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National Marine Monitoring buoy network

The SEPA Marine National Environmental Monitoring Buoy Network provides real time, high frequency environmental data from strategic locations around the coast, as part of SEPA obligations to monitoring the marine environment.
What is being monitored?
Continuous monitoring equipment gathers dissolved oxygen, water temperature, salinity and chlorophyll-a data at regular intervals. The data is stored internally and downloaded at regular maintenance intervals.
Why monitor?
The data is used to assess the state of the marine environment at representative locations.
Salinity is used to indicate changes in water masses. Salinity decreases as freshwater inputs increase and oxygen is more soluble in freshwater than seawater.
Water temperature is closely linked to seasonal changes and oxygen becomes less soluble as the water temperature increases.
Chlorophyll-a is an indicator of the biomass of phytoplankton.  Phytoplankton blooms are common occurrences at the start and end of the growing season in spring and autumn however excessive phytoplankton is indicated by enhanced abundance  throughout the growing season (90%ile concentration >15 µg/l measured from April – September).  Excessive phytoplankton growth may cause an undesirable disturbance to the ecosystem if the decaying algae remove oxygen from the water column and sea bed as a result of microbial breakdown.
Dissolved oxygen is one of the most important indicators of the health of a water body and high levels are needed to support a variety of marine life.  Dissolved oxygen concentrations are affected by salinity, temperature and phytoplankton growth.  Dissolved oxygen produced by photosynthesis may result in supersaturation (>100%) during the growing season. Dissolved oxygen is removed by the microbial breakdown of organic matter.
For more information, please click on a buoy location below:

Data requests

If you require any further information regarding our monitoring buoys please contact us.


The monitoring buoy data is gathered by SEPA to help it fulfil its statutory duties. We publish it online because we recognise that this information may also be useful for others, but we cannot guarantee its currency or availability. Use of the data is subject to our standard terms and conditions of reuse. The majority of our buoys do not have remote telemetry and so data availability is subject to monthly downloads when the buoys undergo maintenance.  

Whilst every effort has been made to ensure the accuracy of the information provided, neither Scottish Environment Protection Agency, nor its employees or agents can be held responsible for any inaccuracies or omissions, whether caused by negligence or otherwise. All data should be regarded as provisional and may be subject to later revision.