TY - JOUR
T1 - Spatially and temporally variable sulfur cycling in shallow-sea hydrothermal vents, Milos, Greece
AU - Houghton, Jennifer L.
AU - Gilhooly, William P.
AU - Kafantaris, Fotios Christos A.
AU - Druschel, Gregory K.
AU - Lu, Guang Sin
AU - Amend, Jan P.
AU - Godelitsas, Athanasios
AU - Fike, David A.
N1 - Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2019/1/20
Y1 - 2019/1/20
N2 - Shallow-sea hydrothermal systems are ideal for studying the relative contributions to sedimentary sulfur archives from ambient sulfur-utilizing microbes and from fluxes of hydrothermally derived sulfur. Here we present data from a vent field in Palaeochori Bay, Milos, Greece using a suite of biogeochemical analytical tools that captured both spatial and temporal variability in biotic and abiotic sulfur cycling. Samples were collected along a transect from a seagrass meadow to an area of active venting. The abundance and isotopic composition of sulfide captured in situ, together with geochemistry from sedimentary porewaters and the overlying water column and solid phase sulfide minerals, record evidence of ephemeral activity of microbial sulfate reduction as well as sulfide oxidation. The sulfur and oxygen isotope composition of porewater sulfates indicate active sulfate reduction within the transition zone between the vents and seagrass, rapid recycling of biologically produced sulfide within non-vent sediments, and reoxidation of abiotic sulfide within the vent field. A phylogenetic survey of sediments also indicates the pervasive presence of a suite of putative sulfur-metabolizing bacteria, including sulfate reducers and sulfide oxidizers, many of which can utilize intermediate valence sulfur compounds. The isotopic composition of pyrite in these sediments consistently records a microbially influenced signature (δ 34 S py of −4.4 to −10.8‰) relative to the hydrothermal endmember (δ 34 S ~ + 2.5‰), independent of distance from the vent source. The narrow range of pyrite δ 34 S across sediments with a highly variable hydrothermal influence suggests that physical mixing (e.g., by storm events) homogenizes the distribution of biogenic and hydrothermal Fe-sulfides throughout the region, overprinting the spatially and temporally variable interplay between biological and hydrothermal sulfur cycling in these environments.
AB - Shallow-sea hydrothermal systems are ideal for studying the relative contributions to sedimentary sulfur archives from ambient sulfur-utilizing microbes and from fluxes of hydrothermally derived sulfur. Here we present data from a vent field in Palaeochori Bay, Milos, Greece using a suite of biogeochemical analytical tools that captured both spatial and temporal variability in biotic and abiotic sulfur cycling. Samples were collected along a transect from a seagrass meadow to an area of active venting. The abundance and isotopic composition of sulfide captured in situ, together with geochemistry from sedimentary porewaters and the overlying water column and solid phase sulfide minerals, record evidence of ephemeral activity of microbial sulfate reduction as well as sulfide oxidation. The sulfur and oxygen isotope composition of porewater sulfates indicate active sulfate reduction within the transition zone between the vents and seagrass, rapid recycling of biologically produced sulfide within non-vent sediments, and reoxidation of abiotic sulfide within the vent field. A phylogenetic survey of sediments also indicates the pervasive presence of a suite of putative sulfur-metabolizing bacteria, including sulfate reducers and sulfide oxidizers, many of which can utilize intermediate valence sulfur compounds. The isotopic composition of pyrite in these sediments consistently records a microbially influenced signature (δ 34 S py of −4.4 to −10.8‰) relative to the hydrothermal endmember (δ 34 S ~ + 2.5‰), independent of distance from the vent source. The narrow range of pyrite δ 34 S across sediments with a highly variable hydrothermal influence suggests that physical mixing (e.g., by storm events) homogenizes the distribution of biogenic and hydrothermal Fe-sulfides throughout the region, overprinting the spatially and temporally variable interplay between biological and hydrothermal sulfur cycling in these environments.
KW - Fe-sulfide minerals
KW - Milos Island
KW - Oxygen isotopes
KW - Palaeochori Bay
KW - Shallow-sea hydrothermal systems
KW - Sulfur cycling
KW - Sulfur isotopes
UR - https://www.scopus.com/pages/publications/85057483561
U2 - 10.1016/j.marchem.2018.11.002
DO - 10.1016/j.marchem.2018.11.002
M3 - Article
AN - SCOPUS:85057483561
SN - 0304-4203
VL - 208
SP - 83
EP - 94
JO - Marine Chemistry
JF - Marine Chemistry
ER -