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极其重要。特别是，沿海地区对氮循环的贡献很大，从陆地上清除了被河流冲入的氮素，从而减少了其对沿海海洋的肥力影响。然而，在微生物的推动下，这些去除过程也促进了氮气的形成，其中一些(N2O、NO、NO2)在全球变暖中起着重要作用。虽然已经做了大量工作来测量温带沿海地区的这些过程，但关于它们如何在热带沿海地区发生，以及导致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重大差异，我们需要了解这些差异，才能了解它们在全球的重要性。我们打算使用N的稳定同位素示踪剂来测量这些重要过程在几个热带沿海沉积物中的速率，以及N循环的不同最终产物的相对重要性。此外，我们将把在科尔纳河口开发的N循环的分子微生物学技术应用于热带沉积物，以确定微生物与温带河口的微生物是不同还是相同；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.