SUBTIDAL:

1

• SUBTIDAL
• Sampling
• Grabs Box corers
• Thorson - 1900s
• Peterson - 1918
• Sanders - 1958
• Rhoads Young - 1970

2

• 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.)

3

• Sinking rates vary from weeks to over a year per
  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

4

• 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
• lt2 of what was in lab at 3 C

5

• (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)

6

• 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

7

• 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
• 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)

8

• 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 400C, 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

9

• 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)

10
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.
11

• Limpets, mussels (Mytilidae) Bathymodiolus
  brevior, clams Calyptogena magnifica, crabs
  Bythograea therydron
• Refugia?? - Taxonomic novelty may be survivors of
  Mesozoic and Cenozoic extinctions