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To assess the origin and degradation state of the organic particles sinking towards the sea bottom of the Mallorca continental slope, the major inorganic and organic components of the total mass flux and its biochemical composition (in terms of protein, carbohydrate, lipid and phytopigment contents) have been analysed. Two instrumented lines were deployed at the western (Soller station, Balearic sub-basin) and southern (Cabrera station, Algerian sub-basin) slopes of Mallorca Island, 900 m depth from November 2009 to January 2011. The two locations are characterized by putatively different environmental settings. Settled material at Soller station has higher lithogenic contents when compared with the Cabrera one. Such difference can be explained by the synergistic presence in the Soller station of large inputs of resuspended material due to the mesoscale variability of the Balearic current and the impact of bottom trapped waves. On the other hand, at the Cabrera station sinking particles are characterized by OM and opal percentages higher than those recorded at the Soller station. This result points out that organic particles reaching the sea floor at the Cabrera station have a pre-eminent pelagic origin. Based on analyses of the C and N stable isotopes of the sinking material, our results also highlight that, overall, the OM reaching the sea floor at the Mallorca slope is mostly of marine origin. In general, the OM settled at the Soller station has a higher nutritional value than that at the Cabrera one. Such a difference, occurring across a relatively reduced spatial scale, let us hypothesizing that the nutritionally richer particles descending in the Cabrera station are exposed to a less energetic environment than that in the Soller setting. This would lead to higher settling velocity of particles in the Soller setting which in turn would result in lower degradation rates of particles during their descent towards the sea bottom.

4 pages, 2 tables .-- DOI of original article: https://doi.org/10.1016/j.jmarsys.2014.04.002, The authors regret that the printed version of the above article contained a number of errors. The correct and final version of Table 1 and Table 2, Acknowledgments and Amores and Monserrat (2014) reference follow. The authors would like to apologise for any inconvenience caused. © 2014 Elsevier B.V., This research was supported by the project CTM2008-04489-C03-01 and CTM2008-04489-C03-02. The isotope analyses were funded by the Government of the Balearic Islands, Acció especial: AAEE0138/09 (DireccióGeneral de Recerca, Desenvolupament Tecnològic i Innovació, Conselleria d'Economia Hisenda i Innovació)

Measures of biodiversity change may be useful as indicators if they are responsive to manageable drivers of biodiversity loss. However, there are many candidate indicators that are considered to be robust to survey artifacts and sensitive to manageable impacts. Using extensive survey data on demersal fish assemblages around the Balearic Islands (western Mediterranean) we analyze relationships among ‘traditional’, taxonomic and functional diversity indices, to identify a minimum set of indices that provide a good representation of the different aspects of diversity. Secondly we model the responses of the demersal fish community diversity to bottom trawl fishing pressure. To do so, we used two different approaches: (i) considering fishing effort and depth as continuous explanatory variables; and (ii) grouping samples according to bathymetric sampling strata and contrasting levels of fishing effort. The results show that diversity can be described using different complementary aspects such as species richness, evenness, and the taxonomic and functional breadth of the species present in a given community, displaying different responses to fishing pressure. However, the changes in diversity in response to fishing may only be detectable in those communities where the levels of fishing pressure have remained relatively low. When communities have been exposed to high levels of fishing pressure for a long period, the relevant changes in diversity may have happened long before the onset of monitoring of the fishery, and hence it may be too late to detect differences between levels of fishing effort. This seems to be the case on the middle slope of the Balearic Islands, where vulnerable species have disappeared or are very infrequent, and have been replaced by species better-adapted to fishing impacts, SI

