Institute of Earth Sciences, The Hebrew University, 91904, Jerusalem, Israel.
Meteorological Unit, Israel Meteorological Service, 84993, Kibbutz Sde Boker, Israel.
Planta. 2023 May 25;258(1):8. doi: 10.1007/s00425-023-04165-5.
Microclimate determines lichens and cyanobacteria distribution in the Negev, with lichens and cyanobacteria inhabit dewy and dewless habitats, respectively. Lichens experiences more frequent and extensive environmental fluctuations than cyanobacteria. The spatial partitioning of chlorolichens (eukaryotes) and cyanobacteria (prokaryotes) are intriguing, especially following recent intense search for extraterrestrial life. This is especially relevant for deserts, where both lithobionts are thought to use rain and dew but may differ in their resilience to environmental extremes and fluctuations. Following the different spatial distribution of lithobionts in a south-facing slope of the Negev Highlands (with cyanobacteria-inhabiting rocks and chlorolichen-inhabiting cobbles), measurements of temperature, non-rainfall water (NRW) and biomass were carried out within the drainage basin aiming to test the hypotheses that (i) cobble-inhabiting lichens may access more water (through NRW) and may be subjected to more extensive environmental fluctuations of temperature and water than bedrock-inhabiting cyanobacteria, and (ii) will therefore have a greater contribution to the ecosystem productivity. In contrast to cyanobacteria, cobble-inhabiting chlorolichens were found to access NRW (up to 0.20 mm of daily amounts in comparison to < 0.04 mm of the cyanobacteria) and to experience higher fluctuations of temperatures (up to 4.1 °C higher and 5.3 °C lower). With lichens and cyanobacteria inhabiting dewy and dewless habitats, respectively, NRW was found responsible for contributing 6.8-fold higher organic carbon to the lithobiontic community. At this site, chlorolichens experience more extensive environmental fluctuations than cyanobacteria, possibly indicating a higher tolerance for environmental fluctuations. These observations may assist in the interpretation of the abiotic conditions responsible for past or present lithobiontic life on Mars.
微气候决定了内盖夫的地衣和蓝藻的分布，地衣和蓝藻分别栖息在有露水和无露水的栖息地。地衣比蓝藻经历更频繁和更广泛的环境波动。绿藻（真核生物）和蓝藻（原核生物）的空间分区很有趣，特别是在最近对外星生命的强烈搜索之后。这对于沙漠尤其相关，在那里，两种岩石生物都被认为利用雨水和露水，但它们在对环境极端和波动的恢复能力方面可能有所不同。在 Negev 高地南坡的一个坡面（蓝藻栖息在岩石上，绿藻栖息在鹅卵石上），根据 Lithobionts 的不同空间分布，对温度、非降雨水（NRW）和生物量进行了测量，目的是测试以下假设：（i）鹅卵石上的地衣可能会获得更多的水（通过 NRW），并且可能会经历比基岩上的蓝藻更广泛的温度和水的环境波动，并且（ii）因此对生态系统生产力的贡献更大。与蓝藻不同，发现鹅卵石上的绿藻可以利用 NRW（每天高达 0.20 毫米，而蓝藻则低于 0.04 毫米），并且经历的温度波动更大（高达 4.1°C 更高和 5.3°C 更低）。由于地衣和蓝藻分别栖息在有露水和无露水的栖息地，因此发现 NRW 使 Lithobiontic 群落的有机碳贡献增加了 6.8 倍。在这个地点，绿藻经历的环境波动比蓝藻更广泛，这可能表明它们对环境波动的耐受性更高。这些观察结果可能有助于解释导致过去或现在火星上 Lithobiontic 生命的非生物条件。
