Feature Activity Sensitivity Tool - list of pressures

List of pressures and revised benchmarks and definitions that will be used in future sensitivity assessments within FeAST (Feature Activity Sensitivity Tool).

The marine pressures list is adapted from an inventory prepared and agreed by OSPAR Joint Assessment Monitoring Programme 2014-2021 (see Table II) to facilitate and standardise assessments of human activities in the marine environment by the OSPAR Contracting Parties.

There are 35 marine pressures, which are listed below. Each pressure has a clear definition and a benchmark at which sensitivities are assessed within the Feature Activity Sensitivity Tool (FeAST).

This pressure list is also being used to facilitate assessments within Scotland's Marine Assessment 2020.

See Feature Activity Sensitivity Tool for further details.

List of contents

Barrier to species movement

Benchmark:

Barrier to species movement

Description:

The physical obstruction of species movements (local, regional, global), in rivers or open waters. May disrupt movements within & between roosting, breeding, feeding areas, or regional/global migrations (e.g. birds, eels, salmon, whales). Could be relevant to crabs that undertake migrations to over-winter or to breed, and where populations are dependent on larval or other propagule supply from outside the site.

Examples:

Infrastructure such as offshore wind farm, wave or tidal device arrays, tidal barrages & devices or dams, and mariculture could obstruct movements as well as some fishing gears (set nets & drift nets). Intensive dredging and some disposal (e.g. sewage or industrial/liquid) activities can cause turbidity that may pose as a physical barrier to fish movement; electromagnetic fields from power cables may also act as a barrier to some exclusively demersal species.

Notes:

Excludes noisy activities which may cause barriers, as covered fully in separate pressures. Excludes fishing other than by set net or drift net, and short-term/transient pressures like shipping and disposal.

De-oxygenation

Benchmark:

Compliance with WFD criteria for good status: fully saline waters is 4 mg/l and within estuaries, the WFD standard for good status is 5 - (0.028 x salinity).

Description:

The lowering, temporarily or more permanently, of oxygen levels in the water or substrate due to anthropogenic causes. Pressure is closely related to the N and P enrichment pressure. The water column immediately above the sea bed can have lower oxygen levels than the general water column, and this is closely linked to the Organic enrichment and Siltation pressures. The estuary standard is more precautionary as it also seeks to protect migratory fish, which are likely to be the most sensitive element. Oxygen is essential for most life, low levels can inhibit respiration, and other life functions.

Examples:

Aquaculture may cause deoxygenation above benchmark close to the seabed due to waste and debris deposition, disposal activities can also reduce oxygen levels.

Notes:

Associations exclude fishing discards, and activities that may cause siltation or discharge of deoxygenated ballast water as either not likely to cause pressure at benchmark or covered in other pressures.

Death or injury by collision below water

Benchmark:

Death or injury by collision below water.

Description:

Injury or mortality from collisions of biota with both static &/or moving structures below the surface of the water, including vessels.

Examples:

Fish, bird & mammal collisions with tidal devices, screens in intake pipes (e.g. fish at power stations) and shipping both recreational and commercial (moving vessels).

Notes:

Does not include collision above water see separate pressure. Excludes activities that may involve vessels for repairs only. OSPAR combines both above and below water collision pressures.

Death or injury by collision above water

Benchmark:

Death or injury by collision above water.

Description:

Injury or mortality from collisions of biota with both static &/or moving structures above the surface of the water. Collision at night may be associated with 'Introduction of light' pressure that may attract some birds.

Examples:

Collision with rigs (e.g. birds) (static) or collisions with wind turbine blades

Notes:

Does not include collision below water - see separate pressure. Excludes activities that may involve vessels for repairs only. OSPAR combines both above and below water collision pressures.

Electromagnetic changes

Benchmark:

Local electric field of 1 volt per meter, or Local magnetic field of 10 telsa (μT) due to anthropogenic means

Description:

Localized electric and magnetic fields associated could alter behaviour (e.g. attract or repel) and migration patterns of sensitive species. Elasmobranch species (sharks, skates and rays) are relatively sensitive to electric fields, and diadromous species are expected to have relatively higher sensitivity to magnetic fields.

