Deep Sea Communities Flashcards
Hydrothermal vents are found at _-____ ___ and _____ zones
they were discovered in ___ using a submersible
mid-ocean ridges
subduction zones
1977
vents are ____(reducing/ oxidizing) habitats
sulfate is ___ to hydrogen sulfide
reducing
reduced
Water coming up from hydrothermal vents is heated ___ and rises up at __-__ degrees, which reduces SO4 2- to ___
underground
350-400 C
H2S
2 main threats to sponge reefs and deep cold water reefs:
- trawl fishing
- oil and gas exploration
plumes of hot water from vents are inhabited by masses of ___ and ___
Also, at these high temps, the water can carry more heavy ___, including __ and ___
bacteria and archaea
metals
iron and sulfides
tube worms are abundant at ___.
How do they get energy here?
vents
They have plumes- sets of tentacles that pass the water over itself to respire and take up H2S
Unusual features of tube worms (riftia pacifica):
- a beard of ciliated ___
- no ___ in trunk region
- no functional ___ as adults
- instead, they have a ___, which contains ___
tentacles
segmentation
gut
trophosome, bacteria (to do chemosynthesis)
Explain the energy process of tube worms
worm takes up H2S, CO2 and O2 from the water through tentacles
passes these to the trophosome where it cultures the bacteria
these bacteria use the energy obtained from oxidizing H2S and O2 to generate ATP
The worm eats the bacteria! (farms and digests them in the trophosome)
Give 2 pieces of evidence that tube worms are Annelid worms:
- larva is a trochophore with a mouth and gut
- segmented opisthosoma
t/f
tube worms have a mouth and gut as a larvae, but not as an adult
true!
can still digest the bacteria it farms in the trophosome
Parts of tube worms (annelids):
Obturactulum=
Vestimentum=
____= houses the trophosome
___= end of the body: a segmented region with setae that are diagnostic of the species
Obturaculum= tentacles for respiration
Vestimentum= collar- secretes tube
Trunk = houses the trophosome
Opisthosoma = end of the body: a segmented region with setae that are diagnostic of the species
What are setae?
protein structures like claws
- allows them to anchor
Blind shrimp have no eyes, just a ___ ___
They live at a ___ vent in Atlantic Ocean and feed on ____
light organ
hydrothermal
bacteria (via gills)
How do blind shrimp (Rimicaris) tell where the vent is?
Has no eyes, but has a visual organ that sense black-body radiation from the vent
Yeti crabs farm bacteria for food on their ___
arms
Cold seeps can be found at ____ in ___ zones and the bases of ____ slopes
give an example location of each
trenches in subduction zones
eg. japan chile
continental
eg gulf of mexico, north sea
t/f
similar to hydrothermal vents, oxidizing chemicals are present at cold seeps
false
reducing chemicals at both vents and seeps
what’s the biggest different between hydrothermal vents and seeps?
temp!
seeps are cold
like hydrothermal vents, cold seeps frequently support a large biomass based on ___ production (eg. __ worms)
chemosynthetic
tube
Methane can seep out of the ocean floor and bubble out. What can happen to it?
- can bubble out and up towards surface (gets used)
- can become compressed because of deep-sea pressure and become a solid on the seafloor
What happens to a whale when it dies?
It falls to the seafloor and feeds a whole community that live off of its organic material
Whale skeletons decompose ____, and ___ bacteria grow on the vertebrae of the whale.
____ animals (like worms, ___, snails) settle on the vertebrae and feed off the bacteria
anaerobically (no oxygen)
methane
vent
sponges
What is the Osedax worm (zombie worms)? What does it eat and what did it used to eat before that?
a bone-eating worm that feeds on whale falls
It came about long before whales did, so it used to feed on dead dinosaurs (in the sea) before whales!
____ ____ reefs are deep water reefs that were discovered in 1987 in the pacific northwest and have since been destroyed in many places
glass sponge reefs
Glass sponges built massive reefs during the Jurassic forming a ___km belt along the northern margin of the ___ ____
7000km
Tethys sea
Glass sponge reefs disappeared during the ___; competition for silica by ___ is blamed for their demise
The Tethys sea was then ___ due to __ drift
Cretaceous
diatoms
lost due to continental drift
t/f
There are no remaining fossils/ evidence of the glass sponge reefs that were in the Tethys sea
false
today that reef can be found in the rocks in europe!
Where can sponge reefs be found now? Where in the ocean do they live?
North of Vancouver Island!
They live in iceberg scours (where icebergs have dragged into the seafloor and left scars; ‘rivers’ run through this with sediment)
How do we see the sponge reefs using technology?
Sidescan sonar!
Sponge reefs are reflective and appear white
The continental shelf is __-__m deep
200-300
The sponge reefs are:
- formed on boulders at the edge of ___ ___
- up to __km long and up to 21m thick
- living sponges are up to __ years old
- The reefs as structures are up to ___ years old, as determined by ___ (ie as soon as ___ left, sponge reefs colonized)
iceberg scours
35km
200yrs
6000yrs
cores
glaciers
Why did sponge reefs only live in the Tethys Sea and now only here?
- Substrate-
- Silicate Levels-
- Temp-
- Light-
- Food-
- substrate- need bare rock and light sediment to cement reef
- silicate levels- much higher concentrations at depth
- temp- cold water (5-12C)
- light- don’t like light
- food- bacteria and flow are abundant on the continental shelf
Do sponge reefs have a nervous system?
No, but they can send electrical signals to stop pumping (need cold water for this to work)
How much do sponges filter? What are they filtering?
100,000-300,000L per day
A LOT
they filter the entire water column above them every day= constant food because the water cycles through
they’re filtering out bacteria to eat
Deep water reefs are made of ___, not ___, and are most common at a depth of ___m
calcium, not silica
1000 (continental shelf depths)
t/f
deep water coral reefs have no photosynthetic symbionts, they just feed on plankton
true!
