Deep Sea (aphotic) - Chapter 11 Living Conditions on the...

Info iconThis preview shows pages 1–18. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Living Conditions on the Deep-Sea Floor Most of the seafloor is covered with thick accumulations of fine sediment particles, mineralized skeletal remains of planktonic organisms = OOZES Ooze accumulates very slowly (about 1 cm/1000 yr). Chapter 11
Background image of page 2
Living Conditions on the Deep-Sea Floor
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Transfer of Oxygen and Energy to the Deep Sea The diffusion and sinking of cold dense water masses are the chief mechanisms of O 2 transport into the deep sea – thermohaline circulation Dissolved O 2 is slowly diminished by animals and bacteria, leaving an O 2 minimum zone at intermediate depths. But cold water is better at holding dissolved oxygen – and water gets colder with depth So below this zone, dissolved O 2 gradually increases to just above the sea bottom. Chapter 11
Background image of page 4
Figure 16.03
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Figure 16.20
Background image of page 6
Transfer of Oxygen and Energy to the Deep Sea Food for deep-sea benthic communities sinks from above at rates that are tightly coupled with primary productivity at the sunlit surface. More productivity – more sinking food. Chapter 11
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Transfer of Oxygen and Energy to the Deep Sea Seafloor images showing the deposition of phytodetritus before (a) and 2 months after (b) a phytoplankton bloom in the photic zone above
Background image of page 8
Life in the Depths Organisms consume food materials as they descend, so food supply decreases as depth in the water column increases – this means fewer organisms can be supported by the ecosystem There are 5x to 10x fewer organisms at 500m than at the surface There are 10x fewer organisms than this at 4000m Chapter 11
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Figure 16.01
Background image of page 10
Mesopelagic Zone The mesopelagic region ranges from approx 200m to 1000m There is a small amount of dim light present during the day – filtering down from the surface Below 1000m there is a complete absence of any light (the end of the mesopelagic) The main thermocline (change in water temperature) occurs in the mesopelagic – below which temperature remain relatively constant Chapter 11
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Mesopelagic Species Zooplankton are found in the mesopelagic (generally similar groups as in the surface epipelagic waters) Krill and copepods, and various shrimp species are the dominant zooplankton Many have PHOTOPHORES or light producing organs OSTRACODS are common – these crustaceans have a shell or CARAPACE which makes them look like clams with legs (but they are not related to bivalves) Amphipods and other crustaceans are also found Chapter 11
Background image of page 12
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 14
Mesopelagic Species Arrow worms (chaetognaths) are major predators in this zone and can be a major component of the zooplankton, especially in the upper mesopelagic Chapter 11
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Jellyfish and siphonophores (colonial jellyfish) Larvaceans (pelagic tunicates/sea squirts) Ctenophores (comb jellies) Pteropods (sea butterflies) - mollusks
Background image of page 16
Mesopelagic Species Squid are also prominent in the mesopelagic Some swim weakly and are planktonic Others are strong swimmer = nekton They often have photophores arranged in different patterns for different species
Background image of page 17

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 18
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 69

Deep Sea (aphotic) - Chapter 11 Living Conditions on the...

This preview shows document pages 1 - 18. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online