English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

. Permafrost degradation in the catchment of major Siberian rivers, combinedwith higher precipitation in a warming climate, could increase the flux ofterrestrially derived dissolved organic matter (tDOM) into the Arctic Ocean(AO). Each year, ∼ 7.9 Tg of dissolved organic carbon (DOC) isdischarged into the AO via the three largest rivers that flow into theLaptev Sea (LS) and East Siberian Sea (ESS). A significant proportion of thistDOM-rich river water undergoes at least one freeze–melt cycle in theland-fast ice that forms along the coast of the Laptev and East Siberian seasin winter. To better understand how growth and melting of land-fast iceaffect dissolved organic matter (DOM) dynamics in the LS and ESS, wedetermined DOC concentrations and the optical properties of coloureddissolved organic matter (CDOM) in sea ice, river water and seawater. Thedata set, covering different seasons over a 9-year period (2010–2019), wascomplemented by oceanographic measurements (T, S) and determination of theoxygen isotope composition of the seawater. Although removal of tDOM cannot be ruled out, our study suggests thatconservative mixing of high-tDOM river water and sea-ice meltwater withlow-tDOM seawater is the major factor controlling the surface distributionof tDOM in the LS and ESS. A case study based on data from winter 2012 andspring 2014 reveals that the mixing of about 273 km3 oflow-tDOM land-fast-ice meltwater (containing ∼ 0.3 Tg DOC)with more than 200 km3 of high-tDOM Lena River waterdischarged during the spring freshet (∼ 2.8 Tg DOC yr−1)plays a dominant role in this respect. The mixing of the two low-salinitysurface water masses is possible because the meltwater and the river waterof the spring freshet flow into the southeastern LS at the same time everyyear (May–July). In addition, budget calculations indicate that in thecourse of the growth of land-fast ice in the southeastern LS,∼ 1.2 Tg DOC yr−1 (± 0.54 Tg) can be expelled fromthe growing ice in winter, together with brines. These DOC-rich brines canthen be transported across the shelves into the Arctic halocline and theTranspolar Drift Current flowing from the Siberian Shelf towards Greenland. The study of dissolved organic matter dynamics in the AO is important notonly to decipher the Arctic carbon cycle but also because CDOM regulatesphysical processes such as radiative forcing in the upper ocean, which hasimportant effects on sea surface temperature, water column stratification,biological productivity and UV penetration.

biogeosciences

The impact of the freeze–melt cycle of land-fast ice on the distribution of dissolved organic matter in the Laptev and East Siberian seas (Siberian Arctic)