Figure

Trends in dissolved inorganic nitrogen and orthophosphate concentrations in transitional, coastal and marine waters in Europe, 1980-2019

Figure Created 05 Sep 2022 Published 12 Sep 2022 Last modified 07 Dec 2023

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Topics: Water and marine environment

Trends in concentrations of nitrogen (dissolved inorganic nitrogen — DIN) and phosphorus (orthophosphate) in the upper 10m of the water column in European seas during the season of low phytoplankton growth (SLPG) are shown for the period 1980-2019. Green circles indicate stations with significant (p<0.05) decreasing trends; orange circles show stations with significant (p<0.05) increasing trends; and grey circles show stations with no significant trends. In these cases, p is a statistical term describing the probability that the trend is significant.

https://eea.europa.eu./data-and-maps/figures/trends-in-dissolved-inorganic-nitrogen/fig01-129834-mar005-v2.eps/image_large

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Metadata

Units:: The trends have no units
Rights:: Copyrights of the datasets: please take a look at https://www.ices.dk/data/guidelines-and-policy/Pages/ICES-data-policy.aspx
and https://www.emodnet-chemistry.eu/data/acknowledgement
Copyrights of the figure: EEA standard re-use policy: unless otherwise indicated, re-use of content on the EEA website for commercial or non-commercial purposes is permitted free of charge, provided that the source is acknowledged (https://www.eea.europa.eu/legal/copyright). Copyright holder: European Environment Agency (EEA).
Owners:: European Environment Agency (EEA)
Processors:: AZTI
Figure type:: Map

Additional information

- DIN refers to the sum of ammonium, nitrite and nitrate concentrations, although in many samples not all three forms of nitrogen were measured.
- To improve the aggregation into time series, data were aggregated into squares of 0.01 degree × 0.01 degree for coastal stations (within 20km of the coastline) and 0.05 degree × 0.05 degree for open water stations.
- SLPG was considered: August-October in the Mediterranean and Black Seas, January-March in the Baltic Sea and January-February in the other regional seas.
- Temporal trends were estimated with the non-parametric Mann-Kendall test. Only stations having data of at least 5 years and having at least data in the last 5-year period (2015-2019) were considered. A p-value <0.05 was used to consider a statistically significant trend.