ALBERT

Description: Temperature and heating-induced temperature differences were measured along a chain of thermistors. SIMBA 2020T76(a.k.a. PRIC_10_04, IRIDIUM number 300234068528490) is an autonomous instrument that was installed on drifting sea ice in the Arctic Ocean during the 3rd leg of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) in April 2020. The buoy was deployed at the site about 2 km from the ship with initial thicknesses of snow and ice of 0.14 and 150 m, respectively, on 4 April 2020. The thermistor chain was 5 m long and included 241 sensors with a regular spacing of 2 cm. The depths for the sensors are 72 to -406 cm, referring to the initial interface between snow and ice. The last sensor was used to measure the air temperature at 1 m above the initial snow surface. The resulting time series describes the evolution of temperature and temperature differences after two heating cycles of 30 and 120 s as a function of depth and time between 4 April 2020 and 20 July 2020 in sample intervals of 6 hours for temperature and 24 hours for temperature differences. In addition to temperature, geographic position, barometric pressure, tilt and compass were measured.

Description: Temperature and heating-induced temperature differences were measured along a chain of thermistors. SIMBA 2020T77 (a.k.a. PRIC_10_05, IRIDIUM number 300234068524740) is an autonomous instrument that was installed on drifting sea ice in the Arctic Ocean during the 3rd leg of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) in April 2020. The buoy was deployed at the site about 2 km from the ship with initial thicknesses of snow and ice of 0.06 and 1.64 m, respectively, on 4 April 2020. The thermistor chain was 5 m long and included 241 sensors with a regular spacing of 2 cm. The depths for the sensors are 84 to -394 cm, referring to the initial interface between snow and ice. The last sensor was used to measure the air temperature at 1 m above the initial snow surface. The resulting time series describes the evolution of temperature and temperature differences after two heating cycles of 30 and 120 s as a function of depth and time between 4 April 2020 and 4 June 2020 in sample intervals of 6 hours for temperature and 24 hours for temperature differences. In addition to temperature, geographic position, barometric pressure, tilt and compass were measured.

Description: Temperature and heating-induced temperature differences were measured along a chain of thermistors. SIMBA 2020T75 (a.k.a. PRIC_10_03, IRIDIUM number 300234068325170) is an autonomous instrument that was installed on drifting sea ice in the Arctic Ocean during the 3rd leg of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) in April 2020. The buoy was deployed at the old helicopter site of central observatorysite with initial thicknesses of snow and ice of 0.12 and 1.64 m, respectively, on 23 April 2020. The thermistor chain was 5 m long and included 241 sensors with a regular spacing of 2 cm. The depths for the sensors are 56 to -422cm, referring to the initial interface between snow and ice. The last sensor was used to measure the air temperature at 1 m above the initial snow surface. The resulting time series describes the evolution of temperature and temperature differences after two heating cycles of 30 and 120 s as a function of depth and time between 23 April 2020 and 6 August 2020 in sample intervals of 6 hours for temperature and 24 hours for temperature differences. In addition to temperature, geographic position, barometric pressure, tilt and compass were measured.

Description: Measurements of cell density, nutrient concentration and genotype composition in a long term experiment (91 days) with the marine phytoplankton species Chaetoceros affinis and Emiliania huxleyi, each consisting of nine genotypes. Cultivation of species was done separately in mono-cultures and together in mix-cultures at three different nutrient regimes (10N:1P, 20N:1P, and 30N:1P) with increasing nitrate concentration in a semi-continuous batch cycle system. Transfer of part of the cells into bottles with new nutrients every 7 days at fixed batch cycle length and after 7,4, and 10 days in a recurring fashion at variable batch cycle length. With the information about the genotype abundance we assessed how intraspecific diversity is maintained in response to species competition and nutrient fluctuations. Individual trait measurements for growth, nutrient uptake, and cell volume of the genotypes at seven nitrate levels in a 4-day experiment allowed us to connect traits to the genotype sorting of the long term experiment.

