Influence of offshore oil and gas structures on seascape ecological connectivity.

Offshore platforms, subsea pipelines, wells and related fixed structures supporting the oil and gas (O&G) industry are prevalent in oceans across the globe, with many approaching the end of their operational life and requiring decommissioning. Although structures can possess high ecological diversity and productivity, information on how they interact with broader ecological processes remains unclear. Here, we review the current state of knowledge on the role of O&G infrastructure in maintaining, altering or enhancing ecological connectivity with natural marine habitats. There is a paucity of studies on the subject with only 33 papers specifically targeting connectivity and O&G structures, although other studies provide important related information. Evidence for O&G structures facilitating vertical and horizontal seascape connectivity exists for larvae and mobile adult invertebrates, fish and megafauna; including threatened and commercially important species. The degree to which these structures represent a beneficial or detrimental net impact remains unclear, is complex and ultimately needs more research to determine the extent to which natural connectivity networks are conserved, enhanced or disrupted. We discuss the potential impacts of different decommissioning approaches on seascape connectivity and identify, through expert elicitation, critical knowledge gaps that, if addressed, may further inform decision making for the life cycle of O&G infrastructure, with relevance for other industries (e.g. renewables). The most highly ranked critical knowledge gap was a need to understand how O&G structures modify and influence the movement patterns of mobile species and dispersal stages of sessile marine species. Understanding how different decommissioning options affect species survival and movement was also highly ranked, as was understanding the extent to which O&G structures contribute to extending species distributions by providing rest stops, foraging habitat, and stepping stones. These questions could be addressed with further dedicated studies of animal movement in relation to structures using telemetry, molecular techniques and movement models. Our review and these priority questions provide a roadmap for advancing research needed to support evidence-based decision making for decommissioning O&G infrastructure

Chemische Mikroumwelten, Pumpensverhalten und microbielle Prozesse in Schwämen

The oxygen dynamics and ventilation behaviour in Dysidea avara and Chondrosia reniformis (Porifera) were investigated using oxygen micro-electrodes and hot-bead thermistors. Both field and laboratory experiments proved the common occurrences of anoxia in the sponge tissue that lasted up to approximately 1 h. Strong temporal and spatial heterogeneity of oxygen concentrations was observed with replicate oxygen profile series across the sponge surface, though tissue close to an osculum was generally better oxygenated. The microbial processes of sponge-associated microbes were investigated in D. avara and C. reniformis. Their presence and rates were established through microsensor measurements of product accumulation and isotope tracer experiments. Total net nitrification occurred at 8.8 and 14.7 nmol cm-3 sponge h-1 for C. reniformis and D. avara, respectively. Rates of denitrification, an anaerobic microbial process, were 10 nmol N consumed cm-3 wet weight sponge h-1 in C. reniformis and 14.9 nmol N cm-3 wet weight sponge h-1 in D. avara while anaerobic ammonium oxidation (anammox) and sulfate reduction were below detectable limits in both species

Chemical micro-environments, ventilation behaviour and microbial processes in sponges

The oxygen dynamics and ventilation behaviour in Dysidea avara and Chondrosia reniformis (Porifera) were investigated using oxygen micro-electrodes and hot-bead thermistors. Both field and laboratory experiments proved the common occurrences of anoxia in the sponge tissue that lasted up to approximately 1 h. Strong temporal and spatial heterogeneity of oxygen concentrations was observed with replicate oxygen profile series across the sponge surface, though tissue close to an osculum was generally better oxygenated. The microbial processes of sponge-associated microbes were investigated in D. avara and C. reniformis. Their presence and rates were established through microsensor measurements of product accumulation and isotope tracer experiments. Total net nitrification occurred at 8.8 and 14.7 nmol cm-3 sponge h-1 for C. reniformis and D. avara, respectively. Rates of denitrification, an anaerobic microbial process, were 10 nmol N consumed cm-3 wet weight sponge h-1 in C. reniformis and 14.9 nmol N cm-3 wet weight sponge h-1 in D. avara while anaerobic ammonium oxidation (anammox) and sulfate reduction were below detectable limits in both species

