A simulated Antarctic ast ice ecosystem
A simulated Antarctic ast ice ecosystem
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模拟南极冰生态系统
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
C. Sullivan
中科院分区：
文献类型：
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作者：
K. Arrigo;J. Kremer;C. Sullivan
一个简单的二维（z，t）模型的第一年海冰结构和动力学耦合到一个高分辨率，时间依赖性模型的微藻生长，其中模拟的生理反应是由环境温度，光谱辐照度，营养浓度和盐度。物理部分利用大气数据来模拟冰的生长、初始盐水截留、脱盐和营养通量。还计算了温度梯度、海冰盐度、盐水盐度和盐水体积。生物部分是基于最大温度依赖性藻类生长速率的概念，该速率由于光照或营养不足以及次优盐度的限制而降低。估计的总初级生产力因呼吸和放牧而减少。初步模拟表明，在水华期间，微藻能够保持其垂直位置相对于较低的南极冰缘，并没有纳入晶体基质的冰盖增厚。模型结果表明，陆地固定海冰包含许多微生境，这些微生境在功能上是不同的，基于控制微藻生长和积累的独特过程。在春季水华的早期阶段，高盐水盐度抑制微藻生长在所有深度内的南极冰，除了附近的骨骼层。光被预测为整个南极洲和血小板冰在这个时候的限制资源。在水华后期，当环境条件更有利于藻类生长时，模型结果表明，生物量的积累在上层浮冰是由微型浮游动物放牧控制的，骨骼层和上层血小板冰中的微藻容易受到营养限制，在这个时候，由于通量减少和高营养需求。在整个水华期间，光线限制了下层片状冰中微藻的生长。结果表明，在最佳条件下，麦克默多海峡的陆地固定海冰可以支持大约0.5 g C m−2 d−1的生产率，其中76%与营养交换率相对较高的血小板层有关。虽然任何生物系数的调整都会改变模型中的产量大小，但其值的不确定性所允许的结果范围完全在积雪正常变化或养分通量速率不确定性可能导致的范围内。
A simple two-dimensional (z,t) model of first year sea ice structure and dynamics is coupled to a high resolution, time-dependent model of microalgal growth in which simulated physiological responses are determined by ambient temperature, spectral irradiance, nutrient concentration, and salinity. The physical component utilizes atmospheric data to simulate congelation ice growth, initial brine entrapment, desalination, and nutrient flux. Temperature gradient, sea ice salinity, brine salinity, and brine volume are also computed. The biological component is based on the concept of a maximum temperature-dependent algal growth rate which is reduced by limitations imposed from insufficient light or nutrients, as well as suboptimal salinity. Estimated gross primary productivity is reduced by respiration and grazing terms. Preliminary simulations indicate that, during a bloom, microalgae are able to maintain their vertical position relative to the lower congelation ice margin and are not incorporated into the crystal matrix as the ice sheet thickens. Model results imply that land fast sea ice contains numerous microhabitats that are functionally distinct based upon the unique suite of processes that control microalgal growth and accumulation within each. In the early stages of the spring bloom, high brine salinity inhibits microalgal growth at all depths within the congelation ice, except near the skeletal layer. Light is predicted to be the limiting resource throughout the congelation ice and platelet ice at this time. Later in the bloom when environmental conditions are more favorable for algal growth, model results suggest that biomass accumulation in the upper congelation ice is controlled by microzooplankton grazing, Microalgae in the skeletal layer and upper platelet ice are susceptible to nutrient limitation at this time due to diminished flux and high nutrient demand. Light limits microalgal growth in the lower platelet ice throughout the bloom. Results indicate that land fast sea ice in McMurdo Sound can support a production rate of approximately 0.5 g C m−2 d−1 under optimal conditions, 76% of which is associated with the platelet layer where rates of nutrient exchange are relatively high. While adjustments in any biological coefficient will alter the magnitude of production in the model, the range of results permitted by uncertainty in their values is well within the bounds likely to result from normal variations in snow cover, or from the uncertainty in the rate of nutrient flux.