Biogeochemical cycling of N in tropical coastal zones: molecular microbial ecology of trace gas production.

海岸带在控制地球元素自然循环的生物地球化学过程中起着极其重要的作用。特别是，沿海地区对氮循环的贡献很大，它清除了被河流从陆地冲进来的氮，从而减少了它对沿海海洋的施肥影响。然而，这些由微生物驱动的去除过程也有助于氮气的形成，其中一些（N2O， NO, NO2）对全球变暖很重要。虽然在温带沿海地区已经做了大量的工作来测量这些过程，但对于它们是如何在热带沿海地区发生的，以及引起这些过程的微生物与温带地区的微生物是否相同或不同，人们知之甚少。最近的信息表明，这些区域之间可能存在显著差异，如果我们要能够理解它们在全球的重要性，我们就需要了解这些差异。我们打算测量几种热带沿海沉积物中这些重要过程的速率，以及不同N循环最终产物的相对重要性，使用N的稳定同位素示踪剂。此外，我们将把在科尔尼河口发展起来的N循环分子微生物学技术应用于热带沉积物，以确定微生物是否与温带河口相同或不同；以及不同的微生物群是否在这两个地区占主导地位。

The coastal zone is extremely important in the biogeochemical processes which control the natural cycle of elements of the Earth. In particular, the coastal zone contributes significantly to the nitrogen cycle, removing nitrogen washed in from the land by rivers and so reducing its fertilizing impact on the coastal seas. However, these removal processes, driven by microorganisms, also contribute to the formation of nitrogen gases, some of which (N2O, NO, NO2) are important in global warming. While a lot of work has been done to measure these processes in temperate coastal regions, there is little known about how they occur in the tropical coastal zone nor whether the microorganisms bringing about the processes are the same or different to those in temperate regions. Recent information suggests that there may be significant differences between these regions which we need to know about if we are to be able to understand their importance globally. We intend to measure the rates of these important processes in several tropical coastal sediments, and the relative importance of the different endproducts of N cycling, using stable isotope tracers of N. In addition, we will apply the techniques of molecular microbiology of N cycling, developed in the Colne estuary, to tropical sediments to determine whether the microorganisms are different or the same as in temperate estuaries; and whether different groups of microorganisms predominate in the two regions.