Deep Sea Communities

Question 1

Hydrothermal vents are found at _-____ ___ and _____ zones
they were discovered in ___ using a submersible

Answer 1

mid-ocean ridges
subduction zones
1977

Question 2

vents are ____(reducing/ oxidizing) habitats
sulfate is ___ to hydrogen sulfide

Answer 2

reducing
reduced

Question 3

Water coming up from hydrothermal vents is heated ___ and rises up at __-__ degrees, which reduces SO4 2- to ___

Answer 3

underground
350-400 C

H2S

Question 4

2 main threats to sponge reefs and deep cold water reefs:

Answer 4

1. trawl fishing
2. oil and gas exploration

Question 5

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 ___

Answer 5

bacteria and archaea
metals
iron and sulfides

Question 6

tube worms are abundant at ___.
How do they get energy here?

Answer 6

vents

They have plumes- sets of tentacles that pass the water over itself to respire and take up H2S

Question 7

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 ___

Answer 7

tentacles

segmentation

gut

trophosome, bacteria (to do chemosynthesis)

Question 8

Explain the energy process of tube worms

Answer 8

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)

Question 9

Give 2 pieces of evidence that tube worms are Annelid worms:

Answer 9

1. larva is a trochophore with a mouth and gut
2. segmented opisthosoma

Question 10

t/f
tube worms have a mouth and gut as a larvae, but not as an adult

Answer 10

true!

can still digest the bacteria it farms in the trophosome

Question 11

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

Answer 11

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

Question 12

What are setae?

Answer 12

protein structures like claws
- allows them to anchor

Question 13

Blind shrimp have no eyes, just a ___ ___
They live at a ___ vent in Atlantic Ocean and feed on ____

Answer 13

light organ

hydrothermal

bacteria (via gills)

Question 14

How do blind shrimp (Rimicaris) tell where the vent is?

Answer 14

Has no eyes, but has a visual organ that sense black-body radiation from the vent

Question 15

Yeti crabs farm bacteria for food on their ___

Answer 15

arms

Question 16

Cold seeps can be found at ____ in ___ zones and the bases of ____ slopes

give an example location of each

Answer 16

trenches in subduction zones
eg. japan chile

continental
eg gulf of mexico, north sea

Question 17

t/f
similar to hydrothermal vents, oxidizing chemicals are present at cold seeps

Answer 17

false

reducing chemicals at both vents and seeps

Question 18

what’s the biggest different between hydrothermal vents and seeps?

Answer 18

temp!
seeps are cold

Question 19

like hydrothermal vents, cold seeps frequently support a large biomass based on ___ production (eg. __ worms)

Answer 19

chemosynthetic
tube

Question 20

Methane can seep out of the ocean floor and bubble out. What can happen to it?

Answer 20

• can bubble out and up towards surface (gets used)
• can become compressed because of deep-sea pressure and become a solid on the seafloor

Question 21

What happens to a whale when it dies?

Answer 21

It falls to the seafloor and feeds a whole community that live off of its organic material

Question 22

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

Answer 22

anaerobically (no oxygen)

methane

vent
sponges

Question 23

What is the Osedax worm (zombie worms)? What does it eat and what did it used to eat before that?

Answer 23

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!

Question 24

____ ____ reefs are deep water reefs that were discovered in 1987 in the pacific northwest and have since been destroyed in many places

Answer 24

glass sponge reefs

Question 25

Glass sponges built massive reefs during the Jurassic forming a ___km belt along the northern margin of the ___ ____

Answer 25

7000km

Tethys sea

Question 26

Glass sponge reefs disappeared during the ___; competition for silica by ___ is blamed for their demise
The Tethys sea was then ___ due to __ drift

Answer 26

Cretaceous

diatoms
lost due to continental drift

Question 27

t/f
There are no remaining fossils/ evidence of the glass sponge reefs that were in the Tethys sea

Answer 27

false

today that reef can be found in the rocks in europe!

Question 28

Where can sponge reefs be found now? Where in the ocean do they live?

Answer 28

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)

Question 29

How do we see the sponge reefs using technology?

Answer 29

Sidescan sonar!
Sponge reefs are reflective and appear white

Question 30

The continental shelf is __-__m deep

Answer 30

200-300

Question 31

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)

Answer 31

iceberg scours

35km
200yrs
6000yrs
cores
glaciers

Question 32

Why did sponge reefs only live in the Tethys Sea and now only here?
- Substrate-
- Silicate Levels-
- Temp-
- Light-
- Food-

Answer 32

• 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

Question 33

Do sponge reefs have a nervous system?

Answer 33

No, but they can send electrical signals to stop pumping (need cold water for this to work)

Question 34

How much do sponges filter? What are they filtering?

Answer 34

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

Question 35

Deep water reefs are made of ___, not ___, and are most common at a depth of ___m

Answer 35

calcium, not silica

1000 (continental shelf depths)

Question 36

t/f
deep water coral reefs have no photosynthetic symbionts, they just feed on plankton

Answer 36

true!