Physical and biogeochemical ocean dynamics can be intermittent and highly variable, and involve interactions on multiple scales. In general, the oceanic fields, processes and interactions that matter thus vary in time and space. For efficient forecasting, the structures and parameters of models must evolve and respond dynamically to new data injected into the executing prediction system. The co...

Part 1: The Earth and its Lithosphere Chemical composition and structure of the Earth. . . . . . . . . . . . . . . . . . . . . . . . . 3 The structure of the Earth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Primordial chemistry: Origin of the elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Formation and evolution of the earth. . . ...

Photoferrotrophy, the process by which inorganic carbon is fixed into organic matter using light as an energy source and reduced iron [Fe(II)] as an electron donor, has been proposed as one of the oldest photoautotrophic metabolisms on Earth. Under the iron-rich (ferruginous) but sulfide poor conditions dominating the Archean ocean, this type of metabolism could have accounted for most of the p...

A mathematical model was developed for describing the transport of arsenic, coupled with microbially-mediated biogeochemical processes. The biogeochemical characteristics of arsenic reactive transport processes were investigated in both batch and column tests, which showed that As(V) was reduced to As(III) by Shewanella sp., with the reduced arsenic species subsequently removed by precipitation...

[1] Mechanisms of nutrient supply in oligotrophic ocean systems remain inadequately understood and quantified. In the North Atlantic Subtropical Gyre, for example, the observed rates of new production are apparently not balanced by nutrient supply via vertical mixing. Mesoscale eddies have been hypothesized as a mechanism for vertical nutrient pumping into the euphotic zone, but the full range ...

The currents, fronts and eddies that comprise the oceanic mesoscale, sometimes referred to as the “internal weather of the sea,” are highly energetic and ubiquitous features of ocean circulation. Dynamical consequences of these phenomena include perturbation of the chemical and biological environment that can dramatically impact biogeochemical cycling in the ocean. The processes that regulate t...

80W 60W 40W 20W 0 Modeling nutrient dynamics and carbon cycling in the ocean requires interdisciplinary research, combining geochemistry, biology, ecology and physics. All of these disciplines are represented in the U.S. JGOFS Synthesis and Modeling Project (SMP). However it is probably fair to say that the SMP, child of the U.S. JGOFS process studies, has focused primarily on characterizing an...

32 33 Marine plankton ecosystems are an important component of biogeochemical cycling in the oceans. 34 Operational plankton functional type (PFT) models, that group plankton according to their 35 biogeochemical properties, are currently being developed to resolve biogenic gas exchange between 36 the ocean and atmosphere, and to model the lowest trophic levels in fisheries models. A 37 fundamen...

Climate change modulates the effects of solar UV radiation on biogeochemical cycles in terrestrial and aquatic ecosystems, particularly for carbon cycling, resulting in UV-mediated positive or negative feedbacks on climate. Possible positive feedbacks discussed in this assessment include: (i) enhanced UVinduced mineralisation of above ground litter due to aridification; (ii) enhanced UV-induced...

[1] Understanding variability patterns of biogeochemical conditions in water is a key issue for water management strategies. Here a unique homogeneous data set of 1041 Swedish boreal lakes, sampled during three lake inventories along an 8 latitudinal temperature gradient, revealed a systematic increase in the variability of the water chemical composition between lakes with increasing temperatur...