DOI:10.1111/j.1574-6941.2006.00221.x

• Main Authors: Communitystructureand Physiological Characterizationof, Antonio Quesada, Max Häggblom
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2006
• Subjects: Antarctic; Byers; Byers peninsula; Livingston Island; South Shetland Islands; Antarc*; Antarctica
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.561.2602; http://www.cen.ulaval.ca/warwickvincent/PDFfiles/205.pdf

Antarctica; microbial mat; nitrogen assimilation; N2 fixation; photosynthesis; photosynthetic pigments. The community structure and physiological characteristics of three microbial mat communities in Byers Peninsula (Livingston Island, South Shetland Islands, Antarctica) were compared. One of the mats was located at the edge of a stream and was dominated by diatoms (with a thin basal layer of oscillatorian cyanobac-teria), whereas the other two mats, located over moist soil and the bottom of a pond, respectively, were dominated by cyanobacteria throughout their vertical profiles. The predominant xanthophyll was fucoxanthin in the stream mat and myxoxanthophyll in the cyanobacteria-dominated mats. The sheath pigment scytonemin was absent in the stream mat but present in the soil and pond mats. The stream mat showed significantly lower d13C and higher d15N values than the other two mats. Consistent with the d15N values, N2 fixation was negligible in the stream mat. The soil mat was the physiologically most active community. It showed rates of photosynthesis three times higher than in the other mats, and had the highest rates of ammonium uptake, nitrate uptake and N2 fixation. These observations underscore the taxonomic and physiological diversity of microbial mat communities in the maritime Antarctic region.