Examples:

Any activities with operational power cables or telecommunication cables (if equipped with power relays), and infrastructure that may create electromagnetic changes, e.g. electromagnetic surveys (CSEM) used in oil and gas. Field strength dissipates quickly and burial of cables increases distance between source and species receptors, so is an effective mitigation.

Notes:

Scientific uncertainty on the sensitivity of species to this pressure is considerable, from individual physiology/behaviour to any population level implications.

Emergence regime changes - local

Benchmark:

A 1 hour change per tidal cycle in the time covered or not covered by the sea for a period of 1 year.

Description:

Changes in water levels may reduce the intertidal zone (and the associated/dependent habitats) by changing either the spatial area and or duration of immersion/exposure during tidal cycles. Changes in tidal flushing can change sediment dynamics that may lead to changing patterns of deposition and erosion and extent of tidal immersion. Impacts include reduced habitats, resources, and feeding times, exposure, and desiccation.

Examples:

Upstream and downstream of a tidal barrage may change the extent of tidal immersion (reduce or increase respectively), beach re-profiling could change gradients and therefore exposure times, capital dredging, managed realignment, and salt marsh creation may change the natural tidal range.

Notes:

1. The benchmark is only relevant to the intertidal, excluding habitats below Chart Datum (CD). Excludes tidal stream 'turbines' but includes tidal barrage. Excludes wave devices as addressed in relation to habitat change (not effecting emergence regime per se).

2. This excludes Climate Change sea level rise, which is being considered separately.

Genetic modification & translocation of indigenous species

Benchmark:

Translocation of indigenous species and/or introduction of genetically modified or genetically different populations of indigenous species that may result in changes in genetic structure of local populations, hybridization, or change in community structure.

Description:

Moving of indigenous or genetically modified species to different areas may cause competition with local populations of species with different genetic make ups, alter the community of the receiving habitat, or provide the opportunity for hybridization between similar species (e.g. Spartina spp. and Mytilus spp.).

Examples:

Deliberate releases, movement or spawning of farmed species into wild via aquaculture, accidental escapes of farmed species, or transfer of organisms via vessels using ballast water.

Notes:

Excludes transfer of organisms via vessel hulls (may be vector but no known evidence), sewage disposal or water extraction.

Introduction of light or shading

Benchmark:

Change in incident light via anthropogenic means.

Description:

Introduction of light on structures may disorientate, repel or attract species (affecting e.g. migration routes), increase algal growth, change communities or species present. Shading from structures may reduce growth, feeding or change communities/species present.

Examples:

Infrastructure such as new promenade or pier lighting, lighting on oil & gas facilities, fish farms, construction of jetties or other artificial structures or vessels, removal of dense kelp canopy will introduce increased light. Includes most night time vessel activity.

Notes:

The introduction of light is unlikely to be relevant for most benthic invertebrates, except where it is possible to interfere with spawning cues, or where dense kelp canopy is removed.

Introduction of microbial pathogens (disease), viruses or parasites

Benchmark:

The introduction of relevant microbial pathogens, metazoan disease vectors or parasites to an area where they are currently not present or likely to cause a significant increase in levels compared to background levels.

Description:

The introduction or increase in levels of pathogens, disease vectors or parasites from anthropogenic activities.

Examples:

Sources of disease, virus and parasites could include untreated or insufficiently treated effluent discharges & run-off from terrestrial sources & vessels, including ballast water releases. Transfer of shellfisheries seed stock may introduce 'infected' seed, or from accidental releases of effluvia. Salmon farming may increase levels of the sea lice parasite (Lepeophtheirus salmonis) which has potential to increase risks to wild salmonids. Escapees’ e.g. farmed salmon could be infected and spread pathogens in the indigenous populations.

