Marine Biogeochemistry and Ecosystem Initiative in QUEST (MARQUEST).

海洋地球化学循环和生态系统是“地球系统”的重要组成部分，地球系统是一套相互关联的物理、化学和生物过程，它们塑造了地球表面的环境。这些地球化学循环不仅对海洋本身（海洋的组成和生活在海洋中的生物种类）很重要，而且对地球的气候也很重要，因为它们对大气的组成（特别是二氧化碳等“温室”气体和二甲基硫化物等其他对气候有重要影响的气体）产生了根本性的影响。从历史上看，全球海洋生物地球化学模型使用的是受物理和化学环境严格约束的生物过程的简单表示，使用的假设包括单一营养限制和恒定的Redfield比率-元素的利用和释放比例恒定。随着我们知识的增长，这种方法的缺点变得越来越明显，逐渐产生了更复杂的生态系统模型-从包括单一明确建模的植物（植物）和动物（动物园）浮游生物的模型到越来越多的各种不同功能类型的浮游生物介导不同的地球化学转变。虽然这些更复杂的模型有可能更忠实地再现海洋生物地球化学以及它将如何对气候和海洋环流的变化作出反应，但复杂性的增加带来了必须知道更多参数才能确定系统的代价。如何验证这些模型--也就是说，判断它们的工作情况如何--或者解决给定问题所需的模型的最佳复杂性是什么，这一点并不一定清楚。我们建议在英国建立一个由几个参与地球化学建模的团体组成的联盟。目前，这两个小组各自独立工作，每个小组的模型在上面概述的复杂性光谱中占据不同的位置。在MARQUEST中，他们将合作，比较模型的预测并分析差异和相似之处的原因。我们还将研究更基本的建模方法，以澄清我们可以从当前类型的模型中期望什么。MARQUEST的新的研究成果将包括：利用遥感海洋颜色数据、现场数据集和欧洲主要方案（如Carbo-Ocean和Euroceans：在相同循环代码中运行的不同生态系统模型的比较）正在进行的观测，开发验证模型的新方法：开发一个模拟沿海生态系统的模块，但可用于全球海洋生物地球化学模拟，和一个准确的物理模拟北大西洋的数据同化的指导下，生态系统模拟可以嵌入。这将有助于将生态系统模型与近几十年的观测结果进行详细比较，包括对海气通量变化的事后预测-这对于帮助限制人为二氧化碳汇的陆地和海洋部分非常有用。我们还将对未来50年和100年从海洋到大气的CO2、氧气和二甲基硫化物通量的演变做出最佳估计。

Ocean biogeochemical cycles and ecosystems are an important part of the 'Earth system' - the set of interlinked physical, chemical and biological processes, which shape the environment at the Earth's surface. These biogeochemical cycles are not only important for the oceans themselves (their composition and the kinds of creatures that live in them) but also for the climate of the planet, through their fundamental influence on the composition of the atmosphere (in particular, 'greenhouse' gases such as carbon dioxide, and other climatically important gases such as di-methyl sulphide). Historically, global ocean biogeochemical models have used simple representations of biological processes that are constrained tightly by the physical and chemical environment, using assumptions such as single-nutrient limitation and constant Redfield ratios - utilization and release of elements in constant proportions. As our knowledge has grown, the shortcomings of this approach have become increasingly apparent, giving rise to progressively more elaborate models of the ecosystem - from models that include a single explicitly modelled plant (phyto-) and animal (zoo-) plankton to increasingly, a variety of different functional types of plankton that mediate different geochemical transformations. While these more complex models have the potential to reproduce more faithfully ocean biogeochemistry and how it will respond to changes in climate and ocean circulation, the increased complexity brings with it the penalty that many more parameters must be known in order to specify the system. It is not necessarily clear how to validate such models - that is, to tell how well they are working - or what is the optimum complexity of model required to address a given problem. We are proposing a consortium of several groups involved in biogeochemical modelling in the UK. Currently, the groups work separately, each on models occupying a different place on the spectrum of complexity sketched above. In MARQUEST they will co-operate, comparing the predictions of their models and analyzing the causes of their differences and similarities. We will also examine more fundamental modelling approaches to the planktonic ecosystem, with the aim of clarifying what we can expect from the current types of model. New research outputs from MARQUEST will include: the development of new methods of validating models, making use of remote sensing ocean colour data, in-situ data sets and the observations ongoing in major European programmes such as Carbo-Ocean and Euroceans: comparison of different ecosystem models run in the same circulation codes: development of a module to simulate the coastal ecosystems, but useable in global ocean biogeochemical simulations, and an accurate physical simulation of the North Atlantic guided by data assimilation into which ecosystem simulations can be embedded. This will enable detailed comparison of ecosystem models with observations over recent decades, including a hindcast of the variation in air-sea fluxes of gases - of great use for helping to constrain both land and ocean components of the sink for anthropogenic carbon dioxide. We will also make best estimates of the evolution of the CO2, oxygen and di-methylsuiphide fluxes from ocean to atmosphere over the next 50 and 100 years.