ABSTRACT The biodiversity of sponges in environments beyond 50 m is poorly known, as access to this type of environment without specialized technology is difficult. This study aims to understand the biodiversity of the group present on the continental shelf of the south-western area of Isla Fuerte and Alta Guajira. Sponge samples were collected via trawls during exploration sessions in hydrocarbon blocks between 73 and 210 m, which were fixed and taken to the sponge collection of the Museum of Marine Natural History of Colombia (MHNMC, Makuriwa) in 2012. Then, in 2022, these samples were processed and identified in the laboratory using standard methods. A taxonomic list is presented, with 89 taxa belonging to the classes Demospongiae and Homoscleromorpha, which are grouped in 16 orders, 33 families, 51 genera, and 45 species, out of which 10 are new records for the Colombian Caribbean. Only one species was identified for Alta Guajira, which could be attributed to a difference in substrate composition and to the fact that, in the Isla Fuerte sector, due to diapirism and gas emanation events in the continental shelf, there is a greater availability of food, which can support the composition of sessile benthic organisms such as sponges.

RESUMEN La biodiversidad de esponjas en ambientes más allá de los 50 m es poco conocida, ya que el acceso a este tipo de ambientes es difícil si no se cuenta con tecnología especializada. Este estudio pretende conocer la biodiversidad del grupo presente sobre la plataforma continental del área suroccidental de isla Fuerte y alta Guajira. Se recolectaron muestras de esponjas mediante redes de arrastre durante jornadas de exploración de bloques de hidrocarburos entre los 73 y 210 m, las cuales fueron fijadas y llevadas a la colección de esponjas del Museo de Historia Natural Marina de Colombia (MHNMC, Makuriwa) en 2012. Luego, en 2022, estas se procesaron e identificaron en laboratorio empleando métodos estándar. Se presenta un listado taxonómico con 89 taxa pertenecientes a las clases Demospongiae y Homoscleromorpha, agrupados en 16 órdenes, 33 familias, 51 géneros y 45 especies, de las cuales 10 son nuevos registros para el Caribe colombiano. Se identificó una sola especie para la alta Guajira, lo que podría atribuirse a una diferencia en la composición de sustrato y a que, en el sector de isla Fuerte, por eventos de diapirísmo y emanación de gases de la plataforma continental, hay una mayor disponibilidad de alimento, lo que puede solventar la composición de organismos bentónicos sésiles como las esponjas.

Resumen El objetivo del presente estudio fue caracterizar los cambios estacionales en la composición y abundancia del microfitoplancton en la plataforma continental de Bahía, una región con presencia de eventos de surgencia. Se realizaron muestreos semestrales durante los veranos e inviernos de 2017 a 2021 en nueve puntos. El microfitoplancton se muestreó utilizando una red cónica de plancton en arrastres horizontales debajo de la superficie, utilizando un medidor de corriente acoplado a la red, para medir el volumen total de agua filtrada. La temperatura y la salinidad fueron medidas in situ, presentando valores típicos de aguas tropicales. Además, las concentraciones de nutrientes inorgánicos disueltos corroboraron el patrón oligotrófico marino tropical. Se identificaron un total de 144 taxones en la región, siendo los phyla Heterokontophyta y Dinoflagellata los más representativos, como se registra típicamente en las regiones costeras tropicales. La densidad varió de 6,08 × 104 a 3,38 × 108 células L-1, con valores promedio más altos en verano. Aunque las cianobacterias representaron solo el 3,2% de la riqueza de especies en la región, debido a las floraciones de verano de Trichodesmium erythraeum (2018, 2019 y 2021), fue el grupo más abundante a lo largo del estudio. Se observó que los eventos de surgencia no parecen establecer condiciones favorables para cambios estacionales marcados en la composición y abundancia del microfitoplancton. Las floraciones de Trichodesmium erythraeum están estrechamente relacionadas con la fisiología y la capacidad ecológica de esta especie. Con excepción de los períodos de floración, el área de estudio presentó patrones de alta riqueza y diversidad de especies a lo largo de la serie temporal analizada.