Notes:

This does not include non-indigenous species as covered in separate pressure. Excludes fishing/dredging for bivalves as low risk of spreading Bonamia. Excludes transfer vessel hulls as introduction mechanism as no known evidence. OSPAR- pressure only refers to pathogens.

Introduction of other substances (solid, liquid or gas)

Benchmark:

Compliance with all Average Annual Environmental Quality Standards, conformance with Probable Effect levels, Environment Assessment Criteria, Effects Range - Low, and any introduction of other solid debris without EQS that may cause changes to species or habitats.

Description:

The 'systematic or intentional release of liquids, gases ' (from MSFD Annex III Table 2) is considered e.g. in relation to produced water from the oil industry. It should, therefore, be considered in parallel with the other chemical contaminants. Other solid debris such as shellfish shells and seaweed debris may also have detrimental effects which are not covered in other pressures.

Examples:

Shellfish shell debris and seaweed debris from aquaculture may fall to seabed around longline equipment during rough weather or harvesting.

Introduction or spread of non-indigenous species & translocations (competition)

Benchmark:

A significant pathway exists for introduction of one or more Invasive non-indigenous species (INIS) (also referred to as Invasive Non-Native Species (INNS)).

Description:

The direct or indirect introduction of invasive non-indigenous species, e.g. Chinese mitten crabs, slipper limpets, Pacific oyster and their subsequent spreading and out-competing of native species. Sensitivity assessment will be made against a prescribed list of INIS as agreed with the Scottish Marine Invasive Non-Native Species Working Group.

Examples:

Aquaculture, mussel or shellfishery activities may cause this pressure due to imported stock or from accidental releases. Ballast water, hull fouling, and some infrastructure e.g. offshore wind farms may also facilitate the spread of such species by acting as stepping stones for spread.

Nitrogen & phosphorus enrichment

Benchmark:

Compliance with WFD criteria for good status (or increases in nutrient loading over background levels if information available).

Description:

Increased levels of the elements nitrogen, phosphorus, silicon (and iron) in the marine environment compared to background concentrations. It may be possible to use information from WFD and CEMP assessments in relation to winter concentrations of DIN (a measure of state) and compare these to WFD standards and status classification outputs. Adverse environmental effects include deoxygenation, algal blooms, changes in community structure of benthos and macrophytes.

Examples:

Nutrients can enter marine waters by natural processes (e.g. decomposition of detritus, riverine, direct and atmospheric inputs) or anthropogenic sources (e.g. waste water runoff, terrestrial/agricultural runoff, sewage discharges, aquaculture, dredge disposal, atmospheric deposition). Nutrients can also enter marine regions from ‘upstream’ locations, e.g. via tidal currents to induce enrichment in the receiving area.

Notes:

Nutrient enrichment may lead to eutrophication, and is closely linked with De-oxygenation and organic enrichment pressures. Excludes seaweed harvesting, as this activity is more likely to reduce nutrient availability. Excludes activities disturbing sediment.

Litter

Benchmark:

Introduction of man-made objects able to cause physical harm (surface, water column, sea floor and/or strandline)

Description:

Marine litter is any manufactured or processed solid material from anthropogenic activities discarded, disposed or abandoned (excluding legitimate disposal) once it enters the marine and coastal environment including plastics, metals, timber, rope, fishing gear etc. and their degraded components, e.g. microplastic particles.

Examples:

Ecological effects can be physical (smothering), biological (ingestion, including uptake of microplastics; entangling; physical damage; accumulation of chemicals) and/or chemical (leaching, contamination from litter).

Notes:

Currently all activities are associated with this pressure, as all have potential to introduce litter. Microplastics may be treated as a contaminant separately in future. Excludes lost fishing gear which causes ghost fishing or entanglement - as these are included in Removal of non-target species

Transition elements & organo-metal (e.g. Chromium, Copper, TBT) contamination. Includes those priority substances listed in Annex II of Directive 2008/105/EC.

Benchmark:

Compliance with all average annual Environmental Quality Standards, or conformance with Probable Effect levels, Environment Assessment Criteria, Effects Range -Low.

