@article {571, title = {Anthropogenic markers in the Holocene stratigraphic sequence of the Gulf of Trieste (northern Adriatic Sea)}, journal = {Marine Geology}, volume = {230}, year = {2006}, note = {069seTimes Cited:37Cited References Count:61}, month = {Aug 2}, pages = {29-51}, abstract = {The Gulf of Trieste is a shallow serni-enclosed marine basin in the northernmost part of the Adriatic Sea that has been affected by the relative rise in sea-level during the Holocene. The sedimentary sequences in three cores, ranging in length from 130 to 320 cm, were investigated through the variability in grain-size parameters, major (Al, Fe, S, N, Ca and Mg) and trace (Ti, Mn, Cr, Ni, Cu, Zn and Hg) elements, organic and inorganic C, delta C-13 and C-14 dating in order to obtain information on paleoenvironmental evolution and the historical development of heavy metal contamination. The potential sources of pollution are: urban sewage from nearly 400,000 inhabitants, industrial effluents, and 500 yr of Hg mining activity in the Idrija region (western Slovenia), located in the upper basin of the Isonzo river, the main freshwater input to the coastal zone. The conventional 14 C ages of bulk sedimentary OC in the basal part of the three cores were 9030 +/- 70 (GTI), 8270 +/- 50 (GT2) and 9160 +/- 120 (GT3) yr BP. An upward increase in highly negative delta C-13(org) values from the core bottoms indicates that lacustrine-swamp conditions in the study area were rapidly followed by a typical marine depositional environment. Cluster analysis performed on the geochemical data for all subsamples of the three cores identifies several groups with a clear stratigraphic meaning. Factor analysis of the data shows related element groups that can be interpreted as being related to, for instance, the natural contribution from alummosilicates and carbonates, from organic matter (peat) and the more recent anthropogenic "impact". Predicted natural linear relationships for metal-Al were obtained from the core subsamples and they can be used as a baseline to evaluate metal enrichments on a regional scale. Results show that more recent sediments in the central sector of the Gulf of Trieste are slightly enriched in Cu (max Enrichment Factor EF=2.1) and Zn (max EF=1.6), and noticeably contaminated by Hg (up to 23.32 mu g g(-1)) to a maximum depth of 90 cm and up to 60 times above the estimated regional background (0.13 mu g g(-1)). The Hg historical trend is well correlated with extraction activity at the Idrija mine, thus allowing indicative sedimentation rate estimation and tentative assessment of the rate of Hg accumulation in bottom sediments (from 1.77 to 31.49 mg m(-2) yr(-1) at the surface). The large inventory of Hg in the core GT2 appeared to be the result of proximity to the fluvial source, which is still active in supplying Hg to the coastal areas and makes the Gulf of Trieste one of the most Hg contaminated area in the whole Mediterranean basin. (c) 2006 Elsevier B.V. All rights reserved.}, issn = {0025-3227}, doi = {10.1016/j.margeo.2006.03.013}, author = {Covelli, S. and Fontolan, G. and Faganeli, J. and Ogrinc, N.} } @article {576, title = {Carbon and nitrogen isotope compositions of organic matter in coastal marine sediments (the Gulf of Trieste, N Adriatic Sea): indicators of sources and preservation}, journal = {Marine Chemistry}, volume = {95}, year = {2005}, note = {934goTimes Cited:76Cited References Count:77}, month = {Jun 1}, pages = {163-181}, abstract = {Terrestrial organic carbon (OC) preserved in marine sediments is an important reservoir in the global carbon cycle, but remains poorly constrained. We determined the elemental and C- and N-isotopic compositions of organic material (OM) in surface sediments and sediment cores from the Gulf of Trieste (N Adriatic), an area characterized by relatively high riverine input. This multiple tracer approach permits evaluation of how sensitive each tracer is for constraining the terrestrial component of OM. Using the relevant terrestrial and marine OM end-members, we estimate that the terrestrial contribution ranges from about 90\% at the mouth of the Isonzo River and decreases to <= 10\% in the center of the Gulf. In the southern part of the Gulf, 32-44\% of terrestrial OC is contributed from smaller rivers, while the delta(15)N values of OM reflect more effective nutrient utilization. Analyses of different size fractions show that smaller particles are consistently more organic-rich and tend to be transported further from the river mouth, depending on river discharge. In the size fraction 2-16 mu m, elemental ratios and delta(13)C(org) and delta(15)N isotopic signatures are consistent with a sedimentary OM pool dominated by bacterially derived biomass. Radiocarbon analyses of sedimentary OC yield depleted Delta(14)C values (-338.7 parts per thousand to -429.4 parts per thousand), indicating a significant fraction of relatively old OC. The natural abundance of C-13 and C-14 tracers suggests a two-component mixture of ancient and modem C in the sediments down to approximately 60 cm sub-bottom, with an estimated similar to 45\% of sedimentary OC probably being derived from ancient sedimentary OC (kerogen). In addition, there is a significant change in the source of organic material downcore in these sediments which, along with geological evidence, indicate contributions from freshwater swamps typical of coastal lakes with intermittent connections to the sea (brackish) prior to similar to 9000 BP. Depth variations in a core from a salt marsh further indicate temporal variability of OM deposition and transformations in a changing brackish-marine environment in the past. (C) 2004 Elsevier B.V. All rights reserved.}, issn = {0304-4203}, doi = {10.1016/j.marchem.2004.09.003}, author = {Ogrinc, N. and Fontolan, G. and Faganeli, J. and Covelli, S.} }