4.5. Monitoring of marine waters

4.5 Monitoring of marine waters

The countries in the EEA area have a long coastline. Bordering the Barents Sea to the north, the Atlantic Ocean and the North Sea to the west and the Mediterranean to the south. In addition, Sweden, Finland, Germany and Denmark have coastlines bordering the Baltic Sea. Several semi-closed seas (eg. the Adriatic Sea, the Irish Sea and the Gulf of Bothnia) and numerous fjords, coastal and estuarine areas are located along the coast of the seventeen countries. Countries sharing marine areas usually establish some form of environmental cooperation, as is for example the case with the Baltic Sea, the North Sea, the North East Atlantic and the Mediterranean. Generally, such cooperation has resulted in the establishment of a monitoring programme covering the specific waterbody. In the EEA area the Oslo and Paris Commissions (OSPARCOM) and North Sea Task Force are responsible for the overall coordination of monitoring in the north-east Atlantic and the North Sea, while the Helsinki Commission (HELCOM) is in charge of the overall coordination of monitoring of the Baltic Sea, the monitoring of the Mediterranean being coordinated by the UNEP/MED POL programme (see also chapter 3).

The countries bordering these marine areas participate in the international monitoring programmes and the monitoring activities are incorporated into the national marine monitoring programmes. The national marine monitoring programmes are, however, generally more comprehensive including more sampling sites, especially in coastal areas, and measurement of more variables. The general purpose of national marine monitoring programmes is to assess the environmental state of the nationally important marine areas, and the national programmes are thus aimed at giving a nation-wide overview of marine environmental issues.

In this section the reported national marine monitoring programmes have been put together and a comparison of similarities and differences between the different monitoring activities has been made. In total information on approximately 38 national marine monitoring programmes from ten countries have been received (Table 4.5.1). No detailed information about marine monitoring programmes has been received from Belgium, Iceland, Italy, Portugal, and Spain. Austria and Luxembourg, of course, have no marine monitoring programmes.

The ten countries usually have one general marine monitoring programme or the general programme has been divided into sub-programmes as for example in Finland that has a coastal monitoring programme and a monitoring programme focused on open marine waters. In addition, there are some more specific monitoring programmes such as the bathing water monitoring programmes (GR-M3, UK-M5) or monitoring focused on specific biological organisms.

Table 4.5.1: National marine monitoring programmes in the EEA area

Water (W): C&P; WQ: chemical and physical water quality variables;
Biota (B):PHYTPL: phytoplankton; ZOOPL: zooplankton, PHYTBEN: phytobenthos, ZOOBEN: zoobenthos; MAPHYT: macrophytes; OMP: organic micropollutants;
Sediment (S):OMP: organic micropollutants.

Most of the marine monitoring programmes include monitoring of chemical and physical variables in the water column, and several also include studies of the biota (phytoplankton, zooplankton, zoobenthos, etc.). The sampling networks generally consist of a number of intensive sampling sites, typically less than 20 sites, at which frequent sampling (> 12/yr) of the water column is made supplemented with an extensive sampling network including several sampling sites and low frequency sampling (1-4/yr) of the water column. Zoobenthos and sediment samples are generally taken at numerous sampling sites.

Variables measured on marine water samples

Around 100 different chemical and physical variables are measured on water samples in the various marine monitoring programmes, more than half of the variables being different organic micropollutants. Only 28 variables, except for organic micropollutants, are measured in more than two marine monitoring programmes (Table 4.5.2).

Table 4.5.2: Chemical and physical water quality variables measured in at least three marine monitoring programmes.

Basic variables

Most of the marine monitoring programmes include measurements of basic variables such as water temperature (TEMPW), salinity (SAL), dissolved oxygen (OX) and pH (PH). In many monitoring programmes basic variables are measured very frequently, typically bimonthly sampling is undertaken.

Table 4.5.3: Basic variables measured in the water column in national marine monitoring programmes.

X: unknown or varying sampling frequency

Suspended particulate matter

Three summary variables used as indicators for the concentration of suspended matter are measured in the marine monitoring programmes: suspended matter (SM) or total organic carbon (TOC) and turbidity (TURB).

Table 4.5.4: Suspended matter variables measured in the water column in national marine monitoring programmes.

X: unknown or varying sampling frequency

Eutrophication - nutrients

All the ten countries have at least one national marine monitoring programme with the purpose of assessing the concentration of nutrients in the water column. As a rule the monitoring programmes include measurement of nitrogen, ie. oxidized nitrogen (NO23N), ammonium (NH4N) and total nitrogen (NTOT); phosphorus, ie. dissolved reactive phosphorus (PO4P) and total phosphorus (PTOT); and silica (SIO2). Additionally, the impact of eutrophication is measured using general indicator variables such as Secchi disc transparency (SDT), chlorophyll a (CHLA) and primary production (BPP).

Table 4.5.5: Nutrients and other eutrophication variables measured in the water column in national marine monitoring programmes.

X: unknown or varying sampling frequency

Metals

Measurement of metals in the water column is also included in many of the national marine monitoring programmes. Denmark and Sweden, however, do not measure metals in the water column. Ireland measures heavy metals in a number of localised and occasional programmes. The heavy metals of mercury (HG), cadmium (CD), chromium (CR), copper (CU), lead (PB), zinc (ZN) and nickel (NI) are the most frequently included metals, while iron (FE), cobolt (CO), manganese (MN) and arsenic (AS) are only included in a few monitoring programmes. The sampling frequency varies from once every third year to 4-5 annual samples.

Table 4.5.6: Metals measured in the water column in national marine monitoring programmes.

X: unknown or varying sampling frequency

Bottom sediment

Several of the marine monitoring programmes include measurement of metals associated with the bottom sediment. The most frequently measured metals are mercury (HG), cadmium (CD), copper (CU), lead (PB), nickel (NI), chromium (CR) and zinc (ZN).

Table 4.5.8: Metals measured on bottom sediments in national marine monitoring programmes.

X: unknown or varying sampling frequency

Measurement of metals in biota

Measurement of the concentration of metals in the tissue of various biological organisms is also included in some monitoring programmes.

Table 4.5.8: Metals measured on biota in national marine monitoring programmes.

X: unknown or varying sampling frequency

Biological assessment of the state of marine waters

Several of the marine monitoring programmes include studies of various biological organisms. Investigation of phytoplankton (PHYTPL) is the most frequent biological variable to be included. These phytoplankton investigations range from monitoring programmes focusing on toxic algae in relation to bathing or shellfish production to detailed investigations of the phytoplankton communities especially in relation to eutrophication problems. Detailed studies of phytoplankton generally also include studies of zooplankton (ZOOPL). In countries where the environmental state of marine waters has deteriorated due to frequent periods of oxygen deficit studies of the benthic invertebrate fauna (ZOOBEN) are included in the national marine monitoring programmes. In some monitoring programmes macrophytes (MAPHYT) and fish (FISH) are studied as well. In Ireland, phytoplankton and zoobenthos are monitored in a number of localised and occasional programmes.

Table 4.5.7: Biological organisms included in national marine monitoring programmes.

X: unknown or varying sampling frequency