ALBERT

Description: During the HALO-(AC)³ campaign in March-April 2022 airborne observations were performed with the High Altitude and LOng range research aircraft (HALO) covering the Fram Strait and north polar regions. The flight tracks covered open ocean areas, the marginal sea ice zone, and closed sea ice cover. Furthermore, cloud conditions were observed during air mass transformation events as marine cold air outbreaks and warm air intrusions. This data set summarizes the flight tracks of HALO and provides longitude, latitude, and altitude defined as position above WGS84. All data are measured by the Basic HALO Measurement and Data System (BAHAMAS) and resampled to 1 Hz temporal resolution.

Description: Macroalgae such as kelp are important ecosystem engineers in the Polar Regions and potentially affected by freshening and ocean warming. The endemic Arctic kelp Laminaria solidungula might be particularly imperiled and become locally extinct from Arctic fjord systems in the future, since temperature increase is most pronounced in the Polar Regions. Additionally, increased temperatures cause glacier and sea ice melting and enhancing terrestrial run-off from snowfields, which eventually can result in hyposaline conditions in fjord systems. We conducted a multiple-stressor experiment at four temperatures (0, 5, 10, 15 °C) and two salinities (SA 25, 35) over 14 days to investigate the combined effects of increasing temperature and decreasing salinities on young L. solidungula sporophytes. The experiment was conducted with laboratory cultures (AWI culture number 3130) at Alfred Wegener Institute - Helmholtz Centre for Polar and Marine Research, Bremerhaven in February 2018. As physiological parameter, the maximum photosynthetic quantum yield of photosystem II (Fv/Fm; Imaging-PAM) was monitored every fourth day with an Imaging-PAM (Walz GmbH Mess- und Regeltechnik, Effeltrich, Germany). The total nitrogen, total carbon content was analyzed with an elemental analyzer and the C:N ratio calculated. Phlorotannins, mannitol as well as absolute pigment concentrations were analyzed using a HPLC and the deepoxydation state of the xanthophyll cycle (DPS) calculated.

Description: The file includes the respiration rate (milligrams of Oxygen per gram of dry mass (without tunic) per day) of three antarctic solitary ascidians (Cnemidocarpa verrucosa, Molgula pedunculata and Ascidia challengeri) under increasing sediment concentrations (from natural seston (NS) to NS + Additional Suspended particulate matter (SPM) from 5 to 400 mg/L). Individuals were sampled carefully by SCUBA diving during austral summer 2006-2007 in Potter Cove (58°43'5.214"W; 62°14'24.184"S) at 20 m depth. Experiments where performed after acclimation to aquarium conditions in the Dallmann laboratory on Carlini station (58°43'5.214"W; 62°14'24.184"S).

Description: The presented dataset contains chamber measurements of methane transport (mg CH₄ g dry plant mass-1 day-1) through individual aerenchymous peatland plants and the ancillary data for these measurements. Chamber measurements were performed for 7 plant species at two peatland sites, an oligotrophic fen and an ombrotrophic bog part of Siikaneva peatland complex in Southern Finland (61.8249° N, 24.1390° E, altitude 170 m a.s.l.) , during growing seasons 2013 and 2014 (between 1st of May and 28th of October). The ancillary data contains measurements of water table depth from the moss surface, air and peat temperature during the measurement as well as leaf area, dry mass of plant material, specific leaf area, number of leaves and the proportion of brown leaves in each sample that was measured. The dataset was collected to quantify the impact of plant species, plant properties and environmental factors on methane transport through aerenchymous plants. Plant CH₄ transport rate was measured using custom-made cylinder-shaped chambers that varied in volume between 0.7 and 5.0 liters. A plant sample of 2–104 leaves (depending on the growth form of the measured plant) belonging to the same species was separated from the peat and moss underneath by two plexiglass plates that were attached together with a hinge and had a smooth rubber seal between them to avoid compression of the plant. The proportion of green leaves in the sample varied from 0 to 100 % depending on the phase of the growing season. The sample was then covered with an opaque plastic chamber that was sealed with the plate by a smooth rubber seal attached to the bottom of the chamber. Airtightness of the system was ensured by tightening a belt that extended from one plate to the other over the chamber. Finally, a rubber stopper was used to seal a vent hole in the top of the chamber. Each plant sample was measured for 35 minutes, during which four 20 ml air samples were drawn from the chamber with a syringe through the rubber stopper in the top of the chamber at 5, 15, 25 and 35 minutes after chamber closure. The air samples were then injected into evacuated 12 ml glass vials (Labco Limited, UK). Simultaneous to the flux measurements, temperatures in the chamber (air) and peat at 5, 15 and 30 cm depth were recorded. WT was measured from a perforated plastic tube installed into the peat next to the sample after the WT level in the tube had stabilized for at least 30 minutes. After the flux measurement, the plant sample was cut with scissors and transported to the laboratory in a plastic bag. In each plant sample, the number of leaves was counted, the leaf area of brown and green leaf parts was measured with a scanner, and the dry weight was obtained for brown and green leaf parts separately after oven drying the sample at 60 °C for 24 hours. Using these data, specific leaf area (SLA, m²/g) was calculated for each sample. CH₄ concentration in the glass vials was analyzed with an Agilent Technologies 7890A gas chromatograph and Gilson GX-271 liquid handler. The CH₄ flux was calculated as the linear change in CH~4~ concentration in relation to time, chamber volume and temperature. Nonlinear changes in CH₄ concentration that were visually detected, were surmised to have resulted from a leak in the chamber or in the vial and were excluded from the analysis. In total 6 % of the measurements were excluded from the final dataset due to such nonlinearities.

