Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
59 Cards in this Set
- Front
- Back
|
Measuring Algal Biomass:
4 techniques |
1) Filter water sample, put filter on nutrient agar - count colonies (only 10% grow)
2) Direct cell counts - Acradine Orange or hemocytometer 3) Chlorophyll measurements - spectrophotometer 4) Chlorophyll measurements - fluorometric |
|
|
Measuring Bacterial Growth
|
measure uptake of 3H (thymidine)
only gorwing cells incorporate, measure incorporation per unti time by scintillation counter |
|
|
Measuring Primary Production
2 techniques |
1) O2 consumption - meausre changes in dissolved O2 in light-dark bottles
2)14C method - provide 14C in bicarb, incubate, filter, count radioactivity on filter |
|
|
Factors affecting photsynthesis
|
1) Light
2) Nutrients -ammonium, nitrate, nitrite, phosphate, silicate, Iron |
|
|
Light
|
Varies w/: depth, season, affected by latitude, water transparency, compensation depth
|
|
|
Nutrients & Photosynthesis
|
Vary with: depth, season/ stratification of water column, affected by rates of "new nutrients" and regeneration of nutrients
*Requires transport molecules* |
|
|
Iron - why critical for life?
|
- Transport of e-
- Uptake of Nitrate Enzymes: - Ferredoxin - Nitrate reductase - Chlorophyll Synthetase - Nitrogenase |
|
|
Ironex Experiments - Ironex I
|
1993 - area S of Galapogos ISlands, HNLC area
- added 2 - 200 pptril Fe to surface, followed patch w/ Drogue - primary production increased 4 fold, stopped after 4 days - why: iron became insoluble and sank |
|
|
Ironex experiments - Ironex II
|
- 3 Fe applications, 3 days apart, used more soluable Fe form
- w/in 1 week phytoplankton biomass increased 30 fold - 2500 tons of CO2 taken up before patch dispersal - Diatoms benefited most from Fe fert. |
|
|
Implications of Ironex
|
- Possible solution for atmospheric CO2 levels and Global warming
Remaining Q's: - does Fe enrichment lead to transport of carbon to deep ocean? - should we even consider fertilization of HNLC areas? |
|
|
3 lake regions
|
Epilimnion - surface mixed layer
Metalimnion - thermocline region Hypolimnion - lower lake region |
|
|
Annual Circulation Patterns in Lakes - 3 major
|
1) Amixis - no circulation
2) Holomixis - when mixing occurs, entire water column mixes 3) Meromixis - mixing does not include entire water column |
|
|
Amixis lakes
|
- no circulation - due to permanent ice cover
- found at very high latitudes / elevations |
|
|
Holomixis Lakes - 4 kinds
|
1) Oligomictic - irregular, short duration mixing
- usually low altitude, equatorial or very deep temperate lake - mixing occurs when warm surface water is colled by cold evening or rain & wind 2) Monomictic - one regular mixing/ yr - Warm: subtropical (and some deep temperate) lakes that stratify in summer but mix for much of the winter - Cold: freeze over in winter; become isothermous and mix during the summer months 3) Dimictic - becomes isotherms - mix in spring & fall (typical temperate lake) 4) Polymictic - many overturns/ continuous mixing (often shallow/ unprotected lakes in subtropic & temperate regions) |
|
|
Meromixis Lakes
|
- dense bottom water remains stagnant & usually anaerobic
- water column divided into mixolimnion & monimolimnion separated by chemocline |
|
|
Lakes classified by trophic status - 3 main
|
1) Oligotrophic
2) Mesotrophic 3) Eutrophic |
|
|
Oligotrophic Lakes
|
- little or few nutrients (<300ug/L N, <10ug/L P)
- U-shaped, very deep; large, - cold hypolimnion - Chl a < 2 ug/L; Secchi > 5m |
|
|
Mesotrophic Lakes
|
- moderate nutrients(300-600 ug/L N, 10-30 ug/L P)
- V-shaped, moderately deep - moderate - small hypolimnion - Chl a 2-5 ug/L; Secchi 2-5 m |
|
|
Eutrophic Lakes
|
- high nutrients(> 600 ug/L N, > 30 ug/L P)
- V-shaped, shallow - small to no hypolimnion - Chl a > 5 ug/L; Secchi < 5 m |
|
|
Eutrophication
|
NATURAL process of organic enrichment of a body of water resulting from increased nutrient loading & subsequent increase in primary production
|
|
|
Characteristics of a Lake undergoing Eutrophication
|
- increased N & P conc.
