ALBERT

Description: The objective of this study is to determine the effects of ocean acidification (OA) on the survival, development and swimming behaviour of embryos of the deep-sea coral Desmophyllum pertusum (syn. Lophelia pertusa). Upon spawning, fertilized embryos were collected and exposed to two pCO2 treatments corresponding to present pCO2 conditions (400 ppm) and future pCO2 conditions predicted under scenario IPCC RCP8.5 for the end of the century (1000 ppm). We monitored survival daily and we measured swimming velocity on day 9 after spawning. Temperature and pH were measured every 24h, salinity was measured every other day, and water samples were collected during the first and last day of the experiment to determine total alkalinity (TA). This dataset includes data on the effects of ocean acidification on swimming velocity of larvae of the deep-sea coral Desmophyllum pertusum. Embryos were exposed to two acidification (pCO2) treatments: present pCO2 conditions (400 ppm) and future pCO2 conditions predicted under RCP8.5 for the end of the century (1000 ppm). After rearing the embryos in the respective treatments for nine days, we recorded the swimming behaviour of larvae with a video camera. Videos were analyzed with manual particle tracking, and here we report the swimming velocity and total traveled distance of larvae in each experimental treatment.

Description: The objective of this study is to determine the effects of ocean acidification (OA) on the survival, development and swimming behaviour of embryos of the deep-sea coral Desmophyllum pertusum (syn. Lophelia pertusa). Upon spawning, fertilized embryos were collected and exposed to two pCO2 treatments corresponding to present pCO2 conditions (400 ppm) and future pCO2 conditions predicted under scenario IPCC RCP8.5 for the end of the century (1000 ppm). We monitored survival daily and we measured swimming velocity on day 9 after spawning. Temperature and pH were measured every 24h, salinity was measured every other day, and water samples were collected during the first and last day of the experiment to determine total alkalinity (TA). This dataset includes data on the effects of OA on embryo and larval survival of the deep-sea coral Desmophyllum pertusum. Embryos (age: first cleavage and 2 cell stage) were exposed to two acidification (pCO2) treatments: present pCO2 conditions (400 ppm) and future pCO2 conditions predicted under RCP8.5 for the end of the century (1000 ppm) and reared for a total of nine days. We counted embryos and larvae daily to determine larval survival under the two treatments.

Description: New inorganic and organic geochemical data from thucholite in the Upper Permian (Wuchiapingian) Kupferschiefer (T1) shale collected at the Polkowice-Sieroszowice Cu-Ag mine in Poland are presented. Thucholite, which forms spherical or granular clusters, appears scattered in the T1 dolomitic shale at the oxic-anoxic boundary occurring within the same shale member. The composition of thucholite concretions and the T1 shale differs by a higher content of U- and REE-enriched mineral phases within the thucholite concretions compared to the T1 shale, suggesting a different mineralising history. The differences also comprise higher Ntot, Ctot, Htot, Stot contents and higher C/N, C/S ratios in thucholite than in the T1 shale. The hydrocarbon composition of the thucholite and the surrounding T1 shale also varies. Both are dominated by polycyclic aromatic compounds and their phenyl derivatives. However, higher abundances of unsubstituted polycyclic aromatic hydrocarbons in the thucholite are indicative of its pyrogenic origin. Pyrolytic compounds such as benz[a]anthracene or benzo[a]pyrene are more typical of the thucholite than the T1 shale. Microscopic observations of the thucholite and its molecular composition suggest that it represents well-rounded small charcoal fragments. These charcoals were formed during low-temperature combustion, as confirmed by semifusinite reflectance values, indicating surface fire temperatures of about 400 °C, and the absence of the high-temperature pyrogenic polycyclic aromatic hydrocarbons. Charred detrital particles, likely the main source of insoluble organic matter in the thucholite, migrated to the sedimentary basin in the form of spherical carbonaceous particulates, which adsorbed uranium and REE in particular, which would further explain their different contents and sorption properties in the depositional environment. Finally, the difference in mineral content between thucholite and the T1 shale could also have been caused by microbes, which might have formed biofilms on mineral particles, and caused a change in the original mineral composition.

