Oscar E Romero

Universitat Autònoma de Barcelona

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Gerhard Fischer

University of Bremen

Barbara Donner

University of Bremen

Gerold Wefer

University of Bremen

Dierk Hebbeln

University of Bremen

Juliane Müller

University of Bremen

James E T Channell

University of Florida

Erin L. McClymont

Durham University

Morten Hvitfeldt Iversen

Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung

Johannes Karstensen

GEOMAR Helmholtz Centre for Ocean Research Kiel

Gesine Mollenhauer

Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung

Cooperative Institutions

International Ocean Discovery Program

101

University of Bremen

Centre National de la Recherche Scientifique

Texas A&M University

Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung

Discovery Place

Consejo Superior de Investigaciones Científicas

Utrecht University

Lamont-Doherty Earth Observatory

Columbia University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Variability in Export Production Documented by Downward Fluxes and Species Composition of Marine Planktic Diatoms: Observations from the Tropical and Equatorial Atlantic

Springer eBooks (1999)

Oscar E Romero Carina B. Lange Gerhard Fischer Ute F Treppke Gerold Wefer

Cape verde

Intertropical Convergence Zone

Tropical Atlantic

10.1007/978-3-642-58646-0_14

Cite

Citations (62)

Climate-Ice Sheet Interactions through the Pliocene-Pleistocene: Preliminary Results from IODP Expedition 341 (Gulf of Alaska)

Erin L. McClymont Maria Luisa Sánchez Montes Juliane Müller Christopher M. Moy Oscar E Romero

Since the Pliocene, global climate history is distinguished by the transition into a colder world, dominated by the onset and intensification of major Northern Hemisphere glaciations which have also changed in their duration and intensity. Potential drivers for these events include falling atmospheric CO2, progressive sub-glacial erosion, tectonic uplift, and associated feedbacks. At present, isolating climate as the driver of evolving continental ice volume since the Pliocene is hindered by the limited long term data sets which directly link climate changes to evidence for ice-sheet advance/retreat, erosion, and tectonic evolution over million year timescales. IODP Expedition 341 drilled a cross-margin transect in the Gulf of Alaska from ice-proximal sites on the continental shelf to distal sites in the deep Pacific. This study focuses on the distal site (Site U1417, c.4190 m water depth) which contains variable biogenic and terrigenous contributions, and evidence for deposition through pelagic, mass movement and glacial processes. Our aim is to investigate links between north-east Pacific paleoceanography and the history of the north-west Cordilleran ice sheet, neither of which are fully understood given limited data pre-dating the Last Glacial Maximum. We reconstruct SSTs during the mid-Pliocene, Plio-Pleistocene Transition (PPT) and mid-Pleistocene transition (MPT) using the UK37’ index. We consider the interaction between SSTs and primary production by examining the absolute and relative abundances of plankton biomarkers (e.g. for haptophytes, diatoms and dinoflagellates), carbon/nitrogen ratios, stable isotopes (δ13C, δ15N) and diatom assemblages. Links between these climatic events and the north-west Cordilleran ice-sheet advance/retreat history are initially made using shipboard stratigraphy; emerging data sets on ice-rafting from members of the Expedition 341 Scientific Party will refine these relationships.

paleoceanography

Antarctic ice sheet

Continental Margin

Source

Cite

Citations (0)

Pronounced subsurface cooling of North Atlantic waters off Northwest Africa during Dansgaard–Oeschger interstadials

Earth and Planetary Science Letters (2012)

Jung-Hyun Kim Oscar E Romero Gerrit Lohmann Barbara Donner Thomas Laepple

Stadial

Tropical Atlantic

Forcing (mathematics)

Marine isotope stage

Paleoclimatology

10.1016/j.epsl.2012.05.018

Cite

Citations (102)

Age-depth points used to construct chronology for IODP Site 303-U1308

David A Hodell James E T Channell Jason H. Curtis Oscar E Romero Ursula Röhl

Chronology

10.1594/pangaea.831734

Cite

Citations (0)

A 750-kyr detrital-layer stratigraphy for the North Atlantic (IODP Sites U1302–U1303, Orphan Knoll, Labrador Sea)

