Assessment and monitoring of ecosystem health in the sea: A description of the Swedish monitoring system for coastal marine areas

Abstract

Abstract Swedish coastal waters range in salinity from 0 psu (practical salinity units = o/oo) in the Bothnian Bay, which is part of the Baltic Sea, to 35 psu in the Skagerrak, which belongs to the North Sea and the Atlantic Ocean. Natural variations in ambient conditions include weather and climate due to latitudinal, seasonal and annual variations. Anthropogenic inputs of pollutants originate from local point sources and diffuse and distant sources. These inputs may cause local and regional as well as national and international problems. Therefore, local and regional monitoring programs are integrated into the Swedish national monitoring program, which is also co-coordinated with other national and international monitoring programs. The aim of this paper is to describe and assess the Swedish monitoring system for the marine and coastal environment and to discuss its strengths and weaknesses. The monitoring system incorporates a combination of chemical-physical and biological parameters. Measured parameters are accompanied with specific quality criteria. In most cases the criteria are based on an estimate of a ‘natural state’ and the appraisals are expressed on a scale of 1-5 (high, good, fair, poor and bad quality). Three major threats to the marine environment are eutrophication, toxic organic pollutants/metals and physical disturbance (exploitation of the coast). The parameters used to assess eutrophication are concentrations of nitrogen, phosphorus and silica, Secchi depth, concentration of chlorophyll, benthic fauna and macrovegetation. Metals and toxic organic pollutants are assessed based on their concentrations in sediment and selected organisms. The assessment of the degree of physical disturbance of coasts and seas is based on the number of buildings along the shoreline, physical disturbance along the shoreline, proportion of exploited/disturbed coastal water zones and jetty length. Other threats, which are also briefly discussed in this paper, are impact from the fishery and the potential toxic impact of contaminants, which are not being measured.