eutrophication and european marine sites
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Marine 50update
WWF-UK
Panda House, Weyside ParkGodalming, Surrey GU7 1XRt: +44 (0)1483 426444f: +44 (0)1483 426409www.wwf-uk.org
Taking action for a living planet
For further information please contact WWF’s Living Seas Programme
Eutrophication and European Marine Sites
August 2001
Introduction
The European Union's Habitats
and Species Directive and the
Wild Birds Directive together
comprise the main nature
conservation policy tool across
the EU. In the UK, marine Special
Areas of Conservation and
intertidal Special Protection
Areas for birds are collectively
known as European Marine Sites.
The UK has at least 67 candidate
or possible marine
Special Areas of
Conservation
and more than
100 intertidal
Special
Protection
Areas. This
Marine Update
looks at
eutrophication as a threat
to the conservation of habitats
and species in the UK's network
of European Marine Sites. The contrast between an estuary with ‘natural’ nutrient inputs (above top) and an estuary withhigh anthropogenic nutrient inputs (above). The mass of algal weed (see close-up inset) can beclearly observed.
• rejection on the basis of cost should
only be applied in the most exceptional
cases; they should be subject to
independent international review and
be dependent on the practicality, costs
and credibility of the creation of areas
having identical characteristics and
capable of supporting the displaced
populations.
EC Directives and OSPARIt is essential that the OSPAR
Eutrophication Strategy and requirements
of the EC Directives are integrated and
transposed into action at a UK level.
WWF recommends:
• the designation of an estuarine or
coastal SA or NVZ should be matched
by its designation as an OSPAR
problem area (and vice-versa), and
the implementation of a programme
for a reduction of nitrogen and
phosphorus inputs by 50 per cent as
soon as is practicable. Should these
reductions be insufficient, additional
reduction measures must be taken, in
accordance with the OSPAR Strategy;
• the speedy implementation of the
source-oriented approach to assess
nutrient inputs;
• strategies to combat diffuse nutrient
sources transferred via water
(fertilisers) and the air (eg ammonia
volatilisation from manure) to be
developed and implemented urgently.
Requirements offshoreFollowing the UK High Court ruling that
the Habitats Directive must be applied
to the continental shelf and superjacent
waters, WWF proposes:
• the UK government should apply all
relevant EC Directives offshore, to the
continental shelf and superjacent
waters;
• single management plans, and
management actions, should be
applied to offshore SACs and SPAs,
including incorporation where
necessary of actions required to meet
the objectives of relevant EC
Directives. They should also be in line
with the OSPAR Eutrophication
Strategy.
Finally, WWF believes that the
management of all UK’s waters, including
land-based nutrient pollution reductions
and management of EMSs, should be set
within the context of a national Oceans
or Marine Policy backed by a single piece
of integrated marine legislation.
Text by Dr Simon Vowles, Dr Sarah Jones and Dr Malcolm MacGarvin
Based on Out of Sight, Out of Mind: Marine Eutrophication in the United Kingdom(Malcolm MacGarvin), available online at www.wwf-uk.org/orca/info.htm
A new report, Out of Sight,
Out of Mind: Marine
Eutrophication in the United
Kingdom, provides a more
detailed and wider review of
marine eutrophication in the
UK (see references below).
ReferencesMacGarvin, M (2001). Out of Sight,
Out of Mind: Marine Eutrophication
in the United Kingdom. modus
vivendi for WWF-UK, Glenlivet.
Additional material can be found in
MacGarvin, M (2000). Scotland’s
Secret?: Aquaculture, nutrient
pollution, eutrophication and toxic
blooms. modus vivendi for WWF
Scotland, Glenlivet.
Both available online at
www.wwf-uk.org/orca/info.htm
UK-EU LIFE biotope reports can be
found at www.english-nature.org.uk/
uk-marine/reports/reports.htm
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in 1999 and an SA in 2000. Langstone
and Chichester harbours on the south
coast of England were also designated
SAs in 1998, also after a long period of
dispute.
In effect, management of European
Marine Sites (EMSs) to meet conservation
objectives has put a double obligation
on member states as they must also
ensure that eutrophication does not
threaten the habitats and species (interest
features) for which the EMSs have been
designated. According to the EU Habitats
Directive the interest features must be
kept at ‘favourable conservation status’.
The UK also recognises the importance
of maintaining sub-features (ecologically
important sub-divisions of an interest
feature) including eelgrass beds, kelp,
saltmarsh and benthic fauna, at
favourable conservation status.
