CICLI BIOGEOCHIMICI PDF

Ocean Tracer and Biogeochemical Modeling at MIT. Here we briefly describe some of our ocean tracer and biogeochemistry studies. Bio, Cicli Biogeochimici. Prof Berna; 3 videos; views; Last updated on Sep 27, Play all. Share. Loading Save. Rappresentazione schematica del ciclo dell’azoto. Si chiama nitratazione la reazione terminale di mineralizzazione dell’azoto nel suolo e consiste Categoria: Cicli biogeochimici.

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The figure shows the mean surface ocean chlorophyll concentration in the Atlantic basin image from the SeaWiFs website. Ocean distributions of anthropogenic transient tracers, such as chlorofluorocarbons CFCs and radiocarbon 14C reveal pathways, rates and mechanisms of ocean circulation and mixing.

The subtropics are depleted in nutrients year round, reflected in low chlorophyll concentrations dark blue. Our overarching aim is to better understand the interactions between the climate system and biogeochijici global carbon cycle.

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We use numerical models of ocean circulation and biogeochemistry to examine the possible effect of interannual changes in meteorological forcing and upper ocean circulation on the fluxes of carbon dioxide and oxygen between the ocean and atmosphere.

The ocean model is losing carbon dioxide from the ocean in regions where carbon rich deep waters upwell to the surface e. biobeochimici

How do changes in ocean circulation and mixing on interannual timescales affect the air-sea exchange of trace gases, such as carbon dioxide and oxygen? We have examined the relationships between regionanal and interannual variations in meteorological forcing and the variability of the spring bloom of biological productivity in the North Atlantic ocean.

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CFC is entirely man-made, and its concentration in the atmosphere increased rapidly from the s to the s. From Follows and Marshall ; read the abstract here.

With graduate student Galen Mckinley, using global ocean circulation estimates from the ECCO consortium we find a significant interannual variability of the air-sea exchange of carbon dioxide biogeocgimici similar magnitude to those estimated from observed atmospheric data related to changes in upper ocean mixing. Here we briefly describe some of our ocean tracer and biogeochemistry studies.

Ecologia microbica

These studies are described in a series of papers click link to download PDF’s: Yellow and light blue indicate high chlorophyll concentrations. The ocean model absorbs carbon from the atmosphere in regions of sea surface heat loss and biological uptake of carbon e.

The comparison shows an improved simulation in models which partially resolve mesoscale eddies – the oceanic equivalent of weather systems which are typically tens of kilometres in lateral scale.

Follows and Dutkiewicz We have examined chlorophyll distributions estimated from remotely sensed ocean color by the SeaWiFs mission.

We have also used a numerical model of the time dependent ocean circulation with a highly simplified representation of the ecosystem of the North Atlantic. We have examined model simulations of the penetration of bomb-radiocarbon the 14C perturbation from atmospheric biogeohimici tests in the ‘s into the ocean. What is the role of ocean circulation and its variability in controlling and modulating global biogeochemical cycles?

An animation, showing the seasonal and interannual variability of the North Atlantic spring bloom, as observed from space by SeaWiFS, can be seen here 1.

Interannual variability in the global flux of carbon dioxide across the model’s sea surface show general agreement with inferences from observed data showing a strong signature of changes in the Tropical Pacific associated with El Nino phenomenon.

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Cicli biogeochimici

The high concentrations in the subpolar gyre reflect the strong late spring and summer bloom in that region. You can find pre-prints, reprints and abstracts of of our papers on these topics here.

What are the feedbacks between climate and biogeochemical processes? We have studied the intensity of the bloom in the subtropical and subpolar North Atlantic, and its relationship to meteorological forcing, using analysis of the SeaWiFS data and numerical models. Comparing model simulations of ocean tracers with observed data can inform us about the veracity of our ocean circulation models.

Monthly images are sequenced, for the two years and We have participated in OCMIPan international comparison of simulations of the ocean uptake of chlorofluorocarbons and the distribution and air-sea exchange of nutrients, carbon and oxygen in the ocean.

This project has been a collaboration with Dr.

Nitratazione

The finer resolution model shows significant ventilation of the western subtropical thermocline due to mesoscale eddy stirring. Comparisons show significant differences between models and data, and between the different models. It is soluble and has been invading the oceans, marking waters which have recently been near the surface. The figure shows the time-mean air-sea flux of carbon dioxide from a global, interannually varying simulation made by Galen McKinley.