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（即温度持续上升和冰融化造成的淡水化的综合影响）对海洋生物和生态系统的影响几乎没有得到考虑。浮游钙化生物在不同的海洋生态系统中发挥着重要作用，包括作为海洋食物网和海洋碳酸盐泵的基础贡献者。除了对包括钙化在内的大量生理过程的一级控制外，温度也影响它们的游泳行为。海洋的热膨胀降低了它的密度，而海水则通过淡化进一步膨胀。在温暖的气候下，由于大陆冰盖的缩小，冰川融水输入海洋变得更加稀释，这种增加的稀释加剧了其酸化。较低的海洋密度和碱度的综合影响可能特别影响到不动的钙化浮游生物，这些浮游生物完全依赖水柱的物理特性来定位，从而影响到它们的漂浮需求。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，但文献中缺乏关于海洋物理特性（如浮力或压力，这很可能会影响浮游生物的生理和形态。不同的钙化种具有不同的最佳生活深度生境，它们适应的深度取决于海洋的不均匀性。这些浮游生物能够通过维持化学梯度而与周围环境失去平衡，然而，由于不动，它们必须始终保持与海水的平衡以保持漂浮。为了栖息在一定的深度，非运动的浮游生物应该调节它们的（细胞）密度，以匹配它们所浸入的周围液体的密度。如果不是这种情况，那么生物体必须重新定位，直到它们达到一个特定的密度水平来平衡。因此，可以说浮游生物的生理对海水的物理特性比化学特性更敏感。在这种程度上，拟议的研究将有助于阐明控制远洋钙化的物理过程，通过调查控制浮游有孔虫（PF）和颗石壳质量变化的关键环境参数，如环境海水密度。

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.