Glossary
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Sabellaria reefs
Subtidal reefs formed by sabellaria spinulosa worms when they occur in very large numbers. Individual tubes built by the worms from sand or fine gravel can clump together to form solid reef structures which arise from the seabed sediment in mounds.
SACs
Special Areas of Conservation. Protected conservation sites designated through the EC Habitats Directive.
Sand waves
Large asymmetric fluvial bedforms, commonly with straight or sinuous crests and lacking localized scours on the lee-side. Bedforms interpreted as sandwaves on some areas of the Continental Shelf are up to 15m high, with wavelengths of up to 1km.
SAPs
Species Action Plans. Conservation strategies for specific species, established under the UK Biodiversity Action Plan.
Scoping
A preliminary environmental assessment of the impact area, the likely impacts and the potential mitigation measures associated with a particular development.
Scottish Executive
The Scottish Executive is the devolved government for Scotland, whose responsibilities include the regulation of marine aggregate extraction.
Screening
Process by which excess quantities of sand and gravel fractions are passed through screens on the vessel and rejected back to the sea.
SEA
Strategic Environmental Assessments are assessments of the environmental impacts of plans and programmes prepared by public bodies.
Secondary aggregates
Aggregates created from the crushing and subsequent screening of waste products and secondary materials produced from other industrial processes, which have the ability to act as a direct replacement for virgin aggregates.
Sedentary
Organisms which are either immobile or are under the seabed, or are unable to move except in constant physical contact with the seabed or subsoil.
Sediment coring
Sediment corers provide a vertical cross-section of the sediment column. There are a range of corers including piston corers, hand corers, gravity corers and vibra-corers.
Sediment Footprint
The geographical area of seabed over which suspended sediment settles out of the sediment plume in the water column.
Sediment load
Sediment transported within the water column.
Sediment plume
Suspended sediment in the water column created as a result of the aggregate extraction process. Loss of sediment occurs due to overflowing, screening, and through the action of the draghead on the seabed.
Sedimentary
These are rocks which are formed from material derived from pre-existing rocks by processes of erosion (sandstone is formed in this way), or from material of organic origin (coal and chalk is formed in this way).
SEERAD
Scottish Executive Environment and Rural Affairs Department.
Sensitivity
A measure of the response of a species or community to an anthropogenic stimulus (such as aggregate extarction).
SEPA
Shingle
Coarse gravel
Sidescan sonar
A form of geophysical survey which uses an acoustic imaging device used to provide wide area, high resolution pictures of the seabed. The instrument towed behind the vessel transmits acoustic signals obliquely through the water and displays the returning echoes via an onboard graphic recorder, providing a depiction of what lies either side of the vessel.
Silt
Material in the size range 63-2um, also found as the fine residue left after washing sand and gravel.
Single-beam echo-sounding
A method of determining water depths by measuring the time lapse between the generation of an initial sound pulse on the ship and the return of the echo. With knowledge of the speed of sound in water, the depth of water can be calculated.
Site of Special Scientific Interest (SSSI)
Site of Special Scientific Interest. A designation for nature conservation, given specific protection in law.
SOLAS
International Convention for the Safety of Life at Sea (1974).
Source
See also emission, point source, line source and area source. The origin of emissions.
SPAs
Special Protected Areas. Protected conservation sites designated through the EC Birds Directive.
Spawning grounds
The areas that a fish stock, or a species will move to and deposit eggs in large numbers(spawn).
SSSI
See Site of Special Scientific Interest.
Strategic Environmental Assessment
Strategic Environmental Assessments (SEAs) are assessments of the environmental impacts of plans and programmes prepared by public bodies.
Strategic Environmental Assessment (SEA)
Strategic Environmental Assessment assesses the environmental impact of plans and programmes prepared by public bodies. Further information
here.
Sub-aerial
Erosional processes acting on or near the surface of the Earth.
Sub-bottom profiler
A device for detecting and mapping sound-reflecting layers in sediments below the seabed.
Sub-bottom profiling
Term used to describe a marine seismic reflection survey. Seismic or sub-bottom profiling equipment uses high energy acoustic pulses to obtain information on the layers of sediment or bedrock strata below the seabed, which can be useful in assessing the nature, quantity and distribution of a buried aggregate resource.
Sustainability
A key objective of Sustainable Development is the need to secure an adequate supply of minerals to meet economic needs, whilst minimising the potential adverse effects of mineral extraction on the environment.
Sustainability Appraisal (SA)
Sustainability Appraisals identify and report on the ability of particular plans to achieve social, environmental, economic and resource objectives.
Sustainable Development
Sustainable Development meets the needs of the present without compromising the ability of future generations to meet their own needs. A key objective of sustainable development is the need to secure an adequate supply of minerals to meet economic needs, whilst minimising the potential adverse effects of mineral extraction on the environment.
Swathe bathymetry
A monitoring method used to provide a high resolution image of the seabed. (see http://www.channelcoast.org/survey_techniques/bathymetric_surveys)