Abstract This study aimed to characterize seasonal changes in microphytoplankton composition and abundance on Bahia continental shelf, a region with upwelling events. Semi-annual sampling was conducted during summer and winter from 2017 to 2021 at nine points. Microphytoplankton was sampled using a conical plankton net through horizontal subsurface drags, using a flowmeter coupled to the net, to measure the total volume of filtered water. Temperature and salinity were measured in situ, presenting typical values of tropical waters. In addition, dissolved inorganic nutrient concentration corroborated a tropical marine oligotrophic pattern. A total of 144 taxa were identified in the region, with the phyla Heterokontophyta and Dinoflagellata being the most representative, as is typically recorded in tropical coastal regions. The density ranged from 6.08 × 104 to 3.38 × 108 cells L-1, with higher average values in summer. Although cyanobacteria accounted for only 3.2% of species richness in the region, due to summer blooms of Trichodesmium erythraeum (2018, 2019, and 2021), it was the most abundant group throughout the study. It was observed that upwelling events do not seem to establish favorable conditions for marked seasonal changes in microphytoplankton composition and abundance. Trichodesmium erythraeum blooms are closely related to physiology and ecological capacity of this species. Except for bloom periods, the study area presented a high species richness and diversity throughout the analyzed time series.

Abstract Formed during marine regression periods, shelf valleys (SVs) are preterit river flows on the exposed continental shelf. This study investigates the influence of tectonic activity on forming these important morphological features. This research combines bathymetric, magnetometry, and seismic data to analyze the role of tectonic events in SV genesis and positioning. The bathymetric dataset provides information on SV locations and geometries along the continental shelf, whereas the 2D seismic sections illustrate that SVs formed above post-rift faults that reached Quaternary deposits. Aeromagnetic data indicates that the shallow and deep structures of the basement and sedimentary column-controlled SV locations and evolution. The multi-data integration demonstrates a strong correlation between neotectonic structures and SV location and geometries from the inner shelf (−25 m) to the shelf break (−55 m). The analysis of the 2D seismic data indicated that high-angle faults, formed under a strike-slip tectonic regime, primarily affected the Middle Miocene deposits beneath the shelf valleys. The formation of “negative flower pattern structures” was identified as a primary structural mechanism that contributed to SV formation. Reactivation events that occurred from the Late Cretaceous onwards, gave rise to these faults, which control SV formation and the capture of preterit drainage on the exposed continental shelf. The SV geometries display straight patterns and abrupt changes in direction (90°) due to the interplay of the NE-SW and NW-SE aligned faults. The results reinforce the importance of considering tectonic activity in the formation and evolution of shelf valleys. periods (SVs features magnetometry positioning D postrift post rift columncontrolled column controlled multidata multi −25 25 (−2 m −55 55 (−5 m. . highangle high angle strikeslip strike slip regime negative onwards 90° 90 (90° NESW NE SW NWSE NW SE −2 2 (− −5 5 9 (90 − ( (9

ABSTRACT This study encompasses the description and evaluation of the length-weight relationship of 104 demersal fish species caught by bottom trawlers targeting shrimps on the southeast continental shelf of Brazil from 2004 to 2006. The regression criteria describing the length-weight relationship for each species were classified as approved (met the criteria), approved with reservations (partially met the criteria), and not approved (did not meet the criteria) based on linear regression parameters to determine whether length is a viable predictor of weight. A total of 141,433 individual fish, comprising 44 families and 104 species, were sampled; the beta parameter (± se) varied from 0.22 ± 0.12 to 3.94 ± 0.19, and the alpha parameter varied from -4.09 ± 0.04 to 0.89 ± 0.02. In total, 22 species were not identified by a recent large survey (2019) conducted in the study area. The results of this study are significant for the management of fishery resources, mainly due to the occurrence of unusual species, the economic importance and enormous effort exerted by the trawling fleet in the region, and the substantial sample size, in which a large number of individuals per species were caught. lengthweight weight 10 200 2006 criteria, , partially did 141433 141 433 141,43 4 sampled ( se 022 0 0.2 012 12 0.1 394 3 94 3.9 019 19 0.19 4.09 409 09 -4.0 004 04 0.0 089 89 0.8 002 02 0.02 2 2019 (2019 area resources region size 1 20 14143 14 43 141,4 0. 01 39 9 3. 4.0 40 -4. 00 08 8 201 (201 1414 141, 4. -4 (20 - (2