Earth and Planetary Science Letters (2011)

James E T Channell David A Hodell Oscar E Romero Claude Hillaire‐Marcel Anne de Vernal

Marine isotope stage

10.1016/j.epsl.2011.11.029

Cite

Citations (132)

Rapid bottom-water circulation changes during the last glacial cycle in the coastal low-latitude NE Atlantic

Quaternary Research (2014)

David Gallego-Torres Oscar E Romero Francisca Martínez‐Ruiz Jung-Hyun Kim Barbara Donner

Abstract Previous paleoceanographic studies along the NW African margin focused on the dynamics of surface and intermediate waters, whereas little attention has been devoted to deep-water masses. Currently, these deep waters consist mainly of North Atlantic Deep Waters as part of the Atlantic Meridional Overturning Circulation (AMOC). However, this configuration was altered during periods of AMOC collapse. We present a high-resolution reconstruction of bottom-water ventilation and current evolution off Mauritania from the last glacial maximum into the early Holocene. Applying redox proxies (Mo, U and Mn) measured on sediments from off Mauritania, we describe changes in deep-water oxygenation and we infer the evolution of deep-water conditions during millennial-scale climate/oceanographic events in the area. The second half of Heinrich Event 1 and the Younger Dryas were recognized as periods of reduced ventilation, coinciding with events of AMOC reduction. We propose that these weakening circulation events induced deficient deep-water oxygenation in the Mauritanian upwelling region, which together with increased productivity promoted reducing conditions and enhanced organic-matter preservation. This is the first time the effect of AMOC collapse in the area is described at high resolution, broadening the knowledge on basin-wide oceanographic changes associated with rapid climate variability during the last deglaciation.

Deglaciation

Circumpolar deep water

Meltwater

paleoceanography

10.1016/j.yqres.2013.11.004

Cite

Citations (12)

Paleoproductivity evolution off central Chile from the Last Glacial Maximum to the Early Holocene

Quaternary Research (2005)

Oscar E Romero Jung-Hyun Kim Dierk Hebbeln

Abstract A geochemical and paleontological reconstruction of paleoproductivity, upwelling intensity and sea surface temperature (SST) off central Chile at 35°S (GeoB3359-3) reveals marked changes from the Last Glacial Maximum (LGM) through the Early Holocene. Surface-water productivity was determined by the interaction between the atmospheric (the Southern Westerlies) and oceanographic (the Antarctic Circumpolar Current, ACC) systems from the LGM through early Termination I (TI). The northward shift of the climate zones during the LGM brought the ACC, as the main macronutrient source, closer to the GeoB3359-3, SST lowered, and surface water productivity and accumulation rates of biogenic components enhanced. With the poleward return of the Southern Westerlies and the ACC, the subtropical high-pressure system became the dominant atmospheric component southward till 35°S during the late TI and Early Holocene and caused surface water productivity to increase through enhanced upwelling.

Westerlies

Last Glacial Maximum

10.1016/j.yqres.2005.07.003

Cite

Citations (46)

High‐latitude forcing of diatom productivity in the southern Agulhas Plateau during the past 350 kyr

Paleoceanography (2015)

