The Pliocene epoch emerges as a pivotal juncture in Earth's climatic evolution, characterized by pronounced warmth and elevated atmospheric carbon dioxide compared to contemporary levels. While the broader climatic context of the Pliocene has garnered attention, there remains an outstanding gap in detailed paleoclimate reconstructions of the early Pliocene, a new potential target for data‐model intercomparison. Addressing this, we investigate the drivers of the early Pliocene “Biogenic Bloom” and implications for nutrient dynamics and climate. By analyzing high‐resolution biotic assemblage and geochemical records from the Agulhas Plateau, southwestern Indian Ocean (International Ocean Discovery Program, IODP Site U1475), we aim to elucidate the forcing and feedback mechanisms driving the early Pliocene marine ecosystems. We identify a distinct shift in coccolithophore assemblages at ∼4.6 million years ago, characterized by a notable change in dominance between the larger and smaller Reticulofenestra and high abundances of Noelaerhabdaceae < 5 µm. Our findings confirm the adaptive strategies of coccolithophore communities to prevailing environmental conditions, underscoring their evolutionary resilience by producing smaller coccoliths while increasing their abundances in a nutrient‐replete ocean. Surface water dynamics, particularly the subtropical front migration and expansion of Southern Ocean waters, in combination with the southern African monsoon variability, emerge as key drivers of phytoplankton productivity during the early Pliocene. We posit that a weakened biological carbon pump, due to increased phytoplankton production driven by intense ocean circulation and mixing during the early Pliocene, served as a potential precursor to the subsequent middle Pliocene abrupt climate extremes.

The late Miocene‐early Pliocene (7.4‐4.5 Ma) is a key interval in Earth's history where intense reorganization of atmospheric and ocean circulation occurred within a global cooling scenario. The Southern African monsoon (SAFM) potentially played an important role in climate systems variability during this interval. However, the dynamics of this important atmospheric system is poorly understood due to the scarcity of continuous records. Here, we present an exceptional continuous late Miocene to early Pliocene reconstruction of SAFM based on elemental geochemistry (Ca/Ti and Si/K ratios), stable isotope geochemistry (δ¹⁸O and δ¹³C recorded in the planktonic foraminiferaOrbulina universa), and marine sediment grain size data from the International Ocean Discovery Program (IODP) Site U1476 located at the entrance of the Mozambique Channel. Spectral characteristics of the Si/K ratio (fluvial input) was used to identify the main orbital forcing controlling SAFM. Precession cycles governed precipitation from 7.4 to ∼6.9 Ma and during the early Pliocene. From ∼6.9 to ∼5.9 Ma, the precession and long eccentricity cycles drove the SAFM. The major Antarctic ice sheet expansion across this interval appear to influence the isotopic records ofO. universaimprinting its long‐term variability signal as a response to the ocean and atmospheric reorganization. Precession cycles markedly weakened from 5.9 to 5.3 Ma, almost the same period when the Mediterranean Outflow Water ceased. These findings highlight important teleconnections among the SAFM, Mediterranean Sea, and other tropical regions.