Abstract Sound speed profiles in the ocean are determined by seawater properties, where horizontal variability of thermal stratification modulates sonar detection distance. This work assesses the impacts of upwelling dynamics on sound speed profile in enclosed coastal areas by means of temperature observations acquired with a low-cost platform in Anjos Cove, Cabo Frio, Brazil. The Integrated Acquisition System for Research in Acoustics (IARA) consists of a customized 10-meter-long chain of smart temperature sensors (±0.1°C accuracy) mounted in an anchored vertical cable and an echo sounder for tide level measurements. From 2021 to 2023 a number of intrusion events of the cold South Atlantic Central Water (SACW) took place along the Cabo Frio continental shelf, some of which were recorded in the inner region of the Anjos Cove by IARA. Sound speed profiles computed by applying TEOS-10 standards indicate that the sound propagation within Anjos Cove varies often, i.e., several orders of magnitude, under the influence of SACW intrusion events. The phenomenon reflects information from deeper waters on a coastal scale, even at small depths. properties distance lowcost low cost Brazil IARA (IARA 10meterlong meterlong 10 meter long ±0.1°C 01C C 0 1 accuracy measurements 202 (SACW shelf TEOS10 TEOS TEOS-1 often ie i e i.e. magnitude scale depths 20 TEOS1 TEOS- i.e 2

Abstract Bioseston is a heterogeneous assemblage of bacterioplankton, phytoplankton, zooplankton, and planktonic debris. A detailed knowledge of biosestons is essential for understanding the dynamics of trophic flows in marine ecosystems. The distributional features of seston biomass in plankton (micro- and mesoplankton) in the Southwest Atlantic Ocean (Rio de Janeiro State, Brazil) were analyzed using stratified samples gathered to a depth of 2,400 m during night time. The horizontal pattern of biomass distribution was analyzed vis-a-vis station depth during both wet and dry periods, with higher values recorded in the continental shelf than in the slope, confirming the terrestrial contribution of nutrient sources to the marine environment. This horizontal variation reinforces the occurrence of seasonal vortices in Cabo Frio and Cabo de São Tomé on the central coast of Brazil. Environmental variables reflect the hydrological signatures of the water masses along the Brazilian coast. The largest seston biomass was related to high temperatures, salinities, and low inorganic nutrient concentrations in tropical and South Atlantic central waters. The observed distribution patterns suggest that seston biomass in plankton in the region may be structured based on partitioned horizontal and vertical habitats and food resources. bacterioplankton phytoplankton zooplankton debris ecosystems micro (micro mesoplankton Rio State Brazil 2400 2 400 2,40 time visavis vis periods slope environment temperatures salinities waters resources 240 40 2,4 24 4 2,

