The turbidity maximum zone of the Yenisei River (Siberia) and its impact on organic and inorganic proxies

A general overview of the processes taking place in the summer mixing zone of the fresh Yenisei River water with the marine waters of the Kara Sea is given in this study, with special emphasis on the interaction between bulk (total suspended matter), inorganic (Fe, Mn) and organic (suspended organic carbon, suspended nitrogen) proxies. Within the mixing zone, a zone of enhanced turbidity (maximum turbidity zone) was observed comparable to studies in other rivers. Flocculation of particles due to changes in salinity and hydrography cause this maximum turbidity zone, and resuspension additionally enhances the turbidity in the near-bottom layers. Organic matter behaves conservatively in the mixing zone in terms of its percentage of suspended matter. It, however, undergoes degradation as revealed by amino acid data. Inorganic, redox- and salinity-sensitive, proxies (Mn, Fe) behave non-conservatively. Dissolved iron is removed at low salinities (<2) due to precipitation of iron oxyhydroxides and adsorption of manganese on suspended particles, enhancing the Mn/Al ratio of the suspended matter in the same zone. At higher salinities within the mixing zone, Fe/Al and Mn/Al ratios of the suspended particles are depleted due to resuspension of sediment with lower Fe/Al and Mn/Al ratios. Dissolved manganese concentrations are significantly higher in the near-bottom layers of the mixing zone due to release from the anoxic sediment. All things considered, the Yenisei River mixing zone shows patterns similar to other world's rivers

Coordinating sustained coastal and ocean observing efforts in Germany

Germany’s national ocean observing activities are carried out by multiple actors including governmental bodies, research institutions, and universities, and miss central coordination and governance. A particular strategic approach to coordinate and facilitate ocean research has formed in Germany under the umbrella of the German Marine Research Consortium (KDM). KDM aims at bringing together the marine science expertise of its member institutions and collectively presents them to policy makers, research funding organizations, and to the general public. Within KDM, several strategic groups (SGs), composed of national experts, have been established in order to strengthen different scientific and technological aspects of German Marine Research. Here we present the SG for sustained open ocean observing and the SG for sustained coastal observing. The coordination effort of the SG’s include (1) Representing German efforts in ocean observations, providing information about past, ongoing and planned activities and forwarding meta-information to data centers (e.g., JCOMMOPS), (2) Facilitating the integration of national observations into European and international observing programs (e.g. GCOS, GOOS, BluePlanet, GEOSS), (3) Supporting innovation in observing techniques and the development of scientific topics on observing strategies, (4) Developing strategies to expand and optimize national observing systems in consideration of the needs of stakeholders and conventions, (5) Contributing to agenda processes and roadmaps in science strategy and funding, and (6) Compiling recommendations for improved data collection and data handling, to better connect to the global data centers adhering to quality standards

Particulate matter fluxes in the southern and central Kara Sea compared to sediments: Bulk fluxes, amino acids, stable carbon and nitrogen isotopes, sterols and fatty acids.

The Kara Sea is one of the arctic marginal seas strongly influenced by fresh water and river suspension. The highlyseasonal discharge by the two major rivers Yenisei and Ob induces seasonal changes in hydrography, sea surfacetemperature, ice cover, primary production and sedimentation. In order to obtain a seasonal pattern of sedimentation inthe Kara Sea, sediment traps were deployed near the river mouth of the Yenisei (Yen) as well as in the central Kara Sea(Kara) within the framework of the GermanRussian project Siberian River run-off; SIRRO. Two and a half years oftime-series flux data were obtained between September 2000 and April 2003 and were analyzed for bulk components,amino acids, stable carbon and nitrogen isotopes as well as sterols and fatty acids.Sediment trap data show that much of the annual deposition occurred under ice cover, possibly enhanced byzooplanktonic activity and sediment resuspension. An early bloom of ice-associated algae in April/May occurred in thepolynya area and may have been very important to sustain the life cycles of higher organisms after the light limitation ofthe winter months due to no/low insolation and ice cover. The strong river input dominated the months JuneAugust inthe southern part of the Kara Sea. The central Kara Sea had a much shorter productive period starting in August and wasless affected by the river plumes. Despite different time-scales of sampling and trapping biases, total annual fluxes fromtraps were in the same order of magnitude as accumulation rates in surface sediments. Terrestrial organic carbonaccumulation decreased from 10.7 to 0.3 gCm 2 a 1 from the riverine source to the central Kara Sea. Parallel to this,preservation of marine organic matter decreased from 10% to 2% of primary productivity which was probably related todecreasing rates of sedimentation

Composition of the varved sections of the sediment core SO130_275KL

Methods * Carbonate, TOC and TN: Total carbon and total nitrogen were analyzed on a Carlo Erba 1500 elemental analyzer (Milan, Italy) with a precision of 0.2% and 0.005%, respectively. Total organic carbon (TOC) was measured with the same instrument after samples were treated with 1 M hydrochloric acid (HCl) to remove inorganic carbon. Analytical precision for organic carbon was 0.02%. Carbonate carbon was calculated as the difference between total carbon and organic carbon. * Biogenic Opal (bSiO2): Biogenic opal was determined photometrically after wet alkaline extraction of biogenic silica (bSiO2). * Lithogenic matter: Lithogenic matter (%) was calculated by subtracting carbonate, organic matter and biogenic opal from 100%

Composition of the silt turbidite sections (F-events) of the sediment core SO130_275KL

Methods * Carbonate, TOC and TN: Total carbon and total nitrogen were analyzed on a Carlo Erba 1500 elemental analyzer (Milan, Italy) with a precision of 0.2% and 0.005%, respectively. Total organic carbon (TOC) was measured with the same instrument after samples were treated with 1 M hydrochloric acid (HCl) to remove inorganic carbon. Analytical precision for organic carbon was 0.02%. Carbonate carbon was calculated as the difference between total carbon and organic carbon. * Lithogenic matter: Lithogenic matter (%) was calculated by subtracting carbonate, organic matter and biogenic opal from 100%

Composition of the thick suspensate deposits (C-events) sections of the sediment core SO130_275KL

Methods * Carbonate, TOC and TN: Total carbon and total nitrogen were analyzed on a Carlo Erba 1500 elemental analyzer (Milan, Italy) with a precision of 0.2% and 0.005%, respectively. Total organic carbon (TOC) was measured with the same instrument after samples were treated with 1 M hydrochloric acid (HCl) to remove inorganic carbon. Analytical precision for organic carbon was 0.02%. Carbonate carbon was calculated as the difference between total carbon and organic carbon. * Lithogenic matter: Lithogenic matter (%) was calculated by subtracting carbonate, organic matter and biogenic opal from 100%

Grain size distribution of the silt turbidite sections (F-events) of the sediment core SO130_275KL

Grain size distribution of the silt turbidite sections (F-events) of the sediment core SO130_275K