This study presents new quantitative data on benthic foraminifera from three bathymetric transects of the Brazil (11-14°S, 420-1900 m) and Campos (22°S, 430-2000 m) basins. The quantity and quality of organic matter flux as well as substrate properties and hydrodynamic conditions at the sediment-water interface are identified as key parameters controlling assemblage distribution. Based on the total (stained and unstained) fauna, a distinct biogeographic divide between a Globocassidulina subglobosa/crassa assemblage in the Campos Basin and a rosalinid/bolivinid assemblage in the Brazil Basin occurs across the bifurcation of the South Atlantic Central Water into its southward subtropical and northward tropical branches. In the Campos Basin, coarser sediments, increased bottom current activity, and variable nutrient supply favor an assemblage of Globocassidulina subglobosa/crassa, Nuttalides umbonifer and Alabaminella weddellensis. Occurrences of cold-water coral mounds in 870 m provide an ecological niche favoring species such as Alabaminella weddellensis which benefit from trapped nutrients. The Brazil Basin is characterized by increased abundances of Rosalina and Bolivina, while Globocassidulina subglobosa/crassa is comparatively less frequent. Assemblages with G. subglobosa/crassa, Rosalina spp., Bolivina variabilis and Bolivina subreticulata are favored by a relatively high nutrient input at 14°S. Further north, assemblages with Bolivina subreticulata, Bolivina variabilis, Epistominella exigua, G. subglobosa/crassa are located beneath the velocity core of the North Brazil Undercurrent (NBUC), coinciding with more clayey sediments rich in TOC. Occurrences of delicate branching forms such as Saccorhiza ramosa indicate a more stable setting, distal to the main current. Rose Bengal stained (living) specimens are scarce in all three regions, as is typical for deep-sea foraminiferal faunas. Their patterns of species distribution largely reflect those observed for the total fauna.

<div> <p><span>Benthic foraminifera colonize a wide range of marine environments, including contourite drift systems (CDS). CDS are characterized by sustained bottom currents and cover large areas on the seafloor, e.g., in the North Atlantic. Due to their high sedimentation rates, they represent fundamental archives for paleoclimatology and paleoceanography. Some studies already highlight the influence of high current velocities on assemblages of epibenthic foraminifera and suggest their applicability as a reliable proxy for bottom current reconstructions (Schönfeld, 2002; Jorissen et al., 2007 and references therein). Certain epibenthic foraminiferal species live as highly adapted opportunistic suspension feeders using elevated substrates as a unique ecological niche. Through their elevated microhabitat, they optimize the uptake of suspended food particles gaining an advantage over other epibenthic organisms. However, their application as a bottom current proxy has so far been limited to the Iberian Margin and has been barely tested outside the Gulf of Cadiz (e.g., Diz et al., 2004).</span></p> </div><div> <p><span>The present study aims to document biogeographic distribution patterns of benthic foraminifera in extended CDS from different latitudes. Two data sets from the high-latitude North Atlantic (50-62°N) are presented here. The surface samples of the first data set originate from the Björn and Gardar drifts between the Reykjanes Ridge and the Rockall Plateau south of Iceland. Deposition is primarily controlled by the Iceland Scotland Overflow Water. The second data set is located further west within the Eirik Drift on the southern slope of the Greenland margin. The main controlling water mass is the Deep Western Boundary Current.</span></p> </div><div> <p><span>Initial results show that epibenthic species dominate over infaunal taxa. The data set is mainly determined by the tubular agglutinated species <em>Rhabdammina abyssorum</em>, <em>Saccorhiza ramosa</em>, and <em>Rhizammina algaeformis</em>, as well as hyaline forms such as <em>Hoeglundina elegans</em>, <em>Cibicidoides wuellerstorfi</em>, and <em>Cibicides refulgens</em>. </span><span>Thus, several different suspension-feeding taxa dominate the data set. Three assemblages of benthic foraminifera are distinguished: agglutinated suspension feeders dominating in more clayey environments, hyaline suspension feeders dominating in sandier environments with increased current velocities, and infaunal detritus feeders dominating below 2000 m water depth.</span></p> </div><div> <p><span>The presented data sets are currently complemented by samples from the Campos drift on the Brazilian margin (10°-22°S). Together, the low, mid and high latitude data sets will improve our understanding of biogeographic distribution patterns of benthic foraminifera in CDS. The expected results will be fundamental to ensure the applicability of foraminifera-based proxy methods for bottom current reconstruction.</span></p> </div><div> <p><strong><span>References</span></strong></p> </div><div> <p><span>Diz, P., Guillermo, F., Costas, S., Souto, C., Alejo, I., 2004. Distribution of benthic foraminifera in coarse sediments, Ria de Vigo, NW Iberian Margin. </span>J. Foraminifer. Res. 34, 258–275. https://doi.org/10.2113/34.4.258</p> </div><div> <p>Jorissen, F.J., Fontanier, C., Thomas, E., 2007. <span>Paleoceanographical proxies based on deep-sea benthic foraminiferal assemblage characteristics, in: Hillaire-Marcel, C., de Vernal, A. (Eds.), Proxies in Late Cenozoic Paleoceanography: Pt. 2: Biological Tracers and Biomarkers. pp. 263–325. https://doi.org/10.1016/S1572-5480(07)01012-3</span></p> </div><div><span>Schönfeld, J., 2002. Recent benthic foraminiferal assemblages in deep high-energy environments from the Gulf of Cadiz (Spain). </span></div><p>Mar. Micropaleontol. 44, 141–162. https://doi.org/10.1016/S0377-8398(01)00039-1</p>