ABSTRACT Functional traits, short life cycles, and the pivotal role in the ocean make copepod diversity a solid foundation for assessing the effect of global changes in marine food webs and ecosystem functioning. Climate change and extreme events, particularly El Niño, can affect coastal ecosystems. The Arvoredo Marine Biological Reserve (MPA), located in highly productive coastal waters of the Southern Brazilian Bight, presents complex climate and oceanographic conditions. This study investigates the influence of oceanographic processes and El Niño 2015-2016 on the copepod functional diversity from 2014 to 2016 in the Arvoredo MPA. Horizontal tows were performed using a WP2 net with a mesh size of 200 µm. The 41 species accounted for 19 functional entities and four functional groups. Our findings reveal that the seasonal intrusion of water masses influenced copepod functional diversity. During summer, the upwelling of South Atlantic Central Water increased nutrient availability and favored large herbivore-omnivores and carnivores. The Plata Plume Water enrichment during winter coincided with a decline in functional richness and abundance, leading to the predominance of the Oithona nana, a small-sized omnivore. Compensatory mechanisms were observed as functional equivalence and species composition shifts. Acartia lilljeborgii and Temora turbinata exhibited functional equivalence and compensated for each other in response to salinity changes associated with upwelling and El Niño. The copepod assemblage demonstrated the ability to maintain functional diversity despite changes in copepod abundance. However, the decline in functional diversity and abundance during the intense winter indicated potential disruption in trophic dynamics and ecosystem functioning. Maintaining balance and compensating for disturbances such as El Niño is crucial for marine food web resilience. The functional trait approach provided a comprehensive understanding of the copepod assemblage in Arvoredo MPA, contributing to a broader knowledge of the impact of oceanographic processes intensification. Monitoring functional diversity and abundance is crucial for evaluating the effects of copepod assemblage changes in ecosystem functionings. traits cycles functioning events ecosystems MPA , (MPA) Bight conditions 20152016 2015 2015-201 201 WP 20 µm 4 1 groups summer herbivoreomnivores herbivore omnivores carnivores nana smallsized small sized omnivore shifts However resilience intensification functionings (MPA 2015201 2015-20 2 201520 2015-2 20152 2015-

Resumo: Corais invasores do gênero Tubastraea apresentam maturidade precoce, rápido crescimento e plasticidade em relação ao substrato que utilizam, o que permitiu ao gênero obter rapidamente sucesso e expandir sua distribuição não nativa. Para o estado de Sergipe existem 23 registros de Tubastraea spp. na zona offshore; aqui relatamos os primeiros registros do coral-sol T. coccinea na costa da zona estuarina do rio Vaza-Barris, expandindo sua área de invasão offshore para o onshore. Plataformas petrolíferas, navios e naufrágios contaminados podem ter fornecido o caminho como vetores, agindo como trampolins que ligam as regiões oceânicas à costa. A dispersão também pode ocorrer através de correntes responsáveis pelo transporte de organismos da plataforma continental para a costa, embora isto pareça menos provável. Assim, reforçamos a importância do monitoramento constante dos vetores e da costa para minimizar os efeitos adversos dos corais invasores sobre a fauna nativa. Resumo precoce utilizam nativa 2 spp coralsol coral sol T VazaBarris, VazaBarris Vaza Barris, Barris Vaza-Barris onshore petrolíferas provável Assim

Abstract: Invasive corals of the genus Tubastraea exhibit early maturity, rapid growth, and plasticity regarding the substrate they use, which has enabled the genus to quickly become successful and expand its non-native range. For the state of Sergipe there are 23 records of Tubastraea spp. on oil platforms; here we report the first records of the sun coral T. coccinea on the coast in the estuarine zone of the Vaza-Barris River, expanding its invasive range from offshore to onshore. Contaminated oil platforms, vessels, and shipwrecks may have provided a pathway as vectors, acting as stepping stones that connect oceanic regions to the coast. Dispersal may also occur through currents responsible for transporting organisms from the continental shelf to the coast, although this seems unlikely. Thus, we reinforce the importance of constant monitoring of vectors and the coast to minimize the adverse effects of invasive corals on native fauna. Abstract maturity growth use nonnative non 2 spp platforms T VazaBarris Vaza Barris River onshore vessels unlikely Thus fauna

