An abyssal hill fractionates organic and inorganic matter in deep-sea surface sediments

作者：Turnewitsch Robert^*; Lahajnar Niko; Haeckel Matthias; Christiansen Bernd

来源：Geophysical Research Letters, 2015, 42(18): 7663-7672.

DOI：10.1002/2015GL065658

• abyssal hill
• abyssal mountain
• benthos
• carbon
• amino acid
• fluid dynamics

Current estimates suggest that more than 60% of the global seafloor are covered by millions of abyssal hills and mountains. These features introduce spatial fluid-dynamic granularity whose influence on deep-ocean sediment biogeochemistry is unknown. Here we compare biogeochemical surface-sediment properties from a fluid-dynamically well-characterized abyssal hill and upstream plain: (1) In hill sediments, organic-carbon and -nitrogen contents are only about half as high as on the plain while proteinaceous material displays less degradation; (2) on the hill, more coarse-grained sediments (reducing particle surface area) and very variable calcite contents (influencing particle surface charge) are proposed to reduce the extent, and influence compound-specificity, of sorptive organic-matter preservation. Further studies are needed to estimate the representativeness of the results in a global context. Given millions of abyssal hills and mountains, their integrative influence on formation and composition of deep-sea sediments warrants more attention.

• 出版日期2015-9-28