Description:

These standards provide good levels of protection for all living organisms where standards are adhered to. For marine sediments the main elements of concern are Arsenic, Cadmium, Chromium, Copper, Mercury, Nickel, Lead and Zinc Organo-metallic compounds such as the butyl tins (Tri butyl tin and its derivatives) can be highly persistent and chronic exposure to low levels has adverse biological effects, e.g. Imposex in molluscs.

Examples:

Sources may include aquaculture (e.g. antifoulants), sewage, dredge and nuclear discharges, and other activities that may disturb contaminated sediment.

Notes:

1. Previously was assessed under the single pressure Non-synthetic compound contamination.
2. There are ongoing discussions to consider additional benchmarks for this pressure for situations where there is exceedance of EQS (e.g. within regulatory mixing zones and significant spills) and bioaccumulation.

Hydrocarbon & PAH contamination. (Includes those priority substances listed in Annex II of Directive 2008/105/EC).

Benchmark:

Compliance with all average annual Environmental Quality Standards, or conformance with Probable Effect levels, Environment Assessment Criteria, Effects Range -Low.

Description:

These standards provide good levels of protection for all living organisms where standards are adhered to. See separate pressures where exceeding EQS may occur and the potential ecological consequences include lethal and non-lethal effects, physiological changes. These are naturally occurring compounds, complex mixtures of two basic molecular structures: straight chained aliphatic hydrocarbons (relatively low toxicity and susceptible to degradation) and multiple ringed aromatic hydrocarbons (higher toxicity and more resistant to degradation). Ecological consequences include tainting, some are acutely toxic, carcinomas, growth defects.

Examples:

These compounds originate from 3 sources (includes both aliphatics and polyaromatic hydrocarbons): 1. petroleum hydrocarbons (from natural seeps, oil spills and surface water run-off) 2. pyrogenic hydrocarbons (from combustion of coal, woods and petroleum) and 3. biogenic hydrocarbons (from plants & animals). Produced water from oil and gas extraction and waste disposal and discharge may contain these compounds.

Notes:

Organic enrichment

Benchmark:

A deposit of 100gC/m2/yr

Description:

This pressure is referring to particulate organic matter and is therefore closely associated with the Siltation pressures. Adverse environmental effects include deoxygenation, algal blooms, changes in community structure of benthos and macrophytes.

Examples:

Resulting from the degraded remains of dead biota & microbiota (land & sea); faecal matter from marine animals; flocculated colloidal organic matter and the degraded remains of: sewage material, domestic wastes, industrial wastes etc. Organic matter can enter marine waters from sewage discharges, aquaculture or terrestrial/agricultural runoff. Black carbon is another source and comes from the products of incomplete combustion (PIC) of fossil fuels and vegetation.

Notes:

Dissolved organic matter is considered covered within the N and P enrichment pressure. Organic enrichment may lead to eutrophication (see also nutrient enrichment). Excludes fisheries discards.

Physical change (to another seabed type)

Benchmark:

The permanent change of one marine habitat type to another marine habitat type, through the change in substratum, including to artificial (e.g. concrete mattresses, rock dumping).

Description:

Two separate possibilities 1) Change in sediment type by one Folk class, 2) Change from sedimentary or soft rock substrata to hard rock or artificial substrata or vice-versa. A change from sediment to hard rock (or vice versa) would affect all types of substratum, and all habitats would be assessed as highly sensitive.

Examples:

Associated activities include the installation of infrastructure (e.g. surface of platforms or wind farm foundations, marinas, coastal defences, pipelines and cables), the placement of scour protection where soft sediment habitats are replaced by hard/coarse substratum habitats, removal of coarse substrata (marine mineral extraction) in those instances where surficial finer sediments are lost, capital dredging where the residual sedimentary habitat differs structurally from the pre-dredge state, creation of artificial reefs, mariculture i.e. mussel beds. Protection of pipes and cables using rock dumping and mattressing techniques. Includes dredge & heavy trawl fisheries due to potential change in sediment particle size.