Abstract Aberrantidae is a small group of polychaetes morphologically homogenous and rarely collected. Adult individuals usually have a few millimeters and about 40 chaetigers. Living specimens are transparent, yellowish-brown with a dark alimentary channel and have reddish eyes. The few records of Aberranta , the only described genus in the family, are from mud, sand, sandy-mud, and coarse sand, from four to 3,250 m. All known species have been recorded from the eastern USA, Mediterranean, and China. The examined material is from three projects coordinated by CENPES/Petrobras, the Brazilian oil company. Samples were collected from continental shelf, canyons, and slope depths. Polychaetes and others benthic organisms were sieved from the sediment, fixed in a 4% formalin solution, conserved in 70% alcohol, and then identified. The sampling was carried out from 25 to 3000 m depth, but individuals were collected from 383 to 1312 m. The new species, Aberranta magnunlanai sp. nov., is characterized by the absence of eyes, branchiae from chaetiger 3, and by having three types of neurochaetae: a) thick and smooth capillaries, b) capillary of intermediary length and with long marginal serration, and c) lyriform chaetae with spinose shaft and distal projections of same length. This is the first record of the genus in the southern hemisphere. 4 chaetigers transparent yellowishbrown yellowish brown eyes family mud sand sandymud, sandymud sandy sandy-mud 3250 3 250 3,25 USA Mediterranean China CENPESPetrobras CENPES Petrobras CENPES/Petrobras company shelf canyons depths sediment solution 70 alcohol identified 2 300 depth 38 131 sp nov nov. neurochaetae capillaries b serration c hemisphere 325 3,2 7 30 13 32 1

RESUMO Este estudo apresenta uma avaliação inicial das características hidrográficas na região do Cânion do Rio Japaratuba, este cânion fica na plataforma continental de Sergipe, Brasil. Foi realizado uma campanha oceanográfica, durante a campanha oceanográfica foram realizados dois transectos de alta resolução espacial nos lados norte e sul do cânion, juntamente com um transecto transversal. Os resultados indicam que as características hidrográficas são semelhantes às encontradas na plataforma continental de Pernambuco, com a massa de água dominante sendo a Água Tropical. No entanto, difere por ter apresentado uma influência maior da Água Costeira, resultado da dispersão da pluma do Rio São Francisco e de pequenos Rios que desaguam na porção norte da plataforma continental do estado de Sergipe, em direção sul. A turbidez e a clorofila próximo ao fundo, foram relativamente mais altas na seção sul, o que pode ser uma indicação de que a presença do cânion pode produzir um efeito de ressurgência localizado, desempenhando um papel no soerguimento da água do topo da termoclina permanente, para uma região mais próxima da costa. Japaratuba Sergipe Brasil transversal Pernambuco Tropical entanto Costeira fundo localizado permanente costa

ABSTRACT This study presents an initial assessment of the hydrographic characteristics in the region of the Japaratuba Canyon on the continental shelf of Sergipe, Brazil. An oceanographic campaign was conducted, during which two high spatial resolution transects were made on the north and south sides of the canyon, along with a transverse transect. The results indicate that the hydrographic features are similar to those found on the continental shelf of Pernambuco, with the dominant water mass being Tropical Water. However, it differs in having a much greater influence from Coastal Water, as a result of the dispersion of the São Francisco River plume to the south and from small rivers that discharge into the northern portion of the continental shelf of the state of Sergipe. The near bottom turbidity and chlorophyll were relatively higher in the southern section, what can be an indication that the presence of the canyon can produce a localized upwelling effect, with the canyon playing a role in allowing the approach of water from the top of the nearest permanent thermocline to the coast. Sergipe Brazil conducted transect Pernambuco Water However section effect coast

ABSTRACT Quarterly collections of demersal fish were conducted between 2014 and 2018 on the adjacent continental shelf and in the Paranaguá Estuarine Complex (PEC). Univariate and multivariate statistical analyses were used to determine the abundance, richness, and composition of demersal fish assemblages and to list predictor variables responsible for the variability in these ecological descriptors by applying generalized linear models. The collected specimens of demersal fish (n = 25,179) were distributed across 19 orders, 31 families, and 72 species. Fish richness was explained by the following predictor variables: the percentage of fine sand in the sediment, the richness of the benthic megafauna, and sampling sites. The abundance was associated with the predictor variables of the percentage of very fine sand in the sediment, percentage of silt in the sediment, salinity, and sampling sites. Canonical correspondence analysis showed that the fish assemblage composition was strongly associated with the salinity gradient and positively correlated with benthic megafaunal species richness. As it is one of the last remnants of the Atlantic Forest, declared by UNESCO as a Natural Heritage of Humanity, the patterns observed in this study will support PEC's coastal management of current developmental demands, particularly related to port activities.

