Carbon cycling in a Patagonian fjord: Strength of biological vs. physical pump

Póster presentado en la 2nd International Ocean Research Conference, celebrada en Barcelona del 17 al 21 de noviembre de 2014.Understanding the role of the pelagic “biological and physical pump” in carbon cycling is critical to climate change adaptation and mitigation efforts especially in coastal areas characterized by intense biogeochemical cycling. Fjords are among the few coastal regions that appear to be net annual sinks for atmosphericCO2. Vertical profiles of temperature and salinity were collected with a CTD revealing intense vertical structure in the water column that could be summarised as 2 layers with a transition-mixing region .Spatio-temporal sampling of physical and biogeochemical (C system, nutrients, Phyto- and Zooplankton, in situ dissolved pCO2) parameters was conducted in Comau Fjord (Puerto Montt-Chile) during Austral spring from the surface and deep layers. Spatial variation in water column structure in the fjord was minimal, however the depth of the upper layer varies probably depending on the surface-water inputs. Surface waters had significantly lower pCO2 values compared to the atmosphere and deeper water. Concentrations of suspended material and chlorophyll a were higher deeper in the water column, suggesting concentration process of material across the halocline. Overall, concentrations of particulate matter and mesozooplankton (during the study period), were low compared to many mid-latitude regions, and near absent in the vicinity of the 2 rivers entering the fjord. The low surface water pCO2 values suggest negative air-water CO2fluxes predominates within Comau Fjord during Austral spring. This preliminary study suggests that the geochemical properties of watershed and the low [DIC] of surface-water inputs, i.e., the physical pump, seems to play an important role in this region.This work was supported by the project 2013CL0013 funded by the CSIC, Fundacion Endesa and Fundación San Ignacio del Huinay. Funding was also provided by the Spanish Ministry of Sciences and Innovation (JAE DOCTORES 2010 contract for E.P.M., JAE PREDOCTORAL scholarship for S.T. and S.F.) and part-funded bythe European Union (European Social Fund, ESF2007-2013) and the Spanish Ministry for Economy and Competitiveness.Peer Reviewe

Nitrous oxide and methane in Atlantic and Mediterranean waters in the Strait of Gibraltar: Air-sea fluxes and inter-basin exchange

14 páginas, 7 figuras, 2 tablas.-- Proyecto CarbochangeThe global ocean plays an important role in the overall budget of nitrous oxide (N2O) and methane (CH4), as both gases are produced within the ocean and released to the atmosphere. However, for large parts of the open and coastal oceans there is little or no spatial data coverage for N2O and CH4. Hence, a better assessment of marine emissions estimates is necessary. As a contribution to remedying the scarcity of data on marine regions, N2O and CH4 concentrations have been determined in the Strait of Gibraltar at the ocean Fixed Time series (GIFT). During six cruises performed between July 2011 and November 2014 samples were collected at the surface and various depths in the water column, and subsequently measured using gas chromatography. From this we were able to quantify the temporal variability of the gas air-sea exchange in the area and examine the vertical distribution of N2O and CH4 in Atlantic and Mediterranean waters. Results show that surface Atlantic waters are nearly in equilibrium with the atmosphere whereas deeper Mediterranean waters are oversaturated in N2O, and a gradient that gradually increases with depth was detected in the water column. Temperature was found to be the main factor responsible for the seasonal variability of N2O in the surface layer. Furthermore, although CH4 levels did not reveal any feature clearly associated with the circulation of water masses, vertical distributions showed that higher concentrations are generally observed in the Atlantic layer, and that the deeper Mediterranean waters are considerably undersaturated (by up to 50%). Even though surface waters act as a source of atmospheric N2O during certain periods, on an annual basis the net N2O flux in the Strait of Gibraltar is only 0.35 ± 0.27 μmol m−2 d−1, meaning that these waters are almost in a neutral status with respect to the atmosphere. Seasonally, the region behaves as a slight sink for atmospheric CH4 in winter and as a source in spring and fall. Approximating the circulation pattern in the Strait to a bi-layer scheme, N2O exchange between basins was also calculated, and a net export from the Mediterranean Sea to the Atlantic Ocean equivalent to 39 μmol m−2 d−1 was foundFunding for this work was provided by the INGOS (Grant Agreement 284274), CARBOCHANGE IP (264879GOCE) and PERSEUS of the European Commission, the CATARINA Project supported by the MICINN and co-funded by FEDER (CTM2010-17141/MAR) and OSIMON project funded by the Regional Government of Galicia (Xunta de Galicia, 09MDS035402PR)Peer reviewe

