Biogenic matter diagenesis on the sea floor: A comparison between two continental margin transects
Biogenic matter diagenesis on the sea floor: A comparison between two continental margin transects
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DOI：
10.1357/0022240963213673
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发表时间：
1996-07-01
影响因子：
0.5
通讯作者：
Pilskaln, C
中科院分区：
文献类型：
--
作者：
Berelson, WM;McManus, J;Pilskaln, C
底栖室对与生物物质成岩作用有关的反应物和产物（氧、铵、硝酸盐、硅酸盐、磷酸盐、TCO2、碱度）进行测量，用于确定这些溶质进出加利福尼亚州南部和中部沉积物的通量。陆上到近海横断面表明这些区域之间的底栖通量有许多相似之处。底栖有机碳氧化随水深变化的模式，结合已发表的沉积物捕集记录，表明垂直降雨提供的有机碳刚好可以满足加州中部地区100-3500 m深度之间的沉积碳氧化+埋藏需求。然而，没有足够的有机碳雨通过上部水柱来支持其在南加州附近盆地的氧化和埋藏。建议在这些盆地内横向传输和集中难熔碳，以解释埋藏的碳。尽管碳雨率相当，但南加州的有机碳埋藏效率 (40-60%) 高于加州中部 (2-20%)。吸氧率对底层水氧浓度和总体重量不敏感。表层沉积物中的有机碳百分比。硝酸盐吸收率由氧气渗透到沉积物中的深度和上覆水柱硝酸盐浓度来明确定义。硝酸盐吸收约占陆架沉积物中发生的总反硝化作用的 50%，反硝化作用 (0.1-1.0 mmolN/m(2)d) 发生在整个研究区域。海门上氧化碳与溶解的蛋白石的比率在很宽的深度范围内都是恒定的 (0.8 +/- 0.2)，这支持了蛋白石溶解动力学可能由高反应性相主导的假设。海底碳酸盐溶解在氧气最小区域内可以忽略不计，并且在该区域的上方和下方达到最大速率（0.2-2.0 mmol/m(2)d）。
Benthic chamber measurements of the reactants and products involved with biogenic matter diagenesis (oxygen, ammonium, nitrate, silicate, phosphate, TCO2, alkalinity) were used to define fluxes of these solutes into and out of the sediments off southern and central California. Onshore to offshore transects indicate many similarities in benthic fluxes between these regions. The pattern of benthic organic carbon oxidation as a function of water depth, combined with published sediment trap records, suggest that the supply of organic carbon from vertical rain can just meet the sedimentary carbon oxidation + burial demand for the central California region between the depths 100-3500 m. However, there is not enough organic carbon raining through the upper water column to support its oxidation and burial in the basins off southern California. Lateral transport and focusing of refractory carbon within these basins is proposed to account for the carbon buried. The organic carbon burial efficiency is greater off southern California (40-60%) compared to central California (2-20%), even though carbon rain rates are comparable. Oxygen uptake rates are not sensitive to bottom water oxygen concentrations nor to the bulk wt. % organic carbon in surficial sediments. Nitrate uptake rates are well defined by the depth of oxygen penetration into the sediments and the overlying water column nitrate concentration. Nitrate uptake accounts for about 50% of the total denitrification taking place in shelf sediments and denitrification (0.1-1.0 mmolN/m(2)d) occurs throughout the entire study region. The ratio of carbon oxidized to opal dissolved on the sea door is constant (0.8 +/- 0.2) through a wide range of depths, supporting the hypothesis that opal dissolution kinetics may be dominated by a highly reactive phase. Sea floor carbonate dissolution is negligible within the oxygen minimum zone and reaches maximal rates just above and below this zone (0.2-2.0 mmol/m(2)d).