Transcript Subtidal and Deep Sea

SUBTIDAL:
Sampling:
• Grabs & Box – corers
•Thorson - 1900’s
• Peterson - 1918
•Sanders - 1958
• Rhoads & Young - 1970
DEEP-SEA:
• Planktonic supply of organic matter to the
benthos decreases with depth and distance from
the shore
• In estuaries, 30-50% of the annual 1º
production reaches bottom sediments
• At 2000-5000 m, only 2-7%
• Very refractory - VERTEX (Wakeham et al.)
• Sinking
per
rates vary from weeks to over a year
1000 m
• As carbon input decreases to the deep sea, so
does benthic metabolism
• Total oxygen consumption decreases greatly
with depth from the shelf to the deep sea
• 11-80 m - 4-40 ml O2 h-1
vs
1325-2900 m - 0.6- 4.5 ml O2 h-1
• Microbial dynamics in deep sea poorly
understood
•Holgar Jannasch - “Alvin Lunch” - Accident
discovery - 1968 – 1540 m - loss of Alvin
overboard; no one killed, recovered 10
months later, NO DECOMPOSITION of the
lunches that were aboard Alvin.
•incubated deep-sea and shallow water bacteria on
C-14-labeled substrates in experimental in-situ
chambers at 5300 m and 1830 m
• <2% of what was in lab at 3 °C
• (Jannasch,
1971) Suggests that increase in
hydrostatic pressure raises the minimal bacteria
growth temperature
• biomass changes with depth (limited by food
supply) *see figure*
• (Dayton & Hessler, 1972): Low rates of predation
might exert regulation effects
• Tunnicliffe, 1991)- High biomass: sloping portions
of trenches - rapid downward transport - Aleutian
Trench. Benthic-Pelagic Coupling – Smith (1998) – Benthic
boundary layer (BBL)
Vents:
• Ballard (1977) - hot vent community
• Amer., French, Canadian, Soviet and
Japanese collaboration on the discovery
• Vent Field - cluster of vents linked in
subsurface
• Vent Site - general area - may include a few
vent fields
• The size of a vent can range in size from 2 m to a
football stadium
• Typically found at the crests of Mid-Ocean Ridge
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History:
Corliss et al., 1979 (Science)
Jannasch et al., 1979 (Bioscience)
Karl et al., 1980 (Science)
Cavanaugh et al., 1981 (Science)
Lutz et al., (Science)
Grassle, 1985 (Science)
Smith et al., 1989 (Nature)
Van Dover, 1990 (Nature)
• Richard
Lutz - - most vent species probably have
lecithotrophic larvae - low temperatures can slow
development and increase larval life
• Comparison of pure hydrothermal fluids with
ambient deep-sea water that are of biological
significance include:
• up to 400°C, pH = 3.2, high sulfide 350 uM,
salinity typically 2 x, oxygen, nitrite, phosphorus
not present.
• Mg - not in vent water, but used to test for purity
• In
the presence of dissolved sulfide ions formation of polymetallic sulfide deposits chemosynthetic microbes (organic carbon)
• Best known vent sites are those on the
Galapagos Rift, East Pacific Rise
• Scales of variability influence biological
processes (see diagrams)
Vent Organisms:
Phylum Pogonophora – Vestiminifera
Lack mouth and gut, Riftia pacyptila and
Ridgeia spp. – 10-155 kg/m2 - can grow 1.5 m
in 1.5 years Harbor symbiotic
chemoautotrophic sulfide-oxidizing
bacteria in vascularized tissue
(trophosome). Manufacture ATP with
energy from sulfide oxidation and reduce
CO2 to organic matter. Have specialized
hemoglobin which binds oxygen to sulfide
for transport to the trophosome.
Limpets, mussels (Mytilidae) Bathymodiolus
brevior, clams Calyptogena magnifica,
crabs Bythograea therydron
Refugia?? - Taxonomic novelty may be
survivors of Mesozoic and Cenozoic
extinctions