Monitoring
Contaminants
Replicate sediment samples are analysed for trace metals,
polychlorinated biphenyls (PCBs) and polycyclic aromatic
hydrocarbons (PAHs).
Dab (Limanda limanda) muscle is analysed for mercury
and arsenic, and liver tissue for cadmium, lead and PCBs.
Biological effects
A number of different factors including EROD
(ethoxyresorufin-O-deethylase), bile metabolites and DNA adducts
are measured from dab liver and muscle to determine the biological
effects of certain contaminants.
- When absorbed PAHs and PCBs cause enzymes to be produced in
fish. The synthesis of these enzymes is measured by the activity of
EROD in fish liver. As these substances are degraded by the liver
they appear as metabolites in the bile.
- DNA adducts are formed when genotoxic chemicals, like
metabolites of PAHs, bind to DNA bases. These DNA adducts may cause
permanent alterations to the genome (gene mutation).
Fish disease and liver pathology is also recorded as the
presence of liver nodules or tumours are significant biological end
points to organic contaminants.
Tributyltin (TBT) specific biological effects (imposex/intersex)
are monitored in the gastropod species Nucella lapillus,
Nassarius reticulata, Buccinum undatum,
Neptunea antiqua and Littorina littorea. Sampling
is designed in accordance with the revised OSPAR guidelines on TBT
effects monitoring.
Benthos
Benthic community analysis is undertaken on sediment replicates
taken from each of the sediment sites. Species are identified to
the lowest possible taxonomic level and are counted and
weighed.
Litter
Items of litter encountered at the fishing sites are counted and
classified annually.
Eutrophication
Water samples are collected during a winter sampling cruise
(using RV
Cefas Endeavour) from opportunistic stations and are
analysed for nutrients, chlorophyll, salinity bottom oxygen
concentrations and temperature. These samples provide good spatial
coverage but automated in situ instrumentation systems are now used
to resolve temporal variability adequately. These marine
observations systems have been developed by Cefas with funding
support by Defra for collecting the high-frequency, near real-time
data needed for the CSEMP.
The Cefas-developed SmartBuoy is one of an array of automated in
situ instrumentation systems that can be deployed for extended
periods at a mooring. SmartBuoy is currently configured to meet the
needs of the CSEMP through monitoring plant nutrient concentrations
and the response of the ecosystem in terms of phytoplankton growth
and species composition. Additional physical measurements are also
made to ensure that a full interpretation of the time-series data
set is possible. Summary data are returned in near real-time
(two-hourly) via satellite telemetry with full data sets recovered
during servicing of the buoy. Data are published on the Internet to
give rapid access to other collaborators and the public.
The CSEMP programme is currently being provided with data from 3
deployment groups, each having a series of linked deployments.