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Full-Text Articles in Earth Sciences
In Situ Acetylene Reduction Activity Of Scytonema Julianum In Vapor Cave (Spain), Antonia Dolores Asencio, Marina Aboal
In Situ Acetylene Reduction Activity Of Scytonema Julianum In Vapor Cave (Spain), Antonia Dolores Asencio, Marina Aboal
International Journal of Speleology
Nitrogen fixation was measured in situ for the first time by acetylene reduction for a greyish mat composed of Scytonema julianum in cave-like environments. Mat-specific rates (129.9-215.7 nmol C2 H4 m-2 s-1 for daytime fixation and 65.1-120.6 nmol C2 H4 m-2 s-1 for nighttime fixation) recorded in the Vapor cave differed considerably due to the energy reserves stored during photosynthesis being exhausted and used in the dark phase. The most influential environmental parameter for nitrogen fixation in the Vapor cave is temperature in the daytime and nighttime fixations. Nitrogen fixation by cyanobacteria may contribute considerably to the overall nitrogen cycle …
A Note On The Occurrence Of A Crayback Stalagmite At Niah Caves, Borneo, Joyce Lundberg, Donald A. Mcfarlane
A Note On The Occurrence Of A Crayback Stalagmite At Niah Caves, Borneo, Joyce Lundberg, Donald A. Mcfarlane
International Journal of Speleology
Crayback stalagmites have mainly been reported from New South Wales, Australia. Here we document a small crayback in the entrance of Painted Cave (Kain Hitam), part of the Niah Caves complex in Sarawak, Borneo. Measuring some 65 cm in length and 18 cm in height, this deposit is elongate in the direction of the dominant wind and thus oriented towards the natural tunnel entrance. It shows the classic humpbacked long profile, made up of small transverse segments or plates, in this case the tail extending towards the entrance. The dark blue-green colour down the centre suggests that cyanobacterial growth follows …