The Amapá margin, part of the Brazilian Equatorial Margin (BEM), is a key region that plays a strategic role in the global climate balance between the North and South Atlantic Ocean as it is strictly tied to equatorial heat conveyance and the fresh/salt water equilibrium with the Amazon River. We performed a new scientific expedition on the Amapá continental shelf (ACS, northern part of the Amazon continental platform) collecting sediment and using instrumental observation at an unstudied site. We show here the preliminary outcomes following the applied methodologies for investigation. Geophysical, geological, and biological surveys were carried out within the ACS to (1) perform bathymetric and sonographic mapping, high-resolution sub-surface geophysical characterization of the deep environment of the margin of the continental platform, (2) characterize the habitats and benthic communities through underwater images and biological sampling, (3) collect benthic organisms for ecological and taxonomic studies, (4) define the mineralogical and (5) elemental components of sediments from the study region, and (6) identify their provenance. The geophysical data collection included the use of bathymetry, a sub-bottom profiler, side scan sonar, bathythermograph acquisition, moving vessel profiler, and a thermosalinograph. The geological data were obtained through mineralogical, elemental, and grain size analysis. The biological investigation involved epifauna/infauna characterization, microbial analysis, and eDNA analysis. The preliminary results of the geophysical mapping, shallow seismic, and ultrasonographic surveys endorsed the identification of a hard substrate in a mesophotic environment. The preliminary geological data allowed the identification of amphibole, feldspar, biotite, as well as other minerals (e.g., calcite, quartz, goethite, ilmenite) present in the substrata of the Amapá continental shelf. Silicon, iron, calcium, and aluminum composes ~85% of sediments from the ACS. Sand and clay are the main fraction from these sediments. Within the sediments, Polychaeta (Annelida) dominated, followed by Crustacea (Arthropoda), and Ophiuroidea (Echinodermata). Through TowCam videos, 35 taxons with diverse epifauna were recorded, including polychaetes, hydroids, algae, gastropods, anemones, cephalopods, crustaceans, fishes, and sea stars.

Background/Objectives: We evaluated eukaryotic diversity in two cores obtained from abyssal sediments collected at depths of 4280 m and 4444 m in the equatorial Atlantic, between the Fernando de Noronha and São Pedro and São Paulo archipelagos, using a DNA metabarcoding approach applied to environmental DNA (eDNA) samples. Results: In total, we detected 248,905 DNA reads that were assigned to 65 amplicon sequence variants (ASVs) in the two core sediments (176,073 DNA reads and 59 ASVs were detected in sediment obtained at 4280 m depth, and 72,832 DNA reads and 14 ASVs were detected in the core at 4444 m). These represented three Kingdoms and five phyla: Fungi (Ascomycota and Basidiomycota), Viridiplantae (Chlorophyta and Streptophyta) and Chromista (Ciliophora), in rank abundance order. Ascomycota was the dominant phylum, followed by Basidiomycota. Didymella sp., Cladosporium sp., Scopulariopsis sp., Alternaria eichhorniae, Curvularia sp., Hortaea werneckii, Penicillium sp. (Ascomycota) and Malassezia globosa (Basidiomycota) were the most abundant taxa. Pseudochlorella pyrenoidosa (Chlorophyta) was the most abundant representative of Viridiplantae detected, and Spirotrachelostyla tani (Ciliophora) was the only Chromista detected, both present as minor components of the assigned eukaryotic diversity and only in the 4280 m core. The eukaryotic assemblages displayed moderate diversity indices, and those from the deeper core (4444 m depth) displayed the highest diversity values. Few assigned taxa were present in both samples. The two cores differed in their geological characteristics, consistent with their location in different depositional basins. The core obtained at 4280 m depth, located further north and more isolated from the adjacent continent by two fracture zones, appears to receive less terrigenous sediment input. In contrast, the core obtained at 4444 m depth is under greater continental influence and receives more terrigenous input from the continent. These geological and geographic differences may contribute to the varying eukaryotic eDNA diversities found. Results: Our metabarcoding study revealed the presence of a sediment eukaryotic community dominated by fungi. This included assigned ASVs representing groups with different ecological roles, such as cosmopolitan and phytopathogenic members and extremophiles, some of which may be able to survive and function in the polyextreme deep-sea abyssal conditions. Abyssal sediments present a potential habitat for studying organisms at the edge of viable conditions for life on Earth. eDNA metabarcoding provides a promising technique for detecting cryptic and uncultured biodiversity compared to traditional approaches, opening avenues for further ecological, evolutionary and biotechnological studies.