Notes:

This pressure assumes a permanent change, while short-term smothering of substrata with sediment is addressed under siltation pressures. The simplified Folk class referred to in the benchmark is based on the simplified classification used for UK SeaMap as described by Long (2006).

Physical loss (to land or freshwater habitat)

Benchmark:

Permanent loss of existing marine habitat (to land or coastal infrastructure).

Description:

The permanent loss of marine habitats by activities or infrastructure that encroaches on the marine area so as to move the MHWS mark seawards

Examples:

This pressure is relevant to coastal features and activities such as land claim, new coastal defences or ports/harbours that encroach on and move the Mean High Water Springs mark seawards.

Notes:

This excludes changes from one marine habitat type to another habitat type.

Physical removal (extraction of substratum)

Benchmark:

Extraction of sediment to 30cm

Description:

This pressure relates to extraction of sediment substrate

Examples:

E.g. capital or maintenance dredging, aggregate extraction, for beach replenishment and some construction processes requiring seabed preparation or dredging.

Notes:

In some cases the substrate may recover/be replenished by natural processes. If permanent change in substrate type, then is also "physical change" pressure.

Radionuclide contamination

Benchmark:

An increase in 10μGy/h above background levels.

Description:

Introduction of radionuclide material, raising levels above background concentrations.

Examples:

Such materials can come from nuclear installation discharges, and from land or sea-based operations (e.g. oil platforms, medical sources). The disposal of radioactive material at sea is prohibited unless it fulfils exemption criteria developed by the International Atomic Energy Agency (IAEA), namely that both the following radiological criteria are satisfied: (i) the effective dose expected to be incurred by any member of the public or ship’s crew is 10 μSv or less in a year; (ii) the collective effective dose to the public or ship’s crew is not more than 1 man Sv per annum, then the material is deemed to contain de minimis levels of radioactivity and may be disposed at sea pursuant to it fulfilling all the other provisions under the Convention. The individual dose criteria are placed in perspective (i.e. very low), given that the average background dose to the UK population is ~2700 μSv/a. Ports and coastal sediments can be affected by the authorised discharge of both current and historical low-level radioactive wastes from coastal nuclear establishments.

Reduction in availability or quality of prey

Benchmark:

Reduction in prey availability or quality of prey

Description:

Reduction in prey availability or quality of prey could be caused by competition (with e.g. other marine predators) or from pressures that affect prey species. Temporary or longer-term impacts can arise from construction, operational and decommissioning phases of infrastructure developments. Consequences include starvation, a poorer diet with knock on effects on energy budget, breeding etc.

Examples:

Increased organic waste, deoxygenation, siltation from many activities may reduce diversity and abundance of prey species available and therefore nutrient value. Fishing or other activities can impact habitats or remove preferred species to levels that drive significant competition for resource, or increase foraging areas and subsequent energetic costs.

Notes:

Some prey species will have separate sensitivity assessments themselves e.g sandeels.

Removal of non-target species (including lethal)

Benchmark:

Accidental or incidental removal of features through pursuit of a target fishery, or harvesting or other extractive activity (commercial, recreational or artisanal scale), including through accidental entanglement with nets or ropes e.g. aquaculture nets, mooring lines or creels.

Description:

Any damage, loss or removal of species through accidental or incidental catch (or by-catch) associated with fishing, harvesting and extraction activities, including extraction of substrate or water. Also includes accidental entanglement in ropes or lines associate with various activities.

Examples:

Most commonly referring to by-catch from commercial fisheries, but can also apply to recreational and artisanal fisheries or collection of fish, shellfish or seaweed. Also relevant to incidental loss of species during removal of dredged material, aggregate or water (e.g. for power station cooling). Non-target species can be mobile, demersal or infaunal. Also applies to lethal entanglement of fish, mammals or birds, not just in active fishing gear, but also ghost (lost) gear, moorings or anti-predator nets, for example.

Notes:

1. The physical effects of fishing gear on sea bed communities are not included, as are addressed by the abrasion pressure, and entanglement from litter or 'ghost fishing' from lost fishing nets/creels are considered under the litter pressure.

