Organic matter distributions in the Eastern North Atlantic–Azores Front region

Abstract

Temperate, transitional and subtropical waters of the remote Azores Front region east of Azores (24-40ºN, 22-32ºW) were sampled during three cruises conducted under increasing stratification conditions (April 1999, May 1997 and August 1998 respectively. Vertical eddy diffusion is 35% and 2% of the spring and summer sinking POC flux, respectively. On the other hand, DOC only contributes 13% to the local oxidation of organic matter in subsurface waters (between the pycnocline and 500m) of the study region.

Major inter-annual variations in microbial dynamics in the Gulf of Trieste (northern Adriatic Sea) and their ecosystem implications

“…In our study, DOC showed a regular and highly pronounced annual pattern: a progressive rise over summer, followed by a gradual decline, a pattern similar to that observed by Avril (2002) (68.2 μM), but, on average, it was 24.1 μM, lower than that determined by Pettine et al (2001) for the North Adriatic area off the Po River delta, by Doval et al (2001) for the eastern North Atlantic-Azores Front region (168 μM) and by Cauwet et al (2002) for the Black Sea (ca. 100 μM).…”

Rates of dissolved organic carbon production and bacterial activity in the eastern North Atlantic Subtropical Gyre during summer

“…Williams (1995) suggested that dissolved inorganic nitrogen limitation of heterotrophic bacteria consuming DOM with high C:N ratios could explain the accumulation of DOC during summer in the North Atlantic Ocean. The seasonal accumulation of semilabile DOC in the surface layer of the ocean is at present well documented (Carlson et al 1994, Yamanaka & Tajika 1997, Hansell & Carlson 1998 and has been reported by Doval et al (2001), who measured an accumulation of semilabile DOC in the upper 100 m of 16.8 g C m -2 in the Azores Front region during August 1998. This seasonal DOC excess could have acted as an autochthonous reservoir and, at least partially, have supported the excess of BCD over DOC production measured in this study.…”

Trace metals in the open oceans: speciation modelling based on humic-type ligands

“…Sources for DOM data DOM concentrations were derived from dissolved organic carbon (DOC) concentration data that were largely taken from papers cited in the review by Dafner and Wangersky [45] together with several other sources. [46][47][48][49][50] DOC values were estimated based on the available data closest to the metal water sample location and depth (estimates are tabulated in the Accessory publication). For the fraction of DOM that can be represented by fulvic acid (referred to here as the fulvic acid activity) we applied values used in recent studies, i.e.…”