deep sea Flashcards
what’s bathymetry and how can it be done
Measurement of the depths of water
Using a weighted line
SONAR / echosounder – single beam & multibeam
Satellite altimetry – subtle variations in sea level
explain the mechanism of seafloor
Continental shelf
Continental slope
Fracture zone
Seamounts (& sea knolls)
Trenches
Abyssal plain
Canyon
Basin
what is a histogram?
distribution of elevations of earth’s surface
hypsographic curve
cumulative elevations of earth’s surface
explain the ocean zonation
Neritic zone – shallow subtidal (0 to ~200 m)
Oceanic zone – deep subtidal (>200 m)
Euphotic (photic) zone – area of the ocean where there is
enough light for photosynthesis to occur
Disphotic zone – dimly lit zone (not enough light for
photosynthesis)
Aphotic zone – no light
epipelagic
<200 m
mesopelagic
200-1000 m
bathypelagic
1000-4000 m
abyssopelagic
4000-6000
hadopelagic
> 6000
define benthic with an example
organisms that live in or on the bottom sediments of rivers, streams, and lakes (clams, crabs)
define pelagic with an example
Pelagic – living in the open sea or water column
Planktonic - drifting
Nektonic - swimming
vampire squid adaptations (inv)
jet propulsion for escaping the predators
slow metabolism to survive OML
anglerfish adaptations
gray or dark brown color that allows them to blend in with the depths of the ocean and hide in dark places along the ocean floor.
flashing bulb that hangs from the top of its head
what are the challenges to life in the deep sea?
Cold water (2-3oC)
High pressure (up to 1100 atm)
No light or very little light
Limited amount of food
(nutrients moderate but useless)
Moderate amount of oxygen below oxygen minimum layer (500 – 1000 m)
Difficulty in finding mates
Constant conditions (salinity, temperature, oxygen, darkness)
amount of oxygen
Deep ocean has reasonable amount of oxygen because rate
of O2 consumption is minimal, high O2 solubility and
thermohaline circulation
biological adaptation to oxygen
Low metabolic rates (rate of oxygen consumption)
Infrequent & slow movement e.g. plankton, idiot fish
(overfished!)
Haemoglobin with high oxygen affinity – very efficient
at extracting what little oxygen is present
adaptations to temperature
Low metabolic rates
Low activity levels
adaptations to pressure
No air spaces / no swim bladders in deep sea fishes
Flabby / gelatinous bodies e.g. jellies, ctenophores,
siphonophores, many fishes
Minimal calcification of bones so that they are soft and
flexible
adaptations to light
Large eyes to capture limited light e.g. squid
Tubular eyes e.g. barreleye fish
Yellow lenses to detect photophore light (Blue Planet fish)
Excellent sense of smell
Pigmentation: camouflage with colour (black, red,
silver) or lack of pigment (transparent)
Some species have an orange- or red-coloured gut so
that they can eat bioluminescent prey and not be
detected themselves e.g. jellies, shrimps
Countershading
Bioluminescence
proposed applications of engineered bioluminescence
Glowing trees to line highways to save government
electricity bills
Christmas trees that do not need lights, reducing danger
from electrical fires
Agricultural crops and domestic plants that luminesce
when they need watering
New methods for detecting bacterial contamination of
meats and other foods
Bio-identifiers for escaped convicts and mental patients
Detecting bacterial species in suspicious corpses
Novelty pets that bioluminesce (rabbits, mice, fish)
adaptations to food
Some food drifts down from upper layers of ocean e.g.
whale carcasses, marine snow, dead plankton, detritus
(vampire squid)
Vertical migration (find food in shallows)
Large mouths e.g. gulper eel
Hinged jaws e.g. stoplight loosejaw fish
Long teeth that point inward e.g. viper fish
Large expandable stomachs e.g. black swallower
Ambush predators rather than expending a lot of energy
searching for food
Bioluminescent lure to attract prey e.g. anglerfish
Male anglerfish is permanently attached to and receives
nutrition from female
adaptations to reproduction
Bioluminescence to help find mates
Excellent sense of smell
Male anglerfish has a special organ to locate female
anglerfish - he provides sperm to the female to which he
is permanently attached (and she provides nutrients to
him)
gigantism
Lack of substrate for pelagic species means that
they can be very large e.g. the siphonophore Praya
can be up to 40 m long
human impacts
minimal
Both on deep sea ecosystems and (especially) on
hydrothermal vent ecosystems due to their inaccessibility
But over time marine litter & chemical pollutants can make
their way to the deep sea and wastes (including nuclear waste)
have been stored in the deep sea
Overfishing e.g. idiot fish
Bottom trawling is damaging to seamount ecosystems
Climate change and ocean acidification
Ocean acidification decreasing marine snow sinking rates
Scientists exploring the deep sea
Deep sea mining is an impending issue
