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It has been suggested that increasing terrestrial water discharge to the Arctic Ocean may partly occur as submarine groundwater discharge (SGD), yet there are no direct observations of this phenomenon in the Arctic shelf seas. This study tests the hypothesis that SGD does exist in the Siberian Arctic Shelf seas, but its dynamics may be largely controlled by complicated geocryological conditions such as permafrost. The field-observational approach in the southeastern Laptev Sea used a combination of hydrological (temperature, salinity), geological (bottom sediment drilling, geoelectric surveys), and geochemical (224Ra, 223Ra, 228Ra, and 226Ra) techniques. Active SGD was documented in the vicinity of the Lena River delta with two different operational modes. In the first system, groundwater discharges through tectonogenic permafrost talik zones was registered in both winter and summer. The second SGD mechanism was cryogenic squeezing out of brine and water-soluble salts detected on the periphery of ice hummocks in the winter. The proposed mechanisms of groundwater transport and discharge in the Arctic land-shelf system is elaborated. Through salinity vs. 224Ra and 224Ra / 223Ra diagrams, the three main SGD-influenced water masses were identified and their end-member composition was constrained. Based on simple mass-balance box models, discharge rates at sites in the submarine permafrost talik zone were 1. 7 × 106 m3 d−1 or 19.9 m3 s−1, which is much higher than the April discharge of the Yana River. Further studies should apply these techniques on a broader scale with the objective of elucidating the relative importance of the SGD transport vector relative to surface freshwater discharge for both water balance and aquatic components such as dissolved organic carbon, carbon dioxide, methane, and nutrients.

The Arctic is undergoing dramatic changes which cover the entire range of natural processes, from extreme increases in the temperatures of air, soil, and water, to changes in the cryosphere, the biodiversity of Arctic waters, and land vegetation. Small changes in the largest marine carbon pool, the dissolved inorganic carbon pool, can have a profound impact on the carbon dioxide (CO2) flux between the ocean and the atmosphere, and the feedback of this flux to climate. Knowledge of relevant processes in the Arctic seas improves the evaluation and projection of carbon cycle dynamics under current conditions of rapid climate change.Investigation of the CO2 system in the outer shelf and continental slope waters of the Eurasian Arctic seas (the Barents, Kara, Laptev, and East Siberian seas) during 2006, 2007, and 2009 revealed a general trend in the surface water partial pressure of CO2 (pCO2) distribution, which manifested as an increase in pCO2 values eastward. The existence of this trend was defined by different oceanographic and biogeochemical regimes in the western and eastern parts of the study area; the trend is likely increasing due to a combination of factors determined by contemporary change in the Arctic climate, each change in turn evoking a series of synergistic effects. A high-resolution in situ investigation of the carbonate system parameters of the four Arctic seas was carried out in the warm season of 2007; this year was characterized by the next-to-lowest historic sea-ice extent in the Arctic Ocean, on satellite record, to that date. The study showed the different responses of the seawater carbonate system to the environment changes in the western vs. the eastern Eurasian Arctic seas. The large, open, highly productive water area in the northern Barents Sea enhances atmospheric CO2 uptake. In contrast, the uptake of CO2 was strongly weakened in the outer shelf and slope waters of the East Siberian Arctic seas under the 2007 environmental conditions. The surface seawater appears in equilibrium or slightly supersaturated by CO2 relative to atmosphere because of the increasing influence of river runoff and its input of terrestrial organic matter that mineralizes, in combination with the high surface water temperature during sea-ice-free conditions.This investigation shows the importance of processes that vary on small scales, both in time and space, for estimating the air–sea exchange of CO2. It stresses the need for high-resolution coverage of ocean observations as well as time series. Furthermore, time series must include multi-year studies in the dynamic regions of the Arctic Ocean during these times of environmental change.

