scholarly journals Cross-slope variations of dissolved organic carbon in the Gulf of Cadiz, NE Atlantic Ocean (February 1998)

1999 ◽  
Vol 189 ◽  
pp. 301-306 ◽  
Author(s):  
EV Dafner ◽  
R Sempéré ◽  
N González ◽  
F Gomez ◽  
M Goutx
Keyword(s):  
Organic Carbon ◽  
Atlantic Ocean ◽  
Dissolved Organic Carbon ◽  
Gulf Of Cadiz ◽  
Ne Atlantic ◽  
Gulf Of Cádiz ◽  
Ne Atlantic Ocean

scholarly journals The Interactive Role of Hydrocarbon Seeps, Hydrothermal Vents and Intermediate Antarctic/Mediterranean Water Masses on the Distribution of Some Vulnerable Deep-Sea Habitats in Mid Latitude NE Atlantic Ocean

Oceans ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 351-385
Author(s):  
Luis Somoza ◽  
José L. Rueda ◽  
Olga Sánchez-Guillamón ◽  
Teresa Medialdea ◽  
Blanca Rincón-Tomás ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Deep Sea ◽  
Hydrothermal Vents ◽  
Water Masses ◽  
Gulf Of Cadiz ◽  
Ne Atlantic ◽  
Hydrocarbon Seeps ◽  
Gulf Of Cádiz ◽  
Ne Atlantic Ocean ◽  
Deep Sea Corals

In this work, we integrate five case studies harboring vulnerable deep-sea benthic habitats in different geological settings from mid latitude NE Atlantic Ocean (24–42° N). Data and images of specific deep-sea habitats were acquired with Remoted Operated Vehicle (ROV) sensors (temperature, salinity, potential density, O2, CO2, and CH4). Besides documenting some key vulnerable deep-sea habitats, this study shows that the distribution of some deep-sea coral aggregations (including scleractinians, gorgonians, and antipatharians), deep-sea sponge aggregations and other deep-sea habitats are influenced by water masses’ properties. Our data support that the distribution of scleractinian reefs and aggregations of other deep-sea corals, from subtropical to north Atlantic could be dependent of the latitudinal extents of the Antarctic Intermediate Waters (AAIW) and the Mediterranean Outflow Waters (MOW). Otherwise, the distribution of some vulnerable deep-sea habitats is influenced, at the local scale, by active hydrocarbon seeps (Gulf of Cádiz) and hydrothermal vents (El Hierro, Canary Island). The co-occurrence of deep-sea corals and chemosynthesis-based communities has been identified in methane seeps of the Gulf of Cádiz. Extensive beds of living deep-sea mussels (Bathymodiolus mauritanicus) and other chemosymbiotic bivalves occur closely to deep-sea coral aggregations (e.g., gorgonians, black corals) that colonize methane-derived authigenic carbonates.

scholarly journals Isotopic evidence (87Sr/86Sr, δ7Li) for alteration of the oceanic crust at deep-rooted mud volcanoes in the Gulf of Cadiz, NE Atlantic Ocean

2009 ◽  
Vol 73 (18) ◽  
pp. 5444-5459 ◽  
Author(s):  
Florian Scholz ◽  
Christian Hensen ◽  
Anja Reitz ◽  
Rolf L. Romer ◽  
Volker Liebetrau ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Oceanic Crust ◽  
Mud Volcanoes ◽  
Gulf Of Cadiz ◽  
Ne Atlantic ◽  
Isotopic Evidence ◽  
Gulf Of Cádiz ◽  
Ne Atlantic Ocean

scholarly journals Paleohydrological changes over the last 50 ky in the central Gulf of Cadiz: Complex forcing mechanisms mixing multi-scale processes

2016 ◽  
Author(s):  
Aurélie Penaud ◽  
Frédérique Eynaud ◽  
Antje Helga Luise Voelker ◽  
Jean-Louis Turon
Keyword(s):  
North Atlantic ◽  
Regional Climate ◽  
Fine Tuning ◽  
General Context ◽  
Gulf Of Cadiz ◽  
Ne Atlantic ◽  
Cell Dynamics ◽  
Gulf Of Cádiz ◽  
Ne Atlantic Ocean ◽  
Forcing Mechanisms

