Pedrosa-Pamies
Rut
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Rut
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ArticleAtmospheric and oceanographic forcing impact particle flux composition and carbon sequestration in the eastern Mediterranean Sea: a three-year time-series study in the deep Ierapetra Basin(Frontiers Media, 2021-02-25) Pedrosa-Pamies, Rut ; Parinos, Constantine ; Sanchez-Vidal, Anna ; Calafat, Antoni ; Canals, Miquel ; Velaoras, Dimitris ; Mihalopoulos, Nikolaos ; Kanakidou, Maria ; Lampadariou, Nikolaos ; Gogou, AlexandraSinking particles are a critical conduit for the export of organic material from surface waters to the deep ocean. Despite their importance in oceanic carbon cycling, little is known about the biotic composition and seasonal variability of sinking particles reaching abyssal depths. Herein, sinking particle flux data, collected in the deep Ierapetra Basin for a three-year period (June 2010 to June 2013), have been examined at the light of atmospheric and oceanographic parameters and main mass components (lithogenic, opal, carbonates, nitrogen, and organic carbon), stable isotopes of particulate organic carbon (POC) and source-specific lipid biomarkers. Our aim is to improve the current understanding of the dynamics of particle fluxes and the linkages between atmospheric dynamics and ocean biogeochemistry shaping the export of organic matter in the deep Eastern Mediterranean Sea. Overall, particle fluxes showed seasonality and interannual variability over the studied period. POC fluxes peaked in spring April–May 2012 (12.2 mg m−2 d−1) related with extreme atmospheric forcing. Summer export was approximately fourfold higher than mean wintertime, fall and springtime (except for the episodic event of spring 2012), fueling efficient organic carbon sequestration. Lipid biomarkers indicate a high relative contribution of natural and anthropogenic, marine- and land-derived POC during both spring (April–May) and summer (June–July) reaching the deep-sea floor. Moreover, our results highlight that both seasonal and episodic pulses are crucial for POC export, while the coupling of extreme weather events and atmospheric deposition can trigger the influx of both marine labile carbon and anthropogenic compounds to the deep Levantine Sea. Finally, the comparison of time series data of sinking particulate flux with the corresponding biogeochemical parameters data previously reported for surface sediment samples from the deep-sea shed light on the benthic–pelagic coupling in the study area. Thus, this study underscores that accounting the seasonal and episodic pulses of organic carbon into the deep sea is critical in modeling the depth and intensity of natural and anthropogenic POC sequestration, and for a better understanding of the global carbon cycle.
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ArticleParticle fluxes in submarine canyons along a sediment-starved continental margin and in the adjacent open slope and basin in the SW Mediterranean Sea(Elsevier, 2022-03-24) Tarrés, Marta ; Cerdà-Domènech, Marc ; Pedrosa-Pamies, Rut ; Rumín-Caparrós, Aitor ; Calafat, Antoni ; Canals, Miquel ; Sanchez-Vidal, AnnaInvestigating the transfer of particulate matter from the continental shelf to the deep basin is critical to understand the functioning of deep sea ecosystems. In this paper we present novel results on the temporal variability of particle fluxes to the deep in three physiographic domains of a 240 km long margin segment and nearby basin off Murcia and Almeria provinces in the SW Mediterranean Sea, which are submarine canyons forming a rather diverse set (namely Escombreras, Garrucha-Almanzora and Almeria), the adjacent open slope and the deep basin. This margin is located off one of the driest regions in Europe and, therefore, its study may help understanding how mainland aridity translates into the export of particles to deep margin environments. Five mooring lines equipped with currentmeters, turbidity-meters and sediment traps were deployed for one entire annual cycle, from March 2015 to March 2016. We combine oceanographic, hydrological and meteorological data with grain size and bulk elemental data (organic carbon, opal, CaCO3, lithogenic) from the collected sinking particles to