Is the Mediterranean Sean Outflow conditioning cold water corals in the North Atlantic?

posterWithin the context of the UE project ATLAS, in September - October 2016 on board RV Sarmiento de Gamboa, the MEDWAVES (MEDiterranean out flow WAter and Vulnerable EcosystemS) targeted areas under the potential influence of the MOW (Mediterranean Water Outflow) within the Mediterranean and Atlantic realms. These include seamounts where cold-water corals (CWC) have been reported, they may act as essential “stepping stones” connecting fauna of seamounts in the Mediterranean with those of seamounts in the continental shelf of Portugal, the Azores and the Mid‐ Atlantic Ridge. During MEDWAVES sampling was conducted through several seamounts: Formigas (Azores), Ormonde & Gazul (North Atlantic) and Seco de los Olivos (Alboran Sea). High quality CO2 measurements were conducted in the 500 meters above the bottom in order to characterize the water masses and detect the MOW spreading. MOW is warm and salty, but also high in alkalinity and pH. Is MOW conditioning CWC

The CARIMED (CARbon IN the MEDiterranean Sea) data synthesis initiative: overview and quality control procedures

posterIn this work we present the data synthesis project CARIMED (CARbon in the MEDiterranean Sea), we aim to create a uniformly formatted consistent quality controlled public database for carbon relevant variables from hydrographic cruises covering the whole water column and the different basins in the MedSea. Both primary and secondary quality control (QC) of the data has been performed following the experience gathered in CARINA and GLODAPv2. The motivation for this initiative stemmed from two CIESM (Mediterranean Science Commission) workshops, the first one in Menton (France) October 2008 (CIESM, 2008) focused on the impact of OA on biological, chemical and physical systems in the MedSea, and the second one in Supetar (Croatia) May 2011 (CIESM, 2012) focused on designing the Mediterranean Sea repeat hydrography program (MED-SHIP). The unresolved issues regarding the CO2 system in the MedSea were summarized in Malanotte-Rizzoli et al. (Oc Sc, 2014), one of them the temporal and spatial variability of the interior CO2 system, clearly justifies the need for CARIMED. Independently two projects focused on compiling CO2 water column data in the MedSea, an initiative within the EU MedSeA project (Gemayel et al., ESD 2015) called MEDICA (T. Lovato personal communication) and the one here presented lead by the Spanish IEO and partially funded by SanLeón-Bartolomé 's PhD project. We hope a product like this will be much welcome by the oceanographic community, both observationist and modellers, as it was the release of the Meteor cruise M84/3 data in CDIAC used in several publications (Palmieri et al., BG 2015; Cossarini et al., BG 2015; Hassoun et al., DSR 2015 & JWROS 2015; Lovato & Vichi, DSR 2015; Gemayel et al., ESD 2015)

Is Deep Sea Cold Water Corals distribution constrained by CO2 distinct signatures?

conferenceObjectThe MEDWAVESThe MEDWAVES (MEDiterranean out flow WAter and Vulnerable EcosystemS) cruise was developed in the framework of the ATLAS project, with the main objective of determining areas under the influence of the Mediterranean Overflow Water within the Mediterranean and Atlantic areas. MEDWAVES cruise (LEG 1: Cadiz – Punta Delgada and LEG 2: Punta Delgada – Málaga) was completed between September-October 2016 on board the Spanish R/V Sarmiento de Gamboa. Within the specific aim of evaluating the biogeochemichal role of the Mediterranean Water, over and around the Formigas, Ormonde and Seco de los Olivos seamounts, and the Gazul Mud volcano, some CO2 system variables were measured on board (pH, total alkalinity and carbonate ion concentration) together with dissolved oxygen samples. The chemistry of the CO2 in the Mediterranean Sea is very particular, characterised by warm, salty and high alkalinity waters [1]. The Mediterranean Water goes into the Atlantic Ocean through the strait of Gibraltar, being clearly identified as the most saline water of the water column located at approximately 1000 dbar [2]. Apart from the water mass characteristic, other properties and organism characteristics of the Mediterranean Sea are spilt into the Atlantic. According to the objectives of MEDWAVES cruise and taking into account the fine scale sampling made over the 400m above the bottom, we will characterise the CO2 system of the four different areas, trying to distinguish the signature of the Mediterranean Water in each seamount. The presence of depth cold water coral in those seamounts is poorly known and we would like to connect those of Mediterranean Sea with those of the continental shelf of Portugal, the Azores and the Mid-Atlantic Ridge with the CO2 variables. Hence, a second step will be to evaluate the connexion between the cold water corals and the CO2 system

Ocean Circulation over Formigas and Ormonde Seamounts

Seamounts constitute an obstacle to the free ocean flow, modifying the patter of circulation. As a result of these alterations, a variety of hydrodynamical processes and phenomena may take place in seamounts, among others, Taylor columns/caps. These oceanographic effects may turn seamounts into very productive ecosystems with high biodiversity. Under these conditions seamounts provide a particularly good environment for the settle of some organisms, acting as stepping stones and contributing to its dispersal. In this study, we verify if these oceanographic effects explain the presence of cold-water corals of Mediterranean origin in the Atlantic. To achieve this, three seamounts in the path of the Mediterranean Outflow Water (MOW) through the Eastern North Atlantic were selected: the Gazul mud volcano, and the Ormonde and Formigas seamounts. In order to determine the hydrographic and dynamical conditions in each one of the three locations, CTD, LADPC and biochemical observations were carried out. Taylor columns were not observed in any of the three sampled areas. Although we found suggestions of upwelling/downwelling systems, their effect was barely noticed in the circulation pattern. The oceanographic processes in those areas are more influenced by the vertical distribution of water masses, which determine the stability of the water column. Moreover, the high values of the Brunt-Väisälä frequency around the MOW halocline can lead to the formation of internal waves. These perturbations in the water column can enhance the vertical mixing, producing suspension, which, in turn, could affect the vertical distribution of cold-water corals