Making waves: marine citizen science for impact

The benefit of engaging volunteers in marine citizen science projects goes beyond generation of data and has intrinsic value with regards to community capacity-building and education. Yet, despite the documented benefits of citizen science, there can be barriers to the process of developing strategic citizen science projects and translating data into valued results with natural resource management applications. This paper presents four case-studies from fifteen years of Reef Check Australia (RCA) marine citizen science research and education projects. These case studies convey approaches and lessons-learned from the process of designing, implementing and sharing citizen science programs with the goal to create valuable social and environmental outcomes: (1) Demonstrating citizen science data quality through a precision study on data and analysis of 15 years of standardized Reef Check (RC) reef health data in Queensland, Australia. (2) Identifying and responding to data gaps through volunteer monitoring of sub-tropical rocky reefs in South East Queensland, Australia. (3) Adapting citizen science protocols to enhance capacity building, partnerships and strategic natural resource management applications through reef habitat mapping. (4) Tailoring new pathways for sharing citizen science findings and engaging volunteers with the community via a Reef Check Australia Ambassadors community outreach program. These case studies offer insights into considerations for developing targeted and flexible citizen science projects, showcasing the work of volunteers and project stakeholders, and collaborating with partners for applications beneficial to research, management and education

Trash or Treasure? Considerations for Future Ecological Research to Inform Oil and Gas Decommissioning

Numerous oil and gas (O&amp;G) installations worldwide will need to be decommissioned in the near future. Complete removal of subsea structures is often the default approach although some regions retain structures under rigs-to-reefs programs. Here, we reviewed the published literature to understand the status of global research on decommissioning, and specifically identify gaps in ecological knowledge. We estimated the frequency of different research categories (i.e., themes, and spatial/temporal scales), and tested the assumption that the number of papers across the categories of each research aspect was even in distribution. However, the frequency of studies focusing on biodiversity at a local (≤100 km2) scale (relative to regional and oceanic and pan-oceanic scales) were significantly higher; while other theme categories (e.g., eco-toxicology, connectivity, structural-integrity, restoration and other) were significantly lower than expected. Temporally, ≤1-year studies were more frequent than multi-year studies, but these frequencies did not significantly deviate from the assumed distribution of equal frequencies. We propose that further research be carried out to evaluate the benefits of both retention and removal of structures. Ecological research on decommissioning should extend its focus beyond biodiversity, to include eco-toxicology, structural-integrity, connectivity at larger spatial and temporal scales. This would provide a more holistic assessment of ecological impacts to inform sustainable and equitable development choices in multiple Blue Economy sectors, as we transition from offshore O&amp;G to marine renewables.</p

Characterisation of the biofouling community on a floating wave energy device

<p>Wave energy devices are novel structures in the marine environment and, as such, provide a unique habitat for biofouling organisms. In this study, destructive scrape samples and photoquadrats were used to characterise the temperate epibenthic community present on prototypes of the Pelamis wave energy converter. The biofouling observed was extensive and diverse with 115 taxa recorded including four non-native species. Vertical zonation was identified on the sides of the device, with an algae-dominated shallow subtidal area and a deeper area characterised by a high proportion of suspension-feeding invertebrates. Differences in species composition and biomass were also observed between devices, along the length of the device and between sampling dates. This research provides an insight into the variation of biofouling assemblages on a wave energy device as well as the potential technical and ecological implications associated with biofouling on marine renewable energy structures.</p

Evidence of nitrification and denitrification in high and low microbial abundance sponges

Aerobic and anaerobic microbial key processes were quantified and compared to microbial numbers and morphological structure in Mediterranean sponges. Direct counts on histological sections stained with DAPI showed that sponges with high microbial abundances (HMA sponges) have a denser morphological structure with a reduced aquiferous system compared to low microbial abundance (LMA) sponges. In Dysidea avara, the LMA sponge, rates of nitrification and denitrification were higher than in the HMA sponge Chondrosia reniformis, while anaerobic ammonium oxidation and sulfate reduction were below detection in both species. This study shows that LMA sponges may host physiologically similar microbes with comparable or even higher metabolic rates than HMA sponges, and that anaerobic processes such as denitrification can be found both in HMA and LMA sponges. A higher concentration of microorganisms in the mesohyl of HMA compared to LMA sponges may indicate a stronger retention of and, hence, a possible benefit from associated microbes