Georgi Laukert

• PhD
• PostDoc Position at Woods Hole Oceanographic Institution

Marine neodymium (Nd) isotope and rare earth element (REE) compositions are valuable tracers for present and past ocean circulation and continental inputs. Yet their supply via high latitude estuaries is largely unknown. Here we present a comprehensive dissolved Nd isotope (expressed as εNd values) and REE data set together with seawater stable oxy...

Freshwater and sea ice in the Arctic Ocean (AO) both respond to climate forcing but changes in their distribution may in turn also significantly affect Northern Hemisphere climate. The exact mechanisms controlling their transport are, however, still subject of ongoing research. Radiogenic neodymium (Nd) isotopes (expressed as εNd) and rare earth el...

Nearly half the inflow of warm and saline Atlantic Water (AW) to the Arctic Ocean is substantially cooled and freshened in the Barents Sea, which is therefore considered a key region for water mass transformation in the Arctic Mediterranean (AM). Numerous studies have focused on this transformation and the increasing influence of AW on Arctic clima...

The Siberian rivers supply large amounts of freshwater and terrestrial derived material to the Arctic Ocean. Although riverine freshwater and constituents have been identified in the central Arctic Ocean, the individual contributions of the Siberian rivers to and their spatiotemporal distributions in the Transpolar Drift (TPD), the major wind-drive...

Radiogenic neodymium (Nd) isotopes (εNd) have the potential to serve as a geochemi- cal tracer of the marine origin of Arctic sea ice. This capability results from pronounced εNd differences between the distinct marine and riverine sources, which feed the sur- face waters from which the ice forms. The first dissolved Nd isotope and rare earth eleme...

The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC, 2019–2020), a year-long drift with the Arctic sea ice, has provided the scientific community with an unprecedented, multidisciplinary dataset from the Eurasian Arctic Ocean, covering high atmosphere to deep ocean across all seasons. However, the heterogeneity of dat...

The Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC, 2019/2020), a year-long drift with the Arctic sea ice, has provided the scientific community with an unprecedented, multidisciplinary dataset from the Eurasian Arctic Ocean, covering high atmosphere to deep ocean across all seasons. However, the heterogeneity of...

The Amazon River accounts for 20% of global freshwater runoff and supplies vital trace metals to the Atlantic Ocean. Suspended particles within its plume are thought to partially dissolve, constituting a large potential source of metals, which is, however, not well constrained. Here we used combined neodymium (Nd) and hafnium (Hf) isotopes to dispr...

Realistic prediction of the near‐future response of Arctic Ocean primary productivity to ongoing warming and sea ice loss requires a mechanistic understanding of the processes controlling nutrient bioavailability. To evaluate continental nutrient inputs, biological utilization, and the influence of mixing and winter processes in the Laptev Sea, the...

Arctic Ocean properties and processes are highly relevant to the regional and global coupled climate system, yet still scarcely observed, especially in winter. Team OCEAN conducted a full year of physical oceanography observations as part of the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC), a drift with the Ar...

The sluggish water mass transport in the deeper North Pacific Ocean complicates the assessment of formation, spreading and mixing of surface, intermediate and deep-water masses based on standard hydrographic parameters alone. Geochemical tracers sensitive to water mass provenance and mixing allow to better characterize the origin and fate of the pr...

The Congo River is the second largest river by discharge in the world and a major source of element inputs into the South Atlantic Ocean. Yet, the element fluxes and transport mechanisms across and beyond its estuary and their impacts on the marine distribution and cycling of many major and trace elements are not well understood. We present the fir...

In this paper, we investigate the seasonal and spatial variability of stratification on the Siberian shelves with a case study from the Laptev Sea based on shipboard hydrographic measurements, year-round oceanographic mooring records from 2013 to 2014 and chemical tracer-based water mass analyses. In summer 2013, weak onshore-directed winds caused...

In contrast to the vigorous deep ocean circulation system of the north- and southwestern Atlantic Ocean, no systematically sampled datasets of dissolved radiogenic neodymium (Nd) isotope signatures exist to trace water mass mixing and provenance for the more restricted and less well ventilated Angola Basin and the Cape Basin in the southeastern Atl...

The water masses passing the Fram Strait are mainly responsible for the exchange of heat and freshwater between the Nordic Seas and the Arctic Ocean (the Arctic Mediterranean, AM). Disentangling their exact sources, distribution and mixing, however, is complex. This work provides new insights based on a detailed geochemical tracer inventory includi...

The warming of the Arctic region in the recent past has proceeded at rates double that of the global average and has been accompanied by rapid sea ice retreat and increased heat and freshwater fluxes to the Arctic Mediterranean (i.e. the Arctic Ocean and the Nordic Seas, AM). Further warming will have strong impacts on ocean circulation, freshwater...

Pyroxenites are an essential component in petrological and geochemical models for melt formation at mid-ocean ridges and ocean islands. Despite their rarity, their origin has been widely discussed and various processes have been invoked for their formation. Here, we present a detailed study of the microtextures and major, minor and trace element co...

Alaskan-type complexes (ATC) are of great scientific and economic interest due to their peculiar internal structure and composition and their primary magmatic enrichment in platinum-group elements (PGE). Characteristics of ATC are their concentrically zoned structure with a dunite core and increasing clinopyroxene-content towards the rim, their hig...

Alaskan-type ultramafic-mafic complexes (ATC) are a type of layered intrusions with a high economically relevance due to their high platinum group elements (PGE) abundances. Recent investigations of ATC worldwide show their common signature. The Alto Condoto ultramafic-mafic complex is located in the Northwest of Colombia, South America. It is part...

The average thickness of the oceanic crust is relatively uniform over a wide range of spreading rates but dramatically decreases at slow- to ultraslow spreading rates (<20 mm/year) until no crust is formed and mantle rocks are directly emplaced onto the ocean floor. It is still under debate if this decrease in crustal thickness is owed dominantly t...

Although pyroxenites are rare along mid-ocean ridges and accordingly have been little studied to date in detail, they are an essential component in models for melt formation at mid-ocean ridges and ocean islands. Their origin has been discussed widely and different formation processes have been suggested. Here, we present a detailed study of microt...