When an interest feature or sub-
feature is not considered to be in a
favourable condition, there is also the
potential for restoration. A UK High Court
decision in 1999 has confirmed that the
Habitats Directive applies beyond 12
nautical miles offshore (the continental
shelf and the contiguous zone which
under the rules of international law are
subject to the limited jurisdiction of the
coastal state). The UWWT and Nitrates
Directives set no outer geographic limit
on their definition of coastal water and
it follows that their provisions fall under
the same interpretation. Therefore if
potential offshore Special Areas of
Conservation (SACs), such as the Dogger
Bank (a submerged sandbank) in the
central North Sea, are affected by
eutrophication arising from the UK, action
should be to be taken under the UWWT
and Nitrate Directives on the relevant
catchments to address the problems.
Water quality, eutrophicationand the management ofEuropean Marine Sites Relevant authorities with a statutory
interest on the ground, and other
competent authorities with duties that
may affect a site, must have regard to
both direct and indirect effects on an
interest feature of EMSs, which may
include consideration of issues outside
the site boundary. Relevant authorities
should ensure that all plans for an EMS
are integrated within a unified manage-
ment scheme and the statutory nature
conservation agencies are preparing
advice on the management of all EMSs.
So in relation to eutrophication, the plans
for an EMS may include measures and
activities to meet international obligations
under the UWWT, Nitrates Directives and
in future the Water Framework Directive
(WFD, 2000/60/EC).
The WFD refers to a geographical
scope generally out to 1nm, but it is
still unclear whether this may extend to
12nm. It is therefore more restricted
in geographic scope than the Habitats,
UWWT and Nitrates Directives, although
there may be advantages in extending
coverage out to the full extent of national
jurisdiction.
Diffuse losses, especially from agri-
culture, have long been recognised as
reducing the effectiveness of other point
source measures to reduce nutrient
inputs. The OSPAR source-oriented
approach of assessing nutrients at input
level is of particular relevance to action
on agricultural nutrient inputs.
Eutrophication and biotopesThe management of marine SACs in
the UK has been greatly advanced by
a UK/EU LIFE-funded programme. This
included a review of biotopes for which
human impacts were assessed. The most
serious eutrophication concerns were
expressed for eelgrass meadows, sub-tidal
kelp (for which aquaculture is identified
as a specific concern), and intertidal
Water Framework Directive
The WFD represents a significant shift towards a holistic approach by considering whole
catchments. It also states that requirements of existing Directives must not be weakened.
The Directive recognises natural variability such as low and medium nutrient conditions and
a move to achieving ecological quality objectives (EcoQOs) that will achieve good ecological
quality within 15 years. This is addressed to some degree in the Environment Agency’s
Eutrophication Strategy for freshwater, but not for marine sites. The OSPAR Comprehensive
Procedure (part of the Eutrophication Strategy) provides the necessary common framework
and mechanism for the assessment of marine eutrophication.
WFD derogations, such as modified water (the scope, if any, for estuarine and coastal waters
is undefined) and excessive economic cost, could potentially give EU member states some
leeway to interpret when good ecological quality does not have to be achieved. In practice,
however, modified waters must still have good ecological potential. The WFD preamble
makes it clear that outcomes must also comply with OSPAR commitments.
soft-sediment sites (a high potential
for impact). In the case of other habitats,
the impact of nutrients on intertidal
seaweeds was acknowledged to be of
at least local significance. With respect
to biogenic reefs (ie reef-forming worms,
shellfish and corals) mussels were
recognised as being vulnerable to some
phytoplankton toxins, while dense blooms
of Phaeocystis (algae) have resulted in
reproductive failure as a result of
starvation. For sea pens, brittle stars and
other burrowing fauna, excessive organic
inputs can cause harm by deoxygenating
the water. The review on circalittoral
(about the shore) faunal turf biotopes,
such as sponge and anemone
communities, considered that
eutrophication posed a variety of threats.
Species in shallow water, lochs and rias
(drowned river valleys) are at particular
risk, primarily through toxic algal blooms
and deoxygenation.
The threat of eutrophicationMarine eutrophication is a set of
symptoms occurring when excessive
nutrients stimulate plant growth resulting
in adverse environmental changes.
This growth occurs in selected species
to the overall detriment of the marine
environment. For example, algal
weed can become so dense that
it blankets mudflats or displaces
important plants such as
eelgrass. This can deprive
wading birds, fish and other
marine wildlife of food and a
nursery habitat. Another result
might be excessive blooms of
single-celled algae – phytoplankton
– which intercept the light that
would otherwise reach fixed
plants such as eelgrass and
kelp. Furthermore, when the
phytoplankton eventually
die back and break down,
an excessive amount of
oxygen is required to fuel
this process, so areas can
become deprived of oxygen.
