Pore water alkalinity below the permanent halocline in the Gdańsk Deep (Baltic Sea) - concentration variability and benthic fluxes
Katarzyna Łukawska-Matuszewska , Bożena Graca
AbstractIn the present work, spatial and temporal variability of benthic ﬂuxes of total alkalinity (AT) and the eﬀect of pyrite burial on sedimentary AT release was studied in the Gdańsk Deep (max. depth of 118m) located in thesouthern Baltic Sea. Cores of surface sediment were collected in summer and winter at three locations. Concentrations of carbonate and non-carbonate (dissolved sulﬁde, ammonia, phosphate, silicate, borate and sulfate) constituents of AT were analyzed in pore water and their sediment-water diﬀusive ﬂuxes were estimated using Fick's I Law. Benthic ﬂux of AT was calculated as the sum of ﬂuxes of particular components. Pyrite burial rate in sediment was estimated based on analysis of pyrite sulfur. The average diﬀusive ﬂux of AT was 1397 ± 511 μmol m−2 day−1 and was dominated by bicarbonate and carbonate. The main non-carbonate component of AT ﬂux was hydrogen sulﬁde with contribution of 1–30%. Assuming complete oxidation of sulﬁde released from the sediment to the bottom water, the net ﬂux of AT in the study area was 1263 ± 518 μmol m−2 day−1. The average pyrite burial rate estimated for the last several hundred years was 242 ± 28 μmol m−2 day−1. This indicates that pyrite formation on average generates 38% of the net AT ﬂux from sediment into the water column of the Gdańsk Deep. These ﬁndings suggest that anaerobic respiration of organic matter and subsequent pyrite formation may have considerable eﬀect on the benthic ﬂuxes of alkalinity in the Baltic Sea.
|Journal series||Marine Chemistry, ISSN 0304-4203, (A 40 pkt)|
|Publication size in sheets||0.6|
|Keywords in English||alkalinity benthic flux, pyrite burial rate, organic matter anaerobic respiration, Baltic Sea|
|ASJC Classification||; ; ;|
|Score||= 40.0, 28-01-2020, ArticleFromJournal|
|Publication indicators||= 3; : 2017 = 1.213; : 2018 = 2.713 (2) - 2018=3.779 (5)|
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