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L 1 in Delaware and Loire Estuaries; <40.0 μ g L 1 in Pearl River Estuary;
<33.3 μ g L 1 in Patuxent River Estuary; <23.0 μ g L 1 in several temperate
estuaries; <18.02 μ g L 1 in estuary of Bedford Basin, Canada; <13.8 μ g L 1
in Sado Estuary; <11.0 μ g L 1 in Changjiang (Yangtze River) Estuary; <8.9 μ g
L 1 in Elbe Estuary; and 0.3-5.4 μ g L 1 in all other estuaries studied (Table 1 ).
Such high contents of Chl a in estuaries are indicative of highly productive
waters, which might be cause by several factors: (i) Estuarine waters contain
high contents of DOM, such as 84-525 μ M C, which are mostly originated
from terrestrial DOM along with the autochthonous DOM and land-derived
nutrients (Table 1 ; see also in chapter Dissolved Organic Matter in Natural
Waters ”) (Hauxwell et al. 2003 ; Monbet 1992 ). Water with high contents of
DOM can significantly enhance primary production in estuaries, along with
factors that have been discussed previously (see also chapter Photosynthesis
in Nature: A New Look ). (ii) Tidally-driven resuspension along with other
associated processes (e.g. tidal mixing, current velocity, light penetration, and
sediment resuspension) can influence the variability of suspended particulate
matter in estuaries (Monbet 1992 ; Nichols and Biggs 1985 ; Allen et al. 1980 ;
Schubel 1971 ). Estuaries with a low tidal range have maximum suspended sedi-
ment load, on the order of 100-200 mg L 1 . In contrast, systems with high tidal
ranges have sediment concentrations of about 1,000-10,000 mg L 1 (Nichols
and Biggs 1985 ). Comparative data analysis from 40 microtidal and macrotidal
estuaries shows that mean annual Chl a levels are significantly lower in systems
with high tidal energy (Monbet 1992 ). In contrast, nitrogen concentrations are
equal to nitrogen levels in the microtidal systems (Monbet 1992 ). The mecha-
nism behind these phenomena is presumably that strong tidal wave along with
strong wind mixing can produce high concentrations of H 2 O 2 , DIC, nutrients,
and so on. These species can be produced either photochemically or microbially
from DOM and POM, and can strongly influence photosynthesis and primary
production as discussed in an earlier chapter (see Photosynthesis in Nature: A
New Look ).
Coastal and Open Oceanic Environments
The Chl a concentrations undergo higher variations, from 0.02 to 2080 μ g L 1
in the waters of coastal and open oceans compared to those of lakes and estuar-
ies (Table 1 ) (Letelier et al. 2004 ; Rochelle-Newall and Fisher 2002 ; Hopkinson
and Barbeau 2008 ; Wheeler et al. 1996 ; Millán-Núñez et al. 1996 ; Gomes et al.
2000 ; Guildford and Hecky 2000 ; Li and Harrison 2001 ; Ediger et al. 2006 ; Parab
et al. 2006 ; Roy et al. 2006 ; Norrbin et al. 2009 ; Xiu et al. 2009 ; Hung et al. 2000 ;
Ahumada et al. 1991 ; Morales et al. 1996 ; Dellarossa 1998 ; Planas et al. 1999 ;
Doyon et al. 2000 ; Gibb et al. 2000 ; Gong et al. 2000 ; Pizarro et al. 2000 ; Kinkade
et al. 2001 ; Olson and Strom 2002 ; Sasaoka et al. 2002 ; Carstensen et al. 2004 ;
Clark et al. 2004 ; Reul et al. 2005 ; Holm-Hansen et al. 2004 ; Pérez et al. 2006 ;
Iriarte et al. 2007 ; Li et al. 2007 ; Seppälä et al. 2007 ; Calbet et al. 2009 ; Kim et al.
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