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You are here: Home / Data and maps / Indicators / Chlorophyll in transitional, coastal and marine waters / Chlorophyll in transitional, coastal and marine waters (CSI 023) - Assessment published Nov 2005

Chlorophyll in transitional, coastal and marine waters (CSI 023) - Assessment published Nov 2005

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Generic metadata

Topics:

Water Water (Primary topic)

Coasts and seas Coasts and seas

Tags:
water | csi
DPSIR: State
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
Indicator codes
  • CSI 023
Geographic coverage:
Belgium Denmark Estonia Finland France Germany Greece Iceland Ireland Italy Latvia Lithuania Netherlands Norway Poland Portugal Spain Sweden United Kingdom
 
Contents
 

Key policy question: Is eutrophication in European surface waters decreasing?

Key messages

There has been no general reduction in eutrophication (as measured by chlorophyll-a concentrations) in the Baltic Sea, the Greater North Sea or the coastal waters of Italy and Greece. Chlorophyll-a concentrations have increased in a few coastal areas and decreased in others.

Mean summer surface concentrations of chlorophyll a in the Baltic Sea Area, 2003

Note: Coastal stations are marked by circles and ICES open-water stations by squares

Data source:

Waterbase (data from OSPAR, HELCOM and EEA member countries compiled by ETC Water).

Downloads and more info

Mean summer surface concentrations of chlorophyll a in the Mediterranean Sea, 2003

Note: Coastal stations are marked by circles

Data source:

Waterbase (data from OSPAR, HELCOM and EEA member countries compiled by ETC Water).

Downloads and more info

Number of coastal stations per country showing no trend, decreasing or increasing trend in summer surface concentrations of chlorophyll-a, 2003

Note: N/A

Data source:

Waterbase (data from OSPAR, HELCOM and EEA member countries compiled by ETC Water).

Downloads and more info

Mean summer surface concentrations of chlorophyll a in the Greater North Sea, the Irish Sea and the north-east Atlantic, 2003

Note: Level classification is based on the 20%, 40%, 60% and 80% percentiles of the chlorophyll a distribution.

Data source:

Waterbase (data from OSPAR, HELCOM and EEA member countries compiled by ETC Water).

Downloads and more info

Mean summer surface concentrations of chlorophyll a in the Black Sea, 2003

Note: Level classification is based on the 20%, 40%, 60% and 80% percentiles of the chlorophyll a distribution.

Data source:

The data used here originate from the database prepared in the framework of the NATO SfP-971818 ODBMS Black Sea Project

Downloads and more info

Key assessment

No overall trend has been observed in summer surface chlorophyll-a concentrations, either in the open-sea areas of the Baltic Sea and the Greater North Sea, or the coastal waters of Italy and Greece in the Mediterranean Sea (Fig. 1). The majority of the coastal stations in the three seas show no trend, however some stations show increasing or decreasing trends. For example, in the Baltic Sea, 11 % of the coastal stations show an increase in chlorophyll-a concentrations and 3 % a decrease. This lack of a clear general trend indicates that measures to reduce loads of nutrients have not yet succeeded in significantly reducing eutrophication.

In the Baltic proper and the Gulf of Finland, high mean summer surface chlorophyll-a concentrations (>2.8 microgram/l) are found in open waters, probably due to summer blooms of cyano-bacteria, specific to the Baltic Sea (Fig. 2). Concentrations greater than 4 microgram/l are observed in estuaries and coastal waters influenced by rivers or cities in some Swedish, Estonian, Lithuanian, Polish and German coastal waters.

In the North Sea, high chlorophyll-a concentrations (>5.8 microgram/l) are observed in the Elbe estuary and Belgian, Dutch and Danish coastal waters influenced by river discharges (Fig. 5). High concentrations are also observed in Liverpool Bay in the Irish Sea. In the open North Sea and Skagerrak, chlorophyll-a concentrations are generally low (<1.4 microgram/l).

In the Mediterranean Sea, 12 % of the stations in Italian coastal waters show a decrease in concentrations of chlorophyll-a, while 8 % show an increase (Fig. 1). The lowest concentrations (<0.35 microgram/l) are observed around Sardinia and in southern Italian and Greek coastal waters. Higher concentrations (>0.6 microgram/l) are observed along the Italian east and west coasts and in the Greek Saronikos Bay. High concentrations (>1.95 microgram/l) are found in the northern Adriatic and along the Italian west coast from Naples to the north of Rome.

Very few chlorophyll-a data are available for the Black Sea. The available data show the highest level (>1.7 microgram/l)  in the Ukrainian waters of the north-western Black Sea (Fig. 6).

Data sources

More information about this indicator

See this indicator specification for more details.

Contacts and ownership

EEA Contact Info

Constança De Carvalho Belchior

Ownership

EEA Management Plan

2005 1.4.2 (note: EEA internal system)

Dates

Frequency of updates

Updates are scheduled every 1 year in July-September (Q3)
Document Actions
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Comments

European Environment Agency (EEA)
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1050 Copenhagen K
Denmark
Phone: +45 3336 7100