Removal of target species (including lethal)

Benchmark:

Removal of target species that are features of conservation importance or sub-features of habitats of conservation importance at a commercial, artisanal or recreational scale.

Description:

Ecological consequences include the sustainability of populations, impacting energy flows through food webs and the size and age composition within populations, alteration to habitat structure, biodiversity or function.

Examples:

Fishing or collection of marine plants and animals, primarily fisheries & shellfisheries but also seaweed harvesting, collection of broodstock or seed/spat. Includes smaller scale harvesting, or species collection, angling and scientific sampling.

Notes:

This pressure addresses only the ecological effects of removal of species and not the effects of the removal process on the species, community or habitat itself e.g. excludes physical effects of fishing gear on sea bed communities - these are addressed by the "abrasion" pressures. Excludes removal of wild seed for shellfish culture.

Salinity changes - local

Benchmark:

Increase from 35 to 38 units for one year or Decrease in salinity by 4-10 units for a year.

Description:

Activities have the potential to increase or decrease local salinity through either input of fresh water or physical changes that may alter water exchange and therefore salinity. Changes to salinity can impact growth, respiration, behaviour, and reproduction, and may ultimately alter communities/habitats, particularly if combination with other stresses such as temperature.

Examples:

Discharges from pipelines, capital dredging if this alters the halocline/tidal exchange, erection of barrages, weirs that alter freshwater and seawater flow or exchange rates.

Notes:

Excludes fin fish fresh water treatment for sealice as not at benchmark (altering salinity for a year). Excludes carbon storage as salt cavern washings not relevant to Scotland.

Siltation rate changes (heavy)

Benchmark:

Heavy deposition of more than 5cm and up to 30cm of fine material added to the habitat in a single discrete event or continuous deposition of fine material.

Description:

Siltation (or sedimentation) is the settling out or deposit of silt or sediments suspended in the water column to the sea bed. Changes relate to those over natural siltation and those above 5 cm (less than this depth is covered by different pressure), or where a high level of deposition is continuous (e.g. fish farming). Siltation of this level can completely smother species and habitats, particularly sessile organisms. Impacts are mainly from hypoxia, inability to feed or photosynthesise and potentially death unless tolerance species or species that can re-emerge.

Examples:

Activities associated with this pressure type include fin fish aquaculture, land claim, navigation dredging, aggregate extraction, cable and pipeline laying, drill cuttings, various construction activities and waste disposal.

Notes:

Excludes shellfish culture (shell/seaweed debris captured under 'intro of other substances'). <5cm cover siltation changes (light) covered by separate pressure.

Siltation rate changes (light)

Benchmark:

Light deposition of up to 5cm of fine material added to the seabed in a single event or continuous deposition of fine material.

Description:

Siltation (or sedimentation) is the settling out or deposit of silt or sediments suspended in the water column to the sea bed. Changes relate to those over natural siltation and up to 5 cm (more than this depth is covered by different pressure), or where a light level of deposition is continuous (e.g. shellfish farming). Siltation of this level may completely smother smaller species and habitats, particularly sessile organisms. Effects can be hypoxia, physical difficulties in feeding, reproduction, reduction in photosynthesis and potentially death for more sensitive species.

Examples:

As for high rate of siltation but where depth is less. Also, shellfish farming faeces/pseudofaeces, shipping propeller wash, towed bottom contacting fishing gear and various infrastructure during construction can cause siltation.

Notes:

Excludes siltation changes (heavy) as covered by separate pressure.

Sub-surface abrasion/penetration

Benchmark:

Damage to species or habitats below the surface of the seabed

Description:

Abrasion damage involving some degree of physical penetration to the seabed or disturbance of habitats or species below the surface of the seabed. Penetration and damage to the soft rock substrata are considered, however, penetration into hard bedrock is deemed unlikely.

