Antarctic stream ecosystems: physiological ecology of a blue-green algal epilithon
Antarctic stream ecosystems: physiological ecology of a blue-green algal epilithon
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南极溪流生态系统：蓝绿藻石碑的生理生态学
DOI：
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发表时间：
1986
期刊：
影响因子：
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通讯作者：
C. Howard
中科院分区：
文献类型：
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作者：
W. Vincent;C. Howard
摘要1.几十个夏季融水流位于麦克默多海湾地区（c。78°S 165°E），位于维多利亚地南部。它们的特点是在昼夜、季节和年度时间尺度上高度可变的流动状态;温度和营养物质含量的大幅度波动;以及非常简单的蓝绿藻（念珠藻属，颤藻科）、细菌、真菌和微型食草动物。
2.南极洲黑暗的冬天，这些石被冻成干燥的垫子，为下一个夏天的生长提供了大量的接种物。这种越冬组合保持了高代谢能力，并迅速响应补液。
3.在一系列人工基质实验中，生物量积累速率通常小于0.1单位d-1。在基质上的定殖和生长与河流的悬浮泥沙负荷呈负相关。天然河床的藻类覆盖率与河水的清澈度之间也存在视觉对应关系。坍塌损失可能限制群落生物量，特别是在浑浊的流动沃茨中。
4.在流水条件下，成熟群落每单位叶绿素的总光合速率（<0.1 μg C（μg chl a.h）−1）和每单位碳的总光合速率（<0.2 μg C（mg生物量C.h）−1）非常低。呼吸作用一般占总光合作用的很高比例（高达92%），这可能反映了群落中微异养生物的高种群密度。
5.植物区系简单的石表垫慢慢积累到极端的生物量水平（>20 μg chl a cm-2，<20 mg C cm-2）。每单位生物量的生产率很低，可能是由于南极溪流环境的寒冷温度，累积的生物量代表了几个生长季节。
SUMMARY. 1. Several dozen summer meltwater streams are located in the McMurdo Sound region (c. 78°S 165°E) of southern Victoria Land. They are characterized by a highly variable flow regime at diel, seasonal and annual times caleis; wide fluctuations in temperature and nutrient content; and a very simple epilithic community of cyanophytes (Nostoc spp., Oscillatoriaceae), bacteria, fungi and microherbivores.
2. The epilithon survives the dark Antarctic winter as dry, frozen mats which provide a large inoculum for growth the following summer. This overwintering assemblage retains a high metabolic capacity and responds rapidly to rehydration.
3. In a series of artificial substrate experiments, biomass accumulation rates were generally less than 0.1 In units d−1. Colonization and growth on the substrates was inversely related to the suspended sediment load of the stream. There was also a visual correspondence between per cent algal cover of the natural streambed and the clarity of the streamwater. Sloughing losses may limit community biomass, particularly in the turbid flowing waters.
4. During running water conditions the mature communities had very low gross photosynthetic rates per unit chlorophyll (<0,1 μg C (μg chl a.h)−1 and per unit carbon (<0,2 μg C (mg biomass C.h)−1). Respiration was generally a high percentage (up to 92%) of gross photosynthesis, which probably reflected the high population densities of microheterotrophs in the community.
5. The floristically simple epilithic mats slowly accumulate to extreme biomass levels (>20 μg chl a cm −2, <20 mg C cm−2). Production rates per unit biomass are low, probably in response to the cold temperatures of the Antarctic stream environment, and the accumulated biomass represents several seasons of growth.