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As the annual expanse of Arctic summer ice‐cover steadily decreases, concomitant biogeochemical and ecological changes in this region are likely to occur. Because the Central Arctic Ocean is often nutrient and light limited, it is essential to understand how environmental changes will affect productivity, phytoplankton species composition, and ensuing changes in biogeochemistry in the region. During the transition from late summer to early autumn, water column sampling of various biogeochemical parameters was conducted along an ice‐floe drift station near the North Pole. Our results show that as the upper water column stratification weakened during the late summer–early autumn transition, nutrient concentrations, particulate dimethylsulfoniopropionate (DMSPp) levels, photosynthetic efficiency, and biological productivity, as estimated by ΔO2/Ar ratios, all decreased. Chemotaxonomic (CHEMTAX) analysis of phytoplankton pigments revealed a taxonomically diverse picoautotrophic community, with chlorophyll (Chl) c3‐containing flagellates and the prasinophyte, Pyramimonasspp., as the most abundant groups, comprising ~ 30% and 20% of the total Chl a(TChl a) biomass, respectively. In contrast to previous studies, the picoprasinophyte, Micromonasspp., represented only 5% to 10% of the TChl abiomass. Of the nine taxonomic groups identified, DMSPpwas most closely associated with Pyramimonasspp., a Chl b‐containing species not usually considered a high DMSP producer. As the extent and duration of open, ice‐free waters in the Central Arctic Ocean progressively increases, we suggest that enhanced light transmission could potentially expand the ecological niche of Pyramimonasspp. in the region.

During the 2018 Multidisciplinary Arctic Program‐Last Ice in the Lincoln Sea, we sampled 45 multiyear ice (MYI) and 34 first‐year ice (FYI) cores, combined with snow depth, ice thickness, and transmittance surveys from adjacent level FYI and undeformed MYI. FYI sites show a decoupling between bottom‐ice chlorophyll a(chl a)and snow depth; however, MYI showed a significant correlation between ice‐algal chl abiomass and snow depth. Topographic control of the snow cover resulted in greater spatiotemporal variability of the snow over the level FYI, and consequently transmittance, compared to MYI with an undulating surface. The coupled patterns of snow depth, transmittance, and chl aindicate that MYI provides an environment with more stable light conditions for ice algal growth. The importance of sea ice surface topography for ice algal habitat underpins the potential ecological changes associated with projected increased ice dynamics and deformation. This study presents first results from the 2018 Multidisciplinary Arctic Program‐Last Ice, the most intensive ecologically focused research project ever conducted within the so‐called “Last Ice Area.” This region is of key importance because it is the only place in the Arctic expected to retain summer sea ice by the year 2050. Continued changes to the sea ice environment will have ecological consequences because sea ice is an important habitat for many animals from microscopic ice algae, the base of the food chain, to seals and polar bears. Since the older ice is being replaced by younger ice, we compared older ice to younger ice in order to provide a glimpse into the future. We found that the older ice has a more stable light environment for ice algae due to snow depth patterns associated with surface topography. This can mean that as the older ice is replaced by newer ice, the availability of ice algae as a food source may become more unpredictable. The importance of surface topography for ice algae indicates that the projected acceleration in sea ice drift and increased ridging due to thinner ice will likely have an impact on key sea ice habitat properties. Spatiotemporal changes in snow cover and transmittance were observed for FYI but remained stable for MYI due to differences in topographyThe spatial distribution of bottom‐ice chl abiomass was coupled to snow depth and transmittance in MYI but decoupled in FYIA projected shift to a more dynamic and deformed sea ice cover is likely to be a key driver of ice‐algal habitat variability in the future

Beschrieben wird die klinische, diagnostische und therapeutische Entwicklung eines bei Krankheitsbeginn 59-jährigen, rechtshändigen Patienten. Der uncharakteristische Beginn mit Dyskinesien der Gesichtsmuskulatur und Sprachstörungen erschwerte die Diagnose und Therapie ebenso wie der Verlauf mit zwischenzeitlichem Verdacht auf Vasculitis bei positiven antinukleären Antikörpern. Auch war das hypokinetisch-rigide Syndrom lange nur mild entwickelt. Erst 6 Jahre nach Beginn der Erkrankung konnte die Diagnose einer kortikobasalen Degeneration gesichert werden. The article describes the development of symptoms in a 59-year-old patient. Dyskinesia and speech disorder were the only clinical features in the beginning. Increased immunological parameters and only slight hypokinetic-rigid signs for a long time made the diagnostical and therapeutical process more difficult, as well as atypical findings in neuroimaging techniques. Corticobasal degeneration was diagnosed about 6 years after onset of clinical symptoms.

