ENVIRONMENTAL STATEMENT BARDOLINO DEVELOPMENT

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Bardolino Development Environmental Statement their lifecycle in the pelagic stage before settling on the benthos. Important groups within this category include the larvae of starfish and sea urchins (echinoderms), crabs and lobsters (decapods), and some fish (DTI, 2001). Zooplankton in the area of the proposed development comprises mostly neritic (coastal) species and intermediate (mixed water) species, with biomass peaking from early May to mid- July until October. The euphasusiid species, Thysanoessa inermis and T. raschi dominate during the spring and summer months. During late summer and autumn, there is an introduction of oceanic species (such as Calanus finmarchicus and Metridia lucens) via an inflow of Atlantic waters. Zooplankton communities can be affected by oil, both directly through the hydrocarbon content of their food and indirectly via a change in the ecosystem. Reduced egg production and an increase in juvenile mortality have been associated with oil contamination, and there is a strong suggestion that oil treated with dispersant has a more pronounced effect. Any possible long-term genetic changes caused by the disruption of internal chemical signals are difficult to recognise and likely to be subtle (SAHFOS, 2001). 4.4.2 Benthos Benthic fauna comprises species which live either within the seabed sediment (infauna) or on its surface (epifauna). Such species, which may be either sedentary or motile, and may encompass a variety of feeding habits (i.e. filter-feeding, predatory or deposit-feeding), occupy a variety of different niches. Bacteria and benthic organisms play a major role in the decomposition of organic material that originates from primary production by phytoplankton in surface waters and settles on the seabed (NSTF, 1993). Some bacteria can degrade hydrocarbons and use it as a source of food source (Clark, 1996). Benthic fauna are also typically divided into various categories, principally according to size. The largest are the megafauna and this comprises animals, usually living on the seabed, which are large enough to be seen in bottom photographs and caught by trawl (i.e. brittle stars, sea urchins, sea cucumbers, sea spiders, sponges, corals). Macrofauna are defined as those animals that are between 250 µm and 300 µm in size. Meiofauna comprises the smaller interstitial animals (mainly nematode worms and harpacticoid copepods) with a lower size limit of between 45 µm and 62 µm. Colonisation of sediments by different species is largely dependent on the type of sediment present and its characteristics. Both physical and biological factors are important in determining species abundance and distribution, including seabed depth, water movements, salinity, temperature and available oxygen. Infaunal species are particularly vulnerable to external influences, which alter the physical, chemical or biological community of the sediment. Such infaunal organisms are largely sedentary and are thus unable to avoid unfavourable conditions. Each species has its own response and degree of adaptability to changes in the physical and chemical environment. Consequently the species composition and relative abundance in a particular location provides a reflection of the immediate environment, both current and historical (Clark, 1996). Benthic fauna are susceptible to physical disturbance of the seabed, for example from fishingtrawls, anchoring, pipeline trenching and rock dumping operations, or smothering from discharged cuttings (DTI, 2001). The effects of discharged cuttings on benthic fauna include physical smothering, the presence of potential toxins (heavy metals and hydrocarbons), and organic enrichment (BMT Cordah, 1998). The responses shown by benthic communities to cuttings discharges are the result of a combination of these effects. Directly below a development, beneath the cuttings pile, the impact is through smothering. Beyond this point, the effects of toxins and organic enrichment become more evident, and the changes in the species composition, diversity and abundance of benthic communities may be attributed to one or all of these impacts (BMT Cordah, 1998). In addition to the possible impact from drilling operations, accidental events such as major oil spills and blow-outs can result in oil reaching the seabed offshore. Effects reported from such accidents range from none detected (e.g. after the Ekofisk blowout in 1977) to chemical contamination but no acute biological effects detectable (e.g. after the wreck of the Braer in 1993) (DTI, 2001). Page 4-20 April 2008
Bardolino Development Environmental Statement During 1986, the whole of the North Sea was surveyed using standard techniques and equipment (Künitzer et al., 1992). This survey identified and classified different species distributions and assemblages of benthic fauna in relation to factors such as latitude, temperature, water depth and sediment type. Based on the findings of this survey, the benthic communities in the proposed Bardolino development area would be expected to be characteristic of the deep-water infaunal assemblage, which typically has high densities (2,863±1,844 individuals per m 2 ) and species richness (51±13 species) (Künitzer et al., 1992). Indicator species of this benthic infaunal assemblage include the Thyasira sp. bivalve complex and the polychaetes Minuspio cirrifera, Aricidea catherinae and Exogone verugera (Künitzer et al., 1992). Epifauna species identified in the area include the starfish Astropecten irregularis and Asterias rubens, the echinoid Echinocardium flavescens, the gastropods Neptunea antique, Colus gracilis and Scaphander lignarius, tunicates and sponges (Basford et al., 1989). Benthic faunal analysis was undertaken as part of the Nelson field seabed survey undertaken in 2005 and 2006 (Section 4.2.6). A total of 204 species was identified from the 12,055 individuals recovered from a total of 18 samples. The seabed area more than 500 m from the Nelson platform was found to be dominated by the polychaetes Paramphiome jeffreysii, Myriochele sp. A., Exogone hebes and the brittle star Ophiura affinis (Hartley Anderson, 2007). Within 500 m of the Nelson platform the dominant species were the polychaetes Chaetozone setosa and Paramphiome jeffreysii (Hartley Anderson, 2007). Paramphiome jeffreysii, present in high numbers at all stations sampled, is an opportunistic colonising polychaete, characteristic of deep, offshore, cohesive sandy mud. This polychaete is common throughout the North Sea in similar habitats and is frequently recorded in the vicinity of offshore platforms. Thyasira sp and Chaetozone setosa were present in large numbers at Station Nel-01, 200 m from the platform. These species are known to be indicative of elevated hydrocarbon concentrations in offshore sediments. C. setosa, in particular, is well adapted to colonise and exploit disturbed and organically enriched habitats. It is a secondary coloniser, able to move into areas once conditions are favourable enough for it to out-compete the primary colonisers such as Raricirrus beryli and Capitella capitata (ERT, 2000). Raricirrus beryli was not present at any of the stations sampled in the 2007 Nelson survey and Capitella capitata was only present at station Nel-01 in very small numbers (7 indiviuals identified in 3 samples). This indicates that the sediment in the immediate vicinity of the Nelson platform (200 m) is now recovering from previous hydrocarbon pollution. Table 4.11 lists the ten dominant species identified at each of the six sample stations. April 2008 Page 4-21
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13 th March 2008 Dear Sir or Madam,
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To: Paul Wood Shell U.K Limited, Se
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What risks to marine mammals do pil
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Noise propagation modelling. Noise
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If, for any reason, piling operatio
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APPPENDIX 1 MARINE MAMMAL RECORDING
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ENVIRONMENTAL STATEMENT BARDOLINO DEVELOPMENT

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