Data Visualization

Trends in chlorophyll-a concentrations in European seas (1980-2019)

Data Visualization Created 18 May 2022 Published 28 Jul 2022 Last modified 25 Aug 2022

1 min read

Topics: Water and marine environment

The chart shows the percentage of locations with statistically significant: (1) decreasing trend (green), (2) no trend (grey) and (3) increasing trend (orange) by marine regions. The total number of locations in each subregion is shown in brackets.

Chart
Table

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More information

• Temporal trends were estimated in locations with data for at least 5 years in the period 1980-2019 and updated in the last 5-year period (2015-2019), using the non-parametric Mann-Kendall test. A p-value of <0.05 was considered to indicate a statistically significant trend.
• Results reflect data availability, which may vary significantly across regions and over time.

Geographical coverage
European marine regions - Baltic Sea, Greater North Sea, Bay of Biscay and the Iberian Coast, Celtic Seas, Mediterranean Sea, Oceanic North- East Atlantic and Macaronesia.

Temporal coverage
1980-2019 (the temporal range specified is the maximum range of dates for raw observations but this range varies upon the availability of observations at each location).

Methodology
Based on datasets produced for the CSI032_MAR006_Chlorophyll in transitional, coastal and marine waters_2021 Indicator, the percentage of the number of locations with significant decreasing trend (green), no trend (grey) and increasing trend (orange) were calculated by marine region and plotted in a bar-type chart.