impact of OM characteristics on the ecological status and ecosystem services of the
river. Since the analytical methods for characterising OM and its interaction with
contaminants were not available in the 1970s, when wastewater contamination was
much higher, it is thus not possible to identify any trend regarding how the influence
of the type of OM on water quality and river system functions has evolved in
comparison to the situation in the 1970s. The studies described in this chapter
nevertheless present the current state of the system and will allow to study in the
future potential changes in OM characteristics and reactivity.
2 Sources and Variability of Organic Matter in the Seine
River Watershed
2.1 Context and Objectives
OM in aquatic systems plays an important role in water quality and biogeochemical
processes [1]. The biogeochemical functioning of the Seine River basin has been
largely studied over the last few decades within the PIREN-Seine multidisciplinary
scientific programme [19]. The water quality and ecological functioning of the Seine
River watershed have been mainly investigated through material budget approaches
applied to biogenic elements [20, 21] as well as to chemical and microbiological
contaminants [22, 23]. Previous investigations concerning carbon in the Seine River
basin mainly focused on organic carbon fluxes [24], biogeochemical mass balances
(C, N, P, Si) [20], methane emissions [25] or production and respiration [21]. However, not only dissolved organic carbon (DOC) quantity but also its quality reflect the
dynamic interaction between OM sources and biogeochemical processes [26] and
are likely to have ecological repercussions [27, 28].
To achieve a better understanding of OM environmental role in aquatic ecosystems, it is essential to improve the knowledge on its physicochemical properties and
composition in the aquatic environment. The main goals of the studies conducted
since 2010 on the biogeochemistry of the Seine River within the PIREN-Seine
programme were to characterise the sources and properties of OM and their spatiotemporal variability in the Seine River watershed.
2.2 Methods for Characterising Organic Matter in River
Water
To assess the variability of OM characteristics from both quantitative and qualitative
points of view, surface water samples were collected in 23 and 39 sites at low water
(November 2011 and September 2012) and 40 sites at flood levels (Fevrier 2013),
from the Seine River, the Oise River, the Marne River and its main tributary the
220
G. Varrault et al.
river. Since the analytical methods for characterising OM and its interaction with
contaminants were not available in the 1970s, when wastewater contamination was
much higher, it is thus not possible to identify any trend regarding how the influence
of the type of OM on water quality and river system functions has evolved in
comparison to the situation in the 1970s. The studies described in this chapter
nevertheless present the current state of the system and will allow to study in the
future potential changes in OM characteristics and reactivity.
2 Sources and Variability of Organic Matter in the Seine
River Watershed
2.1 Context and Objectives
OM in aquatic systems plays an important role in water quality and biogeochemical
processes [1]. The biogeochemical functioning of the Seine River basin has been
largely studied over the last few decades within the PIREN-Seine multidisciplinary
scientific programme [19]. The water quality and ecological functioning of the Seine
River watershed have been mainly investigated through material budget approaches
applied to biogenic elements [20, 21] as well as to chemical and microbiological
contaminants [22, 23]. Previous investigations concerning carbon in the Seine River
basin mainly focused on organic carbon fluxes [24], biogeochemical mass balances
(C, N, P, Si) [20], methane emissions [25] or production and respiration [21]. However, not only dissolved organic carbon (DOC) quantity but also its quality reflect the
dynamic interaction between OM sources and biogeochemical processes [26] and
are likely to have ecological repercussions [27, 28].
To achieve a better understanding of OM environmental role in aquatic ecosystems, it is essential to improve the knowledge on its physicochemical properties and
composition in the aquatic environment. The main goals of the studies conducted
since 2010 on the biogeochemistry of the Seine River within the PIREN-Seine
programme were to characterise the sources and properties of OM and their spatiotemporal variability in the Seine River watershed.
2.2 Methods for Characterising Organic Matter in River
Water
To assess the variability of OM characteristics from both quantitative and qualitative
points of view, surface water samples were collected in 23 and 39 sites at low water
(November 2011 and September 2012) and 40 sites at flood levels (Fevrier 2013),
from the Seine River, the Oise River, the Marne River and its main tributary the
220
G. Varrault et al.