Examples:

This pressure is associated with activities such as anchoring, certain fishing activities, (e.g. scallop dredging, beam trawling), compression of sediment (e.g. jack-up barges & vehicles), taking of sediment/geological cores, cone penetration tests, cable burial (ploughing or jetting), propeller wash from vessels.

Notes:

1. OSPAR combines subsurface and surface abrasion/penetration into one single pressure. 2. Loss, removal or modification of the substratum is not included within this pressure (see the physical loss and change pressures).

Surface abrasion

Benchmark:

Damage to species or habitats living on the seabed. Damage to surface features (e.g. species and physical structures within the habitat).

Description:

Abrasion damage at the surface of the substratum in sedimentary or rocky habitats e.g. epiflora and epifauna.

Examples:

Recreational access and trampling (inc. climbing) by human or livestock, vehicular access, moorings (ropes, chains), fishing gear such as pots or creels and demersal towed gear, cables and chains associated with fixed gears, objects placed on the seabed such as the legs of jack-up barges, and harvesting of seaweeds or other species (trampling).

Notes:

Synthetic compound contamination (inc. pesticides, antifoulants, pharmaceuticals). Includes those priority substances listed in Annex II of Directive 2008/105/EC.

Benchmark:

Compliance with all average annual Environmental Quality Standards, or conformance with Probable Effect levels, Environment Assessment Criteria, Effects Range -Low.

Description:

The EQS standards provide good levels of protection for all living organisms where standards are adhered to. See separate pressures where exceeding EQS may occur and the potential ecological consequences include lethal and non-lethal effects, physiological changes (e.g. growth defects, carcinomas).

Examples:

These chemicals are synthesised from a wide variety of industrial processes and commercial applications (e.g. veterinary use/human consumption) and can include e.g. insecticides, herbicides, rodenticides, fungicides, pharmaceuticals, PCBs, with some being very persistent and often very toxic. Possible sources include fin-fish farms, accidental discharge from vessels, or disturbance of contaminants otherwise immobilised in the sediment.

Notes:

1. There are ongoing discussions to consider additional benchmarks for this pressure for situations where there is exceedance of EQS (e.g. within regulatory mixing zones and significant spills) and bioaccumulation.

Visual disturbance (behaviour)

Benchmark:

The visual disturbance of biota by anthropogenic activities.

Description:

Visual disturbance is only relevant to species that respond to visual cues, for hunting, behavioural responses or predator avoidance, and that have the visual range to perceive cues at distance. It is particularly relevant to fish, birds, reptiles and mammals that depend on sight but less relevant to benthic invertebrates. The cephalopods are an exception but they are only likely to respond to a visual disturbance at close range (from e.g. divers). Not including introduction of light as addressed by separate pressure.

Examples:

The disturbance of biota by anthropogenic activities, e.g. increased vessel movements, such as during construction phases for new infrastructure (bridges, cranes, port buildings, windfarms, etc.), increased personnel movements, increased tourism, increased vehicular movements on shore etc. disturbing bird roosting areas, seal haul out areas etc.

Notes:

Not relevant to habitats.

Water clarity changes

Benchmark:

A change in one rank on the WFD (Water Framework Directive) scale, e.g. from clear to intermediate for one year (ranks are mean suspended particulate matter in units of mg/c: >300 - very turbid; 100-300 - medium turbidity; 10-100 - intermediate; <10 - clear.)

Description:

Changes in water clarity (or turbidity) due to changes in sediment & organic particulate matter and chemical concentrations. It is primarily related to activities disturbing sediment and/or organic particulate matter and mobilizing it into the water column. Particle size, hydrological energy (current speed & direction) and tidal excursion are all influencing factors on the spatial extent and temporal duration. Salinity, turbulence, pH and temperature may result in flocculation of suspended organic matter. Changes in suspended sediment loads can also alter the scour experienced by species and habitats. Therefore, the effects of scour are also addressed here.