11 pages, 6 figures, 4 tables, 1 appendix, The bottom morphology, the surface sediments and the epibenthic community of two adjacent areas within the fishing ground traditionally known as Pesquera Rica (Balearic Islands) were characterized using multibeam echosounder, van Veen dredge and beam trawl. Red algae beds predominate in both areas, but one has been exploited by trawling since at least 90 years ago, whereas the presence of natural barriers prevents this fishing activity in the other one. Comparisons between the two areas showed a biomass reduction of 46.8 and 39.3% of dominant red algae taxonomic groups Peyssonneliaceae and Corallinophycidae, respectively, in the trawled area (TA). Similarly, both mean abundance and biomass of most groups of fauna were higher in the not trawled area (NTA). N biodiversity index showed higher mean values of algae species in NTA than in TA (7.0 and 4.9, respectively), whereas no differences were detected neither for sessile nor for mobile fauna. SIMPER analysis showed that large species of both sessile and mobile epibenthic fauna (e.g. the ascidia Polycarpa mamillaris and the echinoderm Spatangus purpureus, respectively) presented higher abundance and contribution to within area similarity in NTA than in TA. In coincidence, these are the most abundant epibenthic species in the commercial hauls from the Pesquera Rica. The relatively low fishing effort and the gears used, addressed to avoid large catches of algae allowing longer hauls, may explain the subsistence of red algae beds in the Balearic Islands trawl fishing grounds. However, the detrimental effects shown here claim for urgent management measures aiming to preserve these beds., Surveys at sea in 2009 and 2014 were carried out within the project DRAGONSAL (Caracterización del Ecosistema Bentónico de la Plataforma costera del area comprendida entre sa Dragonera, cap de ses Salines y Cala Figuera (Mallorca)), co-funded by the Instituto Español de Oceanografía and the Balearic Islands government . Analysis of the data has been done within the framework of the projects DRAGONSAL and LIFE-IP INTEMARES “Integrated, Innovative and Participatory Management for N2000 network in the Marine Environment” (LIFE15 IPE/ES/000012)

17 pages, 7 figures, 4 tables, Settling particles were collected by a set of moored sediment traps deployed during one year in the western Gulf of Lion along Cap de Creus and Lacaze-Duthiers submarine canyons and on the adjacent southern open slope. These traps collected particles during periods of pelagic settling and also during events of deep water flushing by dense shelf water cascading (DSWC). Analyses of lipid biomarkers (n-alkanes, n-alkan-1-ols, sterols and C-C alkenones) and polycyclic aromatic hydrocarbons (PAHs) showed much higher transfer of terrestrial lipids and PAHs to open deep waters during DSWC than in the absence of cascading. The area of highest lateral fluxes was mostly located at 1000 m depth but also at 1500 m depth and extended along the canyons and to the adjacent slope. Higher fluxes were observed near the bottom (30 m above bottom; mab) than at intermediate waters (500 mab) which is consistent with the formation and sinking of dense water over the continental shelf, and its transport through the canyons towards the continental slope and deep basin. DSWC involved the highest settling fluxes of terrestrial lipids and PAHs ever described in marine continental slopes and the pelagic domain, as illustrated by peak values of C-C odd carbon numbered alkanes (405 ng m d), C-C even carbon numbered alkan-1-ols (850 ng m d), β-sitosterol+sitostanol (4800 ng m d) and PAHs (55 µg m d). The algal lipids also showed higher transfer to deep waters during DSWC but to a lower extent than the terrigenous compounds. However, the C-C alkenones constituted an exception and their settling fluxes were not influenced by DSWC. The lack of influence of the DSWC on the C-C alkenone settling is consistent with absence of haptophyte algal inputs from the continental shelf and reinforces the reliability of these molecules for palaeothermometry and palaeoproductivity measurements in pelagic systems, This research was supported by the HERMES (GOCE-CT-2005-511234-1), HERMIONE (FP7-ENV-2008-1-226354), MEDECOS (CTM2008-05210-E/MAR) and IDEM (11.0661/2017/750680/SUB/EN V.C2) research projects funded by EU. Financial support from the GRACCIE consolider redes project (CTM2014-59111-REDC) funded by the Spanish Ministry of Economy and Competitiveness is acknowledged