Excessive nutrients, and/or
changes in their relative
concentrations, may be one
factor in a chain of events
leading to changes in the
species composition of
phytoplankton communities,
and increased occurrence
of toxic algal blooms and
increased toxin production. Toxic
phytoplankton, when consumed by
shellfish or other species, can affect the
marine food chain, including poisoning
seabirds, mammals and even humans.
The main sources of nutrients (nitrogen
and phosphorus) are from agriculture,
aquaculture, sewage and industrial waste.
In addition, the burning of fossil fuels
results in the atmospheric deposition of
nitrogen compounds.
Eutrophication leads to loss of bio-
diversity and also has economic
implications. For example, the loss
of marine plant communities such as
eelgrass beds can increase coastal erosion
(the plant's roots hold together
sediments) or lead to the loss of
commercial fish nursery areas.
Legislative contextFor more than a decade, there has
been an obligation under the Convention
for the protection of the marine
environment of the North-east Atlantic
(OSPAR) to reduce nutrient inputs to
problem areas by the order of 50 per
cent. The UK, unlike other
North Sea states, has
not recognised its
territorial waters as
a problem area.
In 1998 OSPAR
agreed a
eutrophication
strategy requiring
all estuaries and
coastal waters to
be classified as
problem, possible
problem or non-
problem areas
according to
internationally agreed
criteria, including
Ecological Quality
Objectives (EcoQOs).
This has to be completed
by 2002. By 2010 OSPAR
requires a marine
environment where
eutrophication does not
occur. The new Water
Framework Directive
(2000/60/EC) contains
similar obligations (see
box right).
Where nutrient inputs may contribute
to eutrophication, the EC Urban Waste
Water Treatment Directive (UWWT)
(91/271/EEC) requires these to be
removed from sewage inputs to the
catchments of Sensitive Areas (SAs).
Similarly for agriculture nitrates, addressed
in a sepa-rate Nitrates Directive
(91/6765/EEC), catchments of areas
where eutrophication occurs or is likely to
occur in the future must be designated as
Nitrate Vulnerable Zones (NVZs) and
nitrogen inputs brought under control.
EU member states have some
flexibility on how they implement these
Directives. Many regard the exceptional
effort required for credible case by case
assessment as not cost effective.
Consequently, they either treated their
entire territory as an SA (Denmark,
Luxembourg, the Netherlands and
Sweden) or substantial portions thereof
(Belgium, France and Germany). Similarly
Denmark, Germany, Luxembourg and
the Netherlands all designated their entire
national territory as an NVZ, France
designated half its territory, while Sweden
designated its entire coastal zone.
In contrast, the UK chose the case
by case route, and set a high burden of
proof for designation with little or no
room for precaution. Even in the case of
the Ythan estuary in north-east Scotland –
one of the best documented examples
of eutrophication in the UK – designation
was initially rejected. However, following
lengthy debate, it was designated an NVZ
Nutrient losses from agriculture, for example nitrates from fertilisers used on this beet crop, can pose serious nutrient pollution problems.
Eelgrass(Zostera)
Mussel bed, Findhorn Bay, Scotland.Mussels are one of the speciesthreatened by eutrophication.
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UK response to the effects of eutrophicationIn 1998, the House of Commons
Environment, Transport and the Regions
Select Committee recommended universal
nutrient removal from sewage. In
response, the government stated it was
not persuaded that the benefits of
universal removal justified the cost. In
1998 an Environment Agency (EA)
consultation on a Eutrophication Strategy
concluded that the UK is well endowed
with the main sources (urban waste water
and agriculture) of the nutrients
associated with eutrophication and that
recent evidence, particularly as regards
the freshwater environment, indicates
Country by country review
Environment Agency Strategy on Eutrophication (2000)
The EA Strategy accepts that it will be necessary to go beyond the strict requirements of the
UWWT Directive to deal with eutrophication, and that the Water Resources Act 1991 will be
required for agricultural phosphate controls. It also concurs that the WFD definition of good
ecological status will preclude the occurrence of eutrophication.
But the Strategy assumes that the development of criteria to determine the eutrophication
status of estuarine and marine waters is at an early stage and further research is required.
However, the UK has already developed and applied such criteria (for example at Chichester
harbour) and there is already widespread agreement on quantitative criteria within the
OSPAR eutrophication strategy.
The Strategy rejected whole or substantial national territory designation of Sensitive Areas
and Nitrate Vulnerable Zones. It restricts the application of precaution to conservation sites
of the highest importance, and then only if the cost is considered worthwhile. It is important
to note the requirement under OSPAR, to apply precaution to all areas, and that the rejection
of action on the basis of cost has already been ruled inadmissible in a UK Judicial Review
regarding the UWWT Directive. The EA Strategy also continues to place a strong emphasis
on voluntary action, even though it accepts that this has been ineffective in the past.
