Temporal variability in foraminiferal morphology and geochemistry at the West Antarctic Peninsula: a sediment trap study
Temporal variability in foraminiferal morphology and geochemistry at the West Antarctic Peninsula: a sediment trap study
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DOI：
10.5194/bg-16-3267-2019
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发表时间：
2019-02
期刊：
影响因子：
4.9
通讯作者：
Anna Mikis;K. Hendry;J. Pike;D. Schmidt;K. Edgar;V. Peck;F. Peeters;M. Leng;M. Meredith;Chloe L. Todd;S. Stammerjohn;H. Ducklow
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文献类型：
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作者：
Anna Mikis;K. Hendry;J. Pike;D. Schmidt;K. Edgar;V. Peck;F. Peeters;M. Leng;M. Meredith;Chloe L. Todd;S. Stammerjohn;H. Ducklow
抽象。西南极半岛（WAP）具有很强的空间和时间的海洋学变化，导致高度异质性的生物生产力。生活在WAP附近沃茨的钙化生物对海洋温度和化学的时空变化做出反应。由于沃茨已经自然接近碳酸盐不饱和，这些海洋钙化物可能受到区域气候变化的威胁。由于缺乏历史数据收集和复杂的十年气候变化，对南大洋碳酸盐产量的未来预测具有挑战性。在这里，我们提出了一个长达6年的记录的外壳通量，形态和稳定同位素的变化，极地南极洲帕尔默站附近的浮游有孔虫Neogloboquadrina厚皮（狭义）。该物种是南大洋南极碳酸盐生产的基础，因为它是适应海洋极地环境的极少数南极有孔虫物种之一。我们利用这些新数据来深入了解其生态，并对这种极地物种对环境变化的反应进行了强有力的评估。形态学和稳定同位素组成揭示了这个严格定义的物种内存在不同的生长阶段。有孔虫通量和大小的年际和年内变化是明显的，并由环境强迫参数的组合驱动，最重要的是食物供应，温度和海冰的持续时间和范围。有孔虫的生长在整个南极年发生，并受到环境变化的影响，其中很大一部分是由南方环形模式和厄尔尼诺-南方涛动驱动的。观察到一个明显的季节性生产，在一年中最温暖和最具生产力的月份，壳通量最高。钙化有孔虫在这个地区的环境变化的敏感性，从几个星期到几十年，影响他们对未来气候变化的反应，并为他们的使用作为古气候指标。一个更长的无冰季节可能会增加该地区的碳酸盐产量，至少在碳酸盐饱和度仍然足够高，允许厚测试增长。
Abstract. The West Antarctic Peninsula (WAP) exhibits strong spatial and temporal oceanographic variability, resulting in highly heterogeneous biological productivity. Calcifying organisms that live in the waters off the WAP respond to temporal and spatial variations in ocean temperature and chemistry. These marine calcifiers are potentially threatened by regional climate change with waters already naturally close to carbonate undersaturation. Future projections of carbonate production in the Southern Ocean are challenging due to the lack of historical data collection and complex, decadal climate variability. Here we present a 6-year-long record of the shell fluxes, morphology and stable isotope variability of the polar planktic foraminifera Neogloboquadrina pachyderma (sensu stricto) from near Palmer Station, Antarctica. This species is fundamental to Southern Ocean planktic carbonate production as it is one of the very few planktic foraminifer species adapted to the marine polar environments. We use these new data to obtain insights into its ecology and to derive a robust assessment of the response of this polar species to environmental change. Morphology and stable isotope composition reveal the presence of different growth stages within this tightly defined species. Inter- and intra-annual variability of foraminiferal flux and size is evident and driven by a combination of environmental forcing parameters, most importantly food availability, temperature and sea ice duration and extent. Foraminiferal growth occurs throughout the austral year and is influenced by environmental change, a large portion of which is driven by the Southern Annular Mode and El Niño–Southern Oscillation. A distinct seasonal production is observed, with the highest shell fluxes during the warmest and most productive months of the year. The sensitivity of calcifying foraminifera to environmental variability in this region, from weeks to decades, has implications both for their response to future climatic change and for their use as palaeoclimate indicators. A longer ice-free season could increase carbonate production in this region at least while carbonate saturation is still high enough to allow for thick tests to grow.