Walter Geibert

TL;DR: In this paper, the authors used the U- and Th-decay series of particle sinking rates, turnover rates of particles, as well as aggregation and disaggregation rates have been determined using multiple thorium isotopes measured in various colloidal and particle size fractions.

TL;DR: In this paper, a reverse-phase chromatographic separation of natural organic matter (NOM) was combined with high resolution inductively coupled plasma mass spectrometry to identify dissolved organic carbon/phosphorus and carbon/sulfur ratios.

Abstract: [1] The Southern Ocean (SO) plays a key role in modulating atmospheric CO2 via physical and biological processes. However, over much of the SO, biological activity is iron-limited. New in situ data from the Antarctic zone south of Africa in a region centered at ∼20°E–25°E reveal a previously overlooked region of high primary production, comparable in size to the northwest African upwelling region. Here, sea ice together with enclosed icebergs is channeled by prevailing winds to the eastern boundary of the Weddell Gyre, where a sharp transition to warmer waters causes melting. This cumulative melting provides a steady source of iron, fuelling an intense phytoplankton bloom that is not fully captured by monthly satellite production estimates. These findings imply that future changes in sea-ice cover and dynamics could have a significant effect on carbon sequestration in the SO.

TL;DR: In this paper, the authors provide evidence for at least two episodes during which the Arctic Ocean and adjacent Nordic seas were not only covered by an extensive ice shelf, but also filled entirely with fresh water, causing a widespread absence of thorium-230 in marine sediments.

TL;DR: In this article, the authors extended the 224Ra/228Th disequilibrium approach to examine benthic fluxes of a variety of metals, ranging from alkaline earth (Ba) to redox sensitive elements (U, Mn, and Fe), into the Pearl River Estuary (PRE), China.