Table 1. Surface Samples of Water Quality Data Used in the Analysis^a.

			no. of observations			no. of annual means
region	no. of coastal ecosystems	years	TN	TP	Chla	TN	TP	Chla	source
Chesapeake Bay	7	1984–2006	17133	17465	21427	149	149	159	www.chesapeakebay.net
Denmark coast	10	1977–2006	12409	12354	12211	256	257	257	www.dmu.dk
Tampa Bay	4	1977–2006b	12825	17889	17885	104	120	120	www.tbeptech.org
Wadden Sea (Dutch part)	7	1977–2006c	3828	3878	3323	203	200	204	www.waterbase.nl

^aData were downloaded from public monitoring databases with long time series (>20 years) of coastal ecosystems from four regions.

^bNo TN data before 1981.

^cTN and TP calculated as sum of measured particulate and filtered fractions between 1991 and 1996.