IBAMar DATABASE: 4 decades of oceanographic sampling on the Western Mediterranean Sea

IBAMar (http://www.ba.ieo.es/ibamar) is a regional database that puts together all physical and biochemical data obtained by multiparametric probes (CTDs equipped with different sensors), during the cruises managed by the Balearic Center of the Spanish Institute of Oceanography (COB-IEO). It has been recently extended to include data obtained with classical hydro casts using oceanographic Niskin or Nansen bottles. The result is a database that includes a main core of hydrographic data: temperature (T), salinity (S), dissolved oxygen (DO), fluorescence and turbidity; complemented by bio-chemical data: dissolved inorganic nutrients (phosphate, nitrate, nitrite and silicate) and chlorophyll-a. In IBAMar Database, different technologies and methodologies were used by different teams along the four decades of data sampling in the COB-IEO. Despite of this fact, data have been reprocessed using the same protocols, and a standard QC has been applied to each variable. Therefore it provides a regional database of homogeneous, good quality data. Data acquisition and quality control (QC): 94% of the data are CTDs Sbe911 and Sbe25. S and DO were calibrated on board using water samples, whenever a Rossetta was available (70% of the cases). All CTD data from Seabird CTDs were reviewed and post processed with the software provided by Sea-Bird Electronics. Data were averaged to get 1 dbar vertical resolution. General sampling methodology and pre processing are described in https://ibamardatabase.wordpress.com/home/). Manual QC include visual checks of metadata, duplicate data and outliers. Automatic QC include range check of variables by area (north of Balearic Islands, south of BI and Alboran Sea) and depth (27 standard levels), check for spikes and check for density inversions. Nutrients QC includes a preliminary control and a range check on the observed level of the data to detect outliers around objectively analyzed data fields. A quality flag is assigned as an integer number, depending on the result of the QC check.

Dyfamed-benthos time series observations

In 1990, a benthic component to the DYFAMED (dynamics of fluxes in the Mediterranean) program, the DYFAMED-BENTHOS survey, was established to investigate the possible coupling of benthic to pelagic processes at a permanent station in >2700 m water depth, 52 km off Nice, France. Surface sediment was first sampled at different periods of the year to assess the importance of the biological compartment (particularly metazoan meiofauna) and its relation to seasonally varying particulate matter input to the sea floor (estimated by measuring surface sediment particle size and porosity, as well as chloroplastic pigments, organic carbon, nitrogen and calcium carbonate contents). Beginning in 1993, surface sediment was sampled at an average interval of 1.4 months for over five consecutive years using multicorers. Biogeochemical techniques such as deployments of a free-vehicle benthic respirometer and a near-bottom sediment trap, along with analyses of sediment vertical profiles for dissolved oxygen, nutrients and dissolved metals in the porewater, were developed in conjunction with more extensive biological analyses to characterize the recycling of organic matter, and ultimately increase our understanding of the oceanic carbon cycle. This article provides the scientific background and motivation for the development of the on-going DYFAMED-BENTHOS survey, the general characteristics of the benthic site, as well as a detailed description of the sampling design applied from late 1990-2000.

Geotechnical engineering characterization of sediments at DSDP Leg 72 Holes

The hydraulic piston coring device (HPC-15) allows recovery of deep ocean sediments with minimal disturbance. The device was used during Leg 72 of the Deep Sea Drilling Project (DSDP) aboard the Glomar Challenger. Core samples were recovered from bore holes in the Rio Grande Rise in the southwest Atlantic Ocean. Relatively undisturbed sediment cores were obtained from Holes 515A, 516, 517, and 518. The results of shipboard physical property measurements and on-shore geotechnical laboratory tests on these cores are presented in this chapter. A limited number of 0.3 m cores were obtained and used in a series of geotechnical tests, including one-dimensional consolidation, direct shear, Atterburg limit, particle size analysis, and specific gravity tests. Throughout the testing program, attention was focused on assessment of sample disturbance associated with the HPC-15 coring device. The HPC-15 device limits sample disturbance reasonably well in terrigenous muds (clays). However, sample disturbance associated with coring calcareous sediments (nannofossil-foraminifer oozes) is severe. The noncohesive, granular behavior of the calcareous sediments is vulnerable to severe disturbance, because of the design of the sampling head on the device at the time of Leg 72. A number of modifications to the sampling head design are recommended and discussed in this chapter. The modifications will improve sample quality for testing purposes and provide longer unbroken core samples by reducing friction between the sediment column and the sampling tool.

Micromesistius poutassou (blue whiting) abundance and biomass data in Bay of Biscay estimated from acoustic surveys (2000-2012)

Acoustic and pelagic trawl data were collected during various pelagic surveys carried out by IFREMER in May between 2000 and 2012 (except 2001), on the eastern continental shelf of the Bay of Biscay (Pelgas series). The acoustic data were collected with a Simrad EK60 echosounder operating at 38 kHz (beam angle at -3 dB: 7°, pulse length set to 1.024 ms). The echosounder transducer was mounted on the vessel keel, at 6 m below the sea surface. The sampling design were parallel transects spaced 12 nm apart which were orientated perpendicular to the coast line from 20 m to about 200 m bottom depth. The nominal sailing speed was 10 knots and 3 knots on average during fishing operations. The scrutinising (species identification) of acoustic data was done by first characterising acoustic schools by type and then linking these types with the species composition of specific trawl hauls. The data set contains nautical area backscattering values, biomass and abundance estimates for blue whiting for one nautical mile long transect lines. Further information on the survey design, scrutinising and biomass estimation can be found in Doray et al. 2012.

Survey bottom trawl data of Micromesistius poutassou (blue whiting) in Bay of Biscay and Celtic Sea from the EVHOE time series (1997-2011)

Data were collected during various groundfish surveys carried out by IFREMER from October to December between 1997 and 2011, on the eastern continental shelf of the Bay of Biscay and in the Celtic Sea (EVHOE series). The sampling design was stratified according to latitude and depth. A 36/47 GOV trawl was used with a 20 mm mesh codend liner. Haul duration was 30 minutes at a towing speed of 4 knots. Fishing was restricted to daylight hours. Catch weights and catch numbers were recorded for all species and body size measured. The weights and numbers per haul were transformed into abundances per km**2 by considering the swept area of a standard haul (0.069 km**2).

(Table 1) Age, sex, length, girth and blubber thickness and content of ringed seals (Pusa hispida) in Kongsfjorden in 2000

This study of vertical fatty acid profiles, based on analysis of 58 fatty acids sampled at 3-mm intervals throughout the blubber column of a model marine mammal, the ringed seal (Pusa hispida), revealed three chemically distinct layers. The average depths of the outer and inner layers were quite consistent (~1.5 and ~1 cm, respectively). Consequently, the middle layer varied greatly in thickness, from being virtually absent in the thinnest animals to 2.5 cm thick in the fattest. The relative consistencies of the thickness and composition of the layers as well as the nature of the fatty acids making up each layer support the generally assumed function of the various layers: (1) the outer layer is primarily structural and thermoregulatory, (2) the inner layer is metabolically active with a fatty acid composition that is strongly affected by recent/ongoing lipid mobilization/deposition, and (3) the middle layer is a storage site that contracts and expands with food availability/consumption. The remarkable dynamics of the middle layer along with the discrete pattern of stratification found in the vertical fatty acid profiles have important implications for methodological sampling design for studies of foraging ecology and toxicology based on analyses of blubber of marine mammals.