Although marine powers damage to the environment is significantly less than its energy counterparts, the possible affects to existing ecosystems must be considered.

Although marine powers damage to the environment is significantly less than its energy counterparts, the possible affects to existing ecosystems must be considered. There is the immediate concern that marine mammals and fish may get caught or struck by tidal turbine blades. Even if precautions are taken to avoid this, their presence does have the potential to alter their behaviour. It could cause them to be become agitated or confused, or possibly discourage them from returning to the area. Underwater noise is also a key factor, although it has been suggested that this would be no worse than the noises from current marine transport.

Ultimately it appears marine energy devices can alter the living conditions of those around it - the real question is to what extent? By introducing a large amount of new material, such as buoys, anchors & cables one is effectively introducing a new habitat. The fish or plants that colonize these hard structures will be different to those typically found in sandy habitats. Therefore this may create a new biological community, possibly resulting in novel food or novel predators for the resident, soft-bottom organisms. This may lead to the alienation of a resident species.
Furthermore the lighting on the marine energy devices may affect sea birds to be attracted to or avoid the area, or possibly be confused about their location in relation to the shore. Research however is underway to investigate the different effects of white versus red and flashing versus constant lights on offshore wind turbines. Findings which could be applied to marine energy devices.
A trio of recent studies found that high-voltage electricity surging through undersea power cables doesnt actually bother local sea life; marine animals will cross and even colonize high-voltage cables. One study even found that the thick cables can serve as artificial habitats and host undersea communities. Studies such as this do seem positive for the future of offshore energy, however this research is still in its infancy.
Any devices that are deployed offshore can have an effect on the aquatic life in that area, the issue is that this is very site specific and hard to predict. Therefore suggesting that it is necessary to study each new project individually and carefully before any installation takes place. There are a number of variables to be considered, from the type of device used and the type of foundation to the location (near shore, offshore, deep estuaries etc.), topography and nature of the sea bed. Finally the wildlife itself, their needs and behaviours must be considered.
Despite the benefits of this emerging industry, we must not forget those inhabitants that were there before. It would appear that further research is required, specific to each project and with continued monitoring of devices, to carefully assess any impacts.
UK Marine Energy Conference, 5th July Glasgow, will consider the environmental challenges of marine energy, and the industry in general. See the website for more information: http://www.marineenergyconference.co.uk/