ALBERT

Description: Spatial information on past weather contributes to better understand the processes behind day-to-day weather variability and to assess the risks arising from weather extremes. This dataset provides daily, high-resolution reconstructions of precipitation and temperature fields for Switzerland back to 1864. Reconstructions are provided as "raw" data resulting from an analogue resampling method (ARM), as well as post-processed data (using an ensemble Kalman fitting approach for temperature and quantile mapping for precipitation. For further information, the reader is referred to the references. The dataset comprises the following files: - 2019-10-06_precip_ARM_1864-01-01-2017-12-31.nc (precipitation, analogue reconstructions) - 2019-10-06_precip_qmap_1864-01-01-2017-12-31.nc (precipitation, post-processed) - 2019-10-06_temp_ARM_1864-01-01-2017-12-31.nc (temperature, analogue reconstructions) - 2019-10-06_temp_EnKF_1864-01-01-2017-12-31.nc (temperature, post-processed)

Description: Carbonate separates from listvenite core BT1B, Oman Drilling Project, were analyzed for their stable oxygen and carbon isotope ratios and clumped isotope distribution to constrain the conditions of carbonate mineralization. This data set summarizes all individual measurement results of the reference materials used and of the unknown samples.

Description: The human-induced rise in atmospheric carbon dioxide since the industrial revolution has led to increasing oceanic carbon uptake and changes in seawater carbonate chemistry, resulting in lowering of surface water pH. In this study we investigated the effect of increasing CO2 partial pressure (pCO2) on concentrations of volatile biogenic dimethylsulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP), through monoculture studies and community pCO2 perturbation. DMS is a climatically important gas produced by many marine algae: it transfers sulfur into the atmosphere and is a major influence on biogeochemical climate regulation through breakdown to sulfate and formation of subsequent cloud condensation nuclei (CCN). Overall, production of DMS and DMSP by the coccolithophore Emiliania huxleyi strain RCC1229 was unaffected by growth at 900 µatm pCO2, but DMSP production normalised to cell volume was 12 % lower at the higher pCO2 treatment. These cultures were compared with community DMS and DMSP production during an elevated pCO2 mesocosm experiment with the aim of studying E. huxleyi in the natural environment. Results contrasted with the culture experiments and showed reductions in community DMS and DMSP concentrations of up to 60 and 32 % respectively at pCO2 up to 3000 µatm, with changes attributed to poorer growth of DMSP-producing nanophytoplankton species, including E. huxleyi, and potentially increased microbial consumption of DMS and dissolved DMSP at higher pCO2. DMS and DMSP production differences between culture and community likely arise from pH affecting the inter-species responses between microbial producers and consumers.

Description: Photosynthetic parameters for the TRANSSIZ expedition aboard the RV Polarstern (PS92, ARK-XXIX/1) between the 19th of May and the 26th June of 2015.

Description: Data archives with raw data of burrowing times and proportions of succesfully burrowed clams.

Description: In this study, we present new detailed biomarker-based sea ice records from two sediment cores recovered in the Chukchi Sea and the East Siberian Sea. These new biomarker data may provide new insights on processes controlling recent and past sea ice changes. The biomarker proxy records show (i) minimum sea ice extent during the Early Holocene, (ii) a prominent Mid-Holocene short-term high-amplitude variability in sea ice, primary production and Pacific-Water inflow, and (iii) significantly increased sea ice extent during the last ca. 4.5k cal a BP. This Late Holocene trend in sea ice change in the Chukchi and East Siberian Seas seems to be contemporaneous with similar changes in sea ice extent recorded from other Arctic marginal seas. The main factors controlling the millennial variability in sea ice (and surface-water productivity) are probably changes in surface water and heat flow from the Pacific into the Arctic Ocean as well as the long-term decrease in summer insolation. The short-term centennial variability observed in the high-resolution Middle Holocene record is probably related to solar forcing. Our new data on Holocene sea ice variability may contribute to synoptic reconstructions of regional to global Holocene climate change based on terrestrial and marine archives.

Description: About 50 Gt of carbon is fixed photosynthetically by surface ocean phytoplankton communities every year. Part of this organic matter is reprocessed within the plankton community to form aggregates which eventually sink and export carbon into the deep ocean. The fraction of organic matter leaving the surface ocean is partly dependent on aggregate sinking velocity which accelerates with increasing aggregate size and density, where the latter is controlled by ballast load and aggregate porosity. In May 2011, we moored nine 25 m deep mesocosms in a Norwegian fjord to assess on a daily basis how plankton community structure affects material properties and sinking velocities of aggregates (Ø 80–400 µm) collected in the mesocosms' sediment traps. We noted that sinking velocity was not necessarily accelerated by opal ballast during diatom blooms, which could be due to relatively high porosity of these rather fresh aggregates. Furthermore, estimated aggregate porosity (Pestimated) decreased as the picoautotroph (0.2–2 µm) fraction of the phytoplankton biomass increased. Thus, picoautotroph‐dominated communities may be indicative for food webs promoting a high degree of aggregate repackaging with potential for accelerated sinking. Blooms of the coccolithophore Emiliania huxleyi revealed that cell concentrations of ~1500 cells/mL accelerate sinking by about 35–40%, which we estimate (by one‐dimensional modeling) to elevate organic matter transfer efficiency through the mesopelagic from 14 to 24%. Our results indicate that sinking velocities are influenced by the complex interplay between the availability of ballast minerals and aggregate packaging; both of which are controlled by plankton community structure.