Marine eDNA sampling from submerged surfaces with paint rollers.

Environmental DNA (eDNA) analyses of species present in marine environments is the most effective biological diversity measurement tool currently available. eDNA sampling methods are an intrinsically important part of the eDNA biodiversity analysis process. Identification and development of eDNA sampling methods that are as rapid, affordable, versatile and practical as possible will improve rates of detection of marine species.

Using environmental DNA to better inform decision making around decommissioning alternatives for offshore oil and gas infrastructure.

Artificial reefs are being utilised globally to aid in natural resource management, conservation, restoration or the creation of unique marine habitats. There is discussion around the optimal construction materials and designs for artificial reefs, the influences these have on biological communities, and the resulting ecological and social benefits. This discussion also includes the ecological value of repurposed marine infrastructure, such as decommissioned oil and gas platforms.

Advantages of model averaging of species sensitivity distributions used for regulating produced water discharges.

Produced water (PW) generated by Australian offshore oil and gas activities is typically discharged to the ocean after treatment. These complex mixtures of organic and inorganic compounds can pose significant environmental risk to receiving waters, if not managed appropriately. Oil and gas operators in Australia are required to demonstrate that environmental impacts of their activity are managed to levels that are as low as reasonably practicable, for example, through risk assessments comparing predicted no-effect concentrations (PNECs) with predicted environmental concentrations of PW.

The functional diversity of fish assemblages in the vicinity of oil and gas pipelines compared to nearby natural reef and soft sediment habitats.

As the offshore hydrocarbon industry matures and decommissioning activities are expected to increase, there is a requirement to assess the environmental consequences of different pipeline decommissioning options. Previous research on fish and other ecological components associated with pipelines has focused on examining species richness, abundance and biomass surrounding structures. The extent to which subsea pipelines mimic or alter ecosystem function compared with nearby natural habitats is unknown.

Evidence of fish following towed oil and gas platforms to a reefing site and rapid colonisation.

We investigated the composition and abundance of fish assemblages associated with seven offshore oil and gas platform jackets in the Gulf of Thailand before (pre-lift and pre-tow), and immediately after relocation (post-tow and reefed). Jackets were cut, lifted until partly out of the water, and attached to the rear of a heavy lift vessel. They were towed at speeds of 2.

The Influence of Oil-in-Water Preparations on the Toxicity of Crude Oil to Marine Invertebrates and Fish Following Short-Term Pulse and Continuous Exposures.

Following an oil spill, accurate assessments of the ecological risks of exposure to compounds within petroleum are required, as is knowledge regarding how those risks may change with the use of chemical dispersants. Laboratory toxicity tests are frequently used to assess these risks, but differences in the methods for preparation of oil-in-water solutions may confound interpretation, as may differences in exposure time to those solutions. In the present study, we used recently developed modifications of standardized ecotoxicity tests with copepods (Acartia sinjiensis), sea urchins (Heliocidaris tuberculata), and fish embryos (Seriola lalandi) to assess their response to crude oil solutions and assessed whether the oil-in-water preparation method changed the results.

Complementary molecular and visual sampling of fish on oil and gas platforms provides superior biodiversity characterisation.

Offshore oil and gas platforms have the potential to provide complex refugia for fish and benthic colonisers. We compare two methods of biodiversity assessment for fish and elasmobranchs at seven decommissioned oil and gas platforms as well as five sediment sites, located 5 km from platforms, in the Gulf of Thailand. Using surveys from stereo-video ROV transects, and data from Environmental DNA (eDNA) water-column samples, we detected fish and elasmobranch taxa from 39 families and 66 genera across both platform and sediment sites with eDNA, compared with 18 families and 29 genera by stereo-ROV with platforms yielding significantly greater species richness.

A Comparison of Short-Term and Continuous Exposures in Toxicity Tests of Produced Waters, Condensate, and Crude Oil to Marine Invertebrates and Fish.

Petroleum hydrocarbons can be discharged into the marine environment during offshore oil and gas production or as a result of oil spills, with potential impacts on marine organisms. Ecotoxicological assay durations (typically 24-96 h) used to characterize risks to exposed organisms may not always reflect realistic environmental exposure durations in a high-energy offshore environment where hydrocarbons are mixed and diluted rapidly in the water column. To investigate this, we adapted 3 sensitive toxicity tests to incorporate a short-term pulse exposure to 3 petroleum-based products: a produced water, the water-accommodated fraction (WAF) of a condensate, and a crude oil WAF.

Fish associations with shallow water subsea pipelines compared to surrounding reef and soft sediment habitats.

Offshore decommissioning activities are expected to increase as oil and gas subsea infrastructure becomes obsolete. Decisions on decommissioning alternatives will benefit from quantifying and understanding the marine communities associated with these structures. As a case study, fish assemblages associated with an inshore network of subsea pipelines located on the North West shelf of Western Australia were compared to those in surrounding natural reef and soft sediment habitats using remotely operated vehicles fitted with a stereo-video system (stereo-ROVs).

A comparison of stereo-BRUVs and stereo-ROV techniques for sampling shallow water fish communities on and off pipelines.

We compared and contrasted fish assemblage data sampled by baited remote underwater stereo-video systems (stereo-BRUVs) and stereo-video remotely operated vehicles (stereo-ROVs) from subsea pipelines, reef and soft sediment habitats. Stereo-BRUVs sampled greater fish diversity across all three habitats, with the stereo-ROV sampling ~46% of the same species on pipeline and reef habitats. Larger differences existed in soft sediment habitats, with stereo-BRUVs recording ~65% more species than the stereo-ROV, the majority of which were generalist carnivores.

Carbon isotope fractionation of amino acids in fish muscle reflects biosynthesis and isotopic routing from dietary protein.

1. Analysis of stable carbon isotopes is a valuable tool for studies of diet, habitat use and migration. However, significant variability in the degree of trophic fractionation (Delta(13)C(C-D)) between consumer (C) and diet (D) has highlighted our lack of understanding of the biochemical and physiological underpinnings of stable isotope ratios in tissues.

Extensive drought negates human influence on nutrients and water quality in estuaries.

Impacts of land-use on estuarine environmental parameters and nutrients are well documented, but little is known about these characteristics during extensive periods of low water flow (i.e., drought).