Abstract The extensive coverage of 3-D seismic data on the Santos Basin deep water offered an integrated vision of the local physiography and medium- to small-scale geomorphological features, which enhances the understanding of its constructive/deconstructive natural processes and their interrelations. The Santos Basin is a divergent marginal basin composed of three main physiographic provinces: its continental shelf, continental slope, and the São Paulo Plateau, whose dimensions, orientation, gradients, and relief interact with oceanographic, biological, and geological processes. This study geologically contextualized environmental data related to the Regional Environmental Characterization Project of the Santos Basin (hereinafter referred to as PCR-BS), especially regarding the regional physiographical architecture and deep-water geomorphological provinces as a background for the benthic communities and the distribution of several of its geochemical parameters. The integrated analysis of 3-D seismic and multibeam bathymetric data and its derivatives (gradient and edge maps) — calibrated by 108 piston cores — aimed to evaluate its seafloor physiographic features and geological processes. Edge detection seismic attributes enhance gradient contrast, which, in turn, can map innumerous medium- to small-scale geomorphic features (features solved in maps at a 1:1,000,000 scale or larger), such as canyons, channels, ravines, pockmark units, pockmark fields, lineaments, carbonate and coral mounds, salt-related features (crests, minibasins, and crestal grabens), scars and rugous relief associated with mass-transport deposits, and bottom current-related features (depressions and furrows). The slope and the gently dipping plateau (São Paulo Plateau) that follow it eastward show four geomorphological domains based on their direction, profile, average gradient, shelf break isobath, distribution of its medium-small scale geomorphic features, and the presence or absence of evaporites at subsurface. The central-northern São Paulo Plateau contains salt-related topographic elevations (salt diapirs and walls) and depressions (minibasins) that give a rough aspect to the seafloor relief. 3D D 3 medium smallscale small constructivedeconstructive constructive deconstructive interrelations dimensions orientation gradients oceanographic biological hereinafter PCRBS, PCRBS PCR BS , PCR-BS) deepwater parameters 10 contrast turn 11,000,000 11000000 1 1,000,000 000 1:1,000,00 larger, larger larger) canyons channels ravines units fields lineaments mounds saltrelated salt crests, crests (crests minibasins grabens, grabens grabens) masstransport mass transport deposits currentrelated current furrows. furrows . furrows) direction profile isobath mediumsmall subsurface centralnorthern central northern walls (minibasins PCR-BS 11 11,000,00 1100000 1000000 1,000,00 00 1:1,000,0 11,000,0 110000 100000 1,000,0 0 1:1,000, 11,000, 11000 10000 1,000, 1:1,000 11,000 1100 1000 1,000 1:1,00 11,00 110 100 1,00 1:1,0 11,0 1,0 1:1, 11, 1, 1:1 1:

Abstract This study evaluated the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in Santos Bay (SB) and the adjacent Santos Continental Shelf (SCS) in Brazil. Biliary metabolites were measured in several fish species to establish a baseline for future monitoring programs. Bile samples from different species of fish were collected monthly from July to December 2005 in SB, and in August 2005 and February 2006 on SCS. Metabolite concentrations were determined using high-performance liquid chromatography with fluorescence detectors. Naphthalene, phenanthrene, and benzo[a]pyrene metabolite concentrations ranged from 24 to 810 µg g -1 of bile, 1.8 to 68 µg g -1 of bile, and below the limit of quantitation to 1.3 µg g -1 of bile, respectively. Despite its high concentrations, the levels of naphthalene metabolites were in regions of low-contamination, while benzo[a]pyrene metabolite were in the same range as those reported in moderately contaminated areas, which may indicate pyrolytic contamination by PAHs. No significant differences in the metabolite concentrations were found between the SB and the SCS samples or during the periods of collection. Future studies with a single biomonitoring species should be conducted, considering age, sex, and feeding condition of the individuals. The metabolite data presented in this study is an important baseline information for this urbanized region, which hosts several sources of contaminants. PAHs (PAHs (SB (SCS Brazil programs 200 highperformance performance detectors Naphthalene phenanthrene benzoapyrene benzo pyrene 2 81 1 - bile 18 8 1. 6 13 3 respectively lowcontamination, lowcontamination low contamination, low-contamination areas collection conducted age sex individuals region contaminants 20