Superficial sediments from Cap de Creus to the Rhone Delta, in the Gulf of Lion, Northwestern Mediterranean Sea, including the mid-shelf mud belt and the continental slope were collected between 2005 and 2008 to assess the levels, main sources and distribution patterns of organochlorine pollutants. Discharges from the Rhone River are the main source for all these compounds around the area. The spatial distribution of organochlorine pollutants was also related to their physicochemical properties and to sediment grain size and composition. The concentrations of polychlorobiphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDD and DDE), and the chlorobenzenes (CBzs) – pentachlorobenzene (PeCB) and hexachlorobenzene (HCB) – decreased westwards along the mid-shelf mud belt. In contrast, hexachlorocyclohexane isomers (HCHs), namely lindane (γ-HCH), followed another concentration pattern suggesting a different transport mode. The major concentrations of organochlorine compounds were observed off the Rhone River mouth, in the prodelta, where PCB, DDT and CBz concentrations reached 38, 29 and 8.3 ng g−1, respectively. These average concentrations in the mid continental shelf were two to ten times lower than those found in a study performed about 20 years ago, albeit in almost all the sites the values of PCBs and DDTs still exceed the NOAA’s Sediment Quality Guidelines. In contrast, the concentrations in the continental slope were nearly the same as 20 years ago, which may evidence that even most of these compounds were banned decades ago, their background concentrations associated to diffuse pollution have not decreased in the deep continental margin.

[EN] Borehole PRGL1-4 drilled in the upper slope of the Gulf of Lion provides an exceptional record to investigate the impact of late Pleistocene orbitally-driven glacio-eustatic sea-level oscillations on the sedimentary outbuilding of a river fed continental margin. High-resolution grain-size and geochemical records supported by oxygen isotope chronostratigraphy allow reinterpreting the last 500 ka upper slope seismostratigraphy of the Gulf of Lion. Five main sequences, stacked during the sea-level lowering phases of the last five glacial-interglacial 100-kyr cycles, form the upper stratigraphic outbuilding of the continental margin. The high sensitivity of the grain-size record down the borehole to sea-level oscillations can be explained by the great width of the Gulf of Lion continental shelf. Sea level driven changes in accommodation space over the shelf cyclically modified the depositional mode of the entire margin. PRGL1-4 data also illustrate the imprint of sea-level oscillations at millennial time-scale, as shown for Marine Isotopic Stage 3, and provide unambiguous evidence of relative high sea-levels at the onset of each Dansgaard-Oeschger Greenland warm interstadial. The PRGL1-4 grain-size record represents the first evidence for a one-to-one coupling of millennial time-scale sea-level oscillations associated with each Dansgaard-Oeschger cycle., This study has been supported by the EC PROMESS1 (EVR1-CT-200240024) and HERMIONE (226354- HERMIONE) projects, and the Spanish GRACCIE CONSOLIDER (CSD2007-00067) and DOS MARES (CTM2010-21810-C03-01) projects and CGL2005-24147-E complementary action. The IMAGES programme contributed to the research by providing the MD99-2348 sediment core. French partners benefited from additional support by Agence Nationale de la Recherche (ANR, contract NT05-3-42040). We are also grateful for comments and suggestions of reviewers Jamie Austin and Andre Droxler, which helped to improve the manuscript. We thank Anders Sevensson and Thomas Blunier for providing NGRIP and EDML data, respectively. We are especially grateful to PROMESS1 participating scientists and to the staff of the various laboratories where sediment samples were analysed. We are grateful for the support provided by Fugro Engineers B. V. that made the challenging MV Bavenit cruise a success history. Generalitat de Catalunya recognises CRG Marine Geosciences within its excellence research groups program (ref. 2009 SGR 1305).

