Naslov
Long term fluctuation of organic matter in the northern Adriatic Sea: possible barometar of global changes

Autori
Vojvodić, Vjeročka ; Dautović, Jelena ; Ciglenečki-Jušić, Irena ; Ćosović, Božena ;

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, pp prezentacija, znanstveni

Skup
IMBER Future Oceans

Mjesto i datum
Bergen, Norveška, 22.06.2014. - 27.06.2014

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
Adriatic Sea ; Organic Matter ; DOC ; SAS ; Global changes

Sažetak
One of the Earth's largest reservoirs of organic matter in the sea, dissolved organic carbon (DOC) provides a substrate for life, and is a source for nutrient regeneration, ion exchange capacity, light and heat absorption. Increased measurements accuracy enables detection at concentrations gradients and basin-scale difference, opening its use as a new geochemical tracer. Marine organic carbon represents a dynamic component in the global carbon cycle and is now recognised as an important component of the biochemical system and possibly as barometer of the global change. Shallow northern Adriatic Sea (NA) is characterized by marked seasonal and long-term fluctuations of oceanographic and biological conditions, mainly due to atmospheric forcing: Po River freshwater discharges from the western coast, advection of oligotrophic central Adriatic waters along the eastern coast, and a very variable and complex circulation. In the period from 1988 in the NA massive formation of organic aggregates reported as "mucilage phenomenon" occurred with increased frequency1, 2. The intensity of this phenomenon varied over the years: (1988, 1991, 1997, 2000-2004) > 1998, 1999. From 2004 to the present, mucilage phenomenon didn’t occur. In the period 1998-2013 seasonal and spatial distribution of the DOC content, and concentrations of the reactive part of organic matter with surface active (SA) properties3 have been studied. POC was examined from 2008. Seasonal distribution pattern of DOC and SAS over the whole investigated period clearly shows that after mucilage events of very high intensity (summer 1997) maximum values of DOC and SAS in 1998, and decreasing trend until 2006, in particular after 2000 were recorded. In the same period decrease in the Po River discharge and in phytoplankton biomass was observed 4, 5. We believe that reduced SAS content, together with the absence of significant DOC accumulation in the recent years could have an important role in disappearance of mucilage events, contributing to the improvement of the ecological status of NA ecosystem. However, an increasing trend of DOC and SAS concentrations in the period 2007-2011 may indicate a new cycle of the organic matter accumulation, which accompanied with other favourable conditions may lead to the same biogeochemical processes as found during 1997-2004. At the same time recent results on the organic matter study (DOC, POC) of the coastal and transition part of the Adriatic Sea monitored during 2012-2013 indicate mostly oligotrophic characteristics of the seawater with negligible anthropogenic influence.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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