Marine 9 Ocean depths

temp drops

drops from surface layer to 1000m (strong gradient in the mesopelagic) then stays constant

mesopelagic species examples

crustacean zooplankton-krill etc squid Dominated by bristlemouths and lanternfishes Lancetfish squid all very fragile fish-usually small 20-200mm

camouflage (deep pelagic)

dark, colours often black to conrast with bioluminescance. Most fish are colours that do not reflect light, or their own bioluminescence many transparent- have to have refractive index matching water. hard to achieve. Body structure and chemicals need to be transparent

How deep are the deepest trenches?

10,000m +

krill photophore structure

(organs that produce light) have reflector on outside-made of guanine often May have reflectors, filters, lenses and other control mechanisms have lantern, either with symbiotic bacteria or cells which can make luciferins and luciferases lens-focus light in direction filtering mechanisms to ensure light right wavelength

Depth related conditions?

1) Deep water - source and circulation 2) Temperature 3) Oxygen 4) Pressure 5) Light

What is the name for when an ecosystem gets its food from elsewhere?

Allochthonous

Species groups differ in depth occupancy

And this is related to species traits (such as body size) lipids expensive to produce need high nutrient level so chondrichthians (skates/rays) only found at shallow depths where more food as opposed to actinopterygians can be found much deeper. Bony fishes tend to be deeper than cartilaginous

What is the name for an organism which thrives at high pressures?

Barophilic

food changes in depths?

Biomass in the deep sea reduced compared to other marine communities Reduction primarily due to food available (low due to lack of photosynthesis in perpetual dark) Beyond 1000 meters planktonic organisms consume organic matter from above (not produced here)

deep water origins?

Bottom waters can be 2000 years since last at surface formed from surface water being moved from equatorial to colder polar regions, now it is dense, cold, saline, and oxygenated, stays oxygenated as little around to use up, sinks down to bottom of ocean Travel towards equatorial regions along bottom. large upwelling regions

examples of some camouflaged deep sea fish?

Deep-sea angler fish Deep-sea devil fish Deep-sea bristlemouth Swallower Gulper Anglerfish

DVM

Diurnal vertical migration (mesopelagic) in some cases go back down to several thousand meters. as nights get longer, organisms spend longer in surface waters World's biggest migration takes place daily Estimated at 1000 million tonnes (many phyla) Productivity and predator avoidance Significant carbon shift (shallow to deep). Very important for carbon cyclying of the oceans.

diversity and range of marine organisms over depth?

Diversity of many major groups of marine organisms declines with depth Example from pelagic fishes Deep water species have broader ranges deep water fish distr. throughout whole atlantic pelagic fishes. Density reduces with depth. But range increases with depth (due to the homogeneity of the deeper sea). and need to find food over wider area

Describe prey handling in mesopelagic species?

Efficient predators of animals of similar sizes Big recurved teeth Large eyes

oceanic depth zones and amount of light

Epipelagic 0 to 200 (photic zone) LIGHT Mesopelagic - 200 to 1000 m (twilight zone) SOME LIGHT the categories below are the deep pelagic: Bathypelagic - 1000 to 4000 m. NO LIGHT, OTHER THAN SELF GENERATION Abyssopelagic - 4000 to 6000 m Hadalpelagic - 6000 to 11,000 m (in trenches) Not well explored at all. is above abyssal plain. Pure Hadal zone

Thermohaline conveyor system?

Flow of water driven by temperature and density Bottom waters can be 2000 years since last at surface

How do fish deal with bouyancy, how does this effect their ability to move about in the water column?

Have to stay neutrally buoyant - swim bladder (open or closed), closed means its harder to change position in water column rapidly. Open can. Or can have lipids in the body, expensive to produce, changing in position in the water column rapidly is hard. Liquids compress too, but a lot less. Gas is more effective

What are luciferins and luciferases ?

Light emitting compounds (luciferins) oxidised by enzymes (luciferases) to make light

vision at depths

Mesopelagic species, visual capabilities often very specialised (bioluminescence and residual ambient light) "Deep pelagic" species visual capabilities poor (only bioluminescence) Mesopelagic viperfish e.g.

diffs between migrators and non migrators

Migrators are active predators, non-migrators sit-and-wait Migrators more athletic have swim bladder large eyes and mouths, visual predators. many have photophores. non migrators also have photophores, slightly larger on average? no swim bladder, lipid instead?. weak bones. fleshy muscles.

bioluminescance

Only important visual light source in most of the deep sea blue shifted Take advantage of blue shifted receptors in the eyes of deep sea animals. deep sea organisms have no cones colour vision) have well developed sensitive rod opsins- for dim light flashes Startle predators

What is the OMZ?

