Long-term productivity in the cryptoendolithic microbial community of the Ross Desert, Antarctica
Long-term productivity in the cryptoendolithic microbial community of the Ross Desert, Antarctica
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DOI：
10.1007/bf00182129
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发表时间：
2004
影响因子：
3.6
通讯作者：
E. Friedmann;L. Kappen;M. Meyer;J. Nienow
中科院分区：
文献类型：
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作者：
E. Friedmann;L. Kappen;M. Meyer;J. Nienow
基于实验室测量的二氧化碳交换和3年（1985-1988）的野外纳米气候数据，通过对光合作用响应的计算机分析，计算出以地衣为主的隐内生生物群落的年总生产力。在100和1500 μmol光子m−2s−1辐照水平下，光合最适值从−3°C增加到2°C，而最高补偿点从1°C增加到17°C。水平岩石的年平均代谢活动总时间（温度高于- 10°C且存在水分）为771.3 h，东北方向的斜坡岩石为421.5 h，水平岩石的小洼地（偶尔有地衣的特征地点）为1042.2 h。计算得出水平岩石的平均总生产力值为1215 mg cm−2y−1，净光合增益为606 mg cm−2y−1。从长期事件估计的净生态系统生产力（细胞生物量的年增加量）仅约为3mg C m−2y−1。这两个值之间的差异可能代表了频繁的脱水-再水化和冻融循环或越冬的长期代谢成本，并可能解释了有机物质浸出到岩石中的原因。整个罗斯沙漠地区隐内生微生物群落的年总生产力估计约为120,000-180,000千克碳，其中600-900千克碳是微生物生物量，其余大部分是可溶化合物，它们渗透到岩石中，并可能渗透到山谷中，为湖泊、河流和土壤提供有机物质的来源。
Annual gross productivity of the lichen-dominated cryptoendolithic community was calculated from a computer analysis of photosynthetic response based on laboratory measurements of C02exchange and three years (1985–1988) of field nanoclimate data. Photosynthetic optimum increased from −3 to 2°C between irradiance levels of 100 and 1500 μmol photons m−2s−1, while the upper compensation point rose from 1 to 17°C. The mean yearly total time available for metabolic activity (temperature above −10°C and moisture present) was 771.3 h for horizontal rock, 421.5 h for northeast-oriented sloped rock, and 1042.2 h for a small depression in horizontal rock (the characteristic site of occasional lichen apothecia). The calculated mean gross productivity value for a horizontal rock was 1215 mg C m−2y−1, and net photosynthetic gain was 606 mg C m−2y−1. Net ecosystem productivity (annual accretion of cellular biomass) estimated from long-term events amounted to only about 3 mg C m−2y−1. The difference between these two values may represent the long-term metabolic costs of the frequent dehydration-rehydration and freezing-thawing cycles or of overwintering, and may account for the leaching of organic substances to the rock.The yearly gross productivity of the cryptoendolithic microbial community of the entire Ross Desert area was estimated at approximately 120,000–180,000 kg C. Of this, 600–900 kg C is in microbial biomass, and much of the rest is soluble compounds that leach into the rocks and possibly percolate to the valleys, providing a source of organic matter for lakes, rivers, and soils.