SODIOM - Surface Ocean Density Influence On Mineralisers

虽然目前和未来海洋变暖的过程已经确定，但海洋稀释(即持续升温和冰川融化导致的变暖的综合影响)对海洋生物和生态系统的影响几乎没有考虑到。浮游钙化物在不同的海洋生态系统中扮演着重要的角色，包括对海洋食物网和海洋碳酸盐泵的基本贡献。除了对包括钙化在内的大量生理过程的一级控制外，温度也影响着它们的游泳行为。海洋的热膨胀降低了它的密度，而海水通过淡水进一步膨胀。在气候变暖的情况下，由于大陆冰盖的缩小，冰川融水的输入使海洋变得更加稀释，这种额外的稀释加剧了海洋的酸化。较低的海洋密度和碱度的综合影响可能特别影响不活动的钙化浮游生物，这些浮游生物仅依靠水柱的物理性质进行定位，从而影响它们的漂浮需求。未来稀释对钙化生物的影响可能会对现代碳循环产生重大影响，因此，不仅是变暖或酸化，海洋稀释实际上可能对生态系统和社会构成更大的挑战。尽管海洋化学对浮游生物的影响正在被广泛研究，但关于浮力或压力等海洋物理性质的影响的文献很少，这很可能影响浮游生物的生理和形态。不同的钙化物种有不同的最适生存深度生境，它们根据海洋的非均质性而适应。这些浮游生物通过保持化学梯度，能够在与周围环境不平衡的情况下进行生物合成，然而，作为不活动的生物，它们必须始终保持与海水的平衡才能保持漂浮。为了栖息在一定的深度，非移动的浮游生物应该调节它们的(细胞)密度，以与它们所浸泡的周围液体相匹配。如果不是这样，那么有机体必须重新定位，直到它们达到特定的密度地平线才能平衡。因此，可以说，浮游生物生理学对海水的物理特征比化学特征更敏感。在这一程度上，拟议的研究将有助于通过调查环境海水密度等关键环境参数对浮游有孔虫和球藻壳体质量变化的控制，阐明控制远洋钙化的物理过程。

While the processes of current and future ocean warming are well-established, the impact of ocean dilution (i.e. the combined effect of persistent temperature rise and freshening due to ice melts) on marine life and ecosystems are hardly considered. Planktonic calcifiers play essential roles in different marine ecosystems including being basal contributors to the marine food web and the marine carbonate pump. Besides the first order control on a large number of their physiological processes including calcification, temperature also affects their swimming behaviour. The thermal expansion of the ocean reduces its density, while seawater expands further by freshening. Under warmer climates the ocean becomes even more diluted by the glacial meltwater input due to shrinking continental ice sheets and this added dilution aggravates its acidification. The combined effects of lower ocean density and alkalinity may particularly influence non-motile calcifying plankton that solely depends on the physical properties of the water column for positioning, by affecting their flotation needs. The influence of future dilution on calcifying organisms may have a major impact on the modern carbon cycle and hence, rather than warming or acidification alone, it is oceanic dilution that might actually be a bigger challenge to the ecosystem and the society.Although the effects of ocean chemistry on plankton are being extensively studied there is a lack in the literature about the effects of physical oceanic properties such as buoyancy or pressure, which very likely affect plankton physiology and morphology. Different calcifying species have different optimum living depth habitats, to which they adapt according to the oceanic inhomogeneity. These planktonic organisms are able to biosynthesize out of equilibrium with their ambient environment by maintaining chemical gradients however, as non-motile they must always retain equilibrium with the seawater to remain afloat. To inhabit certain depths, non-motile planktonic organisms should regulate their (cell) density to match that of the surrounding liquid in which they are immersed. Should this not be the case then the organisms must relocate until they reach a particular density horizon to equilibrate. It can thus be argued that plankton physiology is more sensitive to the physical rather than the chemical characteristics of seawater. To this extent the proposed research will help to elucidate the physical processes that control pelagic calcification, by investigating the control on planktonic foraminifera (PF) and coccolith shell mass changes of key environmental parameters such as ambient seawater density.