Unformatted text preview:

NZPNPZ Models of BiologyCirculation/physicsRemineralization timeFeeding efficiencyRespiration, excretionMichaelis-Menten RespirationTemperatureLightZooplanktonWhat’s in a mouth full ofseawater?• 1 Liter of Seawater:– 1-10 trillion viruses– 1-10 billion bacteria– ~0.5-1 million phytoplankton– ~1000 zooplankton– Maybe 1-10 small fish orjellyfish– Some shark , otter, sea lion,or whale poopWhat’s in a mouthful ofseawater in Santa Cruz?Courtesy Steve HaddockClassifications• Size:microzooplankton (20-200 µm, e.g. ciliates);mesozooplankton (200 µm-20 mm, e.g. calanoid copepods);macrozooplankton (2-20 cm, e.g. ctenophores)• Life history:holoplankton (e.g. calanoid copepods);meroplankton (e.g. invertebrate larvae)• Trophic status:herbivores (e.g. small calanoid copepods, barnacle nauplii);omnivores (e.g. cyclopoid copepods); carnivores (e.g. chaetognaths, ctenophores, crab zoea)Life in a viscous mediumIS VISCOSITY IMPORTANT? The Reynolds numberReA large whale swimming at 10 m s-1300,000,000A tuna swimming at 10 m s-1 30,000,000A copepod in a pulse of 20 cm s –1 300A copepod foraging at 1 cm s-1 30An invertebrate larva swimming at 1 mm s-1 0.3•Re < 0.01: Viscous forces govern flow• Re > 10,000: Inertial forces govern flowLife in a viscous mediumVISCOSITY AND FLOW• Re < 0.01: Viscous forces govern flow• Re > 10,000: Inertial forces govern flow • Laminar flow: fluid moves smoothly around objects and can be visualized as moving in layers with no mixing between them; all fluid particles move in more or less parallel, smooth paths Re is low• Turbulent flow: fluid particles move in irregular paths even though the fluid as a whole is moving in one directionRe is high Transition: Re ~ 2,000Physical-biological interactionsNaganuma (1996)Microzooplankton are similar tophytoplankton (dominated by viscousflow)Copepods and other large zooplanktonstraddle the boundary between viscousand inertial flow• Also called arrowworms• very importantcarnivores,intermediate stepbetween smallzooplankton andfishChaetognaths113 226Algal picoplankton andnanoplankton (42,380)Flagellates (8,476)Ciliates (1,695)Crustacean zooplankton (339)Mesopelagic vertical migrators (45.2)Chaetognaths, micronekton (22.6)Small tuna, salmon, squid (3.39)Large tuna, sharks, billfish (0.51)Trophic level1234567Tunicates• Also called seasquirts, salps• Are chordates, butdon’t have a spine• Use jet propulsion• Can grow up to 40%per day in size!• Can be important forexport of organicmaterial to depthSiphonophores• Bodies are more than 95% water• Use a pneumatophore for buoyancy• Colonial organism,with specializedindividuals• Includesnematocysts(stingers)Ctenophores• Also called “comb jellies”, sea gooseberries• Always pelagic, marine• CarnivorousLarvaceans• Form a feedingbell• Very important inthe formation ofmarine snow• Major contributorsto export fluxFig. 1. In situ video frame grabs of steps in the progression from an actively filtering giantlarvacean house to a descending sinker.B H Robison et al. Science 2005;308:1609-1611Published by AAASFig. 2. Carbon flux (gray area) to the deep sea floor and the abundance of active (dotted blueline) and discarded (dotted red line) giant larvacean houses.B H Robison et al. Science 2005;308:1609-1611Published by AAASScyphazoans• True jellyfish• Don’t contain a float-bag• Uses muscularcontraction of the bell toprovide movement• Capable of explosivegrowth by asexualbuddingJellyfish willreplace theapex predatorsif given achance….Lynam et al., “Jellyfish overtake fish in aheavily fished ecosystem”, Current Biology,2006, 16: 292-293.(C) Chrysaora hysoscella;(D) Aequorea forskalea;(E) Cape horse mackerel/Cape hake; and(F) clupeids (sardine, anchovy and round herringcombined)Measuring ZooplanktonThe slow, the Stupid, and the Blind….Causes of PatchinessAggregation around phytoplankton(zooplankton gather around phytoplankton,phytoplankton gather around zooplankton feces)Chemical gradientsSocial factors – I.e. avoidance!"#$%&'()* +,&-$$.Density gradientsInternal wavesFlowCAM--combining flow cytometry with zooplanktonLISST--Sequoia InstrumentsHolographic image of a single Noctiulca cell imaged by the MBARIAUV equipped with a LISST-HOLO (courtesy of John Ryan)Copepod physical-biological interactions! Ability to detect and react to remote fluid disturbances! Well equipped to detect hydromechanical signals! Sensitivity is to the velocity difference between the tip and base of setae! Neurological response at 20 µm s-1! Behavioral response at 130 µm s-1Physical-biological interactionsFeedingFlow considerations:• at low Re, flow is laminar (i.e. eddies are absent) and particle trajectory is predictable• because viscous flow is symmetrical, particles captured by the setae can be maintained trapped in that positionThe flow of matter and energy to high marine trophic levels is greatly influenced by copepod grazingBehavioural components: • search for patches of food • encounter and food recognition• capture, handling and ingestionFeeding currentsKoehl & Strickler (1981) Filter-feeding / sieving“Fling and clap”Pulsing streamat 1 m s-1; Re = 0.75Feeding currentsPathlines ofindividualalgal cellsInterference betweenambient water motion and fluid flow around the copepod Strickler (1984)Cells maybe re-routed by asymmetrical flappingMeasuring Grazing and Growth1) Measure disappearance rate of prey• Clearance Rate is the rate of prey removal• Ingestion Rate is the average feeding of an individual• Efficiency is the fraction of material that is assimilated• Depuration is the time it takes to clear the guts2) Measure Gut Contents• Use fluorescent prey• Chlorophyll Gut Content method• Polystyrene beads or Fluorescently Labeled Bacteria3) Do a mass balance calculationGrazingIngestion and Clearance aredependent on preyavailability….As with phytoplankton,there’s a saturation-typeresponse…Also as with phytoplankton,the curve can moveup/down depending onenvironmental conditions.Gut Clearance Rate:1) Measure gut contents at time zero2) Measure gut contents at additional times, after holding in filteredseawater3) The extrapolated curve gives Gut Clearance Rate4) The x-intercept gives filter (or ingestion) rate, assuming steady-stateMeasuring Grazing and Growth1) Allometry/Physiology• Estimate growth rates from lab


View Full Document

UCSC OS 130 - NPZ Models of Biology

Download NPZ Models of Biology
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view NPZ Models of Biology and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view NPZ Models of Biology 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?