Sampling Stiff Sediments of an Ice‐covered Lake1

May 1962 (Antia et al. 1962). All seawater ing of the role of amino sugars in marine samples were filtered (HA MilliporeB1) ecology and biochemistry.immediately after collection and were N. J. ANTIA~ stored deep-frozen until time of analysis.C. Y. LEES No hexosamine was detected in any of the Fisheries Research Board of Canada, samples examined.It appears from the re-Biological Station, sults that if "free" amino sugar is at all Nanaimo, B.C., Canada.present in seawater, it may occur at levels below 0.06 mg/liter and thus constitute an insignificant fraction ( < 5% C ) of the generally estimated total of dissolved organic matter.The results from the plastic-sphere experiment suggest that it is not produced extracellularly to any significant extent by a typical littoral phytoplankton bloom composed of diatoms and dinoflagellates.The observed absence of measurable "free" amino sugar in oceanic waters raises questions about the manner and degree of turnover of "bound" amino sugar (e.g., chitin) known to occur in a variety of organisms in the marine environment.vironment recommends the method for studies intended to lead to an understandl Registered trademark, Millipore Filter Corporation, Bedford, Massachusetts. Its universal applicabilityto seawater systems ranging from culture media to natural water from any kind of marine en-REFERENCES