Abstract. New dinoflagellate cyst (dinocyst) analyses were carried out at high-resolution in core MD99-2339, retrieved from a contouritic field in the central part of the Gulf of Cadiz, for the Marine Isotope Stage (MIS) 3 interval, allowing to discuss paleohydrological changes over the last 50 ky in the subtropical NE Atlantic Ocean. Some index dinocyst taxa, according to their (paleo) ecological significance, shed light on significant sea-surface changes. Superimposed on the general decreasing pattern of dinocyst export to the seafloor over the last 50 ky, paralleling the general context of decreasing aeolian dust fertilization, a complex variability in dinocyst assemblages was detected at millennial timescale. Enhanced fluvial discharges occurred during Greenland Interstadials (GI) and especially GI 1, 8 and 12, while enhanced upwelling cell dynamics were suggested during the Last Glacial Maximum and Heinrich Stadials. Finally, during the early Holocene, and more specifically during the Sapropel 1 interval (around 7–9 ka BP), we evidenced a strong decrease in dinocyst fluxes, which occurred synchronously to a strong reduction in Mediterranean Outflow Water strength, and that we attributed to an advection of warm and nutrient-poor subtropical North Atlantic Central Waters. Over the last 50 ky, our study thus allows capturing and documenting the fine tuning existing between terrestrial and marine realms in North Atlantic subtropical latitudes, not only in response to the regional climate pattern, but also to monsoonal forcing interfering during precession-driven northern hemisphere insolation maxima. This mechanism, well expressed during the Holocene, is superimposed on the pervasive role of the obliquity as a first major trigger for explaining migration of dinocyst productive centres in the NE Atlantic margin to the subtropical (temperate) latitudes during glacial (interglacial) periods.

scholarly journals Palaeohydrological changes over the last 50 ky in the central Gulf of Cadiz: complex forcing mechanisms mixing multi-scale processes

2016 ◽  
Vol 13 (18) ◽  
pp. 5357-5377 ◽  
Author(s):  
Aurélie Penaud ◽  
Frédérique Eynaud ◽  
Antje Helga Luise Voelker ◽  
Jean-Louis Turon
Keyword(s):  
North Atlantic ◽  
Regional Climate ◽  
Fine Tuning ◽  
General Context ◽  
Gulf Of Cadiz ◽  
Ne Atlantic ◽  
Cell Dynamics ◽  
Gulf Of Cádiz ◽  
Ne Atlantic Ocean ◽  
Forcing Mechanisms

Abstract. New dinoflagellate cyst (dinocyst) analyses were carried out at high resolution in core MD99-2339, retrieved from a contouritic field in the central part of the Gulf of Cadiz, for the Marine Isotope Stage (MIS) 3 interval, allowing for discussion of palaeohydrological changes over the last 50 ky in the subtropical NE Atlantic Ocean. Some index dinocyst taxa, according to their (palaeo)ecological significance, shed light on significant sea-surface changes. Superimposed on the general decreasing pattern of dinocyst export to the seafloor over the last 50 ky, paralleling the general context of decreasing aeolian dust fertilization, a complex variability in dinocyst assemblages was detected at the millennial timescale. Enhanced fluvial discharges occurred during Greenland Interstadials (GIs), especially GI 1, 8 and 12, while enhanced upwelling cell dynamics were suggested during the Last Glacial Maximum and Heinrich Stadials. Finally, during the early Holocene, and more specifically during the Sapropel 1 interval (around 7–9 ka BP), we evidenced a strong decrease in dinocyst fluxes, which occurred synchronously to a strong reduction in Mediterranean Outflow Water strength and which we attributed to an advection of warm and nutrient-poor subtropical North Atlantic Central Waters. Over the last 50 ky, our study thus allows for capturing and documenting the fine tuning existing between terrestrial and marine realms in North Atlantic subtropical latitudes, in response to not only the regional climate pattern but also monsoonal forcing interfering during precession-driven Northern Hemisphere insolation maxima. This mechanism, well expressed during the Holocene, is superimposed on the pervasive role of the obliquity as a first major trigger for explaining migration of dinocyst productive centres in the NE Atlantic margin to the subtropical (temperate) latitudes during glacial (interglacial) periods.

scholarly journals Bacterial survival governed by organic carbon release from senescent oceanic phytoplankton

2013 ◽  
Vol 10 (10) ◽  
pp. 16973-16999 ◽  
Author(s):  
S. Lasternas ◽  
S. Agustí
Keyword(s):  
Cell Death ◽  
Organic Carbon ◽  
Atlantic Ocean ◽  
Dissolved Organic Carbon ◽  
Primary Production ◽  
Heterotrophic Bacteria ◽  
Ne Atlantic ◽  
Phytoplankton Primary Production ◽  
Carbon Release ◽  
Phytoplankton Cell

