Land inputs in the Arctic transported up to the North Pole

M. Charette and his colleagues (2020, see reference below) gathered data on trace elements, radionuclides, dissolved organic matter and many ancillary parameters collected as part of the two Arctic GEOTRACES cruises conducted in 2015 (U.S. GEOTRACES GN01 and German GEOTRACES GN04). They revealed that freshwater runoff from rivers and continental shelf sediments are bringing significant quantities of carbon and trace elements into parts of the Arctic Ocean via the Transpolar Drift—a major surface current that moves water from Siberia across the North Pole to the North Atlantic Ocean. Surprisingly, trace elements are barely scavenged at the land-ocean contact. This is due to the fact that in the Arctic, these elements are strongly bound with abundant organic matter from rivers, which allows the mixture to be transported into the central Arctic, over 1,000 kilometers from their source and acting as surface water fertilizer.

Higher concentrations of trace elements and nutrients previously locked up in frozen soils (permafrost) are expected to increase as more river runoff reaches the Arctic, a hot spot of the climate warming.  However, while an increase in nutrients may boost Arctic marine productivity, the authors caution that the continued loss of sea ice will further exacerbate climate warming, which will impact ecosystems more broadly.

Figure: Map of the 2015 US GEOTRACES GN1 expedition in the Arctic Ocean. (Illustration by Natalie Renier, © Woods Hole Oceanographic Institution).

Reference:

Charette, M. A., et al. (2020). The Transpolar Drift as a Source of Riverine and Shelf-Derived Trace Elements to the Central Arctic Ocean. Journal of Geophysical Research: Oceans, e2019JC015920. DOI: https://doi.org/10.1029/2019jc015920

Latest highlights

North-South section of bioactive cadmium, nickel, zinc, copper and iron along GEOTRACES transect GP19 in the Pacific Ocean

Zheng and his colleagues propose the first full sections of the simultaneous dissolved distributions of five nutrient-type trace metals in the western South Pacific Ocean.

MOTES: a new facility designed for trace element sampling in seawater

Zhang and a group of engineers and researchers from Shanghai and Qingdao are presenting a modular trace element sampling facility.

A thorough estimate of the hydrothermal plumes on neodymium concentration and isotope oceanic cycles

Basak and co-workers investigated the influence of particulate matter on neodymium distributions in the Southern East Pacific Rise Hydrothermal Plume.

What are the drivers of the distributions of cadmium, nickel, zinc, copper and cobalt, manganese and aluminium in the Atlantic Ocean? Two papers are tackling this issue

Chen and co-authors reveal that the distributions of dissolved tracers at depth in the South Atlantic are predominantly controlled by the mixing of North Atlantic Deep Water and waters of Antarctic origin…

Rechercher