Examples:

It could be 'natural' land run-off and riverine discharges or from anthropogenic activities such as all forms of dredging, disposal at sea, propeller wash, cable and pipeline burial, secondary effects of construction works, e.g. breakwaters. Anthropogenic sources are mostly short lived and over relatively small spatial extents. Shellfish and seaweed culture may actually improve water clarity through filtering or settlement of suspended particles.

Notes:

Link with siltation (low) pressure. Excludes sewage discharge as regulations means is unlikely to meet benchmark.

Water flow (tidal current) changes - local

Benchmark:

Peak mean spring tide flow change of greater than 0.1m/s over an area >1km2 or 50% of width of water body for > 1 year

Description:

Changes in water movement associated with tidal streams (the rise and fall of the tide, riverine flows), prevailing winds and ocean currents. The pressure extremes are a shift from a high to a low energy environment (or vice versa), which can alter the biota, substratum, sediment transport and seabed elevation. The potential exists for profound changes (e.g. coastal erosion/deposition) to occur at long distances from responsible activity, with complex interactions.

Examples:

Activities that have the potential to modify hydrological energy flows, e.g. tidal energy generation devices remove (convert) energy and such pressures could be manifested leeward of the device, capital dredging may deepen and widen a channel and therefore decrease the water flow, canalisation &/or structures may alter flow speed and direction; managed realignment (e.g. Nigg Bay, Moray Firth), aquaculture nets or other structures may also alter water flow around the coast. The pressure will be spatially delineated.

Notes:

The Marine Habitat Classification for Britain and Ireland uses tidal flow to help describe biotopes (e.g. The categories for tides are: very strong: >3m/sec; strong: 1.5-3; Moderately strong: 0.5-1.5; weak: <0.5; very weak - negligible). These may help with assessing habitat features against the benchmark.

Wave exposure changes - local

Benchmark:

A change in nearshore significant wave height >3% for one year

Description:

Exposure on open shore determined by local changes in wave length, height and frequency. Significant wave height = the average height of the highest one third of waves and is dependent upon the distance of open sea water over which wind may blow to generate waves (the fetch) and the strength and incidence of winds, and topography; generally significant wave height is <1.2m but can be up to 3m around UK coast.

Examples:

Anthropogenic sources of this pressure include artificial reefs, breakwaters, barrages, wrecks that can directly influence wave action or activities that may locally affect the incidence of winds, e.g. a dense network of wind turbines may have the potential to influence wave exposure, depending upon their location relative to the coastline. Seaweed harvesting and beach replenishment may also affect wave exposure. Further research is required on the correlation between significant wave height and wave exposure scales.

Underwater noise

Benchmark:

Anthropogenic sound sources that exceed levels that elicit a response from an individual, in terms of movement away, or cessation of feeding (for disturbance), for example, or exposure which leads to auditory injury.

Description:

Anthropogenic sounds may be of short duration (e.g. impulsive such as from seismic surveys and piling for wind farms and platforms, as well as explosions) or be long lasting (e.g. continuous such as dredging, shipping and energy installations) affecting organisms in different ways. Marine mammals are most susceptible, however fish and other benthic species including invertebrates may also be affected, although literature is limited.

Examples:

Anthropogenic sound can be emitted from a variety of sources; activities with the potential to affect broad areas can come from (but not limited to) pile driving, seismic surveys, dredging, shipping.

Notes:

All impulsive anthropogenic noisy activities must be registered with the JNCC Marine Noise Register. MSS/CEFAS are currently responsible for monitoring continuous low frequency sound in the marine environment.

Temperature change

Benchmark:

A 5°C change in temp for a one month period, or 2°C for one year

Description:

Events or activities increasing or decreasing local water temperature. This is most likely from thermal discharges, e.g. the release of cooling waters from power stations. This pressure only applies within the thermal plume generated by the pressure source.

Examples:

From power station cooling water discharge, bioprospecting, retained sewage or other industrial discharges, although low likelihood of being sustained for temporal aspect of benchmark.

Notes:

Heat from power cables and sealice treatments are excluded as unlikely to be at benchmark. It excludes temperature changes from climate change which will be at a regional scale. Climate change pressures are being considered separately.