Oxygen minimum zone - Things die, sink, bacteria feed on them, decomposing, using up O2. These zones are likely to become more common, due to climate change, as sea temp increases, as warmer water holds less oxygen.

Describe prey handling in deepsea species?

Smaller eyes More reliant on sit-and-wait Still relatively small fish

deep pelagic species

Specialised for low energy lifestyle Density reduction of all tissues (low bone density) Fleshy animals. Much more adapted to extremely dark conditions (only from bioluminescene), and also adapted to the low energy ecosystem. strong emthasis on lateral line system and bioluminescance

oxygen and depth. and change with climate change?

Surface water has o2 due to it entering from the atmosphere and photosynthesis. within mesopelagic zone have O2 minimum zone from 200-500m as organisms die and sink, bacteria feed upon them creating anoxic environment below that get old oxygenated water and all material has been decomposed with climate change will get warmer waters to deeper depth, warmer waters have less oxygen so oxygen minima will become more widespread

barreleye fish vision (Opisthoproctidae)

These are tube eyes. Lense with a long barrel, and then a retinia. some have secondary side retina in eye to catch light from side as well as above

List some deep see adaptions?

Vertical migrations Camouflage Bioluminescence Vision Trophic morphology (teeth, jaws)

What is the name for when an ecosystem generates its own food?

autocthonous

example species for depth migration and reason?

benthosema (lanternfish) and maurolicus (pearlsides)-following copepods spending night higher in water collumn when cant be seen by visual predators.

photophore/ bioluminescence use

camouflage, so break up silhouette krill-amount of surrounding light directly proportional to amount of light produced, for camouflage then Escape from predators (luminescent ink) Lures (e.g. anglerfish, dragonfish) Species recognition, intraspecific communication (even sexual selection?) (((Ventral bioluminescence hides silhouette from below)))

NUTRIENTS AT DEPTHS allocthonous system as opposed to autocthonous system

food bought in form outside 1-3% of productivity reaches ocean depths

pressure and depth

for every 10m increase 1 atmosphere (pascal is what should be used). 100kpsi = 1 atmosphere. (mass and pressure) Gases compressible Pressure affects gas filled structures (e.g. swim bladders) Compression less of a problem than decompression

spookfish vision

has refractive lens in first eye (standard) and reflective lens in second below, to catch light form below two functional eyes (refractive and reflective optics) LOOK UP PAPER WAGNER ET AL 2009

camouflage mesopelagic example. krill

krill Live primarily in the mesoplagic, etc are red which disappears first so hard to be hunted at depths at night- predators are likely to have vision shifted to pick up on blue light, being red will mean you are not seen. cant be highlighted by bioluminescance (apart from malacosteus) Some species emit redlight to see them.

plankton distribution

large mass at surface, thins down then a bulb whihc is plankton that spend night at depths then come up during day photosynthesis only down to 200m. Then a fairly constant number down to the bottom.

How deep are shelf regions of the pelagic?

less than 200m. This is the photic zone.

lipid/liquid? use for buoyancy LOOK UP LIPID USE

lipids compress slightly as you go deeper Liquids compress too, but a lot less. 1ml of water = 0.984 at 3800m (so 1.6%)

stoplight loosejaw adaptations

malacosteus- see krill as emits red light form photophores in eye, the light of which no other prey/predators can see has chlorophyll derivative aswell in eye to percieve red light

protein diffs at depths

more folded for barophillic fish- to become pressure resistant Barophilic "pressure loving" animals have pressure resistance proteins (evolved to be more efficient under pressure e.g. fish muscles, using pressure-resistant 3D structures). Pressure affects protein structure, so death on decompression can be caused by metabolic disturbance

diff between open and closed swim bladder

open-attached to stomach, so any excess gases during deco can be released closed-european fish

visual use in diff depths?

organisms in epipelagic strong visual use Bathypelagic no light available

barophillic def

pressure loving

light wavelengths and depth

red light lost, then yellow have blueshift in light, only wavelength left Irridiance (light flux density = photons) decreases with depth Longwave (reds) and shortwave (UV) fall off more rapidly than blue. Most light present in oceans is blue, which is why the sea as blue. Many organisms living in mesoplagic zone are sensitive to blue light due to this. Some light penetrates to depth, but not much.

benthic species

scanvengers, hagfish etc, wont be eating particulate matter, mainly waiting for large corpses. Tripod fish. Hagfish. Deep sea spiny eel Most "benthopelagic" so use both habitats Active scavenging Brain olfactory regions highly developed Some sit-and-wait predators (e.g. tripod fish)

FISH WITH CLOSED SWIM BLADDER

sebastes (rockfish)

bioluminescence in mesopelagic

shifted to blue/green light Dominated by bristlemouths and lanternfishes Photophores common, e.g