Ocean Circulation over North Atlantic underwater features in the path of the Mediterranean Outflow Water: Ormonde and Formigas seamounts, and the Gazul mud volcano

Seamounts constitute an obstacle to the ocean circulation, modifying it. As a result, a variety of hydrodynamical processes and phenomena may take place over seamounts, among others, flow intensification, current deflection, upwelling, Taylor caps, and internal waves. These oceanographic effects may turn seamounts into very productive ecosystems with high species diversity, and in some cases, are densely populated by benthic organisms, such corals, gorgonians, and sponges. In this study, we describe the oceanographic conditions over seamounts and other underwater features in the path of the Mediterranean Outflow Water (MOW), where populations of benthic suspensions feeders have been observed. Using CTD, LADPC and biochemical measurements carried out in the Ormonde and Formigas seamounts and the Gazul mud volcano (Northeast Atlantic), we show that Taylor caps were not observed in any of the sampled features. However, we point out that the relatively high values of the Brunt–Väisälä frequency in the MOW halocline, in conjunction with the slope of the seamount flanks, set up conditions for the breakout of internal waves and amplification of the currents. This may enhance the vertical mixing, resuspending the organic material deposited on the seafloor and, therefore, increasing the food availability for the communities dominated by benthic suspension feeders. Thus, we hypothesize that internal waves could be improving the conditions for benthic suspension feeders to grow on the slope of seamounts.En prens

Variability and Trends in Physical and Biogeochemical Parameters of the Mediterranean Sea during a Cruise with RV MARIA S. MERIAN in March 2018

The last few decades have seen dramatic changes in the hydrography and biogeochemistry of the Mediterranean Sea. The complex bathymetry and highly variable spatial and temporal scales of atmospheric forcing, convective and ventilation processes contribute to generate complex and unsteady circulation patterns and significant variability in biogeochemical systems. Part of the variability of this system can be influenced by anthropogenic contributions. Consequently, it is necessary to document details and to understand trends in place to better relate the observed processes and to possibly predict the consequences of these changes. In this context we report data from an oceanographic cruise in the Mediterranean Sea on the German research vessel Maria S. Merian (MSM72) in March 2018. The main objective of the cruise was to contribute to the understanding of long-term changes and trends in physical and biogeochemical parameters, such as the anthropogenic carbon uptake and to further assess the hydrographical situation after the major climatological shifts in the eastern and western part of the basin, known as the Eastern and Western Mediterranean Transients. During the cruise, multidisciplinary measurements were conducted on a predominantly zonal section throughout the Mediterranean Sea, contributing to the Med-SHIP and GO-SHIP long-term repeat cruise section that is conducted at regular intervals in the Mediterranean Sea to observe changes and impacts on physical and biogeochemical variables. The data can be accessed at https://doi.org/10.1594/PANGAEA.905902 (Hainbucher et al., 2019), https://doi.org/10.1594/PANGAEA.913512 (Hainbucher, 2020a) https://doi.org/10.1594/PANGAEA.913608, (Hainbucher, 2020b) https://doi.org/10.1594/PANGAEA.913505, (Hainbucher, 2020c) https://doi.org/10.1594/PANGAEA.905887 (Tanhua et al., 2019) and https://doi.org/10.25921/z7en-hn85 (Tanhua et al, 2020)

Global ocean spectrophotometric pH assessment: consistent inconsistencies

Ocean acidification (OA)—or the decrease in seawater pH resulting from ocean uptake of CO2 released by human activities—stresses ocean ecosystems and is recognized as a Climate and Sustainable Development Goal Indicator that needs to be evaluated and monitored. Monitoring OA-related pH changes requires a high level of precision and accuracy. The two most common ways to quantify seawater pH are to measure it spectrophotometrically or to calculate it from total alkalinity (TA) and dissolved inorganic carbon (DIC). However, despite decades of research, small but important inconsistencies remain between measured and calculated pH. To date, this issue has been circumvented by examining changes only in consistently measured properties. Currently, the oceanographic community is defining new observational strategies for OA and other key aspects of the ocean carbon cycle based on novel sensors and technologies that rely on validation against data records and/or synthesis products. Comparison of measured spectrophotometric pH to calculated pH from TA and DIC measured during the 2000s and 2010s eras reveals that (1) there is an evolution toward a better agreement between measured and calculated pH over time from 0.02 pH units in the 2000s to 0.01 pH units in the 2010s at pH > 7.6; (2) a disagreement greater than 0.01 pH units persists in waters with pH < 7.6, and (3) inconsistencies likely stem from variations in the spectrophotometric pH standard operating procedure (SOP). A reassessment of pH measurement and calculation SOPs and metrology is urgently neede