9 pages, 4 figures, 2 tables, Settling particles were collected by an array of sediment trap moorings deployed along the Cap de Creus (CCC) and Lacaze-Duthiers (LDC) submarine canyons and on the adjacent southern open slope (SOS) between October 2005 and October 2006. This array collected particles during common settling processes and particles transferred to deep waters by dense shelf water cascading (DSWC). Polychlorobiphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlorobenzenes (CBzs)—pentachlorobenzene and hexachlorobenzene—and hexachlorocyclohexanes were analyzed in all samples. The results show much higher settling fluxes of these compounds during DSWC than during common sedimentation processes. The area of highest deposition was located between 1000 and 1500 m depth and extended along the canyons and outside them showing their channelling effects but also overflows of dense shelf water from these canyons. Higher fluxes were observed near the bottom (30 m above bottom; mab) than at intermediate waters (500 mab) which is consistent with the formation and sinking of dense water close to the continental shelf and main displacement through the slope by the bottom. DSWC involved the highest settling fluxes of these compounds ever described in marine continental slopes and pelagic areas, e.g., peak values of PCBs (960 ng·m–2·d–1), DDTs (2900 ng·m–2·d–1), CBzs (340 ng·m–2·d–1) and lindane (180 ng·m–2·d–1), We thank all participants and crews of R/V Garcia del Cid and R/V Universitatis for their help and dedication. We are deeply indepted to Nicole Delsaut (CEFREM) for the prepatation of the trap samples for analysis. This research was supported by the HERMES (GOCE-CT-2005-511234-1) and HERMIONE (FP7-ENV-2008-1-226354) research projects. Financial support from the GRACCIE consolider project (CSD2007-00067) is acknowledged. This work was also sponsored by research groups 2009SGR1178 and 2009SGR1305 from Generalitat de Catalunya

Settled material recorded by two near bottom sediment traps deployed from November 2009 to February 2011 at northern (Sóller) and southern (Cabrera) slopes of Mallorca Island (Western Mediterranean) is studied with the aim of discerning their possible origin. The total settled particulate mass fluxes (TMF) at Sóller station were found to be, on average, 2.8 times greater than at Cabrera location during the deployment period, although both time series had a similar temporal evolution. It is suggested that wind episodes affecting the entire area were the common forcing, causing a primary production enhancement and being responsible of the similar temporal behavior. The greater sediment amounts collected in Sóller are explained on the basis of two physical mechanisms: 1) a number of successive eddies generated by instabilities of the Balearic Current that are regularly observed on satellite images, some of which have been reported to reach the seabed, thus increasing near bottom velocities and causing sediment resuspension. And 2) bottom trapped waves that are evidenced from a wavelet analysis in Sóller which could affect the TFM by enhancing sediment resuspension or advecting material from the surrounding areas. © 2014 Elsevier B.V., This research has been supported by IDEADOS project (CMT2008-04489-C03-03). The work of A. Amores was funded by a JAE-PreDoc grant from Consejo Superior de Investigaciones Científicas (CSIC) and cofunded by Programa Operativo FSE 2007–2013. A. C. was also supported by GRACCIE (CSD2007-00067, Consolider-IngenioProgram) research projects, a Generalitat de Catalunya “Grups de Recerca Consolidats” grant (2009 SGR-1305)

