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Differences in habitat and diet between species are often associated with morphological differences. Habitat and trophic adaptation have therefore been proposed as important drivers of speciation and adaptive radiation. Importantly, habitat and diet shifts likely impose changes in exposure to different parasites and infection risk. As strong selective agents influencing survival and mate choice, parasites might play an important role in host diversification. We explore this possibility for the adaptive radiation of Lake Tanganyika (LT) cichlids. We first compare metazoan macroparasites infection levels between cichlid tribes. We then describe the cichlids' genetic diversity at the major histocompatibility complex (MHC), which plays a key role in vertebrate immunity. Finally, we evaluate to what extent trophic ecology and morphology explain variation in infection levels and MHC, accounting for phylogenetic relationships. We show that different cichlid tribes in LT feature partially non-overlapping parasite communities and partially non-overlapping MHC diversity. While morphology explained 15% of the variation in mean parasite abundance, trophic ecology accounted for 16% and 22% of the MHC variation at the nucleotide and at the amino acid level, respectively. Parasitism and immunogenetic adaptation may thus add additional dimensions to the LT cichlid radiation.

These datasets were used to describe the diversity, ecology and role of non-scleractinian corals on scleractinian cold-water coral carbonate mounds in the Logachev Mound Province, Rockall Bank, NE Atlantic. Cold-water coral carbonate mounds, created by framework-building scleractinian corals, are also important habitats for non-scleractinian corals, whose ecology and role are understudied in deep-sea environments. In total ten non-scleractinian species were identified, which were mapped out along eight ROV video transects. Eight species were identified as black corals (three belonging to the family Schizopathidae, one each to the Leiopathidae, Cladopathidae, and Antipathidae and two to an unknown family) and two as gorgonians (Isididae and Plexauridae). The most abundant species were Leiopathes sp. and Parantipathes sp. 2. Areas with a high diversity of non-scleractinian corals are interpreted to offer sufficient food, weak inter-species competition and the presence of heterogeneous and hard settlement substrates. A difference in the density and occurrence of small vs. large colonies of Leiopathes sp. was also observed, which is likely related to a difference in the stability of the substrate they choose for settlement. Non-scleractinian corals, especially black corals, are an important habitat for crabs, crinoids, and shrimps in the Logachev Mound Province.

The pennate diatom Haslea ostrearia is the emblematic and most studied species of the genus Haslea. H. ostrearia is mainly benthic and epiphyte, forming biofilm on sediment and on macroalgae. The cells produce a blue water-soluble pigment: the marennine with allelopathic, antioxidant, antiviral, antibacterial properties observed in laboratory conditions. Marennine is responsible for the greening of oysters in refining ponds in the Marennes Oléron area (France), a phenomenon that has economical and patrimonial values. Recently, new species of blue Haslea producing marennine-like pigments were described (H. karadagensis, H. nusantara, H. provincialis). Last years, large benthic blooms of blue Haslea spp. have been observed in natural environments, e.g. in Calvi Bay, Corsica France. First the species of Haslea responsible for the bloom were identified using morphological and molecular approaches. Their abundances were determined and cartography of the recent blooms localisations was achieved. Then, within shallow photophilous rocky habitats affected by the bloom, the epiphytic communities of some representant macroalgal species (Padina sp. and Acetabularia sp.) were studied using taxonomic identification tools. This information will be used to define if the release of marennine-like pigments during blooms affects the structure of the benthic epiphytic and epiplithic microfauna and microflora. This work represents the first studies on the dynamic of the bloom of Haslea in natural environment in open water. The Genus Haslea, New marine resources for blue biotechnology and Aquaculture

High-resolution 2D seismic reflection data during research cruise MSM63 in April/May 2017 onboard RV Maria S. Merian. The seismic profiles were acquired with a two-105/105-in3-GI-Gun-array shot at 210 bar every 5 seconds and a 150 m-long streamer with 96 channels and 1.5625 m channel spacing. The resulting shot point distance is approximately 8.75-12.5 m at 3.5-5 kn ship speed. The frequency range of the two-GI-Gun-array is 15-500 Hz. The processing included geometry and delay corrections, static corrections, binning to 1.5625 m and bandpass filtering with corner frequencies of 25, 45, 420, and 500 Hz. Furthermore, a normal-move-out-correction (with a constant velocity of 1488 m/s calculated from CTD measurements) was applied and the data were stacked and then migrated using a 2D Stolt algorithm (1500 m/s constant velocity model). Sub-bottom profiler data acquired during cruise MSM63 using Parasound P70 with 4 kHz as the secondary low frequency to obtain seismic images of the upper 100 m below the seafloor with very high vertical resolution (< 15 cm). We applied a frequency filter (low cut 2 kHz, high cut 6 kHz, 2 iterations) and calculated the envelope within the seismic interpretation software IHS Kingdom. Bathymetric data were acquired with the EM712 system mounted to the hull of RV Maria S. Merian. The survey was designed to provide high-resolution bathymetry with 5 x 5 m resolution. We processed the data using MB Systems software (Caress & Chayes, 2017) and included statistical evaluation of soundings that increased the signal-to-noise ratio. The sound velocity profile for multibeam processing was measured at the beginning and at the end of the cruise.

