South American Hydrological Balance and Paleoceanography during the Late Pleistocene and Holocene (SAMBA) - Cruise No. M125 - March 21 - April 15, 2016 - Rio de Janeiro (Brazil) - Fortaleza (Brazil)

Bahr, André; Albuquerque, Ana Luíza Spadano; Ardenghi, N.; Batenburg, Sietske J.; Bayer, María Sol; Catunda, Maria Carolina Amorim; Conforti, A; Dias, Bruna Borba; Ramos, Roman; Egger, Lisa M.; Evers, Florian; Fischer, Thilo C.; Hatsukano, K.; Hennrich, Barbara; Hoffmann, J. Elis; Jivcov, Sandra; Kusch, Stephanie; Munz, Philipp; Niedermeyer, Eva M; Osborne, Anne H; Raddatz, Jacek; Raeke, Andreas; Reißig, Stefan; Sebastian, U.; Taniguchi, Nancy Kazumi; Venancio, Igor Martins

doi:10.2312/cr_m125

Cited by 6 publications

(20 citation statements)

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“…Gravity core M125-35-3 was retrieved from the upper continental slope (21°53.606'S, 040°00.279'W, 428.6 m water depth), ~100 km off the Paraıba do Sul River mouth in SE Brazil during R/V Meteor cruise M125 in 2016 (Bahr et al, 2016). A total of 4.25 m of sediment was recovered.…”

Section: Methodsmentioning

confidence: 99%

Coupled Oceanic and Atmospheric Controls of Deglacial Southeastern South America Precipitation and Western South Atlantic Productivity

Jaeschke¹,

Rethemeyer²,

Chiessi³

et al. 2022

Front. Mar. Sci.

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Various mechanisms were proposed as substantial drivers of (sub)tropical South American hydroclimate changes during the last deglaciation. However, the interpretation of past precipitation records from the regions affected by the South American Summer Monsoon, the dominant hydroclimatic system in (sub)tropical South America, still insufficiently consider feedbacks between oceanic and atmospheric processes evident in modern observational data. Here, we evaluate ocean-atmosphere feedbacks active in the region from 19 to 4 ka based on a multi-proxy record comprising lipid biomarker, bulk sediment elemental composition and foraminiferal geochemistry from a sediment core retrieved from the tropical western South Atlantic offshore eastern Brazil at ~22°S. Our proxy data together with existing paleoclimate records show that the consideration of large scale synoptic climatic features across South America is crucial for understanding the past spatio-temporal rainfall variability, especially during the last deglaciation. While the paleohydrological data from our study site show relatively stable precipitation across the deglaciation in the core region of the South Atlantic Convergence Zone, distinct hydroclimatic gradients developed across the continent during Heinrich Stadial 1, which climaxed at ~16 ka. By then, the prevalent atmospheric and oceanic configuration caused more frequent extreme climatic events associated with positive rainfall in the northern portion of eastern South America and in the southeastern portion of the continent. These climatic extremes resulted from substantial warming of the sub(tropical) western South Atlantic sea surface that fostered oceanic moisture transport towards the continent and the reconfiguration of quasi-stationary atmospheric patterns. We further find that enhanced continental precipitation in combination with low glacial sea level strongly impacted marine ecosystems via enhanced terrigenous organic matter input in line with augmented nutrient release to the ocean. Extreme rainfall events similar to those that occurred during Heinrich Stadial 1 are likely to recur in South America as a consequence of global warming, because the projected reduction of the intra-hemispheric temperature gradient may lead to the development of atmospheric patterns similar to those in force during Heinrich Stadial 1.

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Section: Methodsmentioning

confidence: 99%

Coupled Oceanic and Atmospheric Controls of Deglacial Southeastern South America Precipitation and Western South Atlantic Productivity

Jaeschke¹,

Rethemeyer²,

Chiessi³

et al. 2022

Front. Mar. Sci.

