Thornber Carol S, DiMilla Peter, Nixon Scott W, McKinney Richard A
Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA.
Mar Pollut Bull. 2008 Feb;56(2):261-9. doi: 10.1016/j.marpolbul.2007.10.031.
The frequency and duration of macroalgal blooms have increased in many coastal waters over the past several decades. We used field surveys and laboratory culturing experiments to examine the nitrogen content and delta(15)N values of Ulva and Gracilaria, two bloom-forming algal genera in Narragansett Bay, RI (USA). The northern end of this bay is densely populated with large sewage treatment plant nitrogen inputs; the southern end is more lightly populated and opens to the Atlantic Ocean. Field-collected Ulva varied in delta(15)N among sites, but with two exceptions had delta(15)N above 10 per thousand, reflecting a significant component of heavy anthropogenic N. This variation was not correlated with a north-south gradient. Both Ulva and Gracilaria cultured in water from across Narragansett Bay also had high signals (delta(15)N= approximately 14-17 per thousand and 8-12 per thousand, respectively). These results indicate that inputs of anthropogenic N can have far-reaching impacts throughout estuaries.
在过去几十年里，许多沿海水域大型海藻暴发的频率和持续时间都有所增加。我们通过实地调查和实验室培养实验，研究了美国罗德岛州纳拉甘西特湾两种形成藻华的藻类——石莼属和江蓠属藻类的氮含量及δ(15)N值。该海湾北端人口密集，有大型污水处理厂输入氮；南端人口较少，通向大西洋。实地采集的石莼在不同地点的δ(15)N有所不同，但除两个例外，其δ(15)N均高于10‰，这反映出大量人为氮的显著影响。这种变化与南北梯度无关。在纳拉甘西特湾各处水域培养的石莼和江蓠也都有较高的信号值（δ(15)N分别约为14‰ - 17‰和8‰ - 12‰）。这些结果表明，人为氮的输入会对整个河口产生深远影响。