- increased turbidity - decreased Secchi depth - decreased depth as lake fills - loss of D O2 in hypolimnion during stratification - decreased species diversity in most habitats - eventual filling of lake to form semi-aquatic, finally terrestrial habitat |
|
|
Cultural/ Artificial Eutrophication
|
-Process greatly accelerated by human activities:
- clearing land (inc runoff & nutrient input) - agriculture (manure & fert application) - release of untreated/ partially treated sewage into lake - release of organic wastes (milk processing wastes) |
|
|
Times scale of Eutrophication
|
Natural: 1,000's to 10,000's yrs
Artificial: yrs to decades |
|
|
Microzooplankton - overview
|
- smallest & most abundant organisms
- many consume by phagocytosis - some osmotrophic - usually consume bacteria (50% of all produced) - marine & freshwater |
|
|
Radiolarians
|
- only marine
- amoeba w/ glass/silica skelton & spines - eat bacteria & phytoplank. - up to 2mm in diameter - very fragile - killed by nets |
|
|
Foraminifera
|
- only marine
- CaCO3 skeleton w/ spines - consume bacteria & phyto - some have symbiotic algae - found in tropical oceans |
|
|
Rotifers
|
- almost entirely freshwater
- multicellular - 2 cilliated disks on anterior end: beat for feeding & motility - eat bacteria & phyto |
|
|
Ciliates
|
- feed on bact, phyto, some mixotrophic
- elongate, ranging from size from about 50 um to over 1 mm in length - covered with rows of cilia - Some "Tintinnids" - have "lorica" (shell) - some "Aloricate" - soft bodied |
|
|
Nauplius
|
- larval crustaceans
- mostly immature copepods - omnivorous |
|
|
Bacteria & Biomass
|
- bacteria usually make up 1/2 or more of the bacterio- /phytoplankton biomass
- bacterial production is about 20% of primary production - if bacterial growth efficiency is ~ 50%, bacteria consume about 40% of primary production. - bacterial populations are stable; therefore bacteria are being grazed at he same rate as they grow |
|
|
Bacteria & food chain
|
- traditional oceanic food chain disproven
- replaced by microbial loop - tiny cells eating other tiny cells - mesoplankton not built for filtering particles from water - major bacteria consumers must be microplankton |
|
|
Microbial Loop Overview
|
DOM -> Heterotrophic Bacteria->
Zooplankton <- Phytoplankton Zooplankton --> Fish & Higher |
|
|
Nekton - Class Crustacea
|
Ex: Antarctic Krill
- important commercially |
|
|
Nekton - Class Cephalopoda
|
Ex: squid, octapus, cuttlefish
- very fast, move by expelling water from siphon |
|
|
Nekton - Reptiles
|
Ex: Crocodiles (alligator is fresh)
- sea turtles - sea snakes (Indian & Pacific Oceans) - evolved from land snakes - young born live - very poisonous, not aggressive |
|
|
Nekton - Order Cetacea
|
Ex: whales, dolphins, propoises
- Mysticeti: Baleen whales - 2 blowholes - Odonticeti: Toothed whales - 1 blowhole - make sounds from nasal area - sounds focused by melon & sent out - returning sounds received - allows whale to echolocate |
|
|
Nekton - Order Pinnipedia
|
Ex: Seals, sea lions, walruses
- 4 fins - All but 1 species marine - eat primarily fish & squid - exploited commerically for oil, fur, etc. |
|
|
Nekton - Order Sirenia
|
Ex: manatees & dugongs
- exploited for meat, oil, & hide - Steller's Sea Cow - First described 1741; Extinct 1768 |
|
|
Nekton - Fish: Class Agnatha
|
Jawless Fishes: Lapreys & hagfish
- circular mouth always open - rows of conical teeth - cone shaped tongue - often parasitic, some predatory (size dependant) |
|
|
Lampreys vs hagfish
|
Lampreys:
- series of holes/ gil slits on body - single median nostril - certilagenous skeleton - certilage "cup" for brain case - Breed in freshwater: Ammocetes larva - burrow into sediments & filter feed Hagfish - deepwater scavangers |
|
|
Nekton - Fish: Class Chondrichthyes
|
