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[MR04] Chlorophyll a in coastal waters
State

Key message
Good

Phytoplankton biomass, expressed as chlorophyll a concentration, reflects nutrient loading in the marine environment. Chlorophyll a concentrations shows a trend towards improvement in the status of the Slovenian sea, as the ecological status has been assessed as high or good over the last period. This is partly due to decreasing concentrations of nutrients in seawater and rivers caused by modernization or construction of sewage systems and municipal wastewater treatment plants in the hinterland, measures to reduce phosphate use in detergents and decreasing river discharges into the Gulf of Trieste.

 

 

Charts

Figure MR04-1: Phytoplankton biomass evaluated as Chlorophyll a (Chl a) concentration in the surface layer of selected monitoring sites in the Slovenian sea
Sources:

Unified Water Quality Monitoring Database, Slovenian Environment Agency, 2021 (15. 03. 2021)

Note:

Thresholds between good and moderate ecological status (G/M ES) and between high and good ecological status (H/G ES) are shown.

Show data
measuring point Unit 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
S Gulf of Trieste (F) µg/L 0,93 0,89 1,07 0,93 1,37 1,14 0,80 1,02 1,17 1,01 1,28 0,94 0,29 0,67 0,51 0,58 0,93 0,43 0,41 0,56 0,58 0,60 0,61 0,55 0,37 0,33 0,56
central Gulf of Trieste (CZ) µg/L 1,10 1,06 1,29 1,08 1,34 1,19 1,54 1,27 1,47 0,84 1,24 1,18 0,40 0,80 0,62       0,53 0,64 0,88 0,75 0,72 0,69 0,41 0,44 0,81
H/G ES µg/L 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64 0,64
G/M ES µg/L 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50 1,50
Figure MR04-2: Locations of monitoring sites for Chlorophyll a sampling within national monitoring program in the Slovenian Sea
Sources:

Unified Water Quality Monitoring Database, Slovenian Environment Agency, Surveying and Mapping Authority of the Republic of Slovenia, 2021 (25. 05. 2021)

Note:

Separately are presented monitoring sites and ecological status assessment based on phytoplankton in the period 2016–2019.

Show data

 

 

Methodology

Date of data source summarization
Last modified
25.05.2021
Author(s)

Elizabeta Gabrijelčič, Slovenian environment agency; Janja Francé, Marine biology station Piran, National institute of biology