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Kaelin M. Cawley Youhei Yamashita Nagamitsu Maie Rudolf Jaffé 《Estuaries and Coasts》2014,37(2):399-410
Dissolved organic carbon (DOC) concentration and dissolved organic matter (DOM) optical properties were analyzed along two estuarine river transects during the wet and dry seasons to better understand DOM dynamics and quantify mangrove inputs. A tidal study was performed to assess the impacts of tidal pumping on DOM transport. DOM in the estuaries showed non-conservative mixing indicative of mangrove-derived inputs. Similarly, fluorescence data suggest that some terrestrial humic-like components showed non-conservative behavior. An Everglades freshwater-derived fluorescent component, which is associated with soil inputs from the Northern Everglades, behaved conservatively. During the dry season, a protein-like component behaved conservatively until the mid-salinity range when non-conservative behavior due to degradation and/or loss was observed. The tidal study data suggests mangrove porewater inputs to the rivers following low tide. The differences in quantity of DOM exported by the Shark and Harney Rivers imply that geomorphology and tidal hydrology may be a dominant factor controlling the amount of DOM exported from the mangrove ecotone, where up to 21 % of the DOC is mangrove-derived. Additionally, nutrient concentrations and other temporal factors may control DOM export from the mangroves, particularly for the microbially derived fluorescent components, contributing to the seasonal differences. The wet and dry season fluxes of mangrove DOM from the Shark River is estimated as 0.27?×?109 mg C d?1 and 0.075?×?109 mg C d?1, respectively, and the Harney River is estimated as 1.9?×?109 mg C d?1 and 0.20?×?109 mg C d?1. 相似文献
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The lipids in a sediment core from Lake Valencia, a hypereutrophic freshwater lake in Venezuela, are examined to understand
environmental changes over the last ∼13,000 years. From the latest Pleistocene to the earliest Holocene, total organic carbon
(TOC) substantially increased from 2.2 to 10%, while total organic carbon over total nitrogen (TOC/TN) decreased from as high
as 34 to as low as 10. Correspondingly, the concentration of terrestrially derived triterpenoids markedly decreased, and the
dominant n-alkane shifted from C31 to C23 or C25. During the same period, algal biomarkers such as botryococcenes, dinosterol, isoarborinol, C20 HBIs and 1,15C32 keto-ol markedly increased in abundance. These changes suggested a greater contribution of algal organic matter at the onset
of the Holocene, which was concurrent with increasing rainfall and the formation of a permanent lake (Lake Valencia) in the
Aragua Valley, Venezuela. The age profile of Paq, a n-alkane based proxy, showed large oscillations (0.20–0.81), reflecting historical variations in source strength of submerged/floating
vs. terrestrial/emergent OM inputs. An abrupt increase in tetrahymanol abundance at ∼7,260 cal years BP suggests the establishment
of an oxic–anoxic boundary in the lake’s water column. After reaching its maximum abundance at ∼2,100 cal year BP, botryococcenes,
a biomarker of Botryococcus braunii, gradually decreased to below the detection limit in the uppermost sediments, while different algal/microbial biomarkers
such as diploptene, dinosterol and isoarborinol substantially increased. These different historical profiles of algal/microbial
biomarkers reflect different responses of source organisms to environmental changes throughout this period. The δ13C determinations presented exceptionally enriched values for botryococcene isomers (−7.7 to −15.1‰), indicating the utilization
of bicarbonate as carbon sources in an extremely productive ecosystem. 相似文献
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Felice Jaffé 《Swiss Journal of Geoscience》2010,103(3):495-502
The Tavetsch Zwischenmassif and neighbouring Gotthard Massif in the Surselva region host 18 gold-bearing sulphide occurrences
which have been investigated for the present study. In the Surselva region, the main rock constituting the Tavetsch Zwischenmassif
(TZM) is a polymetamorphic sericite schist, which is accompanied by subordinate muscovite-sericite gneiss. The entire tectonic
unit is affected by a strong vertical schistosity, which parallels its NE-SW elongation. The main ore minerals in these gold
occurrences are pyrite, pyrrhotite and arsenopyrite. The mineralisation occurs in millimetric stringers and veinlets, everywhere
concordant with the schistosity. Native gold is present as small particles measuring 2–50 μm, and generally associated with
pyrite. Average grades are variable, but approximate 4–7 g/t Au, with several occurrences attaining 14 g/t Au. Silver contents
of the gold are on the order of 20 wt%. A “bonanza” occurrence consists of a quartz vein coated by 1.4 kg of native gold.