Description: It is essential to predict the impact of elevated PCO2 on marine organisms and habitats to anticipate the severity and consequences of future ocean chemistry change. Despite the importance of carry-over effects in the evolutionary history of marine organisms, few studies have considered links between life-history stages when determining how marine organisms will respond to elevated PCO2, and none have considered the link between adults and their offspring. Herein, we exposed adults of wild and selectively bred Sydney rock oysters, Saccostrea glomerata to elevated PCO2 during reproductive conditioning and measured the development, growth and survival response of their larvae. We found that elevated PCO2 had a negative impact on larvae of S. glomerata causing a reduction in growth, rate of development and survival. Exposing adults to elevated PCO2 during reproductive conditioning, however, had positive carry-over effects on larvae. Larvae spawned from adults exposed to elevated PCO2 were larger and developed faster, but displayed similar survival compared with larvae spawned from adults exposed to ambient PCO2. Furthermore, selectively bred larvae of S. glomerata were more resilient to elevated PCO2 than wild larvae. Measurement of the standard metabolic rate (SMR) of adult S. glomerata showed that at ambient PCO2, SMR is increased in selectively bred compared with wild oysters and is further increased during exposure to elevated PCO2. This study suggests that sensitive marine organisms may have the capacity to acclimate or adapt to elevated PCO2 over the next century and a change in energy turnover indicated by SMR may be a key process involved.

Description: A 9-month aquarium experiment with the cold-water Dendrophyllia cornigera was conducted to investigate the single and combined effects of warming, acidification and deoxygenation on its ecophysiological response. The experiment took place at the Aquarium finisterrae (A Coruña, Spain) between 2022-05-06 and 2023-02-24. Treatment values for each parameter (current in situ vs. climate change) were: 12 °C and 15 °C (temperature); ~7.99 and 7.69 (pH); ~8.63 mg/L and 6.45 mg/L (dissolved oxygen concentration). A total of eight treatments (with 3 replicates each, 5 L aquaria) were set up. Respiration rates from each nubbin (3 per aquarium) were assessed after 6 and 9 months under the experimental conditions by means of closed-cell incubations. Oxygen consumption was calculated by measuring the dissolved oxygen concentration of the seawater inside the chamber using an optical oxygen sensor (YSI ProODO) at the beginning and at the end of the incubation time (24 h incubation). Dry mass (g) of the coral nubbins was assessed by means of the buoyant weight technique (Jokiel et al. 1978, Davies, 1989), using an analytical balance (OHAUS AX124, precision 0.1 mg). Tissue surface area (cm2) was assessed on virtual 3D models of each nubbin at the time when the measurements were conducted. Respiration rates were normalised by dry mass and by tissue surface area.

Description: This data set comprises all fish length data collected during the RV ALKOR cruise AL539 conducted in July 2020 (July 5th to July 18th 2020) in the Western Baltic Sea by the University of Hamburg. The cruise was part of the 5-year MARSYS teaching cruise program of the University of Hamburg GFP20-1_047. The fish length data were collected directly on board.

Description: This dataset contains sedimentary parameters pigments (Chlorophyll a, Pheophorbide, Pheophytin) measured from Multicorer (MUC) samples from the Bundesanstalt für Geowissenschaften und Rohstoffe (BGR, Germany) and Global Sea Mineral Resources (GSR, Belgium) license areas in the Clarion Clipperton Fracture Zone collected on onboard the RV Sonne during expeditions SO268 (Leg1 and Leg2) in 2019. Values are given in their respective units (SI) and have been collected and measured by the Marine Biology Research Group of Ghent University (Belgium).

