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Cyanobacteria được tìm thấy trong suốt sự đa dạng về hệ sinh thái trên bề mặt của hành tinh. Họ là những thực dân phong phú của môi trường khô nhất, khác nhau, từ sa mạc lạnh của lục địa Nam Cực đá và cát của sa mạc nóng của thế giới. Chúng tạo thành một thành phần chủ yếu của lớp vỏ bề mặt ở Thung lũng Taylor của Nam Cực, nơi nhiệt độ trung bình tháng Bảy là -32,2 ° C trung bình hơn 3 năm. Họ cũng xảy ra dưới các tảng đá trong sa mạc đá,. | 4 Cyanobacterial Ecology Cyanobacteria are found throughout the great variety of ecosystems on the surface of the planet. They are abundant colonizers of the most dessicated environments ranging from the cold deserts of the Antarctic continent to the stones and sand of the world s hot deserts. They form a predominant component of surface crusts in the Taylor Valley of Antarctica where the mean July temperature was -32.2 C averaged over 3 years. They also occur under rocks in stony desert with surface temperatures reaching 60 C and above Wynn-Williams 2000 . The major locations of cyanobacteria are however in moist or aquatic environments. But even in these more favorable environments cyanobacteria survive in the most extreme conditions. Much research has investigated cyanobacteria in hot springs where spectacular mats of cyanobacteria occur changing their appearance as the temperature falls away from the geothermal source. The genera Synechococcus Phormidium and Oscillatoria are found in hot springs at temperatures from 74 to 55 C Ward and Castenholz 2000 . Cyanobacterial species are also capable of abundant growth over a very wide range of salinity hence osmotic pressure regimes. While the major focus of this volume is freshwater environments saline and hypersaline aquatic environments also provide favorable growth conditions. An example of this is the stromatolites of Shark Bay in Western Australia found in a shallow hypersaline bay in which the normal grazing organisms are suppressed by the salinity Logan 1961 . Cyanobacteria are common in salt lakes and can survive in brine solutions of 3- to 4-M concentration Reed Chudek et al. 1984 . Cyanobacterial species can also survive and opportunistically proliferate in aquatic environments of widely oscillating salinity as in the Peel-Harvey estuary in Western Australia where winter rainfall results in almost freshwater conditions followed by evaporation and increased salinity. Nodularia spumigena flourishes there .
