57
Dissolved Organic Matter in Natural Waters
(Moran et al. 2000; Raymond and Bauer 2001a; Boyd and Osburn 2004; Hummel
and Findlay 2006); 133–453 μM C in Canada (Osburn et al. 2009); 76–1427 μM
C in Europe (Abril et al. 2002; Guéguen et al. 2002; Huguet et al. 2010; Baker
and Spencer 2004; Stedmon et al. 2003). DOC in estuaries is originated from both
autochthonous sources (algae or phytoplankton) and allochthonous sources such
as material of terrestrial plant origin.
DOM Contents in Coastal and Open Oceans
DOC concentrations are substantially higher (50–616 μM C) in coastal seawaters than in the open ocean (40–117 μM C) (Table 2) (Ogawa and Tanoue 2003;
Mitra et al. 2000; Chen and Gardner 2004; Williams and Druffel 1987; Opsahl and
Benner 1998; Wang et al. 2004; Zanardi-Lamardo et al. 2004; Osburn et al. 2009;
Blough et al. 1993; Vodacek et al. 1995; Ferrari et al. 1996; Ferrari and Dowell
1998; Del Castillo et al. 1999, 2000; Mostofa KMG et al., unpublished data).
DOC concentrations in coastal waters are generally regulated by terrestrial or riverine input, zooplankton feeding and algal or phytoplankton production (Lee and
Wakeham 1988; Lee and Henrichs 1993; Mann and Wetzel 1995; Hedges et al.
1997). Increased biomass of primary producers also plays a major role in regulating the DOM contents in coastal areas (Ittekkot 1982; Billen and Fontigny 1987;
Bronk et al. 1998). DOC concentrations in open oceans are relatively low and are
included in the range of 40–117 μM C at epilimnion and 30–90 μM C at hypolimnion (Table 2) (Ogawa and Tanoue 2003). DOC values appear to be relatively uniform in most of the oceans, whilst in coastal areas the DOM pool becomes much
more heterogeneous because of terrestrial inputs. In open oceans, the DOC concentrations in epilimnetic layers follow the order of Arctic Ocean (70–107 μM
C) > subtropical zone (~80 μM C) > tropical (equatorial) and temperate zones
(60–70 μM C) > subarctic and subantarctic regions (50–60 μM C) > Antarctic
region (40–60 μM C) (Ogawa and Tanoue 2003). There are two main sources of
DOC in coastal oceans: allochthonous DOM of terrestrial origin and autochthonous DOM of algal or phytoplankton origin. In open oceans, allochthonous DOM
contents are gradually decreased photolytically depending on the distance from
coastal areas, whilst autochthonous DOM is substantially increased (see the contribution of DOM for detailed discussion). The three major sources of DOC in the
Arctic Ocean are in situ production (56 %), river run-off (25 %), and Pacific water
(19 %) (Kirchman et al. 1995).
6 Factors Affecting DOM in Natural Waters
DOM contents and its dynamics are mostly dependent on two issues: origin and/
or input, as well as its consequent mineralization by various environmental factors that are associated with the watershed activities of natural waters. The rivergroundwater interface can act as a source or sink for DOM, depending on the
volume and direction of flow, DOC concentrations and biotic activity (Brunke
Dissolved Organic Matter in Natural Waters
(Moran et al. 2000; Raymond and Bauer 2001a; Boyd and Osburn 2004; Hummel
and Findlay 2006); 133–453 μM C in Canada (Osburn et al. 2009); 76–1427 μM
C in Europe (Abril et al. 2002; Guéguen et al. 2002; Huguet et al. 2010; Baker
and Spencer 2004; Stedmon et al. 2003). DOC in estuaries is originated from both
autochthonous sources (algae or phytoplankton) and allochthonous sources such
as material of terrestrial plant origin.
DOM Contents in Coastal and Open Oceans
DOC concentrations are substantially higher (50–616 μM C) in coastal seawaters than in the open ocean (40–117 μM C) (Table 2) (Ogawa and Tanoue 2003;
Mitra et al. 2000; Chen and Gardner 2004; Williams and Druffel 1987; Opsahl and
Benner 1998; Wang et al. 2004; Zanardi-Lamardo et al. 2004; Osburn et al. 2009;
Blough et al. 1993; Vodacek et al. 1995; Ferrari et al. 1996; Ferrari and Dowell
1998; Del Castillo et al. 1999, 2000; Mostofa KMG et al., unpublished data).
DOC concentrations in coastal waters are generally regulated by terrestrial or riverine input, zooplankton feeding and algal or phytoplankton production (Lee and
Wakeham 1988; Lee and Henrichs 1993; Mann and Wetzel 1995; Hedges et al.
1997). Increased biomass of primary producers also plays a major role in regulating the DOM contents in coastal areas (Ittekkot 1982; Billen and Fontigny 1987;
Bronk et al. 1998). DOC concentrations in open oceans are relatively low and are
included in the range of 40–117 μM C at epilimnion and 30–90 μM C at hypolimnion (Table 2) (Ogawa and Tanoue 2003). DOC values appear to be relatively uniform in most of the oceans, whilst in coastal areas the DOM pool becomes much
more heterogeneous because of terrestrial inputs. In open oceans, the DOC concentrations in epilimnetic layers follow the order of Arctic Ocean (70–107 μM
C) > subtropical zone (~80 μM C) > tropical (equatorial) and temperate zones
(60–70 μM C) > subarctic and subantarctic regions (50–60 μM C) > Antarctic
region (40–60 μM C) (Ogawa and Tanoue 2003). There are two main sources of
DOC in coastal oceans: allochthonous DOM of terrestrial origin and autochthonous DOM of algal or phytoplankton origin. In open oceans, allochthonous DOM
contents are gradually decreased photolytically depending on the distance from
coastal areas, whilst autochthonous DOM is substantially increased (see the contribution of DOM for detailed discussion). The three major sources of DOC in the
Arctic Ocean are in situ production (56 %), river run-off (25 %), and Pacific water
(19 %) (Kirchman et al. 1995).
6 Factors Affecting DOM in Natural Waters
DOM contents and its dynamics are mostly dependent on two issues: origin and/
or input, as well as its consequent mineralization by various environmental factors that are associated with the watershed activities of natural waters. The rivergroundwater interface can act as a source or sink for DOM, depending on the
volume and direction of flow, DOC concentrations and biotic activity (Brunke