ISSN:
1432-1793
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract A mooring system consisting of an in situ fluorometer at a depth of 50 m and a time-series sediment trap at a depth of 110 m was deployed at the sediment trap site (70°11.536'S; 24°18.679'E; water depth: 300 m) in Breid Bay, Antarctica in austral summer from 28 December 1985 to 13 February 1986. Sinking particles, consisting of diatoms (mainly Thalassiosira antarctica), were analyzed for organic materials, stable carbon and nitrogen isotopes. Vertical fluxes of organic carbon and nitrogen were determined to be within the ranges of 12.3 to 116 mg C m-2 d-1 and 1.79 to 15.4 mg N m-2 d-1, respectively, with maxima in the middle of January 1986, after which time the organic carbon and nitrogen fluxes tended to decrease with a steep gradient. High values of δ13C were found in the organic matter of the sinking particles collected before the middle of January, indicating that the organic matter was derived from the diatoms in the logarithmic phase of their growth. Increased abundance of glucose was found in the water-extractable carbohydrate, which was one of the sinking particles collected in the middle of January. This fact clearly indicated that the diatoms were no longer in the growth phase but rather in the stationary phase, because reserved glucan as well as various cellular organic materials were reportedly accumulated within the algal cells in the stationary phase. Fifteen species of protein amino acids with trace amounts of β-alanine, γ-aminobutyric acid and ornithine were found in the sinking particles upon acid hydrolysis, but the amino acid composition of these samples had not been affected much by biological agents. The essential amino acid index was calculated for the sinking particles collected in the course of the sediment trap experiment. The indices obtained indicated that the sinking particles collected in Breid Bay were more ecologically significant than the sinking and suspended particles from deep waters.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00356292
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