Description: We provide high-resolution surface temperature data for a better understanding of the spatial and temporal variability of sea ice surface characteristics in the Arctic winter. Surface temperature images were recorded during helicopter survey flights with the Infrared VarioCAM HD head 680 from InfraTec. The thermal infrared imaging was performed with a down-looking infrared camera installed in a helicopter. This data set includes 35 flights, which were performed, from a local up to a regional scale, during winter 2019/2020 as part of the MOSAiC expedition in the Arctic Ocean. The measurements were done along the transpolar drift from the northern Laptev Sea towards the Fram Strait between 02.10.2019 and 23.04.2020. The usual flight duration was 90 minutes with a flight altitude of about 300 m. The data set includes one file for every flight in all four different data types: (i) a series of images in NetCDF format, (ii) the displayed map in png format, as well as surface temperature maps in (iii) 1 m resolution and (iv) 5 m resolution, both in NetCDF format. The flights can be identified by the event-related Device Operation label or Flight ID. The metadata of the infrared Camera is registered in the AWI Sensor Web at the current Version under https://hdl.handle.net/10013/sensor.0542bbfb-172a-496f-9bce-b21c59cd02c9. Further information can be found in our Data Manual, linked under *Further details*.

Description: Stalagmites GL-S1, GL-S2, GL-S3 and GL-S4 were collected under scientific license issued by Western Australia's Department of Biodiversity, Conservation and Attractions from Golgotha Cave (34.1°S, 115.1°E) in southwest Western Australia, with collection dates of 2005, 2005, 2008 and 2012, respectively. Cave location is rounded to nearest tenth of a degree as exact locations not disclosed for cave conservation purposes. Speleothems were collected for paleoclimate and paleohydrology studies. Golgotha Cave is located in Eucalyptus forest with dense understorey in the Leeuwin-Naturaliste National Park. The hostrock is Quaternary aeolinite and the soil thickness is variable with measurements ranging from 0.3-3 m deep. The cave entrance is 70 m above sea level. Stalagmites GL-S1 and GL-S4 are located approximately 60 m from the entrance where the limestone thickness overhead is 30 m while GL-S2 and GL-S3 are located approximately 90 m from the entrance where the limestone thickness overhead is 40 m. Mean annual site temperature is 15.6 ±0.5°C and mean annual rainfall is 1101±157 mm (1911-2018 period; Australian Bureau of Meteorology AWRA-L dataset http://www.bom.gov.au/water/landscape. Inside the cave, temperature ranges from 14.5-14.8°C, windspeed is low (≤0.03 m s-1) and relative humidity ranges from 98-100% (Treble et al 2019). Each speleothem was sectioned along the growth axis and milled using a Taig micromill to produce homogenised powders representing increments of 0.1 to 0.2 mm, depending on the speleothem growth rate. Powders were weighed to 180–220 μg and analysed for O and C isotopic values (δ18O and δ13C) using a Finnigan MAT-251 isotope ratio mass spectrometer coupled to a Kiel I carbonate device, or a Thermo MAT-253 isotope ratio mass spectrometer coupled to a Kiel IV carbonate device (using 110–130 μg samples), at the Research School of Earth Sciences, ANU. Analyses were calibrated using NBS-19 standard (δ18Ov-PDB = -2.20 ‰ and δ13Cv-PDB = 1.95 ‰). A further linear correction for δ18O measurements was carried out using the NBS-18 standard (δ18Ov-PDB = -23.0 ‰). The original delta values for NBS-19 and NBS-18 are used to maintain consistency of results through time in the RSES Stable Isotope Facility. Analytical precision for the analyses reported here (NBS-19) are ±0.04 ‰ for δ18O and ±0.02 ‰ for δ13C (N=236) for the MAT-251; and ±0.05 ‰ for δ18O and ±0.01 ‰ (N=27) for the MAT-253 instrument (±1σ standard deviation). Speleothem chronologies were determined by combining information from the date of collection, bomb pulse chronology, laminae counting of annual Sr concentration and U-series disequilibrium (see Supplementary Table 8 in Treble et al., 2022). For GL-S1, the age-depth model for 17th percentile was used in Treble et al., (2022) and the 50th percentile used for other stalagmites.

