Benthic N2 fixation in coral reefs and the potential effects of human-induced environmental change.
Benthic N2 fixation in coral reefs and the potential effects of human-induced environmental change.
复制标题
DOI：
10.1002/ece3.1050
复制
发表时间：
2014-05
影响因子：
2.6
通讯作者：
Wild, Christian
中科院分区：
文献类型：
--
作者：
Cardini, Ulisse;Bednarz, Vanessa N.;Foster, Rachel A.;Wild, Christian
关键词：
热带珊瑚礁是最具生产力和多样性的生态系统之一，尽管被海洋沃茨包围，营养物质供应短缺。底栖生物固氮作用是珊瑚礁生态系统中氮的重要内源来源，但相关信息却很少。在这里，我们回顾了与珊瑚礁生物及其生态系统相关的N2固定知识的现状（和差距）。通过总结现有的文献，我们表明，底栖生物固氮是一个无所不在的过程，在热带珊瑚礁环境。最高的N2固定率检测在珊瑚礁相关的蓝藻垫和海草草甸，清楚地表明这些功能组的意义，如果存在的话，新的N在珊瑚礁生态系统中的输入。尽管如此，硬珊瑚等关键的底栖生物也对珊瑚礁中的底栖N2固定做出了重要贡献。鉴于健康的珊瑚礁系统通常有很高的珊瑚覆盖率，这些结果表明，底栖共生协会可能比以前认为的更重要。事实上，碳（C）和N2固定剂之间的互惠作用可能已经进化，这可能使珊瑚礁群落能够减轻N限制。然后，我们探讨了潜在的影响，越来越多的人类干扰的过程中的底栖生物礁固氮通过改变固氮菌群，酶的活性，或底栖生物底物有利于这些微生物。目前的知识表明，海洋酸化、变暖和脱氧的积极影响以及紫外线辐射增加对珊瑚礁固定氮量的负面影响。富营养化可以促进或抑制N2固定，这取决于营养物质的限制。由于N2固定似乎在营养有限的珊瑚礁生态系统中发挥着重要作用，这些假设需要通过未来的研究工作来扩展和确认，以解决本次审查中确定的知识差距。
Tropical coral reefs are among the most productive and diverse ecosystems, despite being surrounded by ocean waters where nutrients are in short supply. Benthic dinitrogen (N2) fixation is a significant internal source of “new” nitrogen (N) in reef ecosystems, but related information appears to be sparse. Here, we review the current state (and gaps) of knowledge on N2 fixation associated with coral reef organisms and their ecosystems. By summarizing the existing literature, we show that benthic N2 fixation is an omnipresent process in tropical reef environments. Highest N2 fixation rates are detected in reef-associated cyanobacterial mats and sea grass meadows, clearly showing the significance of these functional groups, if present, to the input of new N in reef ecosystems. Nonetheless, key benthic organisms such as hard corals also importantly contribute to benthic N2 fixation in the reef. Given the usually high coral coverage of healthy reef systems, these results indicate that benthic symbiotic associations may be more important than previously thought. In fact, mutualisms between carbon (C) and N2 fixers have likely evolved that may enable reef communities to mitigate N limitation. We then explore the potential effects of the increasing human interferences on the process of benthic reef N2 fixation via changes in diazotrophic populations, enzymatic activities, or availability of benthic substrates favorable to these microorganisms. Current knowledge indicates positive effects of ocean acidification, warming, and deoxygenation and negative effects of increased ultraviolet radiation on the amount of N fixed in coral reefs. Eutrophication may either boost or suppress N2 fixation, depending on the nutrient becoming limiting. As N2 fixation appears to play a fundamental role in nutrient-limited reef ecosystems, these assumptions need to be expanded and confirmed by future research efforts addressing the knowledge gaps identified in this review.
登录
查看更多内容
影响因子：
2.5
作者：
Bertics, Victoria J.;Sohm, Jill A.;Ziebis, Wiebke
通讯作者：
Ziebis, Wiebke
影响因子：
4.4
作者：
Bertics, Victoria J.;Sohm, Jill A.;Ziebis, Wiebke
通讯作者：
Ziebis, Wiebke
影响因子：
2.4
作者：
CAPONE, DG;TAYLOR, DL;TAYLOR, BF
通讯作者：
TAYLOR, BF
影响因子：
2.5
作者：
Bell, PRF;Elmetri, I;Uwins, P
通讯作者：
Uwins, P
影响因子：
4.9
作者：
BORDELEAU, LM;PREVOST, D
通讯作者：
PREVOST, D