Description: Source data of the North Sea well inventory: United Kingdom (UK)- Oil and Gas Authority (Dec. 2018) - https://data-ogauthority.opendata.arcgis.com/datasets/oga-wells-ed50 Contains information provided by the OGA. Wells are extracted for the area of the PGS data set PGS Mega Survey Plus. We measured the distance between all wells of the test group (n = 43) and all those who are within the seismic data set (n = 1,792; presented here) and their closest bright spot with polarity reversal. Furthermore, we calculated the mean RMS amplitudes and RMS amplitude standard deviation for a buffer radius of 300 m around the well paths for all wells inside the seismic data set and the visited wells as 300 m is the distance below which all of the visited wells of the test group showed gas release in form of flares from the seafloor. We test, if the propensity of a well to leak can be identified by using a logistic regression, which includes regressors such as well activity data and/or derived parameters such as mean RMS amplitude and mean RMS amplitude standard deviation, the distance towards the most proximal bright spot with polarity reversal and age (spud date). In order to identify the most suitable regressor combination best subset selection is employed. The main selection criterion chosen was the prediction accuracy from randomly and repeatedly splitting the visited wells into a training and a test set and then using the fitted logistic regression to predict the test data. The most suitable subset turns out to only employ the distance to polarity reversal, producing a prediction accuracy of 89% and the following logistic regression results: In order to obtain confidence intervals using the normal distribution the distance to bright spot with polarity reversal has to be normally distributed, which it is not. Yet it can be transformed to normality by adding 100 meters to the original distance and then taking the natural logarithm: Logistic regression fit for leakage of all visited wells using distance to bright spot with polarity reversal in meters as a regressor. Please find further information on the applied statistical analyses in the supplementary material. EstimateStd. Errorz valuePr(〉|z|)Significance Intercept4,853.9461,735.1282.7970.005150.01 Distance−0.0073610.002700−2.7260.006400.01 The transformed logistic regression model is then used to predict the probabilities of leakage for the wells within our seismic data set in the Central North Sea (here presented data). In order to obtain confidence bands this logistic regression is performed subtracting and adding two standard deviations from the calculated probability. The point estimate predicts leakage from 926 of the 1,792 wells, where the 95% confidence interval ranges from 719 to 1,058.

Description: Two newly developed coring devices, the Multi-Autoclave-Corer and the Dynamic Autoclave Piston Corer were deployed in shallow gas hydrate-bearing sediments in the northern Gulf of Mexico during research cruise SO174 (Oct-Nov 2003). For the first time, they enable the retrieval of near-surface sediment cores under ambient pressure. This enables the determination of in situ methane concentrations and amounts of gas hydrate in sediment depths where bottom water temperature and pressure changes most strongly influence gas/hydrate relationships. At seep sites of GC185 (Bush Hill) and the newly discovered sites at GC415, we determined the volume of low-weight hydrocarbons (C1 through C5) from nine pressurized cores via controlled degassing. The resulting in situ methane concentrations vary by two orders of magnitudes between 0.031 and 0.985 mol kg**-1 pore water below the zone of sulfate depletion. This includes dissolved, free, and hydrate-bound CH4. Combined with results from conventional cores, this establishes a variability of methane concentrations in close proximity to seep sites of five orders of magnitude. In total four out of nine pressure cores had CH4 concentrations above equilibrium with gas hydrates. Two of them contain gas hydrate volumes of 15% (GC185) and 18% (GC415) of pore space. The measurements prove that the highest methane concentrations are not necessarily related to the highest advection rates. Brine advection inhibits gas hydrate stability a few centimeters below the sediment surface at the depth of anaerobic oxidation of methane and thus inhibits the storage of enhanced methane volumes. Here, computerized tomography (CT) of the pressure cores detected small amounts of free gas. This finding has major implications for methane distribution, possible consumption, and escape into the bottom water in fluid flow systems related to halokinesis.

Description: This dataset consists of the results from particulate matter geochemical analyses of sediment cores that were taken during the cruise POS536 in August 2019. The research area was the North Atlantic gyre southwest of the Azores. During this cruise, samples were collected for the JPI Oceans project HOTMIC. The research objective of HOTMIC is the investigation of distribution and transport of microplastic particles from the European coast to the garbage accumulations in the North Atlantic gyre. Sediment samples were taken with a box corer and subsampled with MUC liners. MUC liner subsamples from three stations were sliced for geochemical analyses. Particulate organic carbon and nitrogen, total sulfur and CaCO3 contents of the solid phase were determined with an elemental analyzer.

