Vol.27, No.04. 2016
Table of Contents
Sources of organic matter and paleo-environmental implications inferred from carbon isotope compositions of lacustrine sediments at Inexpressible Island, Ross Sea, Antarctica
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The carbon isotopic composition of organic matter (δ 13 C org ) was determined in two sediment cores (IIL1 and IIL9) recovered from Inexpressible Island, Ross Sea, Antarctica, and analyzed to identify the sources of that organic matter. The δ 13 C org values of sediments of IIL9 were found to vary between −14.6‰ and −11.6‰, with a mean of −13.4‰ (n=48). These values were significantly higher than those of IIL1 sediments which varied between −23.2‰ and −20.4‰, with a mean of −21.8‰ (n=55). The variation in δ 13 C org values in these two sediment cores indicate different sources of organic matter. The relatively high δ 13 C org values in IIL9 are in accordance with a source from algae, while the low δ 13 C org values in IIL1 evince significant influence from penguin guano with algae as the secondary source. Compared with the reference data from other high-latitude lake sediments and plants, the δ 13 C org values in IIL9 were extremely high, a result likely related to intense competition for CO 2 assimilation among algal species during the growing season in this relatively shallow pond. These results indicate that sedimentary δ 13 C org is a reliable proxy for paleo-primary productivity in ponds at Inexpressible Island.
1 Institute of Polar Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China; 2 Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province, Hefei 230031, China; 3 LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; 4 Department of Biology and Marine Biology, University of North Carolina Wilmington, 601S. College Road, Wilmington, NC 28403, USA