The Arctic is undergoing dramatic changes which cover the entire range of natural processes, from extreme increases in the temperatures of air, soil, and water, to changes in the cryosphere, the biodiversity of Arctic waters, and land vegetation. Small changes in the largest marine carbon pool, the dissolved inorganic carbon pool, can have a profound impact on the carbon dioxide (CO.sub.2) flux between the ocean and the atmosphere, and the feedback of this flux to climate. Knowledge of relevant processes in the Arctic seas improves the evaluation and projection of carbon cycle dynamics under current conditions of rapid climate change. Investigation of the CO.sub.2 system in the outer shelf and continental slope waters of the Eurasian Arctic seas (the Barents, Kara, Laptev, and East Siberian seas) during 2006, 2007, and 2009 revealed a general trend in the surface water partial pressure of CO.sub.2 (pCO.sub.2) distribution, which manifested as an increase in pCO.sub.2 values eastward. The existence of this trend was defined by different oceanographic and biogeochemical regimes in the western and eastern parts of the study area; the trend is likely increasing due to a combination of factors determined by contemporary change in the Arctic climate, each change in turn evoking a series of synergistic effects. A high-resolution in situ investigation of the carbonate system parameters of the four Arctic seas was carried out in the warm season of 2007; this year was characterized by the next-to-lowest historic sea-ice extent in the Arctic Ocean, on satellite record, to that date. The study showed the different responses of the seawater carbonate system to the environment changes in the western vs. the eastern Eurasian Arctic seas. The large, open, highly productive water area in the northern Barents Sea enhances atmospheric CO.sub.2 uptake. In contrast, the uptake of CO.sub.2 was strongly weakened in the outer shelf and slope waters of the East Siberian Arctic seas under the 2007 environmental conditions. The surface seawater appears in equilibrium or slightly supersaturated by CO.sub.2 relative to atmosphere because of the increasing influence of river runoff and its input of terrestrial organic matter that mineralizes, in combination with the high surface water temperature during sea-ice-free conditions. This investigation shows the importance of processes that vary on small scales, both in time and space, for estimating the air-sea exchange of CO.sub.2 . It stresses the need for high-resolution coverage of ocean observations as well as time series. Furthermore, time series must include multi-year studies in the dynamic regions of the Arctic Ocean during these times of environmental change.

The Arctic is undergoing dramatic changes which cover the entire range of natural processes, from extreme increases in the temperatures of air, soil, and water, to changes in the cryosphere, the biodiversity of Arctic waters, and land vegetation. Small changes in the largest marine carbon pool, the dissolved inorganic carbon pool, can have a profound impact on the carbon dioxide (CO2) flux between the ocean and the atmosphere, and the feedback of this flux to climate. Knowledge of relevant processes in the Arctic seas improves the evaluation and projection of carbon cycle dynamics under current conditions of rapid climate change. Investigation of the CO2 system in the outer shelf and continental slope waters of the Eurasian Arctic seas (the Barents, Kara, Laptev, and East Siberian seas) during 2006, 2007, and 2009 revealed a general trend in the surface water partial pressure of CO2 (pCO2) distribution, which manifested as an increase in pCO2 values eastward. The existence of this trend was defined by different oceanographic and biogeochemical regimes in the western and eastern parts of the study area; the trend is likely increasing due to a combination of factors determined by contemporary change in the Arctic climate, each change in turn evoking a series of synergistic effects. A high-resolution in situ investigation of the carbonate system parameters of the four Arctic seas was carried out in the warm season of 2007; this year was characterized by the next-to-lowest historic sea-ice extent in the Arctic Ocean, on satellite record, to that date. The study showed the different responses of the seawater carbonate system to the environment changes in the western vs. the eastern Eurasian Arctic seas. The large, open, highly productive water area in the northern Barents Sea enhances atmospheric CO2 uptake. In contrast, the uptake of CO2 was strongly weakened in the outer shelf and slope waters of the East Siberian Arctic seas under the 2007 environmental conditions. The surface seawater appears in equilibrium or slightly supersaturated by CO2 relative to atmosphere because of the increasing influence of river runoff and its input of terrestrial organic matter that mineralizes, in combination with the high surface water temperature during sea-ice-free conditions. This investigation shows the importance of processes that vary on small scales, both in time and space, for estimating the air–sea exchange of CO2. It stresses the need for high-resolution coverage of ocean observations as well as time series. Furthermore, time series must include multi-year studies in the dynamic regions of the Arctic Ocean during these times of environmental change.