A tool for multidimensional variational analysis (divand) is presented. It allows the interpolation and analysis of observations on curvilinear orthogonal grids in an arbitrary high dimensional space by minimizing a cost function. This cost function penalizes the deviation from the observations, the deviation from a first guess and abruptly varying fields based on a given correlation length (potentially varying in space and time). Additional constraints can be added to this cost function such as an advection constraint which forces the analysed field to align with the ocean current. The method decouples naturally disconnected areas based on topography and topology. This is useful in oceanography where disconnected water masses often have different physical properties. Individual elements of the a priori and a posteriori error covariance matrix can also be computed, in particular expected error variances of the analysis. A multidimensional approach (as opposed to stacking 2-dimensional analysis) has the benefit of providing a smooth analysis in all dimensions, although the computational cost is increased. Primal (problem solved in the grid space) and dual formulations (problem solved in the observational space) are implemented using either direct solvers (based on Cholesky factorization) or iterative solvers (conjugate gradient method). In most applications the primal formulation with the direct solver is the fastest, especially if an a posteriori error estimate is needed. However, for correlated observation errors the dual formulation with an iterative solver is more efficient. The method is tested by using pseudo observations from a global model. The distribution of the observations is based on the position of the ARGO floats. The benefit of the 3-dimensional analysis (longitude, latitude and time) compared to 2-dimensional analysis (longitude and latitude) and the role of the advection constraint are highlighted. The tool divand is free software, and is distributed under the terms of the GPL license (http://modb.oce.ulg.ac.be/mediawiki/index.php/divand). PREDANTAR, EMODNET Chemistry 2, SeaDataNet II

In an enclosure experiment, we employed two levels of inorganic NP ratios (10 and 5) for three distinct plankton communities collected along the coast of central Chile (33ºS). Each combination of community and NP level was replicated three times. The experiment lasted 12 days, and the data set include inorganic nutrients (NO3, PO4, DSi), particular organic carbon (POC), nitrogen (PON) and phosphorus (POP), Chlorophyll a, a range of fluorescence based measurements such as photochemical efficiency (Fv/Fm) and community data. The primary effect of the NP treatment was related to different concentrations of NO3, which directly influenced the biomass of phytoplankton. Additionally, low inorganic NP ratio reduced the seston NP and Chl a-C ratios, and there were some effects on the plankton community composition, e.g. benefitting Synechococcus spp in some communities.

Atmospheric _p_CO~2~ is a critical component of the global carbon system and is considered to be the major control of Earth's past, present and future climate. Accurate and precise reconstructions of its concentration through geological time are, therefore, crucial to our understanding of the Earth system. Ice core records document _p_CO~2~ for the past 800 kyrs, but at no point during this interval were CO~2~ levels higher than today. Interpretation of older _p_CO~2~ has been hampered by discrepancies during some time intervals between two of the main ocean-based proxy methods used to reconstruct _p_CO~2~: the carbon isotope fractionation that occurs during photosynthesis as recorded by haptophyte biomarkers (alkenones) and the boron isotope composition (δ^11^B) of foraminifer shells. Here we present alkenone and δ^11^B-based _p_CO~2~ reconstructions generated from the same samples from the Plio-Pleistocene at ODP Site 999 across a glacial-interglacial cycle. We find a muted response to _p_CO~2~ in the alkenone record compared to contemporaneous ice core and δ^11^B records, suggesting caution in the interpretation of alkenone-based records at low _p_CO~2~ levels. This is possibly caused by the physiology of CO~2~ uptake in the haptophytes. Our new understanding resolves some of the inconsistencies between the proxies and highlights that caution may be required when interpreting alkenone-based reconstructions of _p_CO~2~.

