Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | Autochthonous and allochthonous plant contributions to coastal benthic detritus deposits: A dual-stable isotope study in a volcanic lake |
| Abstract | The high numbers of primary producers represent multiple sources of organic matter accumulating onto lake bottoms. The difficulty of distinguishing the relative contribution to the mixture presents considerable challenges to the analysis of these organic deposits. In this study, dual-stable isotope analysis and IsoSource model were used to identify allochthonous and autochthonous components of detritus deposits (Particulate Organic Matter: POM) at two different bottom slope sites of a volcanic lake (lake Bracciano). Experiments were carried out to calibrate IsoSource on constructed plant mixtures and assess changes in isotope ratios during plant decomposition. IsoSource satisfactorily discriminated the constructed mixture sources with a few exceptions. Changes in isotopic enrichment during decomposition were low, and thus did not represent a confounding variable in the isotopic analysis. By contrast, chemical and geological differences of the study sites were associated with differences in plant ?C and ?N values (more than 2% within single plant species). At both sites, the isotopic signals of POM fell between polygons delineated by source end members with an evident shift of ?C toward allochthonous sources. POM amount and diversity were greater at the flatter bottom site, where allochthonous contributions were larger than at the other site. In particular, IsoSource ranked species contributions as follows: A. glutinosa > P. australis > A. donax > S. alba > P. nigra > the benthic macroalga Chara sp. at the first site, and A. glutinosa > P. nigra > the aquatic macrophyte C. demersum at the latter. The composition of littoral POM was determined by allochthonous sources in proportion to their relative abundances (as percent land cover) with differences between sites due to bottom slope. © Birkhäuser Verlag, Basel/Switzerland 2009. |
| Source | Aquatic sciences (Electron. ed.) 72, pp. 227–236 |
| Keywords | C and N isotopic ratios IsoSource mixing model Land cover Detritus sources Lake-bottom slope Volcanic lake |
| Journal | Aquatic sciences (Electron. ed.) |
| Editor | Birkhäuser, Basel, Svizzera |
| Year | 2010 |
| Type | Articolo in rivista |
| DOI | 10.1007/s00027-009-0125-z |
| Authors | Rossi L.; Costantini M.L.; Carlino P.; di Lascio A.; Rossi D. |
| Text | 424559 2010 10.1007/s00027 009 0125 z Scopus 2 s2.0 79955650146 C and N isotopic ratios IsoSource mixing model Land cover Detritus sources Lake bottom slope Volcanic lake Autochthonous and allochthonous plant contributions to coastal benthic detritus deposits A dual stable isotope study in a volcanic lake Rossi L.; Costantini M.L.; Carlino P.; di Lascio A.; Rossi D. Department of Genetics and Molecular Biology, Ecology Area, Sapienza University of Rome, Via dei Sardi 70, 00185 Rome, , Italy; Department of Earth Science, Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, , Italy The high numbers of primary producers represent multiple sources of organic matter accumulating onto lake bottoms. The difficulty of distinguishing the relative contribution to the mixture presents considerable challenges to the analysis of these organic deposits. In this study, dual stable isotope analysis and IsoSource model were used to identify allochthonous and autochthonous components of detritus deposits Particulate Organic Matter POM at two different bottom slope sites of a volcanic lake lake Bracciano . Experiments were carried out to calibrate IsoSource on constructed plant mixtures and assess changes in isotope ratios during plant decomposition. IsoSource satisfactorily discriminated the constructed mixture sources with a few exceptions. Changes in isotopic enrichment during decomposition were low, and thus did not represent a confounding variable in the isotopic analysis. By contrast, chemical and geological differences of the study sites were associated with differences in plant C and N values more than 2% within single plant species . At both sites, the isotopic signals of POM fell between polygons delineated by source end members with an evident shift of C toward allochthonous sources. POM amount and diversity were greater at the flatter bottom site, where allochthonous contributions were larger than at the other site. In particular, IsoSource ranked species contributions as follows A. glutinosa > P. australis > A. donax > S. alba > P. nigra > the benthic macroalga Chara sp. at the first site, and A. glutinosa > P. nigra > the aquatic macrophyte C. demersum at the latter. The composition of littoral POM was determined by allochthonous sources in proportion to their relative abundances as percent land cover with differences between sites due to bottom slope. © Birkhauser Verlag, Basel/Switzerland 2009. 72 Published version http //www.scopus.com/record/display.url eid=2 s2.0 79955650146 origin=inward Articolo in rivista Birkhauser 1420 9055 Aquatic sciences Electron. ed. Aquatic sciences Electron. ed. Aquat. sci. Electron. ed. Aquatic sciences. Electron. ed. AS Electron. ed. david rossi ROSSI DAVID |