Chaun Bay, located on the fringe of the East Siberian Sea, has been described since the mid-20th century to support a unique marine ecosystem that is atypical for the local Siberian Arctic. Here we use ship-board physical, biogeochemical and geological measurements taken in October 2020, along with hydrographic observations taken from land-fast ice in April 2023, to demonstrate that these warm-water biological communities are supported by hydrothermal submarine groundwater discharge that delivers heat, salinity, nutrients, and trace elements to the bay. We identify a cyclonic eddy that mixes the warm nutrient-rich groundwater with oxygen-rich surface water, resulting in a water mass within Chaun Bay that has similar physical and chemical properties to the highly productive waters of the North Pacific and Southern Chukchi Sea. The bay showed elevated concentrations of chlorophyll-a and zooplankton, and the abundance and species diversity of epibenthos significantly exceeded values observed elsewhere in the East Siberian Sea. The benthic communities contained a number of boreal species that are not typically found in the Arctic Ocean. We also observed Thysanoessa krill populations, a pelagic species generally considered an expatriate in Arctic waters.

Two new organo-inorganic hybrids, (C2N2H10)[Cu(H2O)4](BeF4)2 (1) and (C2N2H10)[Cu(H2O)4](SeO4)2 (2), were prepared via the interaction of ethylenediamine, copper fluoroberyllate or selenate, and H2[BeF4]/H2SeO4 in aqueous solutions. The structures of 1 and 2 are similar to each other and the previously reported (C2N2H10)[Cu(H2O)4](SO4)2: monoclinic, P21/c, a = 5.1044(2) Å, b = 11.6171(4) Å, c = 10.1178(3) Å, and β = 94.431(3)° for 1; and a = 5.25020(10), b = 11.7500(2), c = 10.4434(2), and β = 94.5464(17)° for 2. All structures contain a square planar [Cu(H2O)4]2+ species, which coordinates, at rather long distances, two TX42− tetrahedral dianions in κ1 mode, forming relatively weak [Cu(H2O)4(TX4)2]2− complexes. These are linked together via hydrogen bonding into pseudo-chains; the ethylenediammonium cations link them into a 3D architecture. Compound 1 is, to the best of our knowledge, the first—though expected—representative of a hybrid organo-inorganic fluoroberyllate. The crystal chemical relations within the structural family (enH2)[Cu(H2O)4](TX4)2 are discussed.

Following the previously reported (enH 2 )[Co(H 2 PO 3 ) 2 Cl 2 ] (enH 2  = ethylenediammonium cation), we successfully prepared its analogs with other divalent transition metal cations: Mn 2+ , Fe 2+ , Ni 2+ , and Cd 2+ . These compounds are isostructural to each other and the archetypic hydroselenites, (enH 2 )[ M (HSeO 3 ) 2 X 2 ]. Despite evident similarities, some essential differences are observed between hydroselenites and hydrophosphites, both in chemistry and in structural details. Due to smaller size of H 2 PO 3 − relative to HSeO 3 − , only chloride phosphites could be prepared; the reducing capacity of H 2 PO 3 − permits preparation of Fe II compound but not that of Cu II . A single attempt to introduce piperazinediium cation instead of ethylenediammonium results in formation of (pipH 2 )[Co(H 2 PO 3 ) 2 Cl 2 ] with a structure different from (pipH 2 )[Cd(HSeO 3 ) 2 Cl 2 ]. Another serendipitous product is the 1-methylpiperazinediium derivative, (mpipH 2 ) 2 [Co(H 2 PO 3 ) 2 I 3 ][H(H 2 PO 3 ) 2 ], which features a yet unique complex hydrogen-bonded network.

Purple crystals of ethylenediammonium cobalt bis(hydrogen phosphite) dichloride were produced from an aqueous solution containing ethylenediamine, cobalt chloride, and phosphorous acid. The new compound is monoclinic, P 2 1 / c , a  = 8.6665(3) Å, b  = 7.2866(2) Å, c  = 9.7300(3) Å, β  = 112.726(3); V  = 566.74(3) Å 3 , Z  = 2. The 2D structure comprised ethylenediammonium cations sandwiched between the [Co(HPHO 3 ) 2 Cl 2 ] 2− layers. The latter are built of trans -CoO 4 Cl 2 octahedra linked by hydrogen-bonded dimers of hydrophosphite ions, (HPHO 3 ) 2 2− . The new compound is a complete structural analog of the recently reported (C 2 N 2 H 10 )[Co(HSeO 3 ) 2 Cl 2 ] and isostructural analogs with other transition metal dications; it is, in fact, the first representative of a new “layered hydrophosphite” family. Its structure provides yet another illustration of essential similarities in the crystal chemistry of selenites and phosphites, including protonated species, wherein the lone pair of Se IV and the nearly nonpolar P–H enhance formation of loose and/or open-framework structural architectures.