understand what drives particle transfers in such an under-studied setting, and to quantify the resulting fluxes and assess their spatio-temporal variability. Weighted total mass fluxes in canyons range from 1.64 g m−2 d−1 in Almeria Canyon to 7.33 g m−2 d−1 in Garrucha-Almanzora Canyon system, which are rather low values compared to other submarine canyons in the Western Mediterranean Sea. This results from the absence of extreme wind-storm events during the investigated time period combined with the reduced sediment input to the inner shelf by river systems in the study area. Our results also show that wind-storms are the main trigger for off-shelf particle transport to the deep margin, both within submarine canyons and over the open slope. The most significant transfer period is associated to a set of north-eastern storms in early spring 2015, when the off-shelf transport likely was promoted by storm-induced downwelling. However, the prevailing oceanographic conditions restricts the advection of water down the canyon heads to a few hundred meters, thus promoting a bottom-detached transport of particles seaward. Overall physiography, canyon head incision into the continental shelf and the distance of the canyon head to the shoreline (e.g. very short in Garrucha Canyon) play a key role in particle trapping capability and, therefore, in easing downslope particle transport. Further, bottom trawling activities around the Garrucha-Almanzora Canyon system, feed a nepheloid layer at depths in excess of 400 m, subsequently enhancing particle fluxes throughout the study period. In contrast, maximum particle fluxes in the deep basin respond to seasonal phytoplankton blooms. Our study shows that particle export from the shallow inner margin to the deep outer margin in sediment-starved settings, even if limited, does occur as dominated by atmosphere and ocean driven short-lived events. However, that export does not reach too far as at several tens of kilometres from the shelf edge advective fluxes are replaced by vertical ones impelled by phytoplankton dynamics.
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ArticleHurricanes enhance labile carbon export to the deep ocean(American Geophysical Union, 2019-08-16) Pedrosa-Pamies, Rut ; Conte, Maureen H. ; Weber, John C. ; Johnson, RodneyTropical cyclones (hurricanes) generate intense surface ocean cooling and vertical mixing resulting in nutrient upwelling into the photic zone and episodic phytoplankton blooms. However, their influence on the deep ocean remains unknown. Here we present evidence that hurricanes also impact the ocean's biological pump by enhancing export of labile organic material to the deep ocean. In October 2016, Category 3 Hurricane Nicole passed over the Bermuda Time Series site in the oligotrophic NW Atlantic Ocean. Following Nicole's passage, particulate fluxes of lipids diagnostic of fresh phytodetritus, zooplankton, and microbial biomass increased by 30–300% at 1,500 m depth and 30–800% at 3,200 m depth. Mesopelagic suspended particles following Nicole were also enriched in phytodetrital material and in zooplankton and bacteria lipids, indicating particle disaggregation and a deepwater ecosystem response. Predicted climate‐induced increases in hurricane frequency and/or intensity may significantly alter ocean biogeochemical cycles by increasing the strength of the biological pump.
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ArticleEditorial: the oceanic particle flux and its cycling within the deep water column(Frontiers Media, 2022-09-09) Conte, Maureen H. ; Pedrosa-Pamies, Rut ; Honda, Makio C. ; Herndl, Gerhard J.The oceanic particle flux transfers energy and material from the surface through the water column to the seafloor. (See review by Conte (2019) and references therein). The particle flux fuels life below the sunlit photic zone, exerts a major control on the global cycling of carbon and particle-associated elements, and also plays a major role in long-term carbon sequestration. In this Research Topic we present a collection of articles that provide a broad overview of current research on the interlinked processes controlling the magnitude and composition of the oceanic particle flux, and its cycling and depth attenuation within the deep water column.
