A. Puddu et al., Dissolved organic matter and microbial food web interactions in the marineenvironment: the case of the Adriatic Sea, INT J ENV P, 13(1-6), 2000, pp. 473-494
Citations number
152
Categorie Soggetti
Environment/Ecology
Journal title
INTERNATIONAL JOURNAL OF ENVIRONMENT AND POLLUTION
The sources, characteristics and fate of the dissolved organic matter (DOM)
in marine ecosystems are reviewed, with particular emphasis on processes r
elevant to the northern Adriatic Sea. This semi-enclosed basin receives lar
ge riverine discharges that strongly affect its trophic dynamics. The high
organic load, which results from both autochtonous and allochtonous sources
, is responsible for anoxia and massive aggregate formation. The general ch
aracteristics of the microbial food web and its role in the cycling of carb
on are critically evaluated. Factors affecting DOM uptake by bacteria, incl
uding DOM diagenesis and molecular size, nutrient availability, the effect
of temperature and the abiotic alterations of DOM are discussed. Possible c
auses for DOM seasonality are suggested. A restricted bacterial uptake due
to scarce inorganic phosphorus availability, along with strong allochtonous
inputs of refractory compounds and strong water stratification in summer,
appear to be the most important factors. Finally, the distribution of organ
ic carbon between dissolved and colloidal components and the role of colloi
ds in the aggregation phenomena in marine systems are briefly outlined, and
hypotheses for the formation of macroaggregates in the northern Adriatic a
re reviewed.