Connectivity of larval stages of sedentary marine communities between hard substrates and offshore structures in the North Sea

Man-made structures including rigs, pipelines, cables, renewable energy devices, and ship wrecks, offer hard substrate in the largely soft-sediment environment of the North Sea. These structures become colonised by sedentary organisms and non-migratory reef fish, and form local ecosystems that attract larger predators including seals, birds, and fish. It is possible that these structures form a system of interconnected reef environments through the planktonic dispersal of the pelagic stages of organisms by ocean currents. Changes to the overall arrangement of hard substrate areas through removal or addition of individual man-made structures will affect the interconnectivity and could impact on the ecosystem. Here, we assessed the connectivity of sectors with oil and gas structures, wind farms, wrecks, and natural hard substrate, using a model that simulates the drift of planktonic stages of seven organisms with sedentary adult stages associated with hard substrate, applied to the period 2001–2010. Connectivity was assessed using a classification system designed to address the function of sectors in the network. Results showed a relatively stable overall spatial distribution of sector function but with distinct variations between species and years. The results are discussed in the context of decommissioning of oil and gas infrastructure in the North Sea

INGRID: A near-infrared camera for the William Herschel Telescope

‘The definitive version is available at www.blackwell-synergy.com '. Copyright Blackwell Publishing. DOI: 10.1046/j.1365-8711.2003.06982.x [Full text of this article is not available in the UHRA]Rapid developments in near-infrared (NIR) arrays and adaptive optics systems have driven the development of wide-field and high-spatial-resolution, high-optical-quality NIR imagers and spectrographs, providing an unparalleled boost to NIR observations. Based around a 1024 × 1024 pixel2 Hawaii-1 array, the Isaac Newton Group Red Imaging Device (INGRID) imager provides a field of view >16 arcmin2 (at the Cassegrain focus) whilst Nyquist sampling the median summer seeing disc. When used in conjunction with the Nasmyth Adaptive Optics for Multi-Purpose Instrumentation (NAOMI) system and a second set of collimation optics, a high spatial resolution mode (0.04 arcsec pixel−1) is offered, providing near-diffraction-limited imaging. INGRID uses an all-refractive design and employs a cold stop to reduce thermal background emission, critical to the performance as it is used on the non-infrared optimized 4.2-m William Herschel Telescope (WHT). We discuss the design and operation of INGRID and illustrate its performance by discussing commissioning observations of the cluster Abell 2218 and the spiral galaxies NGC 3351 and 1530.Peer reviewe