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ArticleGlobal ocean sediment composition and burial flux in the deep sea(American Geophysical Union, 2021-03-21) Hayes, Christopher T. ; Costa, Kassandra M. ; Anderson, Robert F. ; Calvo, Eva ; Chase, Zanna ; Demina, Ludmila L. ; Dutay, Jean-Claude ; German, Christopher R. ; Heimbürger, Lars-Eric ; Jaccard, Samuel L. ; Jacobel, Allison W. ; Kohfeld, Karen E. ; Kravchishina, Marina ; Lippold, Jörg ; Mekik, Figen ; Missiaen, Lise ; Pavia, Frank ; Paytan, Adina ; Pedrosa-Pamies, Rut ; Petrova, Mariia V. ; Rahman, Shaily ; Robinson, Laura F. ; Roy-Barman, Matthieu ; Sanchez-Vidal, Anna ; Shiller, Alan M. ; Tagliabue, Alessandro ; Tessin, Allyson C. ; van Hulten, Marco ; Zhang, JingQuantitative knowledge about the burial of sedimentary components at the seafloor has wide-ranging implications in ocean science, from global climate to continental weathering. The use of 230Th-normalized fluxes reduces uncertainties that many prior studies faced by accounting for the effects of sediment redistribution by bottom currents and minimizing the impact of age model uncertainty. Here we employ a recently compiled global data set of 230Th-normalized fluxes with an updated database of seafloor surface sediment composition to derive atlases of the deep-sea burial flux of calcium carbonate, biogenic opal, total organic carbon (TOC), nonbiogenic material, iron, mercury, and excess barium (Baxs). The spatial patterns of major component burial are mainly consistent with prior work, but the new quantitative estimates allow evaluations of deep-sea budgets. Our integrated deep-sea burial fluxes are 136 Tg C/yr CaCO3, 153 Tg Si/yr opal, 20Tg C/yr TOC, 220 Mg Hg/yr, and 2.6 Tg Baxs/yr. This opal flux is roughly a factor of 2 increase over previous estimates, with important implications for the global Si cycle. Sedimentary Fe fluxes reflect a mixture of sources including lithogenic material, hydrothermal inputs and authigenic phases. The fluxes of some commonly used paleo-productivity proxies (TOC, biogenic opal, and Baxs) are not well-correlated geographically with satellite-based productivity estimates. Our new compilation of sedimentary fluxes provides detailed regional and global information, which will help refine the understanding of sediment preservation.
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ArticleTransport and distributions of naturally and anthropogenically sourced trace metals and arsenic in submarine canyons(Elsevier, 2023-09-09) Tarres, Marta ; Cerda-Domenech, Marc ; Pedrosa-Pamies, Rut ; Baza-Varas, Andrea ; Calafat, Antoni ; Sanchez-Vidal, Anna ; Canals, Miquel F.Continental margins play a key role in the cycling of natural and anthropogenic trace metals (TMs) as pathways at the interface between landmasses and deep ocean basins but also as sinks. Knowledge of how short-lived forcings alter the export dynamics of TMs is essential for our understanding of their fate in that setting. Here we report time series of particulate metal fluxes in three submarine canyons —namely Escombreras, Almeria and the Garrucha-Almanzora system— of the South-Western Mediterranean Sea. Our research focuses on combining multi-elemental TMs (Al, Fe, Ti, Co, Cu, Mn, Ni, Pb and Zn) and As (a metalloid) contents of settling particles collected near the bottom by automated particle traps during one year, and seafloor sediment samples from below the traps. We assess the role of storms and bottom trawling in the off-shelf transport of particulate TMs and As, and the natural and anthropogenic contributions of TMs by using enrichment factors (EFs). The TM export fluxes and composition changed over the study period, from March 2015 to March 2016. TM fluxes increase in early spring 2015 in association with short-lived storm events and during calm months in the Garrucha-Almanzora Canyon system, likely due to sediment resuspension triggered by bottom trawling. In terms of composition, TMs in the sinking fluxes appear to be closely associated with lithogenic (Al, Fe and Ti) and authigenic (Mn) particles’ proxies. During storm events, the mass of settling particles in Escombreras and Almeria canyons was impoverished in Al, Fe, As, Co, Cu, Mn and Ni compared to other periods. The Garrucha-Almanzora Canyon system behaves differently as the above-described differences, are not observed there. Moreover, the TM composition of the sediments —with higher contents of Fe, Ti and several other TMs— in this canyon is barely tied to the composition of the settling particles. Finally, Cu and Zn contents, together with Pb in the northernmost Escombreras Canyon, are best explained by referring to anthropogenic sources. This work provides insights into the profound influence of the natural and anthropogenic forcings controlling the distributions and seasonal dynamics of particulate TMs and As in submarine canyons.