Special issue The wrapping up of the IDEADOS project: International Workshop on Environment, Ecosystems and Demersal Resources, and Fisheries.-- 11 pages, 3 figures, 3 tables.-- Corrigendum to “Structure and dynamics of food webs in the water column on shelf and slope grounds of the western Mediterranean” [J. Mar. Syst. 138 (2014) 171–181], Journal of Marine Systems 139: 505–508 (2014) https://doi.org/10.1016/j.jmarsys.2014.09.005, Benthic-pelagic coupling is an important process connecting species throughout the water column, particularly, in deep-sea systems where faunal assemblages can be dense if indirectly sustained by production from the above. Through stable isotope analyses, this study explored the sources of production, trophic structure, and bentho-pelagic coupling in two locations with contrasting oceanographic conditions from the western Mediterranean, in the Balearic (BsB) and the Algerian (AsB) sub-basins. The samples of 89 dominant species (23 decapods, 19 cephalopods, 33 fishes, among the other taxa), inhabiting the hyperbenthic and pelagic domains, from the shelf break (250m), upper slope (650m), and middle slope (850m) were analyzed. Results suggested long food webs of approximately four trophic levels (TrLs) that were sustained by planktonic source material in shallower waters and degraded particulate organic matter of planktonic origin in deeper waters. Most of the collected species (70%) occupied intermediate trophic positions between the 3rd and 4th TrLs. The species δ15N and δ13C values exhibited a broad range, consistent with the high diversity that might be attributed to the oligotrophic conditions. As the depth increased, stronger segregation occurred between the trophic groups, and spatial differences were found among consumers of the two locations. Species in the AsB always had consistently higher δ15N values than in the BsB, which could possibly be attributed to the basal δ15N that was present through the food web. Despite the contrasting basin characteristics, a similarly close bentho-pelagic coupling pattern was observed at both locations, except at the deepest ground, especially at the AsB, where the mean δ13C values from the hyperbenthic and pelagic compartments were more distant. This could be related to the higher degree of reworking of organic matter in the AsB. Overall, these findings suggested the need for a depth-stratified approach to analyze deep-sea food webs in the study site in future studies. © 2014 Elsevier B.V., This research was supported by the project CTM2008-04489-C03-01 and CTM2008-04489-C03-02. The isotope analyses were funded by the Government of the Balearic Islands, Acció especial: AAEE0138/09 (DireccióGeneral de Recerca, Desenvolupament Tecnològic i Innovació, Conselleria d'Economia Hisenda i Innovació)

Monthly catches per unit of effort (CPUE) of adult red shrimp (. Aristeus antennatus), reported in the deep water bottom trawl fishery developed on the Sóller fishing ground off northern Mallorca (Western Mediterranean), and the mean ocean surface vorticity in the surrounding areas are compared between 2000 and 2010. A good correlation is found between the rises in the surrounding surface vorticity and the drops in the CPUE of the adult red shrimp. This correlation could be explained by assuming that most of the surface vorticity episodes could reach the bottom, increasing the seabed velocities and producing sediment resuspension, which could affect the near bottom water turbidity. A. antennatus would respond to this increased turbidity disappearing from the fishing grounds, probably moving downwards to the deeper waters. This massive displacement of red shrimp specimens away from the fishing grounds would consequently decrease their accessibility to fishing exploitation. Similar although more intense responses have been observed during the downslope shelf dense water current episodes that occurred in a submarine canyon, northeast of the Iberian peninsula. The proposed mechanism suggesting how the surface vorticity observed can affect the bottom sediments is investigated using a year-long moored near-bottom current meter and a sediment trap moored near the fishing grounds.The relationship between vorticity and catches is also explored for fish species (. Galeus melastomus, Micromesistius poutassou, Phycis blennoides) and other crustacean (. Geryon longipes and Nephrops norvegicus), considered as by-catch of the deep water fishery in the area. Results appear to support the suggestion that the water turbidity generated by the vorticity episodes is significant enough to affect the dynamics of the demersal species. © 2013 Elsevier B.V., This research has been partially sponsored by the IDEADOS project (CMT2008-04489-C03-01 and 03). The work of A. Amores has been funded by a JAE-PreDoc grant from Consejo Superior de Investigaciones Científicas (CSIC) and co-funded by Programa Operativo FSE 2007– 2013

