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Transport and mineralization rates in North Sea sandy intertidal sediments, Sylt‐Rømø Basin, Wadden Sea
Author(s) -
de Beer Dirk,
Wenzhöfer Frank,
Ferdelman Timothy G.,
Boehme Susan E.,
Huettel Markus,
van Beusekom Justus E. E.,
Böttcher Michael E.,
Musat Niculina,
Dubilier Nicole
Publication year - 2005
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2005.50.1.0113
Subject(s) - intertidal zone , total organic carbon , organic matter , mineralization (soil science) , water column , environmental chemistry , sediment , sulfate , pore water pressure , oceanography , chemistry , environmental science , geology , nitrogen , geomorphology , geotechnical engineering , organic chemistry
We investigated the rates of the main microbiological processes (primary production, aerobic and anaerobic carbon degradation) and transport phenomena in an intertidal sand plate with a combination of in situ microsensor measurements and incubations. The sand was coarse, organically poor (0.6–1 mg of total organic carbon per gram dry weight of sediment), and highly permeable to water flow ( k = 1.5–7 x 10 −11 m 2 ). Aerobic respiration rates ranged from 105 to 175 mmol m 2 d −1 , sulfate reduction rates from 0.08 to 13.7 mmol m 2 d −1 , and net primary production ≪35 mmol m 2 d −1 . In situ microsensor measurements showed large changes in oxygen and sulfide concentrations in the top 10 cm, depending on tides and waves. The observed dynamics and high aerobic degradation rates imply that pressure gradients drive advective influx of oxygen and organic material from the water column into the sediments. Our results show that intertidal porous sand plates have high aerobic degradation rates, despite having an organic matter content that is one to two orders of magnitude lower than that of fine‐grained deposits with similar decomposition rates.