Gordon & Betty Moore FoundationGordon and Betty Moore Foundation [5596]; Canada Research Chairs FoundationCanada Research Chairs; European Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant [747946]; Fundacao para a Ciencia e Tecnologia I.P. Portugal (FCT); Direcao-Geral de Politica do Mar (DGPM) [2/2017/001-MiningImpact 2]; FCTPortuguese Foundation for Science and TechnologyEuropean Commission [CEECIND005262017, UID/MAR/00350/2013, IF/01194/2013, IF/00029/2014/CP1230/CT0002, Mining2/0005/2017]; RF State Assignment [0149-2019-0009]; Horizon 2020 Agricultural Interoperability and Analysis System (ATLAS) projects [678760]; JM Kaplan Fund; National Science FoundationNational Science Foundation (NSF) [OCE 1634172]; JPI Oceans project Mining Impact -Environmental Impacts and Risks of Deep-Sea Mining Aug 2018-Feb 2022 (NWO-ALW) [856.18.001] info:eu-repo/semantics/publishedVersion

The dataset contains carbon (C) and nitrogen (N) stable isotope compositions analysed in the muscle tissue and energy density values and concentrations of 19 elements analysed in whole bodies of 15 meso- to bathypelagic species sampled in the twilight zone (deep pelagic area) of the Bay of Biscay, North-East Atlantic. The species included 4 crustacean species (Pasiphaea sivado, Sergia robusta, Systellaspis debilis, Ephyrina figueirai) and 11 fish species (Xenodermichthys copei, Searsia koefoedi, Myctophum punctatum, Notoscopelus kroeyeri, Lampanyctus crocodilus, Argyropelecus olfersii, Arctozenus risso, Stomias boa, Serrivomer beanii, Chauliodus sloani, Aphanopus carbo). The elements included 6 major constitutive elements (macro-minerals) and 13 trace elements among which 9 essential (micro-nutrients) and 4 non-essential elements (undesirables, with no know biological function). Specimens were collected during a single fishery in a canyon of the slope of the Bay of Biscay in October 2017, during the EVHOE fishery survey (“Evaluation Halieutique de l'Ouest de l'Europe”; https://doi.org/10.17600/17002300) conducted each autumn by the “Institut Français de Recherche pour l'Exploitation de la Mer” (Ifremer) on R/V Thalassa. A total of 266 individuals belonging to the 15 species were collected at night using a 25 m vertical opening pelagic trawl in the deep scattering layer (ca. 800 m depth in the water column; 1330 m bottom depth). All organisms were collected during one haul of 60 min, at a speed of approximately 4 knots (geographical coordinates at the beginning of the turn/end of the fishing: 45.103°N, -3.543° W).

In permafrost areas, seasonal freeze-thaw cycles result in upward and downward movements of the ground. For some permafrost areas, long-term downward movements were reported during the last decade. We measured seasonal and multi-year ground movements in a yedoma region of the Lena River Delta, Siberia, in 2013–2017, using reference rods installed deep in the permafrost. The seasonal subsidence was 1.7 ± 1.5 cm in the cold summer of 2013 and 4.8 ± 2 cm in the warm summer of 2014. Furthermore, we measured a pronounced multi-year net subsidence of 9.3 ± 5.7 cm from spring 2013 to the end of summer 2017. Importantly, we observed a high spatial variability of subsidence of up to 6 cm across a sub-meter horizontal scale. In summer 2013, we accompanied our field measurements with Differential Synthetic Aperture Radar Interferometry (DInSAR) on repeat-pass TerraSAR-X (TSX) data from the summer of 2013 to detect summer thaw subsidence over the same study area. Interferometry was strongly affected by a fast phase coherence loss, atmospheric artifacts, and possibly the choice of reference point. A cumulative ground movement map, built from a continuous interferogram stack, did not reveal a subsidence on the upland but showed a distinct subsidence of up to 2 cm in most of the thermokarst basins. There, the spatial pattern of DInSAR-measured subsidence corresponded well with relative surface wetness identified with the near infra-red band of a high-resolution optical image. Our study suggests that (i) although X-band SAR has serious limitations for ground movement monitoring in permafrost landscapes, it can provide valuable information for specific environments like thermokarst basins, and (ii) due to the high sub-pixel spatial variability of ground movements, a validation scheme needs to be developed and implemented for future DInSAR studies in permafrost environments.