Coastal and Ocean Processes

Understanding from small to large scale processes controlling the distribution and cycling of trace elements (TEs) and organic carbon (OC) in coastal environments and the open ocean is a primary endeavor of the geoscience community. This require a wide array of integrated knowledge, spanning from geochemistry, biology / microbiology and modelling, to unravel the complexity of freshwater, coastal and marine environments.

Some of the work collaborators and myself have been tackling include:

  • The assessment of freshwater, shelf ocean interaction and sediment resuspension events as significant source terms of bioactive TEs (e.g., Fe, Mn) to coastal water and the Arctic Ocean interior .
Sharp increase in dissolved and particulate Fe, as well as other lithogenic-derived TEs, in the Canadian Arctic Archipelago at places where sediment resuspension was higher (i.e., > transmissivity drop), whereas noticeable lower values were measured in the tranquil waters in the western archipelago region.
Sharp increase in dissolved and particulate Fe, as well as other lithogenic-derived TEs, in the Canadian Arctic Archipelago at places where sediment resuspension was higher (i.e., > transmissivity drop), whereas noticeable lower values were measured in the tranquil waters in the western archipelago region.
  • The study of lateral transport of dissolved and particulate TEs by energetic boundary currents, which incorporate resuspended sediment from the slope, transporting this high signature over long distances at intermediate depth waters.

  • The investigation of the dynamic interplay among primary production (i.e., synthesis of organic matter), remineralization (i.e., microbial degradation) and scavenging removal modulating the distributions of numerous biogenic derived TEs, phosphorus, nitrogen and OC in the Arctic Ocean and North Subarctic Atlantic Ocean.
The positive correlation between apparent oxygen utilization (AOU) and dissolved Fe (dFe) concentrations in intermediate water depth in Baffin Bay and the Labrador Sea evidence the input of this important micronutrient as result of organic matter degradation by microbial activity. On the contrary, at greater depths, scavenging removal overpass remineralization inputs as shown in the dFe vs. AOU relationship for Baffin Bay Deep Waters (BBDW) and Denmark Strait Overflow Waters (DSOW).
The positive correlation between apparent oxygen utilization (AOU) and dissolved Fe (dFe) concentrations in intermediate water depth in Baffin Bay and the Labrador Sea evidence the input of this important micronutrient as result of organic matter degradation by microbial activity. On the contrary, at greater depths, scavenging removal overpass remineralization inputs as shown in the dFe vs. AOU relationship for Baffin Bay Deep Waters (BBDW) and Denmark Strait Overflow Waters (DSOW).

  • The redox cycling of dissolved Fe and Mn at the sediment water interphase, as well as, the study of microbially mediated Mn oxidation in subsurface Arctic waters.

  • The understanding of oceanic processes such water masses circulation in the Arctic Ocean employing dissolved Pb distribution as a transient tracer. Exploiting the large differences in Pb concentrations in the Arctic Ocean, and coupling field observations with model outputs, we traced the evolution of water masses circulating in the Arctic. In addition, we studied the scavenging dynamics developing a pseudo first order scavenging model to study the behaviour of dissolved Mn in deep, old and isolated waters.

    The relative contribution of Arctic waters vs. Atlantic derived waters –having a higher dissolved Pb signature due to anthropogenic contamination– is reflected in the dPb profiles. At station BB3 the greater contribution of Arctic waters mixing with Atlantic derived water result in a modest increase in dPb in the ~400-800 m range, while at BB1 the larger proportion of Atlantic waters clearly translate in much higher dPb at this station.
    The relative contribution of Arctic waters vs. Atlantic derived waters –having a higher dissolved Pb signature due to anthropogenic contamination– is reflected in the dPb profiles. At station BB3 the greater contribution of Arctic waters mixing with Atlantic derived water result in a modest increase in dPb in the ~400-800 m range, while at BB1 the larger proportion of Atlantic waters clearly translate in much higher dPb at this station.


For more details about “Coastal and Ocean Processes” related studies, please see the “Publications section” (filter tag: Coastal & Ocean)

Manuel Colombo
Manuel Colombo
Assistant Professor of Marine Science

Biogeochemistry Across Boundaries // VIMS and W&M