Description: This database contains the data resulting from a study of Antarctic Ice Sheet history, over the last ~500 thousand years. Iceberg-rafted debris (IRD), considered as an indicator of the presence of a continental ice sheet in the source area, is counted and analyzed in relation to the other components of the studied size fraction. The study materials are derived from two cores raised from a deep-water marine site in the southeastern Atlantic Ocean: the piston core TN057-6-PC4 and the associated drill core from the Ocean Drilling Program (ODP) Leg 177 Site 1090 (177-1090). Because the top portion of the 177-1090 drill core was apparently disturbed by the drilling, the piston core TN057-6-PC4 has been used to represent the most recent part of the record. The site is located at ~43 deg S, 9 deg E, about 2/3 of the way from the Antarctic coast to South Africa. The location from which both cores were raised is on the southern slope of the Agulhas Ridge, on the northern edge of the Agulhas Basin, in the southeastern Atlantic Ocean. The initial cleaning and preparation of samples from these cores was carried out by Kathryn Venz and David Hodell (UF). The methods used here to examine the IRD are those described by Allen and Warnke (1991, doi:10.2973/odp.proc.sr.114.118.1991), Stanton (1997), and Murphy et al. (2002, doi:10.1016/S0031-0182(01)00495-3). The samples were first weighed, then separated by sieving into four size fractions: 〈150 microns, 150-250 microns, 250 microns to 2 mm, and 〉2 mm. The medium to coarse sand size fraction (250 microns to 2 mm) was utilized for our study. Within this, a split of about 1000 grains was obtained; the grains in this split were counted. Grains that were counted within categories that included: quartz, feldspar, mafic minerals, lithic fragments, volcanic lithics, volcanic ash, diatoms, planktic forams, benthic forams, radiolarians, and 'other'. The counts of quartz, feldspar, mafic minerals and lithic non-volcanic fragments were then summed as IRD. Following the suggestion of Murphy et al. (2002), the final step of this stage was a brief overview of the non-counted portion of the 250 micron to 2 mm size fraction, primarily to look for 'background rafting'. Background rafting refers to the presence of IRD in the non-counted portion (i.e., outside of the counted split) of the size fraction. For this study, a note was made of the presence or absence only of any IRD clasts in the non-counted portion.

Description: Zooplankton metabolic processes play an important role in carbon budgets and fluxes of pelagic ecosystems. Respiration rates of several copepod species were determined to reveal their energy requirements and assess their significance in the carbon cycle. Respiration rates were measured by optode respirometry and allometrically based on body dry mass (DM). For the on-board measurements, a 10-channel optode respirometer (PreSens Precision Sensing Oxy-10 Mini) was used and experiments were run in gas-tight glass bottles (13-14 ml) filled with filtered seawater to reduce bias by microbial respiration. In addition, respiration rates for all dominant copepod species during MSM80 including copepodite stages C4 to C6 were determined based on individual DM and respective ambient temperatures after Bode et al. (2018). For that, individual DM, if not available from frozen specimens, was determined from formalin/Steedman-preserved samples by weighing the dried samples on a microbalance. Losses in body DM due to formalin/Steedman preservation were considered after Schukat et al. (2021). Respiration rates were calculated separately for the copepod family Eucalanidae (a) as they are rather sluggish while all other copepods exhibited normal activity (b). (a) lnRTF = -2.180 + 0.787 ln(DM) + 0.131T and (b) lnRAC = -0.890 + 0.646 ln(DM) + 0.094T, where R (μl O2 ind-1 h-1) is the individual respiration rate for eucalanid (RTF) and active (RAC) copepods, DM represents dry mass in mg and T the average temperature (°C) of the sampling interval. Respiration rates of the medium- to larger-sized copepods (female prosome length (PL) of 1.2-6.0 mm) were compared to those of "small copepods" (all copepods with female PL 〈1.1 mm and young stages). Medium- to larger-sized species ingested on average 13-212 mg C m-2 d-1 in coastal regions while "small copepods" on average consumed 118-328 mg C m-2 d-1. The potential egestion varied on average from 5-64 mg C m-2 d-1 for medium to larger-sized copepods and 35-98 mg C m-2 d-1 for "small copepods". Data of energy demands, consumption and egestion rates of copepod species differing in size are essential to improve carbon budgets and food-web models in the Humboldt Current System.