Isolation of chlorophyll a in Microsystis spp. for determination of stable isotopes of carbon and nitrogen, and variation in Suwa lake

• Published in: BUNSEKI KAGAKU Vol. 39; no. 8; pp. 451 - 456
• Main Authors: KATASE, Takao, WADA, Eitaro
• Format: Journal Article
• Language: Japanese; English
• Published: Tokyo The Japan Society for Analytical Chemistry 01.08.1990; Nippon Bunseki Kagakkai; Japan Science and Technology Agency
• Subjects: chlorophyll a; Microcystis spp; stable isotope ratios of carbon and nitrogen; Suwa lake
• ISSN: 0525-1931
• DOI: 10.2116/bunsekikagaku.39.8_451

We studied on an isolation of chlorophyll a for determination of stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) and applied it to determine in Microcystis spp. from Suwa lake, Japan. The algae were collected four times between June and September, 1987 by using a 20l plankton net (40μm, mesh size). Collected freezed-samples (7.320.6 g, wet base) ground with anhydrous Na2SO4 using a mortor and a pestle were extracted with acetone (200 ml). The extracts were precipitated with 1, 4-dioxane (crude chlorophyll) and consequently purified chlorophyll a (2.38.1 mg) was obtained quantitatively by successive chromatography with DEAE-Toyopearl 650 M (2288μm) and Sepharose CL6B (45165μm) packed in glass tubings. The ratio, (δ13C, ‰ ) of chlorophyll a in the algae had changed from -33.8±0.05 in June 19 to -27.5±0.3 September with different growth. Difference (Δ13C) between δ13C of chlorophyll a and that of a whole body of the algae had also changed from -9.4±0.05 to -3.4±0.1.Comparing to the carbon ratios, the both ratios of δ15N and Δ15N slightly changed from 22.0 to 23.5 and 12.9 to 16.0, respectively. The change of heavy isotopes in Δ13C and Δ15N was reverse: The heavy carbon was depleted and heavy nitrogen was enriched.