<p>Contourites occur where along-slope bottom currents induce large accumulations of sediments in the deep sea (Faugères and Stow, 2008). Distinguishing among contourites and other depositional facies on continental slopes is fundamental for paleoenvironmental reconstructions like bottom current velocities. Nonetheless, reliable and easily applicable diagnostic criteria to properly differentiate between contourites and other coarse-grained and/or graded deep-water deposits such as turbidites are still sparse (e.g., de Castro et al., 2020). The differentiation and interpretation of these deposits is particularly complex in areas where downslope and along-slope sedimentary processes co-occur.</p><p>The SW Iberian Margin represents an ideal natural laboratory to study the complex interaction of downslope and along-slope processes. Persistent bottom current activity of Mediterranean Outflow Water (MOW) since the early Pliocene (García-Gallardo et al., 2017) resulted in the deposition of thick contourite drift bodies in the Gulf of Cádiz (Hernández-Molina et al., 2014). At the same time, downslope transport, channeled through submarine canyons, occurs frequently. Extensive turbidite intervals - intercalated between contouritic layers and often reworked by bottom currents - have been identified in several Pleistocene and Pliocene sediments in this area (Stow et al., 2013).</p><p>The aim of this study is to define diagnostic criteria to differentiate normally graded contourites and turbidites as well as reworked turbidites based on microfaunal analyses. Benthic foraminiferal assemblages along Pleistocene contouritic (~0.5 Ma) and turbiditic (~0.9 Ma, ~1.1 Ma) sequences in the Gulf of Cádiz (IODP Site U1389) are evaluated to test if their faunal composition provides a reliable tool to distinguish these deposits and the underlying sedimentary processes.</p><p> </p><p> </p><p> </p><p>References:</p><p>de Castro, S., Hernández-Molina, F.J., de Weger, W., Jiménez-Espejo, F.J., Rodríguez-Tovar, F.J., Mena, A., Llave, E., Sierro, F.J., 2020. Contourite characterization and its discrimination from other deep‐water deposits in the Gulf of Cadiz contourite depositional system. Sedimentology. https://doi.org/10.1111/sed.12813</p><p>Faugères, J.C., Stow, D.A.V., 2008. Contourite Drifts. Nature, Evolution and Controls. Dev. Sedimentol. 60, 257–288. https://doi.org/10.1016/S0070-4571(08)10014-0</p><p>García-Gallardo, Á., Grunert, P., Voelker, A.H.L., Mendes, I., Piller, W.E., 2017. Re-evaluation of the “elevated epifauna” as indicator of Mediterranean Outflow Water in the Gulf of Cadiz using stable isotopes (δ13C, δ18O). Glob. Planet. Change 155, 78–97. https://doi.org/10.1016/j.gloplacha.2017.06.005</p><p>Hernández-Molina, F.J., Llave, E., Preu, B., Ercilla, G., Fontan, A., Bruno, M., Serra, N., Gomiz, J.J., Brackenridge, R.E., Sierro, F.J., Stow, D.A.V., García, M., Juan, C., Sandoval, N., Arnaiz, A., 2014. Contourite processes associated with the Mediterranean Outfl ow Water after its exit from the Strait of Gibraltar: Global and conceptual implications. Geology 42, 227–230. https://doi.org/10.1130/G35083.1</p><p>Stow, D.A.V., Hernández-Molina, F.J., Llave, E., Bruno, M., García, M., Díaz del Rio, V., Somoza, L., Brackenridge, R.E., 2013. The Cadiz Contourite Channel: Sandy contourites, bedforms and dynamic current interaction. Mar. Geol. 343, 99–114. https://doi.org/10.1016/j.margeo.2013.06.013</p>

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Cruise AL534/2 is part of a multi-disciplinary research initiative as part of the JPI Oceans project HOTMIC and sought to investigate the origin, transport and fate of plastic debris from estuaries to the oceanic garbage patches. The main focus of the cruise was on the horizontal transfer of plastic debris from major European rivers into shelf regions and on the processes that mediate this transport. Stations were originally chosen to target the outflows of major European rivers along the western Europe coast between Malaga (Spain) and Kiel (Germany), although some modifications were made in response to inclement weather. In total, 16 stations were sampled along the cruise track. The sampling scheme was similar for most stations, and included: 1) a CTD cast to collect water column salinity and temperature profiles, and discrete samples between surface and seafloor, 2) sediment sampling with Van Veen grab and mini-multi corer (mini-MUC), 3) suspended particle and plankton sampling using a towed Bongo net and vertical WP3 net, and 4) surface neusten sampling using a catamaran trawl. At a subset of stations with deep water, suspended particles were collected using in situ pumps deployed on a cable. During transit between stations, surface water samples were collected from the ship’s underway seawater supply, and during calm weather, floating litter was counted by visual survey teams. The samples and data collected on cruise AL534/2 will be used to determine the: (1) abundance of plastic debris in surface waters, as well as the composition of polymer types, originating in major European estuaries and transported through coastal waters, (2) abundance and composition of microplastics (MP) in the water column at different depths from the sea surface to the seafloor including the sediment, (3) abundance and composition of plastic debris in pelagic and benthic organisms (invertebrates), (4) abundance and identity of biofoulers (bacteria, protozoans and metazoans) on the surface of plastic debris from different water depths, (5) identification of chemical compounds (“additives”) in the plastic debris and in water samples.