Sedimentary Anaerobic Microbial Biogeochemistry in the Gulf of Trieste, Northern Adriatic Sea: Influences of Bottom Water Oxygen Depletion

• Published in: Biogeochemistry 1997-10, Vol.39 (1), p.65-86
• Main Authors: Hines, Mark E., Faganeli, Jadran, Planinc, Rado
• Format: Article
• Language: English
• Subjects: Biogeochemistry; Bioturbation; Bottom water; Carbon; Earth sciences; Earth, ocean, space; Exact sciences and technology; Geochemistry; Marine; Marine and continental quaternary; Microbiology; Nitrates; Oxidation; Oxygen; Oxygen depletion; Pore water; Sea water; Sediment samplers; Sediments; Slurries; Soil and rock geochemistry; Sulfate reduction; Sulfates; Sulfides; Surficial geology
• ISSN: 0168-2563; 1573-515X
• DOI: 10.1023/A:1005806508707

Sediment samples from two locations in the Gulf of Trieste (northern Adriatic Sea) were collected during periods of maximum and minimum temperatures for two years. Both sites were rich in carbonate material and inhabited by a diverse benthic infaunal community. However, Site F exhibited a deeper dwelling faunal community, higher content of carbonate minerals, and larger grained sediments than at site MA, which was closer to shore. Depth profiles of sulfate reduction and potential rates of iron and manganese reduction were determined together with measurements of pore water and solid phase chemistry. Bottom waters at all sites were nearly saturated with oxygen for all of the dates sampled except for September 1993 when bottom waters at site F were less than 50% saturated. Sulfate reduction rates were as high as 400 nmol ml-1 day-1 during late summer and fall when temperatures were >20 °C, while rates during March (∼8 °C) were