Two new organo-inorganic hybrids, (C2N2H10)[Cu(H2O)4](BeF4)2 (1) and (C2N2H10)[Cu(H2O)4](SeO4)2 (2), were prepared via the interaction of ethylenediamine, copper fluoroberyllate or selenate, and H2[BeF4]/H2SeO4 in aqueous solutions. The structures of 1 and 2 are similar to each other and the previously reported (C2N2H10)[Cu(H2O)4](SO4)2: monoclinic, P21/c, a = 5.1044(2) Å, b = 11.6171(4) Å, c = 10.1178(3) Å, and β = 94.431(3)° for 1; and a = 5.25020(10), b = 11.7500(2), c = 10.4434(2), and β = 94.5464(17)° for 2. All structures contain a square planar [Cu(H2O)4]2+ species, which coordinates, at rather long distances, two TX42- tetrahedral dianions in κ1 mode, forming relatively weak [Cu(H2O)4(TX4)2]2- complexes. These are linked together via hydrogen bonding into pseudo-chains; the ethylenediammonium cations link them into a 3D architecture. Compound 1 is, to the best of our knowledge, the first-though expected-representative of a hybrid organo-inorganic fluoroberyllate. The crystal chemical relations within the structural family (enH2)[Cu(H2O)4](TX4)2 are discussed.Two new organo-inorganic hybrids, (C2N2H10)[Cu(H2O)4](BeF4)2 (1) and (C2N2H10)[Cu(H2O)4](SeO4)2 (2), were prepared via the interaction of ethylenediamine, copper fluoroberyllate or selenate, and H2[BeF4]/H2SeO4 in aqueous solutions. The structures of 1 and 2 are similar to each other and the previously reported (C2N2H10)[Cu(H2O)4](SO4)2: monoclinic, P21/c, a = 5.1044(2) Å, b = 11.6171(4) Å, c = 10.1178(3) Å, and β = 94.431(3)° for 1; and a = 5.25020(10), b = 11.7500(2), c = 10.4434(2), and β = 94.5464(17)° for 2. All structures contain a square planar [Cu(H2O)4]2+ species, which coordinates, at rather long distances, two TX42- tetrahedral dianions in κ1 mode, forming relatively weak [Cu(H2O)4(TX4)2]2- complexes. These are linked together via hydrogen bonding into pseudo-chains; the ethylenediammonium cations link them into a 3D architecture. Compound 1 is, to the best of our knowledge, the first-though expected-representative of a hybrid organo-inorganic fluoroberyllate. The crystal chemical relations within the structural family (enH2)[Cu(H2O)4](TX4)2 are discussed.

Two new organo-inorganic hybrids, (C[sub.2]N[sub.2]H[sub.10])[Cu(H[sub.2]O)[sub.4]](BeF[sub.4])[sub.2] (1) and (C[sub.2]N[sub.2]H[sub.10])[Cu(H[sub.2]O)[sub.4]](SeO[sub.4])[sub.2] (2), were prepared via the interaction of ethylenediamine, copper fluoroberyllate or selenate, and H[sub.2][BeF[sub.4]]/H[sub.2]SeO[sub.4] in aqueous solutions. The structures of 1 and 2 are similar to each other and the previously reported (C[sub.2]N[sub.2]H[sub.10])[Cu(H[sub.2]O)[sub.4]](SO[sub.4])[sub.2]: monoclinic, P2[sub.1]/c, a = 5.1044(2) Å, b = 11.6171(4) Å, c = 10.1178(3) Å, and β = 94.431(3)° for 1; and a = 5.25020(10), b = 11.7500(2), c = 10.4434(2), and β = 94.5464(17)° for 2. All structures contain a square planar [Cu(H[sub.2]O)[sub.4]][sup.2+] species, which coordinates, at rather long distances, two TX [sub.4] [sup.2−] tetrahedral dianions in κ[sup.1] mode, forming relatively weak [Cu(H[sub.2]O)[sub.4](TX [sub.4])[sub.2]][sup.2−] complexes. These are linked together via hydrogen bonding into pseudo-chains; the ethylenediammonium cations link them into a 3D architecture. Compound 1 is, to the best of our knowledge, the first—though expected—representative of a hybrid organo-inorganic fluoroberyllate. The crystal chemical relations within the structural family (enH[sub.2])[Cu(H[sub.2]O)[sub.4]](TX [sub.4])[sub.2] are discussed.