Seasonal nitrogen assimilation and carbon fixation in a fjordic sea loch |
| |
Authors: | Rees AP; Owens NJP; Heath MR; Plummer DH; Bellerby RS |
| |
Institution: | 1 Plymouth Marine Laboratory Prospect Place, The Hoe, Plymouth PL1 3DH, UK
2Scottish Office Agriculture and Fisheries Department, Marine Laboratory Aberdeen, AB9 8DP, UK
3Present address: Department of Marine Sciences and Coastal Management, University of Newcastle Newcastle upon Tyne, NE1 7RU, UK |
| |
Abstract: | Carbon (C) fixation and nitrogen (N) assimilation rates havebeen estimated from 14C and 15N techniques for a 12 month periodin a Scottish sea loch. The maximum rate of nitrogen assimilated(29.92 mmol N m2 day1) was in April at the mostseaward station; similar high rates were experienced duringMay at the other stations. Carbon fixation rates were maximal(4884047 mg C m2day1) at the time of highphytoplankton biomass (maximum 8.3 mg m3 chlorophylla) during May, whilst nitrate concentrations remained >0.7µ.mol l1. C:N assimilation ratios suggest nitrogenlimitation only during the peak of the spring bloom, althoughat times nitrogen (nitrate and ammonium) concentration fellto 0.2 µmol l1 in the following months. The verticalstability of the water column, influenced by tidal and riverineflushing, varied along the axis of the loch, resulting in markeddifferences between sampling stations. Although ammonium waspreferentially assimilated by phytoplankton, >50% of productionwas supported by nitrate uptake and only during the summer monthswas the assimilation of ammonium quantitatively important. |
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|