Anthropogenic and natural CO2 exchange through the Strait of Gibraltar

The exchange of both anthropogenic and natural inorganic carbon between the Atlantic Ocean and the Mediterranean Sea through Strait of Gibraltar was studied for a period of two years under the frame of the CARBOOCEAN project. A comprehensive sampling program was conducted, which was design to collect samples at eight fixed stations located in the Strait in successive cruises periodically distributed through the year in order to ensure a good spatial and temporal coverage. As a result of this monitoring, time series namely GIFT (GIbraltar Fixed Time series) has been established, allowing the generation of an extensive data set of the carbon system parameters in the area. Data acquired during the development of nine campaigns were analyzed in this work. Total inorganic carbon concentration (CT ) was calculated from alkalinity-pHT pairs and appropriate thermodynamic relationships, with the concentration of anthropogenic carbon (CANT) being also computed using two methods, the 1C* and the TrOCA approach. Applying a two-layer model of water mass exchange through the Strait and using a value of −0.85 Sv for the average transport of the outflowing Mediterranean water recorded in situ during the considered period, a net export of inorganic carbon from the Mediterranean Sea to the Atlantic was obtained, which amounted to 25±0.6 TgC yr−1. A net alkalinity output of 16±0.6 TgC yr−1 was also observed to occur through the Strait. In contrast, the Atlantic water was found to contain a higher concentration of anthropogenic carbon than the Mediterranean water, resulting in a net flux of CANT towards the Mediterranean basin of 4.20±0.04 TgC yr−1 by using the 1C* method, which constituted the most adequate approach for this environment. A carbon balance in the Mediterranean was assessed and fluxes through the Strait are discussed in relation to the highly diverse estimates available in the literature for the area and the different approaches considered for CANT estimation. This work unequivocally confirms the relevant role of the Strait of Gibraltar as a controlling point for the biogeochemical exchanges occurring between the Mediterranean Sea and the Atlantic Ocean and emphasizes the influence of the Mediterranean basin in the carbon inventories of the North Atlantic.Peer reviewe

Reconstruction of the seasonal cycle of air–sea CO2 fluxes in the Strait of Gibraltar

The present study reports and discusses water surface fCO2 measurements from 36 cruises in the Strait of Gibraltar made over an eleven-year period (1997 to 2009). Underway measurements of sea surface CO2 fugacity (fCO2sw), sea surface temperature (SST) and sea surface salinity (SSS) compiled during the cruises were analysed and integrated into a single database which provided the resolution/sensitivity required for an examination of the seasonal variability of the fCO2sw; these data allowed the reconstruction of the climatological seasonal cycle for the year 2005. The seasonal cycle of both SST and SSS was found to be within the range of the thermohaline signature of the North Atlantic Surface Water, which is the main water mass that flows into the Mediterranean Sea through the Strait of Gibraltar at the surface. The seasonal distribution of fCO22005 was characterised by a monthly minimum value of 334 ± 12 μatm in May, followed by a gradual increase to a maximum of 385 μatm during late summer, due to the warming of surface waters. The spatial variability of fCO2sw observed in the area also indicated that superimposed phenomena, occurring at scales other than seasonal, could affect the dissolved CO2 distribution. In particular, intense vertical mixing processes generated by internal waves in this region may have an impact on the surface fCO2sw on a tidal scale. Seasonal CO2 cycle dynamics indicated that the surface waters of the Strait of Gibraltar acted as an atmospheric CO2 source during summer and autumn and a CO2 sink during winter and spring. When these sink/source strengths are integrated on an annual basis, the Strait of Gibraltar was close to equilibrium with atmospheric CO2, resulting in a neutral atmosphere-ocean exchange (− 0.06 ± 0.12 mol C m− 2 yr− 1).Funding for this work was provided by the CARBOOCEAN IP of the European Commission (511176GOCE) and by the Spanish Ministry of Education and Sciences through the Projects CAIBEX (CTM2007-66408) and (CTM2006-26206-E/MAR). Author Mercedes de la Paz acknowledges the financial support of the CSIC postdoctoral program JAE-Doc.Peer reviewe

