Eutrophication and European Marine Sites

WW

F-U

K R

egis

tere

d C

harit

y N

umb

er 1

0812

47 P

rinte

d o

n re

cycl

ed p

aper

mad

e fr

om 1

00 p

er c

ent

pos

t co

nsum

er w

aste

P

and

a sy

mb

ol ©

198

6 W

WF

® W

WF

Reg

iste

red

Tra

dem

ark

142

3/A

ugus

t 20

01

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

CO

VE

R P

HO

TO

GR

AP

HS

: M

AL

CO

LM

MA

CG

AR

VIN

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.

PJ

BA

NK

S/W

WF

-UK

M M

AC

GA

RV

IN

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.

J M

EL

HU

ISH

/WW

F-U

K

M M

AC

GA

RV

IN

M M

AC

GA

RV

IN

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.

C H

OO

D/W

WF

-UK

J N

UN

N

M M

AC

GA

RV

IN

M M

AC

GA

RV

IN