England
Brent geese feeding on green algae inLangstone Harbour (south coast ofEngland). The algae has a lower food valuethan the eelgrass it has replaced.
Wales
Nitrogen and phosphorus inputs increased
dramatically in England during the 20th
century. For example, a two to six-fold
increase for the Alde-Ore and Deben
estuaries in Suffolk occurred between
the 1930s and 1990s. This was a result
of increased fertiliser use and settlement
in coastal locations.
Nutrient inputs to the North and Irish
Seas reached a high plateau in the 1980s.
As a result, nutrient levels in many English
estuaries are well above those considered
to be hypernutrified and at risk of
eutrophication. The highest levels occur
in the Wash estuaries. The Wash and
North Norfolk coast is an EMS designated
for six different interest features:
sandbanks, mudflats, lagoons, shallow
inlets, reefs and the common seal. Coastal
waters beyond the estuaries also have
unnaturally high levels of nutrients,
particularly in the area running from
the Humber to the Thames and those
off north-west England. Nutrient levels
are well above those predicted in Danish
studies to have an impact on eelgrass
and dependant species due to shading
by increased levels of phytoplankton.
In Denmark, at sites where nutrients were
reduced, the eelgrass has made a come-
back. The English east coast has many
EMSs including the Humber, the Deben
and the Arde-Ore. Brent geese on the
Humber were almost completely lost
when the eelgrass disappeared.
Also of concern is the proliferation
of algal weed mats on intertidal flats at
sites ranging from Lindisfarne, through
Suffolk and Essex, to the south coast.
Such proliferation was the reason for
designating Langstone and Chichester
harbours as SAs. Additionally, these
harbours are among the south coast
estuaries designated as EMSs.
Given the many important conservation
sites in Wales, marine eutrophication
studies in the Principality are sparse. Sixty
per cent of the Welsh coast is covered by
EMS designations. The highest levels of
nutrients in Wales occur in the estuaries
on the south coast adjacent to intensively
farmed areas and large urban settlements,
extending from Carmarthen and Swansea
Bays along the coast off the Vale of
Glamorgan to the Severn estuary. One
SA, the Tawe Estuary, was designated in
1998. Phytoplankton levels are high along
the north coast. There are grounds,
however, for establishing SAs, NVZs and
possible OSPAR problem areas along the
north coast, and the south coast from
Carmarthen Bay to the Usk.
In Wales relatively small changes in
nutrient levels at naturally nutrient-poor
(oligotrophic) sites nevertheless represent
a large proportional change. These may
pose a threat to species requiring
nutrient-poor conditions to survive. The
Countryside Council for Wales (CCW) has
expressed concern that general UK-wide
objectives may have little relevance for
these sites with naturally low nutrient
levels. For example, salt marsh plants –
some already endangered – adapted to
Swansea Bay, Wales.
low nutrient levels may be eliminated,
even though conditions such as extensive
algal weed growth are absent. The need
in Wales (as for the rest of the UK) to
maintain or restore low-nutrient
conditions has yet to be addressed.
Green algal mats at Deben tank, Suffolk, east coast of England.
that aquatic eutrophication is more than
a limited localised problem. It also cited
evidence of an increasing frequency of
algal blooms in coastal waters. The final
EA Eutrophication Strategy, published in
2000, contains important conclusions
(see box below). It also recognised
international requirements to protect
the interest features of EMSs from the
threat of eutrophication. It is unclear,
however, how the interest features of
EMSs will be protected from eutro-
phication, particularly since the cause of
eutrophication within EMSs can often be
initiated from outside the sites. Potential
SACs and SPAs offshore will also require
further consideration.
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Scotland
Northern Ireland
In eastern Scotland, the Ythan, with
significant arable agriculture and animal
husbandry, has the highest Scottish nitrate
concentrations. The proliferation of algal
weed mats and their effect are well
documented, yet designation as an NVZ
was twice rejected before finally being
accepted. It has yet to be designated as
a Problem Area under the OSPAR
eutrophication strategy, which would
require a 50 per cent reduction of
nutrients in the estuary.
The South Esk/Montrose Basin and the
Eden estuary are important conservation
sites that are also EMSs for their SPA
designations. All three UK species of
eelgrass were present at these two sites
at least until the 1970s. Both sites have
elevated nutrient concentrations, large
areas covered by algal weed mats, and
can be considered as vulnerable to eutro-
phication. Yet neither site has been
designated as a NVZ or SA.