Ex: Sharks, skates, rays
- cartilagenous skeleton - descended from bony fish - complete brain case - heterocercal tail (spine continues into upper fin of tail) - 5 to 7 gil slits - Sexes very evident (both have cloaca) - males have extension of pectoral fins (claspers) |
|
|
Nekton - Fish: Class Osteichthyes
|
Bony Fishes
- bony skeleton - one gill slit - paired moveable fins - non-homocercal tail - 20,000 species - commercially important |
|
|
Bony fish feeding habits
|
- Piscivorous: prey on other fish
- Plankivorous: prey on plankton - few scavangers - few herbivorous |
|
|
Perciform body type
|
- ctenoid scales
- 1 or 2 dorsal fins - 1 or 0 ventral fins - 2 paired fin sets (pecs and pelvics) - pectoral fins almost even w/ pelvic - spiny rayed fins - found in slow flowing water - pectoral |
|
|
Salmonid body type
|
- cycloid scales
- pelvic & pectorals distant - trout & salmon - found in fast flowing water |
|
|
Oceanic Depth Zones 3
|
1) Epipelagic Zone: <200m
2) Mesopelagic Zone: 200-1000m 3) Bathplelagic zone: >1000m |
|
|
Epipelagic Zone
|
- <300 species
- where most common fish from - tuna, mackrel, bill fish, snapper, eels, bass - Large, active predators - associated w/ areas of high primary production |
|
|
Mesopelagic Zone
|
- Lantern fish, cyclothones, lanset fish
- small aprx. 15 cm - plankton feeders - diurnal migration - have bioluminescent spots on bottom on body for camoflaugue |
|
|
More on Bioluminescent spots and Camoflague
|
- allows for camo from preds below
- breaks up outline of body against lighter water - dots are aggregates of bacteria (vibrio-fisherii) - colony grows when sufficient size & adaquate energy -fish have "blinds" to open/close spots - some put "filters" on spot to adjust wavelengths of light emitted |
|
|
Bathopelagic Zone
|
- fish have very large mouths to engulf large peices of food if found
- Gulper-eel, angler-fish, Rattail, Halosaur, cyclothones - diversity great, density low |
|
|
Planktivores
|
Ex: Menhaden
- use gill rakers to entrap plankton - all fish have gil rakers - used for protection on other species - can filter 6-7 gals water/ min - large commercial fish, most important in bay -fished using purser seine - used in fish & poultry food, dietary supplements, cosmetics industry |
|
|
Shark Prey Detection
|
Lateral Line:
- sensitive to water movement - movement send vibration, forces water into lateral line - sense of smell also very good Ampullae of Lorenzini: - on snout, detects electrical field - Have taste buds on body surface |
|
|
Fish Body Shape & swimming habits
|
- Very thin & elongate = acceleration
- Round/ pie plate = manuverability - medium build, w/ narrow peduncle = cruising - vertically elongage tail - fusiform body: max height @ 1/3 down length of body |
|
|
Temp Regulation types
|
Poikilotherms: body temp dictated by environment
Homeotherms: body temp independant of environment -Ex: Tuna - Has Rete Mirablile |
|
|
Rete Mirabile
|
- keeps inner body blood warm by counter current exchange
- outgoing blood continuously cooled by incoming cold blood - Incoming blood warmed by already warm outgoing blood - Can keep core body temp 20 degs. above water temp |
|
|
Bouyancy
|
Sharks: lipids - stored in liver as oil
Fish: swim bladders - 2 kinds: Physoclist: bladder independant, gas gland secretes gases from blood to fill bladder Physostome: connected to esophagus, fish can gulp air to fill bladder in addition to gland |
|
|
Catadromous migration
|
Ex: American Eeel
- live in freshwater as adults, spawn & spend juvenile stages in marine habitats |
|
|
Anadromous migration
|
Ex: Atlantic Salmon
- live in marine habitat as adults, travel to freshwater to spawn & spend juvenile stages |
|
|
Oceanadromous migration
|
Fish migrate from one portion of ocean to another
- young need food source in different location |