Abstract Santonian-Campanian tuffaceous siltstone, epiclastic siltstone, arkose, and fossiliferous mudstone occur in a 45-m-thick section of well 1-BRSA-37-RJS drilled in the southern Campos Basin, offshore SE Brazil. Well log data and petrographic and lithogeochemical data obtained from cutting samples were used to propose a schematic model of the volcano's sedimentary paleoenvironment. The volcaniclasts in the tuffaceous siltstone and epiclastic siltstone are scoria basalts, typical of spatter cones associated with monogenetic fields worldwide. The combination of these features with the petrographic ones of the arkoses found in the same well interval is likely to be related to volcaniclastic processes taking place on the continental shelf. Ratios between the immobile trace elements of the volcaniclastic rocks can be explained by mixing between sources in the upper continental crust adjacent to southern Campos and the scoria basalts extruded in the monogenetic fields. The little differentiated, olivine-rich basalts extruded from the scoria and spatter cones suggest a rising asthenosphere mantle extending from hundreds of kilometers eastwards till southern Campos in the Santonian-Campanian. This may have resulted in regional discordances in the Santonian, both in the Campos and Santos basins, and also places the petroleum systems in the southern Campos Basin under the thermal influence of such a rising asthenosphere in the Santonian-Campanian. SantonianCampanian Santonian Campanian arkose 45mthick mthick 45 m thick 1BRSA37RJS BRSARJS 1 BRSA 37 RJS Brazil volcanos volcano s paleoenvironment worldwide shelf differentiated olivinerich olivine rich SantonianCampanian. Campanian. basins 4 3

ABSTRACT The ocean bottom morphology, depth, sediment grain size, sediment sorting, carbonate content, and water depth are used to compose seafloor maps as support for biological studies. Sediments are reworked by waves and currents and accumulate according to the hydrodynamic level on the continental shelf. In contrast, sediments are accumulated by pelagic settling, mass wasting, turbidity flows, and boundary currents on the slope. Sea level oscillations during the Quaternary also played an important role in modifying the shelf seabed's morphology and sedimentary mosaic composition. The work addresses these topics in the Santos Basin based on extensive bathymetric data, shallow seismic records, and stratified bottom sediment samples in water depths ranging from 25 to 2,400m, as part of The Santos Basin Regional Environmental Characterization Project (PCR-BS). The main objective is to provide broad background information on the sedimentology and morphology of Santos Basin, focusing on the continental shelf. The morphology, sediment supply, shelf orientation, and ocean climate imprint the Santos Basin's characteristics. The Northern shelf sector is the most dynamic because of the narrow shelf, steep gradient, and East-West shoreline orientation, providing conditions for storm waves to approach and mobilize sediment in the ocean bottom shallow than 50 m water depth. The Southern sector of the shelf is much broader than the Northern sector; it displays a gentler gradient, and its orientation is Northeast-Southwest; therefore, less subject to storm waves than the Northern sector. size sorting content studies contrast settling wasting flows slope seabeds seabed s composition data records 2 2400m 400m 2,400m PCRBS. PCRBS PCR BS . (PCR-BS) supply Basins characteristics gradient EastWest East West 5 NortheastSouthwest Northeast Southwest Northeast-Southwest therefore (PCR-BS