Open, Deep and Cold Flashcards
What are some examples of oceanic planktonic life?
- salps
- sea dragons
- sea butterflies
- larvaceans
- arrowworms
What are some key environmental features of the epipelagic zone?
- fluctuations in salinity/temperature
- constantly changing environment
- light exposure
- patchy food availability
What are two challenges from living in the epipelagic and what adaptations are there?
- staying afloat –> swimming (with cilia, appendages or undulating) and reducing sinking rate (increased SA and gas/fat pockets for buoyancy)
- surviving predators –> self defense (cnidae, ink clouds), hiding their presense (transparency, countershading) and being in groups
Why is there low primary productivity in the open ocean?
- stratified water layers (cold nutrient rich water sinks while warm nutrient poor water remains at surface)
- distribution of plankton in patches is determined by gyres/eddies, wind and local turbulence
What are the main characteristics of the food web in the open ocean?
- base layers made up of phytoplankton, viral plankton and heterotrophic bacteria that form a DOM loop
- more than the average 10% of organic matter gets passed to upper levels
- predominantly nanoplankton (diatoms, dinoflagellates, coccolithophores)
- ocean chains tend to be long so only a few number of species can be supported (less branching)
What is the twilight zone?
depths around 150-450m where small light can be found for photosynthesis but deeper is aphotic zone
What are some key environmental features of the deep sea?
- little variation in salinity, temperature
- soft sediment
- high pressure (countered by matching internal pressure to environment)
- cold (allows for slower metabolism and longer lifespans)
- no light (strong evolutionary pressure)
How do fish like the barreleye adapt to see in the deep sea?
- eyes are tubular vs round
- have a main retina for close images and accessory retinas for distant images
- barreleyes’ eyes can rotate to look directly above it through transparent head
What are two challenges from living in the deep ocean and what adaptations are there?
- finding each other –> advertising their sex (signals with symbiotic luminescent bacteria), attaching to each other
- finding food –> vertical migration (i.e lanternfish), ingesting large prey, luring in prey
What are the trends in abundance, biomass and richness at varying depths?
abundance = exponentially decreases after 1000 m
biomass = linear decline
richness = highest at equator, decreases moving away
What are the main characteristics of the food web at the ocean floor?
- dominated by deposit feeders
- nutrients sourced whale falls and marine snow
Where are deep sea vents found?
along oceanic ridges/rift zones
What are the differences between white and black smokers?
black smoker = very hot, narrow and tall, acidic, rich in copper/iron/zinc
white smoker = cooler, short, alkaline, rich in barium/calcium/silicon
What are the main characteristics of the food web near hydrothermal vents?
- primary production from chemotrophic bacteria (H2S into organic energy)
- bacteria forms symbiotic relationships with other organisms (stored in trophosomes)
What are some findings from the paper by Pershing et al ?
large whales like blue whales are capable of storing large quantities of carbon
What nutrients are limiting in the ocean?
nitrogen and iron
What are some key environmental features of the poles?
- snow/ice
- cold temperatures
- drastic changes in photoperiod
Describe the directionality of water in the Arctic ocean
- 2 outlets (Atlantic and Pacific)
- 2 currents (Bureaufort gyre and transpolar current)
- multiple stratified rivers
Describe the directionality of water in the Antarctic ocean
- completely surrounded by open water
- no rivers
- no stratification
- innermost thermohaline circulation and outermost Atlantic convergence current
What are the differences between Arctic and Antarctic pack ice?
Arctic
- lasts multiple years
- 3-4 m thick
- high abundance regardless of season
- forms small, irregular icebergs
Antarctic
- seasonal (<1 year old)
- 1-2 m thick
- thicker in winter, barely present in summer
- forms large, tabular icebergs
What plankton is found in the edges of pack ice?
pennate diatoms (more abundant in Antarctic)
What are the dominant protists/metazoans in each pole?
Arctic = mostly rotifers, nematodes and flatworms
Antarctic = mostly flatworms and copepods
How does pack ice contribute to phytoplankton booms?
pack ice melts and melted water containing phytoplankton travels and reaches upwellings
What are the main characteristics of the food web at the poles?
- detritus/phytoplankton/waste based
- primary productivity of algae/diatoms
- copepods and krill as primary consumers, seabirds/seals/whales as secondary
- killer whales apex in Antarctic, polar bears in Arctic
What are the differences in the benthic floor of Arctic and Antarctic oceans?
Arctic = soft sediment from river deposits
Antarctic = hard substrate due to a lack of sediment deposits (rivers)
What is the difference in primary productivity between the poles?
similar productivity but Arctic lacks inorganic nutrients while Antarctic lacks iron
