企鹅粪土层中石英砂表面的化学溶蚀形貌及实验模拟

利用电镜扫描的方法分析了南极阿德雷岛Y2湖企鹅粪土沉积层中石英砂微形貌的特征,发现在企鹅粪含量高的沉积层中石英砂表面具有明显的碗状溶蚀坑等化学溶蚀特征,这一溶蚀特征在Y2湖企鹅粪含量低的沉积层和研究区的其他未受企鹅粪影响的沉积环境中均未明显出现。为了揭示这一特殊化学溶蚀现象的作用机制,根据Y2湖企鹅粪土沉积层自然沉积环境,通过条件实验确定在实验室内使用酸性较高的氟溶液(1mol.L-1HF溶液)对石英砂进行溶蚀实验,通过对比分析发现,实验室模拟条件下可以得到与企鹅粪土沉积层中石英砂相近的表面微形貌特征,这表明它们是在相似的过程中形成的。企鹅粪土沉积层酸性高氟环境中可能存在的HF酸化学溶蚀作用是形成企鹅粪土层中石英砂表面特有溶蚀坑的主要原因。在南极特殊的自然条件下碗状溶蚀坑与企鹅粪之间存在一定的因果关系,从而使石英砂的表面微形貌分析成为南极企鹅生态研究的一种新的辅助手段。     

南极Amanda湾帝企鹅卵的生态生物学及与其它南极海鸟卵的比较

对南极Amanda湾帝企鹅的卵进行了生态生物学观测与相应的统计分析。结果显示,帝企鹅卵为典型的卵形卵,平均长、短径分别为121.3mm和83.8mm;平均卵容量409.3ml(322.6-506.4ml),卵的平均壳厚为1.11mm(0.94-1.23mm)。帝企鹅和南方巨鹱、白眉企鹅以及灰贼鸥等南极海鸟的卵相比较,卵的形态大小与容量成正比,同时,容量较大的卵具有较厚的卵壳,以增强对卵的保护。这些海鸟卵的生态生物学特征,包括保护色的有无、卵容量的大小,以及卵壳厚度等特征参数,是这些海鸟种的明显特征,并与亲鸟在繁殖期的窝卵数以及孵化习性相协调,以达到对南极环境的适应与生存。     

Trace metals in sediment cores from Deception and Penguin Islands (South Shetland Islands, Antarctica)

This paper presents information on the levels of trace elements in sediments collected at Deception and Penguin Islands and tracks the sources of natural and anthropogenic inputs of metals into this sub-Antarctic region. The results suggest that natural processes, such as volcanic activity, hydrothermal processes and sediment transport, are more important than anthropogenic inputs in accounting for the metal concentrations measured in sediments at Deception Island. The higher levels of trace metals recorded in sediments at Penguin Island seem to reflect the composition of the source rocks of the island, which are dominated by the olivine-basalt group. Our findings show that human activities in the study areas may contribute to negligible levels of trace metals associated with anthropogenic inputs (e.g., Cr and Zn) in sediments, and these results can be used in the future as background levels related to low anthropogenic impacts.     

南极阿德雷岛湖泊沉积物Sr/Ba与B/Ga比值特征

测试了南极企鹅聚集区阿德雷岛湖泊沉积物Sr、Ba、B、Ga的垂向含量变化,阿德雷岛湖泊沉积物元素平均含量为:Sr为1 069.36±422.10 mg/kg,Ba为213.84±39.48 mg/kg,B为6.89±3.79 mg/kg,Ga为16.65±3.91 mg/kg,阿德雷岛湖泊沉积物Sr/Ba比值为4.92±1.53,B/Ga比值为0.43±0.26,Sr/Ba比值远大于1.0,而B/Ga比值小于3.3,这表明在特殊的生态环境下Sr/Ba比值不能用来判别沉积物的沉积相,南极阿德雷岛湖泊沉积的Sr/Ba比值异常是通过企鹅生物地球化学过程沉积改造而引起的,受到企鹅粪沉积影响.     

A 1,800-year record of arsenic concentration in the penguin dropping sediment,Antarctic

Heavy/toxic metals have been widely investigated in the Antarctic. However, there are rare reports on arsenic up to now. Here, we analyzed a 1,800-year record of arsenic concentration in lake sediments affected by penguin droppings. We found that arsenic enriches in the penguin dropping sediments with 12.41 ± 0.45 μg/g (on dry weight), which is about two times higher than the one in the background sediments with absence of penguin. Historical change in arsenic concentration was found to significantly correlate with the fluctuation of penguin number, indicating that penguin activity will result in the enrichment of arsenic somewhere in the maritime Antarctic.     

Potential of Svalbard reindeer winter droppings for emission/absorption of methane and nitrous oxide during summer

Droppings of Svalbard reindeer (Rangifer tarandus platyrhynchus) could affect the carbon and nitrogen cycles in tundra ecosystems. The aim of this study was to evaluate the potential of reindeer droppings originating from the winter diet for emission and/or absorption of methane (CH₄) and nitrous oxide (N₂O) in summer. An incubation experiment was conducted over 14 days using reindeer droppings and mineral subsoil collected from a mound near Ny-Ålesund, Svalbard, to determine the potential exchanges of CH₄ and N₂O for combinations of two factors, reindeer droppings (presence or absence) and soil moisture (dry, moderate, or wet). A line transect survey was conducted to determine the distribution density of winter droppings at the study site. The incubation experiment showed a weak absorption of CH₄ and a weak emission of N₂O. Reindeer droppings originating from the winter diet had a negligible effect on the exchange fluxes of both CH₄ and N₂O. Although the presence of droppings resulted in a short-lasting increase in N₂O emissions on day 1 (24 h from the start) for moderate and wet conditions, the emission rates were still very small, up to 3 μg N₂O m⁻² h⁻¹.