Seasonal variation in the biochemical composition of particulate material collected by sediment traps at Signy Island, Antarctica |
| |
Authors: | Geoffrey C Cripps Andrew Clarke |
| |
Institution: | (1) Marine Life Sciences Division, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK e-mail: g.cripps@bas.ac.uk, Fax: +44-1223-221259, GB |
| |
Abstract: | Particulate material recovered over an 18-month period from sediment traps deployed at a shallow-water nearshore Antarctic
site was analysed for photosynthetic pigments, aliphatic hydrocarbons and fatty acids. All components showed a distinct seasonal
variation, with high recovery rates during the summer open-water phytoplankton bloom and low rates under winter fast ice.
The amount of trapped material differed between the two summers, indicating inter-annual variability of vertical flux associated
with differences in the intensity of the summer phytoplankton bloom. Particulate material trapped in summer was dominated
by that which originated in diatoms. High recoveries of chlorophyll a, fucoxanthin, n-C21:6 hydrocarbon, 20:5(n-3) fatty acid and shorter chain (C15–C24) aliphatic hydrocarbons all pointed to a significant summer flux of ungrazed diatoms. There were, however, also signals of
zooplankton grazing activity (notably pyrophaeophorbide a), and the presence of C18:4(n-3) and C22:6(n-3) fatty acids suggested a small flux of material from flagellates and other
sources. Longer chain n-alkanes (C25–C34) indicative of nanoplankton were detected all year, but there was no significant deposition of zooplankton material in any
sample. The major recovery rate of photosynthetic pigments was in late summer (February to April), and the major grazing signal
occurred after the peak of the summer diatom bloom. Most of the diatom bloom appeared to settle out from the water column
without being grazed. The major seasonal contrast in the biochemistry of the trapped material was the dominance of the diatom
signature in summer, and in winter the predominance (but at much lower recovery rates) of material from nanoplankton.
Received: 2 March 1998 / Accepted: 12 June 1998 |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|