Boron isotopes (δ¹¹B) measured in planktonic foraminifera are widely used to reconstruct past surface ocean pH and atmospheric pCO₂, yet their application in tropical regions relied on understanding of species-specific ecology and size-dependent vital effects. Here we present new data from Globigerinoides ruber (sensu stricto) and Trilobatus sacculifer spanning the last ~60 kyr from Tropical Atlantic Ocean. Our dataset comprises paired analyses of multiple size fractions (200–250 µm, 250–300 µm, 300–355 µm, and ≥355–400 µm), which enabled an assessment of species’ vital effects and how they vary with size. During the Younger Dryas, Heinrich Stadial 1 and Heinrich Stadial 4, G. ruber varied from ~19.0–19.5‰ (200–250 µm), increased to ~19.0–20.0‰ (250–300 µm) and reached values up to ~20–21‰ in the largest studied size fraction (300-350 µm). This positive relationship between δ¹¹B and test size demonstrates a pronounced size-dependent enrichment, consistent with strong biological control and near-surface calcification. In contrast, T. sacculifer exhibits lower δ¹¹B values during the same intervals, ranging from ~18.5–19‰ (200–250 µm), 18.25-17.80 ‰ (250-300 µm), 18.2-19‰ (300-355 µm). Paired species analyses from identical depth horizons reveal persistent interspecific offsets, with G. ruber recording higher δ¹¹B values than T. sacculifer across all size fractions. These offsets are maintained throughout YD, HS1, and HS4. The magnitude of size-related offsets within each species (up to ~1‰) is comparable to the expected glacial–interglacial δ¹¹B signal, underscoring the first-order importance of size fraction. We conclude that robust δ¹¹B-based reconstructions in the Equatorial Atlantic require strict size-fraction control and species-specific ecological interpretation. These findings highlight that different planktonic foraminifera record distinct levels of the upper ocean carbonate system during periods of rapid climate change, providing new constraints on tropical ocean buffering during abrupt climate events.Keywords: Boron Isotopes, Globigerinoides ruber, Trilobatus sacculifer, Tropical Atlantic Ocean

Oxygen Minimum Zones (OMZ) are water layers characterized by low oxygen saturation state in response to a complex interplay of biological, chemical, and physical processes. Modern OMZs are typically found along the western side of continents (i.e., Arabian Sea, Eastern Pacific Ocean, Eastern Tropical Atlantic Ocean, and the Southeast South Atlantic Ocean). Low oxygen conditions can however be more widely prevalent in shallower, continental shelf environments. Here, we study the evolution of bottom water oxygen conditions of Brazil’s continental shelf Santos Basin from the Southeast Atlantic. The Santos Basin which is located near the Cabo Frio upwelling system. We reconstructed bottom water oxygen conditions using the enhanced Benthic Foraminifera Oxygen Index (EBFOI) using samples from the Santos Basin Slope core C4-GC-2 ( 25°51.519’S/ 45°30.685’W, 395 m water depth). These data are integrated with mineralogical analysis and oxygen and carbon stable isotope data from the benthic foraminifera Cibicidoides spp. The age model was constructed based on four radiocarbon dating samples, which covers most part of the Heinrich Stadial 1 (HS1, 17.8–15.7 kyr). From 16.8 kyr to 16 kyr the continental shelf of Santos Basin was characterized by low oxic conditions as revealed by relatively low EBFOI values (1.9-5.3). The mineralogical analysis from the studied core revealed the presence of pyrite during this time interval, which together with geochemical proxy signatures, indicates low oxygenation of bottom-water conditions, with the development of localized anoxic microenvironments within the sediments. Notably, at 15.8 kyr marine oxygenation decreased to suboxic conditions (EBFOI = -20.3). Elevated δ¹⁸O values indicate cold conditions during HS1, likely associated with intensified upwelling, while low δ¹³C values are comparable to those recorded in Eastern Pacific intermediate waters during the same interval. The dominance of low-oxygen tolerant benthic foraminifera suggests reduced bottom-water oxygenation at ~395 m depth, consistent with a shoaling or expansion of the regional OMZ rather than methane seepage. These conditions were likely sustained by poor ventilation during HS1, limiting benthic foraminiferal diversity.Keywords: Benthic Foraminifera Assemblage, Isotope Geochemistry, Oxygen Minimum Zone