In western and northern Scotland
where there are at least 25 marine
SACs, there are grounds for concern
about the impact of increasing nutrient
inputs from aquaculture on marine
communities, in particular the sub-tidal
eelgrass (Zostera marina). The recent
closures of scallop fisheries on the west
coast of Scotland, because of toxic algae,
may in part be due to excessive nutrient
inputs from aquaculture (Loch Sunart
candidate Special Area of Conservation
(SAC), Lochs Duich, Long, Alsh SAC and
Loch Maddy SAC are effected by nutrient
inputs from aquaculture). It is a matter of
concern that the UK initially classified the
north-west coast as an OSPAR non-
problem area, and has only recently
agreed to conduct the comprehensive
eutrophication assessment procedure. As
for Wales, there is some evidence that
natural nutrient levels there are lower
than English coastal waters, and it is
important that action on nutrients reflects
lower relative concentrations.
Northern Ireland currently has two
marine SACs – Strangford Lough and
Rathlin Island. Even though Strangford
Lough has been defined as a rapid
flushing system, the inner part has a
long residence time. Hence, in bays
and inlets at the top of the Lough
where flow rates are weak, there
is a potential for localised
eutrophication. There have been
incidences of nutrient pollution in the
tributary rivers running into Strangford
Lough (the river Quoile is regarded
as eutrophic), and certain areas of
the Lough can be considered as
bottlenecks for nutrient enrichment
with potential associated impacts.
Elsewhere, the inner Belfast Lough
is known to be a hotspot for
anthropogenic nutrient enrichment
and clearly exhibits eutrophication
symptoms. A study on Larne Lough
highlighted high nitrogen and
phosphorous concentrations indicating
eutrophication at low tide in the
southern sections of the Lough.
Additionally, the significant proportion
of ammonia in the total soluble
nitrogen indicates pollution from
sewage effluents.
In 1999, a Northern Ireland
consultation exercise on a strategy to
control nutrient enrichment by the
Environment and Heritage Service
Coral colouredbeadlet anemone.Aneomes areanother speciesthreatened byeutrophication
Ythan Estuary, Scotland.
Conclusion and recommendationsIn order to prioritise actions regarding eutrophication with
reference to EMSs, it is necessary to consider the management
action required under European Union Directives and the OSPAR
Convention. While there is a general requirement to create an
environment where eutrophication does not occur by 2010,
there is merit in prioritising action within that overall timeframe
for EMSs. Priority should also be given to non-EMS sites with
naturally low nutrient levels that are suffering from relatively
high anthropogenic nutrient inputs compared with their natural
state.
SAC management plansWWF proposes two specific requirements with respect to the
assessment and action on eutrophication (as covered in the 1994
UK Regulations to implement the Habitats Directive):
• the integration with SAC management plans of other
plans that affect the site, regardless of whether they have
specific implications relating to the Habitats Directive. For
eutrophication, the management of nutrients from within the
marine SAC should be part of the SAC management plan;
• specific management action to reduce eutrophication, with
respect to features and sub-features within the site (for
instance, for eelgrass and soft sediment communities). The
actions should apply to both direct and indirect impacts, and
from inside or outside the site (eg the catchment area for an
estuary, or the sources of coastal currents that influence an
offshore site).
Achieving favourable conservation statusIf the favourable conservation status of an EMS is affected by, or
vulnerable to, eutrophication there is a requirement to introduce
nutrient reduction measures on inputs. WWF proposes:
• the relevant authorities should regularly review the
eutrophication status of EMSs, at an interval not greater than
four years, as an integral part of the periodic review required
for Directives and the OSPAR Strategy;
• nutrient reduction control measures should be promptly
imposed for diffuse (eg agriculture) and point sources (eg
sewage) when sites are vulnerable to such inputs;
• restoration plans should be introduced for interest features
and their sub-features that have been degraded by
eutrophication.
Site designations and the precautionaryapproachIt will be necessary to apply precaution and be prepared to act
on the balance of probabilities, or even on grounds of reasoned
concerns, for EMSs. WWF recommends:
• if there is a potential threat from eutrophication for any EMS,
the precautionary approach should be vigorously applied and
the site designated as an OSPAR problem area, and as an SA
and/or NVZ, as appropriate;
Reed bed, Trent Falls, Humberestuary, North-east England.
focused almost solely on freshwater
with little consideration of the
potential problems within the marine
loughs, bays and inlets. The Northern
Ireland Assembly's current Programme
for Government states, however, its
intention to produce, by the end of
2001, a strategy to reduce
eutrophication.
Strangford Lough, one of the twomarine SACs in Northern Ireland.
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