Melt ponds have a strong impact on the Arctic surface energy balance and the ice‐associated ecosystem because they transmit more solar radiation compared to bare ice. In the existing literature, melt ponds are considered as bright windows to the ocean, even during freeze‐up in autumn. In the central Arctic during the summer‐autumn transition in 2018, we encountered a situation where more snow accumulated on refrozen melt ponds compared to the adjacent bare ice, leading to a reduction in light transmittance of the ponds even below that of bare ice. Results from a radiative transfer model support this finding. This situation has not been described in the literature before, but has potentially strong implications for example on autumn ecosystem activity, oceanic heat budget, and thermodynamic ice growth. Arctic sea ice is covered with snow during autumn, winter and spring. During summer, melt ponds evolve in response to surface melting. After snow fall starts again in autumn, these ponds can be filled with a lot of snow compared to bare ice because of their recessed surface. Indeed, during an expedition close to the North Pole in summer and autumn 2018, we measured a thick snow cover on ponds. This thick snow cover reduced the light availability underneath the ponds to levels below that underneath adjacent bare ice. This is a surprising finding, because it is different from the established theory of high light availability underneath melt ponds during both summer and autumn and how this is described in most computer models. It has consequences for our understanding of the ice‐associated ecosystem (organisms that live in and under sea ice). It might also impact the mass and energy balance of central Arctic sea ice during summer‐autumn transition when new sea ice starts forming. Refrozen melt ponds may collect a thicker snow cover compared to bare sea ice due to their recessed topographySuch snow‐covered melt ponds transmit less light compared to bare ice of similar typeThis scenario has not been documented before and should be accounted for in studies involving light in a refreezing Arctic Ocean Refrozen melt ponds may collect a thicker snow cover compared to bare sea ice due to their recessed topography Such snow‐covered melt ponds transmit less light compared to bare ice of similar type This scenario has not been documented before and should be accounted for in studies involving light in a refreezing Arctic Ocean

The synthesis of [Ph4As+]2[Cl4Re(NS)(NSCl)2-] · CH2Cl2(4) from the reaction of S4N4, Cl4ReN, and Ph4AsCl is reported. CH2Cl2is used as solvent. The reaction of S4N4with Re2Cl10 similarly leads to the salt [Ph4As+][Cl2ReNS-] (5) in a smaller yield. 4 crystallizes in the triclinic space group P1̅ with Z = 2, a - 10.434(2), b = 12.1454(6), c = 21.125(2) Å, a = 81.210(6), β = 86.70(1), γ = 76.624(8)°.

The metallacycles [Cl3MS2N3]2(M = Mo, W) 1a and 2a have been obtained from reactions of S4N4with Mo2Cl10and WCl6, respectively, and from S3N3Cl3with the hexacarbonyls M(CO)6. The adducts Cl3MS2N3· CH3CN 1b and 2b are formed with acetonitrile, and the salts [Ph4As+][Cl4MS2N3-] 1c and 2c with addition of Ph4AsCl. Reactions of Mo2Cl10and WCl6, respectively, with related S -N com pounds lead predominantly to 1a and 2a; Mo2Cl10reacts with S3N2Cl2to give 1a , and with [Me3SiN]2S to give [Cl3MoN]x, while WCl6yields Cl4WNSCl with S3N2Cl2, and 2a with [Me3SiN]2S. [Cl3MoN ]xdoes not react with S4N4, but [Cl3WN]xforms 2a. Reactions of VCl4and VOCl3with [Me3SiN]2S give [Cl2V S2N3]x, 3. 2c has also been obtained by the reaction of [Ph4As+][Cl5WNSCL-] with [Me3SiN]2S. The oxidation states of the metal atoms are +6 for 1a-c and 2a-c, and +5 for 3, respectively; as determined by 51V and 95Mo NMR spectroscopy and magnetic susceptibility measurements. The UV/VIS spectra of 1b , 1c , 2b, c and 3 are discussed. The electrical conductivity of 3 is reported.

The formation of platelet ice is well known to occur under Antarctic sea ice, where subice platelet layers form from supercooled ice shelf water. In the Arctic, however, platelet ice formation has not been extensively observed, and its formation and morphology currently remain enigmatic. Here, we present the first comprehensive, long‐term in situ observations of a decimeter thick subice platelet layer under free‐drifting pack ice of the Central Arctic in winter. Observations carried out with a remotely operated underwater vehicle (ROV) during the midwinter leg of the MOSAiC drift expedition provide clear evidence of the growth of platelet ice layers from supercooled water present in the ocean mixed layer. This platelet formation takes place under all ice types present during the surveys. Oceanographic data from autonomous observing platforms lead us to the conclusion that platelet ice formation is a widespread but yet overlooked feature of Arctic winter sea ice growth. Platelet ice is a particular type of ice that consists of decimeter sized thin ice plates that grow and collect on the underside of sea ice. It is most often related to Antarctic ice shelves and forms from supercooled water with a temperature below the local freezing point. Here we present the first comprehensive observation of platelet ice formation in freely drifting pack ice in the Arctic in winter during the international drift expedition MOSAiC. We investigate its occurrence under the ice with a remotely controlled underice diving robot. Measurements of water temperature from automatic measurement devices distributed around the central MOSAiC ice floe show that supercooled water and thus platelet ice occur widely in the winter Arctic. This way of ice formation in the Arctic has been overlooked during the last century, as direct observations under winter sea ice were not available and contrary to typical Antarctic observations; manifestation of platelet ice in Arctic ice core stratigraphy has been more challenging to identify. Here we present extensive observations of platelet ice formation under Arctic winter sea iceThe subice platelet layer appears to form locally due to seed crystals in ocean surface supercooling

N2S3Cl+ SbCl6- was prepared by chlorination of N4S4· SbCls5with elemental chlorine. The crystals are monoclinic, P21/c, with a = 1492.4(4), b = 1233.6(2), c = 1437.5(4) pm, β = 91.40(2)°, and R = 0.059 for 3663 observed reflections. There are two independent cations and anions in the asymmetric symmetric unit. The appreciable interionic interaction results in a high density of ρ = 2.642 g · cm -3 (calcd).

A complex type (III), containing other tertiary phosphines or phosphites, so far are not isolated.