Carroll Michael L, Johnson Beverly J, Henkes Gregory A, McMahon Kelton W, Voronkov Andrey, Ambrose William G, Denisenko Stanislav G
Akvaplan-niva, Polar Environmental Centre, N-9296 Tromsø, Norway.
Mar Pollut Bull. 2009;59(4-7):193-206. doi: 10.1016/j.marpolbul.2009.02.022. Epub 2009 Apr 25.
Identifying patterns and drivers of natural variability in populations is necessary to gauge potential effects of climatic change and the expected increases in commercial activities in the Arctic on communities and ecosystems. We analyzed growth rates and shell geochemistry of the circumpolar Greenland smooth cockle, Serripes groenlandicus, from the southern Barents Sea over almost 70 years between 1882 and 1968. The datasets were calibrated via annually-deposited growth lines, and growth, stable isotope (delta(18)O, delta(13)C), and trace elemental (Mg, Sr, Ba, Mn) patterns were linked to environmental variations on weekly to decadal scales. Standardized growth indices revealed an oscillatory growth pattern with a multi-year periodicity, which was inversely related to the North Atlantic Oscillation Index (NAO), and positively related to local river discharge. Up to 60% of the annual variability in Ba/Ca could be explained by variations in river discharge at the site closest to the rivers, but the relationship disappeared at a more distant location. Patterns of delta(18)O, delta(13)C, and Sr/Ca together provide evidence that bivalve growth ceases at elevated temperatures during the fall and recommences at the coldest temperatures in the early spring, with the implication that food, rather than temperature, is the primary driver of bivalve growth. The multi-proxy approach of combining the annually integrated information from the growth results and higher resolution geochemical results yielded a robust interpretation of biophysical coupling in the region over temporal and spatial scales. We thus demonstrate that sclerochronological proxies can be useful retrospective analytical tools for establishing a baseline of ecosystem variability in assessing potential combined impacts of climatic change and increasing commercial activities on Arctic communities.
识别种群自然变异的模式和驱动因素，对于评估气候变化以及北极地区商业活动预期增加对群落和生态系统的潜在影响至关重要。我们分析了1882年至1968年近70年间，来自巴伦支海南部的环北极格陵兰光滑鸟蛤（Serripes groenlandicus）的生长速率和贝壳地球化学特征。通过每年沉积的生长线对数据集进行校准，并将生长、稳定同位素（δ¹⁸O、δ¹³C）和微量元素（Mg、Sr、Ba、Mn）模式与从每周到十年尺度的环境变化联系起来。标准化生长指数显示出具有多年周期性的振荡生长模式，这与北大西洋涛动指数（NAO）呈负相关，与当地河流流量呈正相关。在最靠近河流的地点，河流流量变化可解释高达60%的Ba/Ca年度变异性，但在更远的地点这种关系消失了。δ¹⁸O、δ¹³C和Sr/Ca模式共同提供了证据，表明双壳类动物的生长在秋季温度升高时停止，并在早春最冷的温度时重新开始，这意味着食物而非温度是双壳类动物生长的主要驱动因素。将生长结果的年度综合信息与更高分辨率的地球化学结果相结合的多指标方法，对该区域在时间和空间尺度上的生物物理耦合进行了可靠的解释。因此，我们证明了年代学指标可以作为有用的回顾性分析工具，用于建立生态系统变异性的基线，以评估气候变化和商业活动增加对北极群落的潜在综合影响。