Description: Severe flood losses have been on the rise, and this trend is expected to become increasingly prevalent in the future due to climate and socio-economic changes. Swiftly identifying flooded areas is crucial for mitigating socio-economic losses and facilitating effective recovery. Synthetic aperture radar (SAR) sensors are operational in all-weather, day-and-night conditions and offer a rapid, accurate, and cost-effective means of obtaining information for quick flood mapping. However, the complex nature of SAR images, such as speckle noise, coupled with the often absence of training/labeled samples, presents significant challenges in their processing procedures. To alleviate such hindrances, we can benefit from unsupervised classification approaches (also known as clustering). Clustering methods offer valuable insights into newly acquired datasets without the need for training or labeled samples. However, traditional clustering approaches are predominantly linear-based and overlook the spatial information of neighboring pixels during analysis. Thus, to attenuate these challenges, we propose a deep-learning (DL)-based clustering approach for flood detection (DC4Flood) using SAR images. The primary advantage of DC4Flood over existing DL-based clustering approaches lies in its ability to capture multiscale spatial information. This is achieved using multiple dilated convolutions with varying dilation rates and subsequently fusing the extracted multiscale information to effectively and efficiently analyze SAR images in an unsupervised manner. Extensive experiments conducted on SAR images from six different flood events demonstrate the effectiveness of the proposed DC4Flood. The code of the work will be available at https://github.com/Kasra2020/DC4Flood .

Description: Project “Saptarshi” was initiated by the National Centre for Geodesy, Indian Institute of Technology Kanpur to set up the modern space geodetic infrastructure in the country. This project primarily focuses on the establishment of an Indian Geodetic VLBI network. The purpose of this paper is to anticipate the potential impact of the geodetic VLBI network in India to the national and international scientific products. Saptarshi proposes to establish three VLBI stations along with a correlator at one facility. In this work, we investigate how adding proposed Indian VLBI antennas will affect terrestrial and celestial reference frames as well as Earth Orientation Parameters (EOP). Additionally, we shortly demonstrate scenario of VLBI observations of one of the Indian regional navigation satellite system called Navigation with Indian Constellation (NavIC) to determine its orbit. Two VLBI networks were simulated to observe the NAVIC satellite along with quasars to check how well the orbit of this satellite can be recovered from VLBI observations. To investigate the impact on the terrestrial reference frame, three types of 24-h sessions, IVS-R1 (legacy), IVS-VGOS (next generation VLBI), and IVS-AOV (Asia Oceania VLBI), were studied to examine the gain in precision of geodetic parameters when adding the proposed Indian VLBI antennas. IVS-type Intensive sessions were also investigated with the proposed Indian antennas to assess the improvement in the estimation of dUT1 as one important VLBI product. Furthermore, the u-v coverage of some radio sources of the southern hemisphere was compared utilizing observing networks with and without the proposed Indian antennas. Apart from that, we briefly discuss other benefits of the establishment of Indian geodetic VLBI in the scientific fields of atmosphere, metrology, and space missions.

Description: The shallow meridional overturning cells of the Atlantic Ocean, the Subtropical Cells (STCs), consist of poleward Ekman transport at the surface, subduction in the subtropics, equatorward flow at thermocline level and upwelling along the equator and at the eastern boundary. In this study we provide the first observational estimate of transport variability associated with the horizontal branches of the Atlantic STCs in both hemispheres based on Argo float data and supplemented by reanalysis products. Thermocline layer transport convergence and surface layer transport divergence between 10°N and 10°S are dominated by seasonal variability. Meridional thermocline layer transport anomalies at the western boundary and in the interior basin are anti-correlated and partially compensate each other at all resolved time scales. It is suggested that the seesaw-like relation is forced by the large-scale off-equatorial wind stress changes through low-baroclinic-mode Rossby wave adjustment. We further show that anomalies of the thermocline layer interior transport convergence modulate sea surface temperature (SST) variability in the upwelling regions along the equator and at the eastern boundary at time scales longer than 5 years. Phases of weaker (stronger) interior transport are associated with phases of higher (lower) equatorial SST. At these time scales, STC transport variability is forced by off-equatorial wind stress changes, especially by those in the southern hemisphere. At shorter time scales, equatorial SST anomalies are, instead, mainly forced by local changes of zonal wind stress.

