Impact of seawater pCO2 on calcification and Mg/Ca and Sr/Ca ratios in benthic foraminifera calcite: results from culturing experiments with Ammonia tepida
Impact of seawater pCO2 on calcification and Mg/Ca and Sr/Ca ratios in benthic foraminifera calcite: results from culturing experiments with Ammonia tepida
复制标题
DOI：
10.5194/bg-7-81-2010
复制
发表时间：
2010-01-01
期刊：
影响因子：
4.9
通讯作者：
Bijma, J.
中科院分区：
文献类型：
--
作者：
Dissard, D.;Nehrke, G.;Bijma, J.
越来越多的证据表明，溶解的二氧化碳浓度不断增加，特别是在海洋表层，并对钙化生物产生了相关影响。在这些生物中，底栖有孔虫和浮游有孔虫是造成全球大量沉淀碳酸钙的原因。因此，它们对酸化海洋的反应可能对未来的无机碳循环产生重要影响。为了评估底栖有孔虫对二氧化碳水平变化和随后海水碳酸盐化学变化的敏感性，我们在两种大气CO2浓度（230和1900 ppmv）和两种温度（10摄氏度和15摄氏度）下培养了浅水物种Ammonia tepida的标本。壳重和元素组成进行了测定。将高和低pCO（2）对元素组成的影响与在环境条件下生长样品的先前实验的结果进行比较（380 ppvm，然而，没有在环境条件下生长的样品的壳重测量可用）。结果表明，壳重随着[CO 32-]的降低而降低，尽管即使在碳酸钙不饱和的存在下也观察到钙化，并且也随着温度的升高而降低。因此，变暖和海洋酸化可能会在未来减少贝壳重量。[CO 32-]或总溶解无机碳的变化不影响Mg分配系数。相反，增加[CO 32-]会促进Sr的掺入。讨论了这些结果对有孔虫古海洋学应用的影响。
Evidence of increasing concentrations of dissolved carbon dioxide, especially in the surface ocean and its associated impacts on calcifying organisms, is accumulating. Among these organisms, benthic and planktonic foraminifera are responsible for a large amount of the globally precipitated calcium carbonate. Hence, their response to an acidifying ocean may have important consequences for future inorganic carbon cycling. To assess the sensitivity of benthic foraminifera to changing carbon dioxide levels and subsequent alteration in seawater carbonate chemistry, we cultured specimens of the shallow water species Ammonia tepida at two concentrations of atmospheric CO2 (230 and 1900 ppmv) and two temperatures (10 degrees C and 15 degrees C). Shell weights and elemental compositions were determined. Impact of high and low pCO(2) on elemental composition are compared with results of a previous experiment were specimens were grown under ambient conditions (380 ppvm, no shell weight measurements of specimen grown under ambient conditions are, however, available). Results indicate that shell weights decrease with decreasing [CO32-], although calcification was observed even in the presence of calcium carbonate under-saturation, and also decrease with increasing temperature. Thus both warming and ocean acidification may act to decrease shell weights in the future. Changes in [CO32-] or total dissolved inorganic carbon do not affect the Mg distribution coefficient. On the contrary, Sr incorporation is enhanced under increasing [CO32-]. Implications of these results for the paleoceanographic application of foraminifera are discussed.