Actualités et séminaires

The stability of methane hydrates at continental margins faces a significant threat from rising ocean temperatures. This scenario could potentially trigger the release of substantial (yet unconstrained) amounts of methane into the overlying water column and eventually into the atmosphere. Within marine sediments, the biologically mediated process of anaerobic oxidation of methane (AOM) is critical in mitigating such benthic methane discharge. However, AOM is not always ‘super’-efficient. There are two reasons why.

The multi-temporal high resolution spatial database provides an indispensable dataset for geological study and morphologic evolutions analysis. However, due to its involvement in military and national security issues, the technology regarding to geomorphologic data acquisition has become a mysterious and arduous project in the traditional surveying and mapping field. As a result, geoinformatic datasets are difficult to obtain or inaccessible.

Fine natural sediments like clay particles are transported in rivers and deposited in riverbeds. Historically, these particles are considered wash-load, i.e., passive material that travels in suspension, having little to no interaction with other river processes. However, river water enters the porous beds, bringing with it those fine particles that are filtrated and immobilized in the riverbed. Over time, they accumulate and clog the riverbed voids, dramatically attenuating hyporheic exchange and diminishing the connection between surface and groundwater.

The detection of metallic particles in the subsurface, e.g. for ore exploration or investigation of landfills, has been an important field in applied geophysics for several decades. Because of the high conductivity and high polarizability of metallic particles, geophysical methods using electrical properties, especially induced polarization, are highly relevant.

Le résumé de ma mission d'un an sur l'île Amsterdam en 20 questions

Rodrigo Ramírez‑Álvarez, Sergio Contreras, Aurélien Vivancos, Malcolm Reid, Ruby López‑Rodríguez & Konrad Górski

Inland waters play an important role in global nitrogen (N) cycling and transport substantial N from land to sea. However, it remains unclear whether, when and why freshwater biogeochemical N cycling has changed in response to human activities, climate change, and other environmental conditions.