swimming medusa (large) stage and the small (millimetres) polyp stage (sometimes benthic). Medusae reproduce sexually, and polyps asexually bud more polyps and tiny medusae (1–2 mm).
General questions? are jelly populations increasing? – endemic vs. alien are they more episodic? NB: sampling – difficult to quantify abundance ( see Mills, 2001, Hydrobiologia 451: 55 ) would an increase in gellies be good or bad for fish? (examples of both – yes and no) for carbon flux? do jellies change community structure? predation (top down control) on zooplankton, fish eggs, larval fish prey for fish and other gellies effect of climate change
Survival of scyphozoan Chrysaora at five DO concentrations; is ability to survive hypoxia involved important in eutrophic waters? Condon et al., Hydrobiologia 451: 89
Citations in Lyman et al JMBA 85:435 Sanderia malayensis Cyanea capillata Yangtze Estuary catch went from 0% in late 1980s to >90% in 2000 Pollution? (not visual predators) Overfishing? Climate change (temp, ocean circulation)?
Pelagia noctiluca Model with probability of bloom; 100 years of data in Mediterranean Sea: closed = bloom; open = no bloom. Predictor was lack of rainfall, associated with high temperature and atmospheric pressure from May to August. Purcell (2005) J. Mar. Biol. Ass. U.K. 85: 461
Brodeur et al., Fisheries Oceanography 8: 296 N. Pacific “regime” shift – no clear reason for increase in gellies (declined since 2000) Jellyfish biomass (thousand metric tons)