Description: High-resolution multi-proxy records from two lakes on the southern Tibetan Plateau, Nam Co and Tangra Yumco, are used to infer long-term variations in the Asian monsoon system. We examine the moisture evolution during the Late Glacial Maximum and Holocene using the trace element and stable isotope composition of ostracod shells. The sediment records covering the past 24 cal. ka BP and 18 cal. ka BP, respectively, demonstrate the suitability of ostracod shell chemistry as paleoenvironmental proxy. We analysed (i) Mg/Ca, Ba/Ca and Sr/Ca ratios as salinity proxies, (ii) Fe/Ca, Mn/Ca and U/Ca ratios representing redox conditions and microbial activity, and (iii) rare earth elements (REEs) reflecting weathering and changes in provenance.

Description: A multi-proxy palaeoecological investigation including pollen and spore, loss-on-ignition, total organic carbon, stable carbon isotope and micro- and macrocharcoal was carried out on two peat cores collected from coastal area in eastern Sumatra. The study was conducted to understand the development and dynamics of the coastal peatlands, the Kampar Peninsula in Sumatra. Pollen and spore was extracted follwing Fagri and Iversen (1989) and identified using available literature (e.g. Anderson and Muller, 1975; Cheng et al., 2020; Hofmann et al., 2019; Jones and Pearce, 2015; Pollen and Spore Image Database of the University of Goettingen). Microcharcoal analysis was conducted following point count method (Clark, 1982) and counted counted on the same slides for pollen and spore analysis. Macrocharcoal analysis was conducted following protocols in Rhodes (1998) and Stevenson and Haberle (2005). Loss-on-ignition analysis was carried out following (Chambers et al., 2011). Organic carbon content and isotopes were determined in Euro EA3000 elemental analyzer and Thermo Finnigan Delta Plus mass spectrometer, respectively, at the Leibniz Centre for Tropical Marine Research (ZMT), Bremen.

Description: Diatom assemblages document surface hydrographic changes over the Bermuda Rise. Between 19.2 and 14.5 ka, subtropical diatom species and Chaetoceros resting spores dominate the flora, as in North Atlantic productive regions today. From 16.9 to 14.6 ka, brackish and fresh water diatoms are common and their contribution is generally coupled with total diatom abundance. This same interval also contains rare grains of ice-rafted debris. Coupling between those proxies suggests that successive discharge of icebergs might have stimulated productivity during Heinrich event 1 (H1). Iceberg migration to the subtropics likely created an isolated environment involving turbulent mixing, upwelled water, and nutrient-rich meltwater, supporting diatom productivity in an otherwise oligotrophic setting. In addition, the occurrence of mode water eddies likely brought silica-rich waters of Southern Ocean origin to the euphotic zone. The persistence of lower-salinity surface water beyond the last ice rafting suggests continued injection of fresh water by cold-core rings and advection around the subtropical gyre. These results indicate that opal productivity may have biased estimates of meridional overturning based on 231Pa/230Th ratios in Bermuda Rise sediments during H1.

Description: Predation is a key modifier of community dynamics, but information on its magnitude in community regulation in systematically understudied Arctic coastal habitats is sparse. To test the magnitude and direction of predation effects on the diversity and structure of Arctic benthic communities, we conducted caging experiments in which consumers were excluded from plots at two intertidal sedimentary sites in Svalbard (Longyearbyen and Thiisbukta) for 2.5 months. At the end of the experiment, we took a sediment core from each plot and quantified the total biomass and, separately for each taxon encountered, the number of individuals. At both sites, the exclusion of predators changed the species composition of the communities, but had negligible effects on biomass, total abundance, species richness, evenness and Shannon index. In addition, we found spatial variability and artifact effects at both sites on several response variables.