Description: The upper-ocean circulation of the tropical Atlantic is a complex superposition of thermohaline and wind-driven flow components. The resulting zonally- and vertically-integrated upper-ocean meridional flow is referred to as the upper branch of the Atlantic Meridional Overturning Circulation (AMOC) - a major component and potential tipping element of the global climate system. We investigate the tropical part of the northward AMOC branch, i.e. the return flow covering the upper 1,200 m, based on Argo data and repeated shipboard velocity measurements. The western boundary mean circulation at 11°S is realistically reproduced from high-resolution Argo data showing a remarkably good representation of the vertical structure of meridional velocity and the volume transport of water mass layers when compared to results from direct velocity measurements along a repeated ship section. Thus, we extend the analysis to the inner tropical Atlantic. Within the AMOC return flow, a diapycnal upwelling of central water into the thermocline layer of ~2 Sv is derived between 11°S and 10°N which is about half the magnitude of previous estimates, likely due to improved horizontal resolution. The mean strength of the AMOC return flow is ~16 Sv across 11°S and 10°N. At 11°S, northward transport is concentrated at the western boundary where the AMOC return flow enters the tropics at all vertical layers above 1,200 m. At 10°N, northward transport is observed both at the western boundary and in the interior predominantly in the surface and intermediate layer indicating recirculation and transformation of thermocline and central water within the tropics.

Description: Physical oceanography variables and carbon remineralisation (juveniles/adults of Cyclothone species and Argyropelecus hemigymnus) were analysed during the BATHYPELAGIC cruise (North Atlantic, June 2018). This dataset contains the depth, temperature, and conductivity which were recorded from surface to a maximum depth of 2000 m using a SeaBird SBE 25plus CTD equipped with a Seabird-43 Dissolved Oxygen sensor and a Seapoint Fluorometer. Values of numerical abundance, biomass, specific ETS activity, specific respiraton and respiration flux data analyzed from Northwest Africa (20° N, 20° W) to the South of Iceland are presented. A. hemigymnus specimens were collected using a ''Mesopelagos” net (5 x7 m mouth opening, 58 m total length) equipped with graded-mesh netting (starting with 30 mm and ending with 4 mm) and a multi-sampler for collecting samples from 5 different depth layers. However, Cyclothone specimens were collected using the Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS-1 m²) zooplankton net with a 0.2 mm mesh size and with several nets for collecting samples from 8 different depth layers. The Mesopelagos catches were sorted out and identified on board to the lowest possible taxon, and specimens selected for Electron Transfer System (ETS) analyses were immediately frozen in liquid nitrogen for later analysis in the laboratory. MOCNESS samples were preserved in 5% buffered formalin, and specimens were sorted out later in the laboratory. Stomiiforms respiration in the meso- and bathypelagic zones of the ocean were estimated along the transect. Abundance, biomass, specific ETS activity, specific respiration and respiration are given by layer between e.g. 100 m and 1000 m depth (MOCNESS net, 1900–1600 m, 1600–1300 m, 1300–1000 m, 1000–700 m, 700–400 m, 400–200 m, 200–100 m and 100–0 m; Mesopelagos, 1900–1200 m, 1200–800 m, 800–500 m, 500–200 m and 200–0 m).

Description: During the Transatlantic Equatorial Cruise II (TRATLEQ II) with the R/V METEOR (M181) from 17. April to 28. May 2022 (Brandt, 2022), 44 Lagrangian drifters were deployed along the Equator (between 7°W and 37°W) to monitor the surface flow in the upper meter. The equatorial section covered the region of the Atlantic cold tongue that seasonally develops during boreal summer east of 23°W and the western equatorial Atlantic characterized by warmer surface waters and deeper mixed layer depths. In particular, the cruise M181 took place during the warm phase with relatively homogeneous warm surface layer in the whole equatorial Atlantic. Drifters were deployed every 1° longitude (~111 km) between 7°W and 37°W. The drifters were designed and built at Helmholtz-Zentrum Hereon to follow the upper surface flow (approx. 50 cm). The main body of these Hereon drifters consists of a 7.5 cm x 20 cm long tube with a floatation ring at the top. It is attached to a drogue of 35 cm in both length and diameter through a flexible cord within a distance of 20 cm to the tube. When deployed about 5 cm of the tube protrude from the water surface, resulting in a ratio of drag area inside to drag area outside the water of 21. The tube contains a battery pack and an electronic board, which acquires and reports the GPS position every 5 minutes via a global satellite network in near real time. Table 1 provides some information on the 44 deployed Hereon Drifters, which consists of deployment and working time, total covered distance and number of recorded GPS positions.