Marine ecology progress series | |
High rates of N fixation in seagrass sediments measured via a direct 30N2 push-pull method | |
Lillian R. Aoki^11  | |
[1] Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22904, USA^1 | |
关键词: Nitrogen fixation; Seagrass; Zostera marina; Push-pull; 30N2; | |
DOI : 10.3354/meps12961 | |
学科分类:海洋学与技术 | |
来源: Inter-Research | |
【 摘 要 】
Highly productive seagrass meadows often occur in oligotrophic waters, and nitrogen (N) fixation may play a role in supporting the N demand of the meadows. To date, most studies of N fixation in seagrass sediments have relied on indirect measurements via the acetylene reduction technique. Recent measurements of N fixation in submerged estuarine sediments using direct methods (e.g. N2:Ar ratio) in laboratory core incubations have shown higher rates than acetylene reduction measurements. Direct methods have not yet been applied to seagrass sediments in situ. In this study, we used a new in situ 30N2 push-pull method to measure N fixation rates in seagrass sediments and compared those rates to traditional acetylene reduction slurries. On average, hourly rates of N fixation measured via the 30N2 push-pull method were more than an order of magnitude greater than the acetylene reduction rates during summer (388 and 7.8 µmol m-2 h-1, respectively). These push-pull rates exceeded other published rates of N fixation in seagrass sediments (measured via acetylene reduction) but were within the range of reported rates for direct measurements of N fixation in submerged estuarine sediments. These results indicate the need for further investigation of N fixation rates in seagrass sediments via direct and in situ measurements. In order to fully understand the role of seagrass meadows in coastal N cycling, it is critical to accurately determine the magnitude of N fixation that occurs in these highly productive ecosystems.
【 授权许可】
Unknown
【 预 览 】
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RO201910259691283ZK.pdf | 445KB | download |