Abstract. Bacteria recycle vast amounts of organic carbon, playing key biogeochemical and ecological roles in the ocean. Bacterioplankton dynamics are expected to be dependent on phytoplankton primary production, but there is a high diversity of processes (e.g. sloppy feeding, cell exudation, viral lysis) involved in the transference of primary production to dissolved organic carbon available to bacteria. Here we show cell survival of heterotrophic bacterioplankton in the subtropical Atlantic Ocean to be determined by phytoplankton extracellular carbon release (PER). PER represents the fraction of primary production released as dissolved organic carbon, and changes in the PER variability was explained by phytoplankton cell death, with the communities experiencing the highest phytoplankton cell mortality showing a larger proportion of extracellular carbon release. Both PER and the percent of dead phytoplankton cells increased from eutrophic to oligotrophic waters, while heterotrophic bacteria communities, including 60 to 95% of living cells (%LC), increased from the productive to the most oligotrophic waters. The percentage of living heterotrophic bacterial cells increased with increasing phytoplankton extracellular carbon release, across oligotrophic to productive waters in the NE Atlantic, where lower PER have resulted in a decrease in the flux of phytoplankton DOC per bacterial cell. The results highlight phytoplankton cell death as a process influencing the flow of dissolved photosynthetic carbon in the NE Atlantic Ocean, and demonstrated a close coupling between the fraction of primary production released and heterotrophic bacteria survival.

Three species of Reteporella (Bryozoa: Cheilostomata) in a diapiric and mud volcano field of the Gulf of Cádiz, with the description of Reteporella victori n. sp.

Zootaxa ◽  
2018 ◽  
Vol 4375 (1) ◽  
pp. 90 ◽  
Author(s):  
LAÍS V. RAMALHO ◽  
CARLOS M. LÓPEZ-FÉ ◽  
JOSÉ LUIS RUEDA
Keyword(s):  
New Species ◽  
Cold Water ◽  
Mud Volcanoes ◽  
Gulf Of Cadiz ◽  
Ne Atlantic ◽  
Invertebrate Fauna ◽  
Gulf Of Cádiz ◽  
Ne Atlantic Ocean ◽  
The Common ◽  
A New Species

Diapirs and mud volcanoes (MVs) are formed by the migration and extrusion of fluids and mud to the seafloor, respectively. In the Gulf of Cádiz there are ca. 60 MVs and several diapirs with different environmental conditions and seepage activity. Previous studies, mainly on MVs, have demonstrated that the invertebrate fauna associated with these seafloor structures can be very diverse, including chemosymbiotic species, mostly mollusks and frenulate polychaetes, as well as vulnerable suspension feeders, such as cold-water corals and sponges, among others. Previous studies of the bryozoan fauna in this area have recorded species belonging to 28 families. One of these families is Phidoloporidae, which comprises 27 genera worldwide, including the common Rhynchozoon, Reteporellina, and Reteporella. In the present study, two species belonging to Reteporella are redescribed, and a new species is described from diapirs and MVs on the shelf and slope of the Gulf of Cádiz. The samples were collected during several oceanographic expeditions carried out by the Instituto Español de Oceanografia. This genus is well represented in the NE Atlantic Ocean and the Mediterranean Sea, and our study extends its occurrence on MVs and diapirs fields of the Gulf of Cádiz. 

scholarly journals The percentage of living bacterial cells related to organic carbon release from senescent oceanic phytoplankton

2014 ◽  
Vol 11 (22) ◽  
pp. 6377-6387 ◽  
Author(s):  
S. Lasternas ◽  
S. Agustí
Keyword(s):  
Cell Death ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Primary Production ◽  
Bacterial Cell ◽  
Bacterial Cells ◽  
Ne Atlantic ◽  
Carbon Release ◽  
Ne Atlantic Ocean ◽  
Phytoplankton Cell

Abstract. Bacteria recycle vast amounts of organic carbon, playing key biogeochemical and ecological roles in the ocean. Bacterioplankton dynamics are expected to be dependent on phytoplankton primary production, but there is a high diversity of processes (e.g., sloppy feeding, cell exudation, viral lysis) involved in the transfer of primary production to dissolved organic carbon available to bacteria. Here, we show the percentage of living heterotrophic bacterioplankton in the subtropical NE Atlantic Ocean in relation to phytoplankton extracellular carbon release (PER). PER represents the fraction of primary production released as dissolved organic carbon. PER variability was explained by phytoplankton cell death, with communities experiencing higher phytoplankton cell mortality showing a larger proportion of phytoplankton extracellular carbon release. Both PER and the percentage of dead phytoplankton cells increased from eutrophic to oligotrophic waters, while abundance of heterotrophic bacteria was highest in the intermediate waters. The percentage of living heterotrophic bacterial cells (range: 60–95%) increased with increasing phytoplankton extracellular carbon release from productive to oligotrophic waters in the subtropical NE Atlantic. The lower PERs, observed at the upwelling waters, have resulted in a decrease in the flux of phytoplankton dissolved organic carbon (DOC) per bacterial cell. The results highlight phytoplankton cell death as a process influencing the flow of dissolved photosynthetic carbon in this region of the subtropical NE Atlantic Ocean, and suggest a close coupling between the fraction of primary production released and heterotrophic bacterial cell survival.

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