Deep Sea Adaptations (Guest Lecture) Flashcards
The sinking of the titanic helped to develop ___. How? What is it?
SONAR= sound navigation and ranging
b/c they wanted a technology to find the titanic
- sound bounces off of objects; can see shapes/ topography
How was a lead line used to map the ocean floor?
a line was dropped off the ship with lead at the end (it dropped to the bottom)- then measured how far it went down
- one of the earliest methods for determining depth
How does echo sounding map the ocean floor?
uses pulses of sound that rebound from the ocean floor
How does side-scan sonar map the ocean floor? Give 2 advantages of this method
used fan-shaped pulses of sound to generate 3D maps over small areas
benefits:
-can map in swaths, not just certain points= easier to get an idea of a whole area
- high frequency gives high resolution
echo sounding bounces back quickly from a ___ sea floor surface, and penetrates deeper into a ___ seafloor
rocky (little penetration)
muddy
For accurate mapping, ____ scanning and ____ altimetry are used
For example, multibeam echo sounders use multiple ___ of sound ____
multibeam
satellite
frequencies
simultaneously
How does satellite altimetry work? Why does this work?
measures the time taken by a radar pulse to travel from the satellite antenna to the surface of the ocean and back to the satellite receiver
- it doesn’t have to see through the water; it measures the height of the water itself
This works because water forms a ‘bump’ over underwater mountains because gravity causes attraction of water to the feature
- very accurate! up to 3cm
When collecting specimens, the HMS challenger missed a lot of ___-___ animals. why?
soft bodied (gelatinous animals)
b/c they are fragile and they used aggressive collection
pelagic=
lives in the water column of the sea
Pelagic communities are further classified horizontally:
___= near shore
___= open water
neritic
oceanic
The ocean can be classified by levels of light.
Areas where light penetrates= ____ zones
Areas with no light penetration= ___ zones
- the upper ___ zone is _photic, and the lower zone is __photic
photic
aphotic
upper photic zone= euphotic (lots of sunlight)
lower photic zone= dysphotic (much less sunlight- photosynthesis not possible but can use light to see a bit)
The ___ wavelength is lost first as you go deeper into the ocean
___(long/short) wavelengths are lost first, and ___ remain at deeper depths
red
long
blue
List the names of pelagic layers (shallowest to deepest) as you go down the water column
- Epipelagic (continental shelfs ~200m
- Mesopelagic (to 1000m)
- Bathypelagic (1000-3000m)
- Abyssopelagic (below 3000m)
- Hadalpelagic (in a trench)
The supply of nutrient-rich particles to the deep sea is ___(low/high). This depends on:
1
2
3
low
- distance from shore
- depth and time of travel of material from surface to bottom (decomp- deeper= more time to decompose)
- low primary production over remote deep sea bottoms
organic matter flux in the deep sea comes from the ___
surface
ie input of organic matter from the water column declines with depth and distance from shore
T/F
biodiversity changes linearly with depth
false!
the graph is an upside-down parabola
conditions at different depths determine what can live there
Why are carnivorous animals less common in the abyssal bottoms?
fewer potential prey species
- they also need lots of oxygen to chase prey etc, and there is not much oxygen there
t/f
the ocean is the most common living habitat in our biosphere
true!
Physical characteristics of the pelagic deep sea:
1. No ___ deeper than 1000m
2. Mean temp= __C
3. constant ____ (34-35ppt)
4. ___ available except for ___ ___ zone
light (very dark)
3.5 (cold)
salinity
oxygen
oxygen minimum zone
Physical characteristic of the pelagic deep sea:
1. gradients of inorganic nutrients are steep in the ____ zone
2. particles are lost as they ___ through the ___ zone
3. high ___ (increases by 1atm per __m depth)
4. some ____
mesopelagic
*important for upwelling
sink
mesopelagic
pressure
1atm/ 10m
seasonality
nutrients may be high in areas where phytoplankton can’t grow. Why?
they’re not being taken out of the water by phytoplankton!
ie nutrients is not the limiting factor for phytoplankton growth (may be light etc)
Azoic zone hypothesis=
conditions are so unfavorable in the deep sea that there should be no life down there
proved wrong by challenger etc
Explain the accidental Alvin Lunchbox Experiment and what it implies
Lunch slipped offboard and sunk to 1500m- they recovered it months later and found it very well preserved
- greater preservation in the deep sea! From pressure? much slower decomp rate
What is marine snow?
Non-living organic particles that are visible to us; detritus that has formed at the surface
(it’s the food!!)
What is marine snow? List 5 things it can be
- dead organisms (phytoplankton, kelp, pollen, insects, etc)
- fecal pellets
- mucus products (filter structure secreted by zooplankton like larvacean houses)
- secretions of organisms
- bubbles
Give 2 reasons why marine snow is so important
- microhabitat: for associated organisms; generally microorganisms are found at [high] where there’s marine snow (it’s a FOOD SOURCE)
- transport: of surface derived organic matter to depth
Why are crustacean fecal pellets so important?
they’re covered with a layer of polysaccharides; it’s a dense package that can sink to the bottom quickly
- They’re important for bringing nutrients and carbon to the seafloor quickly
Explain the small scale ecological succession that occurs after marine snow enters the water
- marine snow enters water
- colonized by bacteria
- bacteria decrease, colonized by flagellates
- flagellates decrease, colonized by ciliates
what are 3 advantages for organisms who interact with marine snow?
-food
- can use the buoyancy of marine snow to save energy
- travel on them= guaranteed dispersal for larvae etc
Most carbon is remineralized in the upper 1000m of the sea- so how do mesopelagic/ deep sea organisms get food? List 5 ways
- detritus/ marine snow
- vertical migration to the surface to feed
- “ladder of vertical migration’ predation (daily migration of predators- they chase the herbivores who move up to feed)
- predation
- chemosynthesis at hydrothermal vents/ spreading zones
What differences might you expect in 2 mesopelagic fish that live at the same depth, but one migrates up to feed and one doesn’t?
In the one that migrates:
- bigger eyes to see (more light up there)
- swim bladder to help with buoyancy
- well developed bones and muscles to swim up and big distances
opposite in the one that doesn’t migrate
The 3 major adaptations to the deep sea have to do with (list 3)
feeding
mating
bioluminescence