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“…The north-eastern part stretches from Cabo Sao Roque to Belmonte and includes the Brazil Basin (5-16°S; Figure 1; Martins and Coutinho, 1981;da Silveira et al, 2020). Reduced continental erosion and low marine sedimentation rates result in a very narrow continental shelf (Figures 2A, B) less than 10 km in width (Summerhayes et al, 1976;Knoppers et al, 1999;Bahr et al, 2016). Extensive canyon systems are common and determine seafloor topography along the continental slope (Bahr et al, 2016).…”

Section: Study Areamentioning

confidence: 99%

“…Reduced continental erosion and low marine sedimentation rates result in a very narrow continental shelf (Figures 2A, B) less than 10 km in width (Summerhayes et al, 1976;Knoppers et al, 1999;Bahr et al, 2016). Extensive canyon systems are common and determine seafloor topography along the continental slope (Bahr et al, 2016). Further south (16-23°S), the east coast extends to Cabo Frio including the Campos Basin.…”

Section: Study Areamentioning

confidence: 99%

“…The shelf area is considerably wider compared to the north and may reach a width of up to 90 km (Figure 2C; Martins and Coutinho, 1981;Knoppers et al, 1999). The upper slope is characterized by bottom current-induced and contour-parallel erosional ridges (Viana et al, 2002;Bahr et al, 2016). Contouritic deposits shaped by bottom currents characterize the middle and lower slope of the Campos Basin (Viana, 2001).…”

Section: Study Areamentioning

confidence: 99%

“…During R/V METEOR expedition M125, the Brazilian continental shelf and slope were sampled between 10°S and 23°S (Bahr et al, 2016), offering a unique opportunity to document benthic foraminiferal distribution patterns north of 20°S. Here we investigate recent benthic foraminiferal assemblages from three bathymetric transects in the Brazil (11°S, 14°S) and Campos (22°S) basins.…”

Section: Introductionmentioning

confidence: 99%

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Controlling Parameters of Benthic Deep-Sea Foraminiferal Biogeography at the Brazilian Continental Margin (11-22°S)

et al. 2022

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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.

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Insolation and Greenhouse Gas Forcing of the South American Monsoon System Across Three Glacial‐Interglacial Cycles

Hou

Bahr

Raddatz

et al. 2020

Geophysical Research Letters

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Precipitation extremes with devastating socioeconomic consequences within the South American Monsoon System (SAMS) are expected to become more frequent in the near future. The complexity in SAMS behavior, however, poses severe challenges for reliable future projections. Thus, robust paleomonsoon records are needed to constrain the high spatiotemporal variability in the response of SAMS rainfall to different climatic drivers. This study uses Ti/Ca ratios from X‐ray fluorescence scanning of a sediment core retrieved off eastern Brazilian to trace precipitation changes over the past 322 Kyr. The results indicate that despite the spatiotemporal complexity of the SAMS, insolation forcing is the primary pacemaker of variations in the monsoonal system. Additional modulation by atmospheric pCO2 suggests that SAMS intensity over eastern Brazil will be suppressed by rising CO2 emissions in the future. Lastly, our record reveals an unprecedented strong and persistent wet period during Marine Isotope Stage 6 driven by anomalously strong trade winds.

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South American Hydrological Balance and Paleoceanography during the Late Pleistocene and Holocene (SAMBA) - Cruise No. M125 - March 21 - April 15, 2016 - Rio de Janeiro (Brazil) - Fortaleza (Brazil)

Cited by 6 publications

References 0 publications

Coupled Oceanic and Atmospheric Controls of Deglacial Southeastern South America Precipitation and Western South Atlantic Productivity

Coupled Oceanic and Atmospheric Controls of Deglacial Southeastern South America Precipitation and Western South Atlantic Productivity

Controlling Parameters of Benthic Deep-Sea Foraminiferal Biogeography at the Brazilian Continental Margin (11-22°S)

Insolation and Greenhouse Gas Forcing of the South American Monsoon System Across Three Glacial‐Interglacial Cycles

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