Description: This dataset consists of the results from pore water geochemical analyses of sediment cores that were taken during the cruise POS536 in August 2019. The research area was the North Atlantic gyre southwest of the Azores. During this cruise, samples were collected for the JPI Oceans project HOTMIC. The research objective of HOTMIC is the investigation of distribution and transport of microplastic particles from the European coast to the garbage accumulations in the North Atlantic gyre. Sediment samples were taken with a box corer and subsampled with MUC liners. MUC liner subsamples from three stations were sliced for geochemical analyses and pore water from the sediment slices was extracted with rhizones. Geochemical analyses include the quantification of major anions and cations using inductively coupled plasma atomic emission spectroscopy and ion chromatography, respectively.

Description: This dataset consists of the results from particulate matter geochemical analyses of sediment cores that were taken during the cruise POS536 in August 2019. The research area was the North Atlantic gyre southwest of the Azores. During this cruise, samples were collected for the JPI Oceans project HOTMIC. The research objective of HOTMIC is the investigation of distribution and transport of microplastic particles from the European coast to the garbage accumulations in the North Atlantic gyre. Sediment samples were taken with a box corer and subsampled with MUC liners. MUC liner subsamples from three stations were sliced for geochemical analyses. Particulate organic carbon and nitrogen, total sulfur and CaCO3 contents of the solid phase were determined with an elemental analyzer.

Description: This dataset consists of the results from particulate matter geochemical analyses of sediment cores that were taken during the cruise POS536 in August 2019. The research area was the North Atlantic gyre southwest of the Azores. During this cruise, samples were collected for the JPI Oceans project HOTMIC. The research objective of HOTMIC is the investigation of distribution and transport of microplastic particles from the European coast to the garbage accumulations in the North Atlantic gyre. Sediment samples were taken with a box corer and subsampled with MUC liners. MUC liner subsamples from three stations were sliced for geochemical analyses. Particulate organic carbon and nitrogen, total sulfur and CaCO3 contents of the solid phase were determined with an elemental analyzer.

Description: This dataset consists of the results from pore water geochemical analyses of sediment cores that were taken during the cruise POS536 in August 2019. The research area was the North Atlantic gyre southwest of the Azores. During this cruise, samples were collected for the JPI Oceans project HOTMIC. The research objective of HOTMIC is the investigation of distribution and transport of microplastic particles from the European coast to the garbage accumulations in the North Atlantic gyre. Sediment samples were taken with a box corer and subsampled with MUC liners. MUC liner subsamples from three stations were sliced for geochemical analyses and pore water from the sediment slices was extracted with rhizones. Geochemical analyses include the quantification of major anions and cations using inductively coupled plasma atomic emission spectroscopy and ion chromatography, respectively.

Description: This dataset consists of the results from pore water geochemical analyses of sediment cores that were taken during the cruise POS536 in August 2019. The research area was the North Atlantic gyre southwest of the Azores. During this cruise, samples were collected for the JPI Oceans project HOTMIC. The research objective of HOTMIC is the investigation of distribution and transport of microplastic particles from the European coast to the garbage accumulations in the North Atlantic gyre. Sediment samples were taken with a box corer and subsampled with MUC liners. MUC liner subsamples from three stations were sliced for geochemical analyses and pore water from the sediment slices was extracted with rhizones. Geochemical analyses include the quantification of major anions and cations using inductively coupled plasma atomic emission spectroscopy and ion chromatography, respectively.

Description: This dataset consists of the results particulate matter geochemical analyses of sediment cores that were taken during the cruise AL534/2 in March 2020. The research areas were the coastal waters close to major river mounds off the coasts of Spain, Portugal, Belgium, Great Britain, the Netherlands and Germany. During this cruise, samples were collected for the JPI Oceans project HOTMIC. The research objective of HOTMIC is the investigation of distribution and transport of microplastic particles from the European coast to the garbage accumulations in the North Atlantic gyre. Sediment samples were taken with a mini multi corer and, in one case, with a mini box corer. Particulate organic carbon and nitrogen, total sulfur and CaCO3 contents of the solid phase were determined with an elemental analyzer.

Description: This dataset consists of the results particulate matter geochemical analyses of sediment cores that were taken during the cruise AL534/2 in March 2020. The research areas were the coastal waters close to major river mounds off the coasts of Spain, Portugal, Belgium, Great Britain, the Netherlands and Germany. During this cruise, samples were collected for the JPI Oceans project HOTMIC. The research objective of HOTMIC is the investigation of distribution and transport of microplastic particles from the European coast to the garbage accumulations in the North Atlantic gyre. Sediment samples were taken with a mini multi corer and, in one case, with a mini box corer. Particulate organic carbon and nitrogen, total sulfur and CaCO3 contents of the solid phase were determined with an elemental analyzer.