Seagrass restoration reestablishes the coastal nitrogen filter through enhanced burial
Seagrass restoration reestablishes the coastal nitrogen filter through enhanced burial
复制标题
DOI：
10.1002/lno.11241
复制
发表时间：
2019-07-16
影响因子：
4.5
通讯作者：
Oreska, Matthew P. J.
中科院分区：
文献类型：
--
作者：
Aoki, Lillian R.;McGlathery, Karen J.;Oreska, Matthew P. J.
海草草甸具有重要的生态功能，可以过滤来自周围流域的营养物质，特别是氮。通过增强氮的去除过程，包括氮在沉积物中的埋藏和反硝化作用，海草草甸改善水质。随着全球海草草甸的加速丧失，海草恢复在重建这些沿海生态系统功能中起着关键作用。然而，很少有测量存在的N埋藏率在温带海草草甸，没有被公布恢复草甸。在这项研究中，我们测量了N的埋藏率在一个大的（6.9公里（2））恢复鳗草（Zostera滨海）草甸和比较N去除通过埋葬以前的测量去除通过反硝化。我们还比较了氮去除输入从外部负载和固定和N同化海草生物量。我们发现，在这片草甸中，埋藏是氮去除的主要过程; 3.52 g N m（-2）yr（-1）的埋藏速率与播种后10年内天然草甸的速率相当，是邻近裸露沉积物速率（0.17 g N m（-2）yr（-1））的20倍以上。我们还发现，高速率的N同化（2.62克N米（-2）年（-1））创造了一个实质性的，但暂时的氮在生长季节的水槽。我们的研究结果突出了海草草甸如何通过高埋葬率介导N循环，迄今为止，在文献中研究不足。恢复后的N过滤器功能的成功返回，在这里首次显示，可以激励继续努力海草恢复和保护。
Seagrass meadows perform an important ecological function as filters for incoming nutrients from surrounding watersheds, especially nitrogen (N). By enhancing N removal processes, including N burial in sediments and denitrification, seagrass meadows improve water quality. With accelerating losses of seagrass meadows worldwide, seagrass restoration plays a key role in reestablishing these coastal ecosystem functions. However, few measurements exist of N burial rates in temperate seagrass meadows and none have been published for restored meadows. In this study, we measured N burial rates in a large (6.9 km(2)) restored eelgrass (Zostera marina) meadow and compared N removal through burial to previous measurements of removal via denitrification. We also compared N removal to inputs from external loading and fixation and to N assimilation in seagrass biomass. We found that, in this meadow, burial was the dominant process of N removal; the burial rate of 3.52 g N m(-2) yr(-1) was comparable to rates in natural meadows within 10 yr after seeding and was more than 20x the rate in adjacent bare sediments (0.17 g N m(-2) yr(-1)). We also found that the high rates of N assimilation (2.62 g N m(-2) yr(-1)) created a substantial though temporary sink for nitrogen during the growing season. Our results highlight how seagrass meadows mediate N cycling through high rates of burial, which to date has been understudied in the literature. The successful return of the N filter function after restoration, shown here for the first time, can motivate continued efforts for seagrass restoration and conservation.