ALBERT

Description: Eastern boundary upwelling systems (EBUS) are among the most productive marine ecosystems on Earth. The production of organic material is fueled by upwelling of nutrient-rich deep waters and high incident light at the sea surface. However, biotic and abiotic factors can mod- ify surface production and related biogeochemical processes. Determining these factors is important because EBUS are considered hotspots of climate change, and reliable predic- tions of their future functioning requires understanding of the mechanisms driving the biogeochemical cycles therein. In this field experiment, we used in situ mesocosms as tools to improve our mechanistic understanding of processes con- trolling organic matter cycling in the coastal Peruvian up- welling system. Eight mesocosms, each with a volume of ∼ 55 m3, were deployed for 50 d ∼ 6 km off Callao (12◦ S) during austral summer 2017, coinciding with a coastal El Niño phase. After mesocosm deployment, we collected sub- surface waters at two different locations in the regional oxy- gen minimum zone (OMZ) and injected these into four meso- cosms (mixing ratio ≈ 1.5 : 1 mesocosm: OMZ water). The focus of this paper is on temporal developments of organic matter production, export, and stoichiometry in the indi- vidual mesocosms. The mesocosm phytoplankton commu- nities were initially dominated by diatoms but shifted to- wards a pronounced dominance of the mixotrophic dinoflag- ellate (Akashiwo sanguinea) when inorganic nitrogen was exhausted in surface layers. The community shift coincided with a short-term increase in production during the A. san- guinea bloom, which left a pronounced imprint on organic matter C : N : P stoichiometry. However, C, N, and P export fluxes did not increase because A. sanguinea persisted in the water column and did not sink out during the experiment. Accordingly, export fluxes during the study were decou- pled from surface production and sustained by the remain- ing plankton community. Overall, biogeochemical pools and fluxes were surprisingly constant for most of the experiment. We explain this constancy by light limitation through self- shading by phytoplankton and by inorganic nitrogen limita- tion which constrained phytoplankton growth. Thus, gain and loss processes remained balanced and there were few oppor- tunities for blooms, which represents an event where the sys- tem becomes unbalanced. Overall, our mesocosm study re- vealed some key links between ecological and biogeochem- ical processes for one of the most economically important regions in the oceans.

Description: This dataset represents abundance data from soil macro- and mesofauna from three alpine sites across the European Alps, sampled in summer 2017. The sites were: (1) Furka Pass, Uri, Switzerland, (2) Matsch Valley, South Tyrol, Italy, (3) Untersulzbach Valley, Salzburg, Austria, (4) Mallnitz, Carinthia, Austria, and (5) Innergschlöss, Tyrol, Austria. On each site we chose 3-6 snowbeds, where litter and soil core samples were taken. Each snowbed was subdivided into three sections: top (early snowmelt), middle, and bottom (late snowmelt). The data was used to evaluate how soil animal communities are responding to life conditions across snowbeds along a west-east transect of the European Alps, and to create a reference inventory for future investigations of climate change effects on snowbed ecosystems.

Description: Compound-specific radiocarbon dating often requires working with small samples of 〈 100 µg carbon (µgC). This makes the radiocarbon dates of biomarker compounds very sensitive to biases caused by extraneous carbon of unknown composition, a procedural blank, which is introduced to the samples during the steps necessary to prepare a sample for radiocarbon analysis by accelerator mass spectrometry (i.e., isolating single compounds from a heterogeneous mixture, combustion, gas purification and graphitization). Reporting accurate radiocarbon dates thus requires a correction for the procedural blank. We present our approach to assess the fraction modern carbon (F14C) and the mass of the procedural blanks introduced during the preparation procedures of lipid biomarkers (i.e. n-alkanoic acids) and lignin phenols. We isolated differently sized aliquots (6-151 µgC) of n-alkanoic acids and lignin phenols obtained from standard materials with known F14C values. Each compound class was extracted from two standard materials (one fossil, one modern) and purified using the same procedures as for natural samples of unknown F14C. There was an inverse linear relationship between the measured F14C values of the processed aliquots and their mass, which suggests constant contamination during processing of individual samples. We used Bayesian methods to fit linear regression lines between F14C and 1/mass for the fossil and modern standards. The intersection points of these lines were used to infer F14Cblank and mblank and their associated uncertainties. We estimated 4.88±0.69 μgC of procedural blank with F14C of 0.714±0.077 for n-alkanoic acids, and 0.90±0.23 μgC of procedural blank with F14C of 0.813±0.155 for lignin phenols. These F14Cblank and mblank can be used to correct AMS results of lipid and lignin samples by isotopic mass balance. This method may serve as a standardized procedure for blank assessment in small-scale radiocarbon analysis.