The origin of the gold is unknown. On the assumption that the sericite schists are derived from original felsic volcanic tuffs,
the gold-bearing sulphides may have been introduced during pre-Alpine magmatism. 相似文献
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Lipid biomarkers in suspended particles from a subtropical estuary: assessment of seasonal changes in sources and transport of organic matter 总被引：1，自引：0，他引：1
Temporal and spatial variations in the composition of particulate organic matter (POM) from Florida Bay, USA were examined. The predominance of short-chain homologues for n-alkanes, n-alcohols and n-fatty acids as well as relatively high abundance of C(27) and C(28) sterols suggested that an autochthonous/marine source of OM was dominant bay-wide. Several biomarker proxies such as P(aq) [(C(23)+C(25))/(C(23)+C(25)+C(29)+C(31)) n-alkanes], short/long chain n-alkanes, (C(29)+C(31)) n-alkanes and taraxerol indicated a spatial shift in OM sources, where terrestrial OM rapidly decreased while seagrass and microbial OM markedly increased along a northeastern to southwestern transect. Regarding seasonal variations, POM collected during the dry season was enriched in terrestrial constituents relative to the wet season, likely as a result of reduced primary productivity of planktonic species and seagrasses during the dry season. Principal component analysis (PCA) classified the sample set into sub-groups based on PC1 which seemed to be spatially controlled by OM origin (terrestrial-mangrove vs. marine-planktonic/seagrass). The PC2 seemed to be more seasonally controlled suggesting that hydrological fluctuations and seasonal primary productivity are the drivers controlling the POM composition in Florida Bay. 相似文献
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Andreas Jaffé 《Theoretical and Applied Climatology》1960,10(3):376-395
Zusammenfassung Am Hintereisferner wurden im Sommer 1956 Strahlungsmessungen an Gletschereisplatten mit Hilfe eines Solarimeters Moll-Gorczynski durchgeführt. Dabei ergab es sich, daß die Albedo der Eisplatten gesetzmäßig mit der Plattendicke zunimmt und außerdem von der Sonnenhöhe abhängig ist. Durchlässigkeitsmessungen lieferten für die Schicht zwischen 10 und 35 cm Tiefe einen mittleren Extinktionskoeffizienten von 0,085 cm–1.Auf theoretischem Wege wurde versucht, die Beziehungen zwischen Extinktion, Zerstreuung und Reflexion sowie die Strahlungsverhältnisse im Innern der Eisplatten zu erfassen; auf diese Weise war es auch möglich, auf die vertikale Intensitätsverteilung der eindringenden Strahlung in den obersten Dezimetern des Gletschers zu schließen und die in den verschiedenen Tiefenschichten umgesetzten Energiebeträge abzuschätzen.
Mit 6 Textabbildungen 相似文献
Summary Measurements of the radiative properties of slabs of glacier ice were implemented in summer 1956 on the Hintereisferner. The instrument used was a Solarimeter Moll-Gorczynski. As a result of these investigations a simple law governing the increase of the albedo of the slabs with thickness could be stated. The albedo was also found to vary with solar altitude. Measurements of transmissiblity yield a mean extinction coefficient of 0,085 cm–1 for the layer between 10 cm and 35 cm below the surface.The interrelations of extinction, diffusion and reflection as well as the radiative properties in the interior of the ice slabs were studied theoretically. The vertical distribution of the downward radiation in the uppermost decimetres of the glacier was deduced from the theory. An estimate was made of the amounts of energy involved in the radiative processes occurring at various levels.
Résumé Des mesures de rayonnement effectuées en été 1956 au Hintereisferner sur des plaques de glace du glacier au moyen d'un solarimètre Moll-Gorczynski, ont montré que l'albédo de ces plaques augmente avec leur épaisseur et dépend de la hauteur du soleil. Des mesures de transparence ont fourni pour la couche de 10 à 35 cm de profondeur un coefficient moyen d'extinction de 0,085 cm–1.En cherchant à établir théoriquement les relations entre l'extinction la dispersion et la réflexion, ainsi que les conditions de rayonnement à l'intérieur des plaques de glace, il fut possible de déterminer la distribution verticale d'intensité du rayonnement incident dans les premiers décimètres de la surface du glacier et d'estimer les quantités d'énergie échangées aux différentes profondeurs.
Mit 6 Textabbildungen 相似文献
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