Oscar E Romero Ji‐Hoon Kim María Ángeles Bárcena I.R. Hall R. Zahn

Abstract The hydrography of the Indian‐Atlantic Ocean gateway has been connected to high‐latitude climate dynamics by oceanic and atmospheric teleconnections on orbital and suborbital timescales. A wealth of sedimentary records aiming at reconstructing the late Pleistocene paleoceanography around the southern African continent has been devoted to understanding these linkages. Most of the records are, however, clustered close to the southern South African tip, with comparatively less attention devoted to areas under the direct influence of frontal zones of the Southern Ocean/South Atlantic. Here we present data of the composition and concentration of the diatom assemblage together with bulk biogenic content and the alkenone‐based sea surface temperature (SST) variations for the past 350 kyr in the marine sediment core MD02‐2588 (approximately 41°S, 26°E) recovered from the southern Agulhas Plateau. Variations in biosiliceous productivity show a varying degree of coupling with Southern Hemisphere paleoclimate records following a glacial‐interglacial cyclicity. Ecologically well‐constrained groups of diatoms record the glacial‐interglacial changes in water masses dynamics, nutrient availability, and stratification of the upper ocean. The good match between the glacial maxima of total diatoms concentration, Chaetoceros spores abundance, and opal content with the maximum seasonal cover of Antarctic ice and the atmospheric dust records points to a dominant Southern Hemisphere forcing of diatom production. Suborbital variability of SST suggests rapid latitudinal migrations of the Subtropical Front and associated water masses over the southern Agulhas Plateau, following millennial contractions and expansions of the subtropical gyres. Warmings of the upper ocean over site MD02‐2588 during terminations IV to I occurred earlier than that in the Antarctic Vostok, which is indicative of a Northern Hemisphere lead. Our multiparameter reconstruction highlights how high‐latitude atmospheric and hydrographic processes modulated orbital highs and lows in primary production and SST as triggered by northward transport of Si, eolian dust input, and latitudinal migrations of frontal zones.

paleoceanography

Subtropical front

10.1002/2014pa002636

Cite

Citations (29)

Seasonal flux patterns and carbon transport from low oxygen eddies at the Cape Verde Ocean Observatory: lessons learned from a time series sediment trap study (2009–2016)

Gerhard Fischer Oscar E Romero Johannes Karstensen Nasrollah Moradi Morten Hvitfeldt Iversen

Abstract. Mesoscale eddies are abundant in the eastern tropical North Atlantic and can form an oasis for phytoplankton growth due to local enrichment of nutrients in an otherwise oligotrophic ocean. It is not clear, whether these eddies can efficiently transfer organic carbon and other flux components to depth and if they are important for the marine carbon budget. Due to their transient and regionally restricted nature, measurements of eddies’ contribution to bathypelagic particle flux are difficult to obtain. The rare observations of export flux associated with low oxygen eddies have suggested efficient export from the surface to the deep ocean, indicating that organic carbon flux attenuation might be low. Here we report on particle flux dynamics north of the Cape Verde Islands at the oligotrophic Cape Verde Ocean Observatory (CVOO, approx. 17°35’ N/ 24°15’W). This region is a corridor for eddies and low-oxygen eddies regularly passing the position of CVOO between 2009 and 2016, while we collected biogenic and lithogenic particle flux with sediment traps moored at ca. 1 and 3 km water depth. Overall, we observed quite consistent sine-wave flux patterns during the passages of low oxygen eddies in the winters of 2010, 2012 and 2016. We found flux increases in 3 km depth in October-November when the eddies approached CVOO and distinct flux peaks in February–March, clearly exceeding low oligotrophic background fluxes in winter 2011 and showing an enhanced particle flux seasonality. During spring, we observed a stepwise flux decrease leading to summer flux minima. The flux pattern of biogenic silicate (BSi) shows a stronger seasonality compared to organic carbon. Additionally, the deep fluxes of total mass show an unusually higher seasonality compared to the 1 km traps. We assume that BSi and organic carbon/lithogenics had different sources within the eddies. BSi-rich particles may originate at the eddy boundaries where large diatom aggregates are formed due to strong shear, resulting in gravitational settling and, additionally, in an active local downward transport. Organic carbon associated with the lithogenic material is assumed to originate from the interior of eddies or from mixed sources both constituting smaller, dust-ballasted particles. Our findings suggest that the regularly passing low-oxygen Anticyclonic Modewater Eddies (ACME) at CVOO repeatedly release characteristic flux signals to the bathypelagic in the winter-spring season far above the oligotrophic background fluxes and sequester higher organic carbon than expected for oligotrophic settings. However, the reasons for a lower carbon flux attenuation below ACMEs remain elusive.

Sediment trap

Eddy

Cape verde

10.5194/bg-2021-114

Cite

Citations (0)

International ocean discovery program expedition 353 preliminary report Indian Monsoon Rainfall

Steven C. Clemens Wolfgang Kuhnt Leah J. LeVay Pallavi Anand Takuto Ando

Source

Cite

Citations (6)