Description: Contains a table with the information for each specimens used in the present study. The fish ID number (Fish_ID), the file name of Fastq raw reads of methylation sequencing that are deposited in NCBI with accession ID PRJNA605637 (Sequence_Filename), species name (Species), the family of the fish (Family_ID), the treatment (Treatment) and sex (Sex).

Description: Laboratory-bred males of three-spined sticklebacks (Gasterosteus aculeatus) were assigned to one of two treatments: exposure to the nematode parasite Camallanus lacustris (exposed) or control (i.e. unexposed). After infection key fitness and immune traits were measured. Fish were then sacrificed and liver tissue was dissected. Reduced representation bisulfite sequencing was conducted on DNA extracted from whole liver tissue. Overall we aimed to investigated the role of host DNA methylation modifications to respond to parasite infections.

Description: Contains a table with the number of methylated sites (NMS) and the number of methylated regions (NMR), as well as the ratio of methylated sites (RMS) and the ratio of methylated regions (RMR) for each fish. Furthermore, the fish ID number (Fish_ID), the species name (Species), the fish family (Family_ID), the year of dissection (Year) and the treatment (Treatment) are given.

Description: Contains a table with the values of eight fish fitness traits. Furthermore, the fish ID number (Fish_ID), the species name (Species), the fish family (Family_ID), the year of dissection (Year), treatment (Treatment) and fish sex (Sex) are given. The fitness traits measured include the length in mm and weight in g of fish, the body condition estimated using the residuals of the linear regression of log10-transformed weight against log10-transformed body length, the head-kidney weight in g, liver weigth in g, the weight of testes in g, the respiratory burst activity and the concetration of sperm motility (number of spermatozoa/µL) (Sperm concentration).

Description: This is community, environmental, and nutrient data collected from two ROV video transects and two respective CTD casts taken of Sognefjord during a SponGES cruise with the RV G.O. Sars and ROV Ægir 6000 in July 2017.

Description: This is a diatom oxygen isotope record from Lake Kotokel (southern Siberia, Russia), with implications for responses of the lake system and its environment to global change over the past 46 cal. ka BP. The δ¹⁸O diatom values vary between +23.7 and +31.2‰ over the record. The results present mainly diatom assemblages of summer blooming periods, except for the time span between 36 and 32 cal. ka BP, when the isotopic signal records mainly a shift from summer to spring blooming conditions. Possible water temperature changes only partly explain the changes in the isotopic record. The observed isotopic patterns are mainly produced by isotope changes in lake water in response to variations in air temperature, hydrology, and atmospheric circulation in the region. During Marine Isotope Stage (MIS) 2 (Last Glacial maximum), high δ¹⁸O diatom resulted from rapid evaporation and low fluvial inputs. The relatively high δ¹⁸O diatom values during the first half of MIS 1 (Holocene interglacial) suggest an increased portion of summer precipitation associated with southern/southeastern moisture transport. The decrease in δ¹⁸O diatom values during the second half of MIS 1 is due to the overall hemispheric cooling and increased moisture supply to the area by the Atlantic air masses. The Lake Kotokel record provides an example of complex interplay among several climatic/environmental controls of δ¹⁸O diatom during the Late Pleistocene and the Holocene.