Bonaglia S, Nascimento F J A, Bartoli M, Klawonn I, Brüchert V
Department of Geological Sciences, Stockholm University, 106 91 Stockholm, Sweden.
Department of Ecology, Environment and Plant Sciences, Stockholm University, 106 91 Stockholm, Sweden.
Nat Commun. 2014 Oct 16;5:5133. doi: 10.1038/ncomms6133.
Denitrification is a critical process that can alleviate the effects of excessive nitrogen availability in aquatic ecosystems subject to eutrophication. An important part of denitrification occurs in benthic systems where bioturbation by meiofauna (invertebrates <1 mm) and its effect on element cycling are still not well understood. Here we study the quantitative impact of meiofauna populations of different abundance and diversity, in the presence and absence of macrofauna, on nitrate reduction, carbon mineralization and methane fluxes. In sediments with abundant and diverse meiofauna, denitrification is double that in sediments with low meiofauna, suggesting that meiofauna bioturbation has a stimulating effect on nitrifying and denitrifying bacteria. However, high meiofauna densities in the presence of bivalves do not stimulate denitrification, while dissimilatory nitrate reduction to ammonium rate and methane efflux are significantly enhanced. We demonstrate that the ecological interactions between meio-, macrofauna and bacteria are important in regulating nitrogen cycling in soft-sediment ecosystems.
反硝化作用是一个关键过程，它可以减轻富营养化水生生态系统中过量氮素的影响。反硝化作用的一个重要部分发生在底栖系统中，其中小型动物（<1毫米的无脊椎动物）的生物扰动及其对元素循环的影响仍未得到充分理解。在这里，我们研究了在有大型动物和没有大型动物的情况下，不同丰度和多样性的小型动物种群对硝酸盐还原、碳矿化和甲烷通量的定量影响。在小型动物丰富多样的沉积物中，反硝化作用是小型动物较少的沉积物中的两倍，这表明小型动物的生物扰动对硝化细菌和反硝化细菌有刺激作用。然而，在双壳类动物存在的情况下，小型动物的高密度并不会刺激反硝化作用，而异养硝酸盐还原为铵的速率和甲烷通量则显著增加。我们证明，小型动物、大型动物和细菌之间的生态相互作用对于调节软沉积物生态系统中的氮循环很重要。
