Photosynthetic light requirements and vertical distribution of macroalgae in newly ice-free areas in Potter Cove, South Shetland Islands, Antarctica
Photosynthetic light requirements and vertical distribution of macroalgae in newly ice-free areas in Potter Cove, South Shetland Islands, Antarctica
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DOI：
10.1007/s00300-015-1679-y
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发表时间：
2016-01-01
期刊：
影响因子：
1.7
通讯作者：
Zacher, K.
中科院分区：
文献类型：
--
作者：
Deregibus, D.;Quartino, M. L.;Zacher, K.
在南极洲的波特湾，由于冰川的消退，出现了新的无冰区。同时，沉积物的流入增加，减少了水下光合作用有效辐射(PAR，400-700 nm)。本研究的目的是确定两种大型藻类在三个新的无冰区A1、A2和A3上定居的光合作用特性，从A1到A3，冰川影响的程度逐渐增加。测量了浊度、盐度和温度，计算了光衰减系数(K-d)，并将其作为冰川沉积物输入的替代指标。红藻、落叶棕榈藻和褐藻在A3、A2和A1中的分布深度分别为10m、20m和30m。然后在海拔5米和10米的所有地区采集了这两个物种。测定了光合作用参数和日代谢碳平衡(CB)。A3组的K-d显著高于A1和A2组。落叶松的CB在A1区显著高于A2和A3区，且浅层显著高于深层。与其他区域和深度相比，大叶黄杨A3和A2的CB显著低于其他区域和深度。藻类分布下限与透光率呈正相关。全球变暖导致的沉积物径流增加可能会导致深度分布下限的上升，但冰川的消退可能会为大型藻类的定居开辟新的空间。这些变化可能会影响波特湾的大型藻类初级生产力，从而对沿海生态系统造成影响。
In Potter Cove, Antarctica, newly ice-free areas appeared due to glacial retreat. Simultaneously, the inflow of sediment increased, reducing underwater photosynthetically active radiation (PAR, 400-700 nm). The aim of this study was to determine the photosynthetic characteristics of two macroalgal species colonizing three newly ice-free areas, A1, A2 and A3, with increasing degree of glacial influence from A1 to A3. Turbidity, salinity and temperature were measured, and light attenuation coefficients (K-d) calculated and considered as a proxy for glacial sediment input. The lower depth distribution of the red alga Palmaria decipiens and the brown alga Himantothallus grandifolius was 10 m in A3, 20 m in A2 and 30 m in A1. Both species were then collected, at 5 and 10 m at all areas. Photosynthetic parameters and the daily metabolic carbon balance (CB) were determined. K-d was significantly higher in A3 compared with A1 and A2. The CB of P. decipiens was significantly higher in A1 followed by A2 and A3, and significantly higher at shallower than at greater depth. For H. grandifolius CB was significantly lower in A3 and in A2 at deeper depths compared with the rest of areas and depths. The lower distribution limit of the algae was positively correlated to the light penetration. An increase in the sediment run-off due to global warming might lead to an elevation of the lower depth distribution limit but retreating glaciers can open new space for macroalgal colonization. These changes will probably affect macroalgal primary productivity in Potter Cove with consequences for the coastal ecosystem.