Ecological role of an offshore industry artificial structure

Decommissioning of oil and gas infrastructure globally has focused attention on its importance as hard substratum on continental shelf and slope habitats. Observational studies are needed to improve understanding of faunal assemblages supported by offshore infrastructure and better predict the effect of removal. Here, we present results from visual inspection and physical sampling of a small oil and gas industry structure decommissioned from an oil field in the North East Atlantic. This is supported by observations of similar structures nearby and by photographs of the surrounding seabed from environmental baseline surveys. The structure supported a reasonably high biomass and diversity of invertebrates (>10 kg and >39 macrofaunal and 17 megafaunal species) and fishes (>20 kg biomass and >4 species). The invertebrate megafaunal species present on the structure were a sub-set of the hard substratum fauna observed on surrounding seabed. Porifera were absent from the structure. Biological succession in the first 2 years occurred as follows. Sparse colonies of the hydroid Obelia sp. stet were early colonisers then subsequent development of thick hydroid turf (Obelia sp. stet. and Halecium sp. stet.) supported an invertebrate assemblage (2654 individuals kg wet mass–1) dominated by saddle oysters [Pododesmus squama (Gmelin, 1791) and Heteranomia sp. stet.)] and scale worms (Harmothoe spp.). Percentage cover of hydroid turf varied significantly over the structure, with most growth on sections exposed to strongest currents. Commercially important fish species present around the structure included Gadus morhua (Atlantic cod), Pollachius virens (saithe) and Lophius piscatorius (monkfish). Studies of artificial structures such as this provide much needed data to understand their role in the ecology of seafloor habitats and inform environmental decision making on all stages of industry from exploration to decommissioning. We show that the ecological role of the decommissioned three-dimensional structures was to enhance the biomass of a sub-set of epifaunal invertebrates found in the area. This supported diverse associated macrofaunal organisms, providing a food source for motile invertebrates and fishes in an area where background hard substratum can be lost through the impacts of drilling

Untangling the effects of fishing effort and environmental variables on benthic communities of commercially fished scallop grounds

The Isle of Man fishing industry is currently predominated by two lucrative and heavily exploited scallop fisheries, targeting Pecten maximus and Aequipecten opercularis. The impacts of which have previously been investigated, however without the addition of environmental information. This thesis represents a unique long-term investigation into the impacts of fishing pressure and environmental variables on the benthic invertebrate communities of fishing grounds found around the Isle of Man. A significant positive trend in seawater temperature was found, along with an inverse correlation with chlorophyll-α. Fishing pressure was found to have a small, significant negative effect on indices of diversity; however environmental variables were unable to explain the remaining patterns in diversity. The composition of each of the benthic communities was then investigated in more detail. Fishing pressure had a significant negative effect on densities of benthic invertebrates at some grounds; however this study showed that many of the heavily fished sites were composed of dredge-tolerant species. Significant relationships were found between the densities of Asterias rubens and Porania pulvillus and several environmental variables on the south-west fishing grounds, suggesting that environmental variation, rather than fishing pressure was responsible for variations in these species. Further evidence was found of the negative impact of scallop dredging from the long-term analysis of a closed area, implemented in 1989. Recovery of P. maximus has occurred within this closure, without the concurrent increase in of the predatory starfish A.rubens. Relationships between several benthic species with the closed area and environmental variables were found. However, the results of this study indicate a complex ecosystem, which is also affected by predator-prey interactions. The overall findings of this research indicate that closed area management is a relatively straightforward and effective measure in this region. Future management decisions will however, have to account for the potential effects of climate change

with Comments on Feeding Biology

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The occurrence of cadmium in seawater and in marine organisms and sediments

Methods have been developed for determining cadmium in seawater, marine organisms, and marine sediments. The procedure, based on the dithizone extraction method of Saltzman, is capable of detecting less than 10 mµg of the element and can be used for determining cadmium in silicate rocks; only thallium interferes. To confirm the presence of cadmium and to ensure freedom from contamination, the dithizone extracts were examined spectrographically

CE16004

The first annual Irish Beam trawl Ecosystem (IBES) took place from 6-16th March 2016 on RV Celtic Explorer in the western Celtic sea. The main objective of the survey is to connect the Irish Anglerfish and Megrim Survey (IAMS) to the UK beam trawl surveys in the Celtic Sea, English Channel and Irish Sea, with the purpose of providing a swept-area biomass estimate for anglerfish (Lophius piscatorius and L. budegassa) in area VII. Secondary objectives are to collect data on the distribution and relative abundance of commercially exploited species as well as invertebrates and by-catch species, particularly vulnerable and indicator species. The survey also collects maturity and other biological information for commercial fish species in the western Celtic Sea. The IBES survey is coordinated with the CEFAS Q1 South-west Ecosystem Survey (Q1SWECOS) and uses the same gear and methods

Global Diversity and Phylogeny of the Asteroidea (Echinodermata)

Members of the Asteroidea (phylum Echinodermata), popularly known as starfish or sea stars, are ecologically important and diverse members of marine ecosystems in all of the world's oceans. We present a comprehensive overview of diversity and phylogeny as they have figured into the evolution of the Asteroidea from Paleozoic to the living fauna. Living post-Paleozoic asteroids, the Neoasteroidea, are morphologically separate from those in the Paleozoic. Early Paleozoic asteroid faunas were diverse and displayed morphology that foreshadowed later living taxa. Preservation presents significant difficulties, but fossil occurrence and current accounts suggests a diverse Paleozoic fauna, which underwent extinction around the Permian-Triassic interval was followed by re-diversification of at least one surviving lineage. Ongoing phylogenetic classification debates include the status of the Paxillosida and the Concentricycloidea. Fossil and molecular evidence has been and continues to be part of the ongoing evolution of asteroid phylogenetic research. The modern lineages of asteroids include the Valvatacea, the Forcipulatacea, the Spinlosida, and the Velatida. We present an overview of diversity in these taxa, as well as brief notes on broader significance, ecology, and functional morphology of each. Although much asteroid taxonomy is stable, many new taxa remain to be discovered with many new species currently awaiting description. The Goniasteridae is currently one of the most diverse families within the Asteroidea. New data from molecular phylogenetics and the advent of global biodiversity databases, such as the World Asteroidea Database (http://www.marinespecies.org/Asteroidea/) present important new springboards for understanding the global biodiversity and evolution of asteroids