FIELD DISTRIBUTION AND SULFIDE TOLERANCE OF CAPITELLA-CAPITATA (ANNELIDA, POLYCHAETA) AROUND SHALLOW WAFER HYDROTHERMAL VENTS OFF MILOS (AEGEAN SEA) - A NEW SIBLING SPECIES
I. Gamenick et al., FIELD DISTRIBUTION AND SULFIDE TOLERANCE OF CAPITELLA-CAPITATA (ANNELIDA, POLYCHAETA) AROUND SHALLOW WAFER HYDROTHERMAL VENTS OFF MILOS (AEGEAN SEA) - A NEW SIBLING SPECIES, Marine Biology, 130(3), 1998, pp. 447-453
The cosmopolitan polychaete Capitella capitata, known as a complex of
opportunistic sibling species, usually dominates the macrobenthos of p
olluted or unpredictable environments. PL population of C. capitata, t
ermed Capitella sp. M, was found in a shallow water hydrothermal vent
area south of Miles (Greece). Here, this population occurs close to ve
nt outlets (termed the ''transition zone''), an environment with steep
gradients of temperature, salinity and pH and increased sulphide conc
entrations of up to 710 mu M. The field distribution of C. capitata in
relation to sulphide concentrations around the vent outlets was inves
tigated and sulphide tolerance experiments were conducted on laborator
y-cultured worms to elucidate possible adaptations of Capitella sp. M
to these extreme environmental conditions. In order to investigate whe
ther the population from the Miles hydrothermal vent area can be consi
dered a distinct sibling species within the C. capitata complex, cross
breeding experiments and analysis of general protein patterns were con
ducted with Capitella sp. M and three other C. capitata populations of
different ecological ranges. Capitella sp. M showed high resistance (
median survival time: 107 +/- 38 h) to anoxia plus high sulphide conce
ntrations of 740 mu M. It seems that the ability to survive high-sulph
ide conditions in combination with reduced interspecific competition e
nables the polychaete to maintain a continuous population in this rigo
rous habitat. From the extremely high tolerance to anoxia and sulphide
, shown in both the crossbreeding experiments and the analysis of tota
l proteins, it can be concluded that Capitella sp. M from the Miles hy
drothermal vent area represents a separate sibling species within the
C. capitata complex.