Environmental Impact of Offshore Gas Activities on the Benthic Environment: A Case Study

Abstract

Multidisciplinary monitoring of the impact of offshore gas platforms on northern and central Adriatic marine ecosystems has been conducted since 1998. Beginning in 2006, 4-5 year investigations spanning the period before, during, and after rig installation have explored the effects of its construction and presence on macrozoobenthic communities, sediment, water quality, pollutant bioaccumulation, and fish assemblages. In this study, sediment samples collected at increasing distance from an offshore gas platform before, during and after its construction were subjected to chemical analysis and assessment of benthic communities. Ecological indices were calculated to evaluate the ecological status of the area. Ecotoxicological analysis of sediment was performed to establish whether pollutants are transferred to biota. The study applied a before-after control-impact design to assess the effects of rig construction and presence and provide reference data on the possible impacts of any further expansion of the gas extraction industry in the already heavily exploited Adriatic Sea. Only some of the metals investigated (barium, chromium, cadmium, and zinc) showed a different spatial and/or temporal distribution that may be platform-related. In the early phases, the sediment concentrations of polycyclic aromatic hydrocarbons were below the detection limit at all sites; they then became detectable, but without significant spatial differences. The present findings suggest that the environmental effects of offshore gas platforms may be difficult to quantify, interpret, and generalize, because they are influenced by numerous, often local, abiotic, and biotic variables in different and unpredictable ways.

Semi-Automated Data Processing and Semi-Supervised Machine Learning for the Detection and Classification of Water-Column Fish Schools and Gas Seeps with a Multibeam Echosounder

“…The MBES data from surveys 1 and 2 are publicly available at (access date 23 April 2021) [ 37 ]. These surveys were carried out as part of an ongoing monitoring program by CNR-IRBIM of gas platforms in the central Adriatic Sea since the late 1990s [ 11 , 24 , 38 ].…”

“…The MBES data from surveys 1 and 2 are publicly available at https://doi.org/10.17882/79142 (access date 23 April 2021) [37]. These surveys were carried out as part of an ongoing monitoring program by CNR-IRBIM of gas platforms in the central Adriatic Sea since the late 1990s [11,24,38]. The seafloor (Figures 3 and 4) was detected in real time from the MBES measurements by the SIS software using the recommended "basic filters" settings, since no significant peaks or pits were expected on the seafloor.…”

Metal‐based micro and nanosized pollutant in marine organisms: What can we learn from a combined atomic force microscopy‐scanning electron microscopy study

“…To achieve this goal, we characterized marine molluscs, Mytilus galloprovincialis collected, in the framework of multiannual and multidisciplinary monitoring programmes, in the proximity of several gas extraction platforms in the Adriatic Sea, where the specimens were likely exposed to different kinds of metallic nano‐pollutants 14‐17 . Mussels are, indeed, ideal organisms to evaluate the potential effects of nano‐pollutants, as they are inexpensive, easily available and stationary.…”

Global assessment of marine biodiversity potentially threatened by offshore hydrocarbon activities

“…Managing offshore hydrocarbon activities to minimize threats to the environment is challenging, given the little we know about the ocean and how it can be affected by hydrocarbon activities (Rabalais, ). Quantifying and generalizing the effects of hydrocarbon activities on biodiversity is complex, as they are influenced by many biotic and abiotic variables, often in a unique manner at a local level (Punzo et al, ).…”