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Modelling primary production in seasonally ice-covered regions of the Arctic Ocean and its response to climate change.

机译：模拟北冰洋季节性冰雪覆盖地区的初级生产及其对气候变化的响应。

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摘要

I developed a 1D coupled sea ice-ocean-biological (including ice algae) model to study the controlling effect of sea ice on primary and biogenic particle export production in the western Arctic and the impacts of climate change (reduction in sea ice cover duration and thickness, and in surface freshwater fluxes) on these productions. The model was developed in two steps to maximize validation of model results with as much data as possible. I first developed a coupled snow-ice-ice algae model for bottom landfast ice in Resolute (Canadian Archipelago). Next, I developed and coupled a pelagic component (NPZD type) to the ice algal model. The coupled model was implemented on the Mackenzie shelf in the Canadian Beaufort Sea. And finally, I used simulations of future climate change from the Canadian Global Climate Model (CGCM2) to force the 1D model and obtain projections of future primary production on the Beaufort Sea shelf for two 18-year periods (2042-2059, and 2082-2099).;The model results show that ice algae are light limited at the beginning of the bloom, then fluctuate between light and nutrient limitation, to finally remain nutrient limited toward the end of the bloom. The bottom ice melt rate regulates the maximum biomass attained in Resolute, while biomass accumulation remains low in the Beaufort Sea due to nutrient limitation. The termination of the bloom is triggered by melting of the snow cover and results from (i) increased ice algal losses due to high bottom ice melt rate and (ii) decreased ice algal growth due to nutrient limitation caused by the formation of a meltwater lens below the ice. The snow and sea ice cover melt and/or break-up also controls the timing of the phytoplankton bloom. However, primary producers on the Beaufort Sea outer shelf are essentially nutrient limited and total annual primary production is controlled in part by nutrient "pre-conditioning" in the previous fall and winter and by the depth of winter convective mixing, that are controlled in part by the supply of fresh water from runoff and ice melt. The spring bloom sometimes represents an important fraction of the total annual primary production, which occurs in great part at the base of the mixed layer. Future projections show an increase in average annual primary production of 6% between the periods 1975-1992 and 2042-2059, and of 9% between 1975-1992 and 2082-2099. The relative contribution of the ice algal and spring phytoplankton blooms to annual primary production is reduced in the future runs due to a reduction in the length of the ice algal growth season (resulting from earlier snow and ice melt) and to a reduction in the replenishment of nutrient to the mixed layer in winter. The duration of the summer subsurface phytoplankton bloom increases, which favours the development of the main copepod species and leads to an increase in export production (16% between 1975-1992 and 2082-2099) that is greater than the increase in primary production. This leads to an increase in averaged simulated e-ratio of 10% between the first and last period.
机译：我开发了一个一维耦合的海冰-海洋-生物（包括冰藻）模型，以研究海冰对北极西部西部初级和生物颗粒出口生产的控制效果以及气候变化的影响（海冰覆盖持续时间的减少和厚度和表面淡水通量）。该模型分两步开发，以最大程度地利用尽可能多的数据来验证模型结果。我首先为Resolute（加拿大群岛）的陆底冰开发了一种冰冰冰藻耦合模型。接下来，我开发了浮游成分（NPZD型）并将其耦合到冰藻模型中。耦合模型在加拿大Beaufort海的Mackenzie陆架上实施。最后，我使用了来自加拿大全球气候模型（CGCM2）的未来气候变化的模拟来强制采用一维模型，并获得了两个18年周期（2042-2059和2082- 2099）。模型结果表明，冰藻在开花开始时受光限制，然后在光照和养分限制之间波动，最终在开花结束前保持养分受到限制。底部冰的融化速度调节了Resolute中获得的最大生物量，而由于养分的限制，Beaufort海中的生物量积累仍然很低。积雪的融化触发了水华的终止，其原因是：（i）由于高的底部冰融化速率导致冰藻损失增加，以及（ii）由于形成融水晶状体而造成的养分限制导致冰藻生长减少在冰下。雪和海冰覆盖物的融化和/或破裂还控制浮游植物开花的时间。但是，波弗特海外围海域的初级生产者基本上是营养有限的，并且每年的初级总产量部分受前一个秋冬季的养分“预处理”和冬季对流混合深度的控制，而对流混合的深度则受到部分控制来自径流和冰融化的淡水供应。春季开花有时代表了年度初级总产量的重要部分，大部分发生在混合层的底部。未来的预测表明，在1975-1992年至2042-2059年期间，年平均初级生产量将增长6％，而在1975-1992年至2082-2099年期间将增长9％。由于冰藻生长季节的缩短（由于较早的雪和冰融化而导致）的减少以及补给的减少，在未来的运行中，冰藻和春季浮游植物开花对每年初级生产的相对贡献减少了。在冬季向混合层注入营养。夏季地下浮游植物开花的持续时间增加，这有利于主要co足类的发展，并导致出口产量的增加（1975-1992年至2082-2099年间为16％），大于初级产量的增加。这导致第一个和最后一个周期之间的平均模拟e比率增加了10％。

著录项

  • 作者

    Lavoie, Diane.;

  • 作者单位

    University of Victoria (Canada).;

  • 授予单位 University of Victoria (Canada).;
  • 学科 Climate Change.;Biogeochemistry.;Biology Oceanography.;Physical Oceanography.
  • 学位 Ph.D.
  • 年度 2008
  • 页码 186 p.
  • 总页数 186
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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