Case Reports1. A Late Presentation of Loeys-Dietz Syndrome: Beware of TGFβ Receptor Mutations in Benign Joint Hypermobility

Background: Thoracic aortic aneurysms (TAA) and dissections are not uncommon causes of sudden death in young adults. Loeys-Dietz syndrome (LDS) is a rare, recently described, autosomal dominant, connective tissue disease characterized by aggressive arterial aneurysms, resulting from mutations in the transforming growth factor beta (TGFβ) receptor genes TGFBR1 and TGFBR2. Mean age at death is 26.1 years, most often due to aortic dissection. We report an unusually late presentation of LDS, diagnosed following elective surgery in a female with a long history of joint hypermobility. Methods: A 51-year-old Caucasian lady complained of chest pain and headache following a dural leak from spinal anaesthesia for an elective ankle arthroscopy. CT scan and echocardiography demonstrated a dilated aortic root and significant aortic regurgitation. MRA demonstrated aortic tortuosity, an infrarenal aortic aneurysm and aneurysms in the left renal and right internal mammary arteries. She underwent aortic root repair and aortic valve replacement. She had a background of long-standing joint pains secondary to hypermobility, easy bruising, unusual fracture susceptibility and mild bronchiectasis. She had one healthy child age 32, after which she suffered a uterine prolapse. Examination revealed mild Marfanoid features. Uvula, skin and ophthalmological examination was normal. Results: Fibrillin-1 testing for Marfan syndrome (MFS) was negative. Detection of a c.1270G > C (p.Gly424Arg) TGFBR2 mutation confirmed the diagnosis of LDS. Losartan was started for vascular protection. Conclusions: LDS is a severe inherited vasculopathy that usually presents in childhood. It is characterized by aortic root dilatation and ascending aneurysms. There is a higher risk of aortic dissection compared with MFS. Clinical features overlap with MFS and Ehlers Danlos syndrome Type IV, but differentiating dysmorphogenic features include ocular hypertelorism, bifid uvula and cleft palate. Echocardiography and MRA or CT scanning from head to pelvis is recommended to establish the extent of vascular involvement. Management involves early surgical intervention, including early valve-sparing aortic root replacement, genetic counselling and close monitoring in pregnancy. Despite being caused by loss of function mutations in either TGFβ receptor, paradoxical activation of TGFβ signalling is seen, suggesting that TGFβ antagonism may confer disease modifying effects similar to those observed in MFS. TGFβ antagonism can be achieved with angiotensin antagonists, such as Losartan, which is able to delay aortic aneurysm development in preclinical models and in patients with MFS. Our case emphasizes the importance of timely recognition of vasculopathy syndromes in patients with hypermobility and the need for early surgical intervention. It also highlights their heterogeneity and the potential for late presentation. Disclosures: The authors have declared no conflicts of interes

Acidificación oceánica: un riesgo global a escala regional

Trabajo presentado en el III Congreso de Jóvenes Investigadores del Mar, celebrado en Granada (España), del 6 al 9 de septiembre de 202

Situación de los océanos del mundo ante la crisis global

Trabajo presentado en Think Tank del Club Nuevo Mundo, celebrado en modalidad virtual el 12 de mayo de 2020Ponente invitada en el Think Tank organizado por el Club Nuevo Mundo y publicado en la revista Tendencias21 y participación en debate posterio