15 pages, 14 figures, An array of mooring lines deployed between 300 and 1900 m depth along the Lacaze-Duthiers and Cap de Creus canyons and in the adjacent southern open slope was used to study the water and sediment transport on the western Gulf of Lions margin during the 2006 intense cascading period. Deep-reaching cascading pulses occurred in early January, in late January and from early March to mid-April. Dense water and sediment transport to the deep environments occurred not only through submarine canyons, but also along the southern open slope. During the deep cascading pulses, temporary upper and mid-canyon and open slope deposits were an important source of sediment to the deep margin. Significant sediment transport events at the canyon head only occurred in early January because of higher sediment availability on the shelf after the stratified and calm season, and in late February because of the interaction of dense shelf water cascading with a strong E–SE storm. During the January deep cascading pulses, increases in suspended sediment concentration within the canyon were greater and earlier at 1000 m depth than at 300 m depth, whereas during the March–April deep cascading pulses sediment concentration only increased below 300 m depth, indicating resuspension and redistribution of sediments previously deposited at upper and mid-canyon depths. Deeper than 1000 m depth, net fluxes show that most of the suspended sediment left the canyon and flowed along the southern open slope towards the Catalan margin, whereas a small part flowed down-canyon and was exported basinward. Additionally, on the mid- and lower-continental slope there was an increase in the near-bottom currents induced by deep open-sea convection processes and the propagation of eddies. This, combined with the arrival of deep cascading pulses, also generated moderate suspended sediment transport events in the deeper slope regions, We thank all participants, UTM technicians and crews of R/V Garcia del Cid and R/V Universitatis, for their help and dedication during the cruises. The research projects HERMES (GOCE-CT-2005-511234-1), HERMIONE (FP7-ENV-2008-1-226354), DOS MARES (CTM2007-66316-C02-01/MAR) and GRACCIE-CONSOLIDER (CSD2007-00067) supported this research. A.S.V., C.P., A.C. and M.C. belong to CRG on Marine Geosciences, supported by Grant 2009 SGR 1305 of the Generalitat de Catalunya. A.P., P.P. and J.M. belong to CRG on Littoral and Oceanic Processes, supported by Grant 2009 SGR 899 of the Generalitat de Catalunya. J.M was partially funded through a JAE-Doc contract granted by CSIC and co-financed by CEE

From October 2005 through October 2006 sediment traps were moored along the Lacaze–Duthiers and Cap de Creus submarine canyons and on the adjacent southern open slope in the Gulf of Lion (Northwestern Mediterranean). During the Winter 2006 (January–March), an intense Dense Shelf Water Cascading (DSWC) event was found to be a major driver of particle transport, increasing lateral advection of material at all stations. In this study, we assessed the sources and degradation of organic matter (OM) advected along canyons during both DSWC and quiescent conditions using specific organic biomarkers, including pigments, lignin phenols and amino acids. Three major events of fresh, marine OM inputs were detected during the study period. The largest one was in spring (March–May), with smaller events also observed in winter (December 2005) and summer (August 2006), suggesting that both spring blooms and sporadic blooms associated with wind-driven mixing affects carbon fluxes in this system. The DSWC event that partially overlapped the spring-bloom enhanced the overall transfer of OM down canyons. The lignin phenol data show no significant, along-canyon dilution and are consistent with constant advection of terrigenous material. In contrast, amino acid and chloropigment compositions indicate that part of the OM is degraded both prior to reaching the canyons and within the canyons themselves. Overall, our results illustrate the importance of both seasonal and sporadic pelagic and continental shelf/lateral events in controlling the exchange of organic matter across this margin.

15 páginas, 8 figuras, 3 tablas., Settling particles were collected using sediment traps deployed along three transects in the Lacaze-Duthiers and Cap de Creus canyons and the adjacent southern open slope from October 2005 to October 2006. The settling material was analyzed to obtain total mass fluxes and main constituent contents (organic matter, opal, calcium carbonate, and siliciclastics). Cascades of dense shelf water from the continental shelf edge to the lower continental slope occurred from January to March 2006. They were traced through strong negative near-bottom temperature anomalies and increased current speeds, and generated two intense pulses of mass fluxes in January and March 2006. This oceanographic phenomenon appeared as the major physical forcing of settling particles at almost all stations, and caused both high seasonal variability in mass fluxes and important qualitative changes in settling material. Fluxes during the dense shelf water cascading (DSWC) event ranged from 90.1 g m−2 d−1 at the middle Cap de Creus canyon (1000 m) to 3.2 g m−2 d−1 at the canyon mouth (1900 m). Fractions of organic matter, opal and calcium carbonate components increased seaward, thus diminishing the siliciclastic fraction. Temporal variability of the major components was larger in the canyon mouth and open slope sites, due to the mixed impact of dense shelf water cascading processes and the pelagic biological production. Results indicate that the cascading event remobilized and homogenized large amounts of material down canyon and southwardly along the continental slope contributing to a better understanding of the off-shelf particle transport and the internal dynamics of DSWC events., This research has been supported by HERMES (GOCE-CT-2005-511234-1), SESAME (GOCE-036949), HERMIONE (FP7-ENV-2008-1-226354), and GRACCIE (CSD2007-00067, Consolider-Ingenio Program) research projects, a Generalitat de Catalunya “Grups de Recerca Consolidats” grant (2009 SGR-1305) and a FP7 Marie Curie Reintegration Grant (PERG04-GA-2008-239175). C. Pasqual is supported by an F.P.U. grant from the Spanish government.

13 pages, 9 figures, We present a 1-yr (2005-2006) record of organic carbon (OC) and total nitrogen (TN) contents and their isotopic ratios (δ13Coc and δ15N) in sinking particles from the western Gulf of Lions. Maximum OC and TN fluxes recorded in January 2006 and March-April 2006 were associated with negative near-bottom temperature anomalies. This reveals large inputs of resuspended organic matter from the shelf basinwards to depths > 1500 m by dense shelf-water cascading. The first pulse of organic matter had low δ13Coc (-25.5%0) and N: C (0.08) and high δ15N (6.6%0) values, indicative of the arrival of organic matter of terrestrial origin. In contrast, the second pulse had high δ13Coc (-21.9%0) and N: C (0.15) and extremely low δ15N (0.0%0) values, indicative of the transfer of organic matter with higher marine contribution. Though downslope export of organic matter from the adjacent shelf predominated, particles escaping from surface waters remained an important source of organic matter during low-energy and low-flux periods and especially during summer conditions, with significant contribution of N2 fixation to organic matter export. Overall, our results suggest the export of organic matter from different sources to the deep Mediterranean basin, which in turn might alter within a couple of months the quality of the sedimentary organic matter deposited on the sea floor and thus the dynamics of the deep ecosystems. © 2009, by the American Society of Limnology and Oceanography, Inc, This research has been supported by a Marie Curie Individual Fellowship (re. MEIF-CT-2006-024068) to A. Sanchez-Vidal, the research projects Hotspot Ecosystem Research on the Margins of European Seas (ref. GOCE-CT-2005-511234-1), Southern European Seas: Assessing and Modelling Ecosystem Changes (ref. GOCE-036949), Estudio Integrado de Cañones y Taludes Profundos del Mediterráneo Occidental: un hábitat esencial (ref. CTM2007-66316-C02-01/MAR), Multidisciplinary Research Consortium on Gradual and Abrupt Climate Changes, and Their Impacts on the Environment (ref. CSD2007-00067, Consolider Ingenio 2010 Program), and a Generalitat de Catalunya ‘‘Grups de Recerca Consolidats’’ grant (2005 SGR-00152)

5 pages, 3 figures, 2 tables.-- Supporting information http://onlinelibrary.wiley.com/doi/10.1029/2007GL032825/suppinfo, During winter 2005–2006, particle fluxes and near-bottom currents were measured in and around the Lacaze-Duthiers and Cap de Creus submarine canyons (western Gulf of Lion). Current anomalies show the occurrence of a major dense shelf water cascading event down to the slope, the latest recorded up to date in the area. Concomitant increased total mass fluxes highlight the ability of cascading waters to transport large amounts of coarse sediment and organic matter, which is predominantly of terrestrial origin. In addition, results reveal that the current regime and associated grain size sorting is the responsible for a geochemical gradient of settling organic particles along the slope, This research has been supported by a Marie Curie individual Fellowship (MEIF-CT-2006-024068) to A. Sánchez Vidal, a FPU fellowship to C. Pasqual, an by the HERMES (GOCE-CT-2005-511234-1), SESAME (GOCE-036949) and PROMETEO (CTM2007-66316-C02-01/MAR) research projects