Monitoring of Descending Dredged Material Plumes

Author Institution: International Minerals and Chemicals CorporationMonitoring of 2 disposal operations on Lake Erie near Ashtabula, Ohio, provided an opportunity to employ different approaches to study the physical impact of the disposal of dredged material on the hydraulic regime of the lake in this area. A study conducted in August 1975 involved utilization of several transmissometers placed on 4 anchored vessels and one moving vessel. The transmissometers were used to monitor the dispersing plume over time. Three-dimensional plots revealed that plumes tended to decrease in intensity beyond about 100 m from the point of discharge. Data interpretation was hampered due to difficulties in correlating data obtained from different transmissometers and because the direction of the plume could not always be anticipated with accuracy, resulting in that the major portion of the plume sometimes bypassed the boat further away undetected

Organoclays Trap Recalcitrant Metals And Organic Compounds In Sediments Simultaneously

The capability of organoclays as components of permeable sediment barriers has been researched extensively over the past several years. Organoclays have been used in permeable walls to block the movement of a DNAPL plume from an abandoned wood treating site, and for sediment stabilization at an old MGP site (from a power and light company). Laboratory column tests and batch tests with organoclays have revealed that a standard, non-polar organoclay fixates all heavy metals, including lead, zinc, nickel, chrome and cadmium, but also inorganic aqueous mercury. In terms of organic hydrocarbons, such diverse compounds as dioxin and nitro-benzenes, as well as PCP, PCB, PNHA and BTEX are trapped effectively. Studies with polar organoclays, which can easily be blended with the non-polar types, fixate arsenate, selenite, chromate, perchlorate, etc. This article presents data showing these capabilities, as well as case histories

A Two-Year Study of the Lake and Wind Currents on Lake Erie Near Ashtabula, Ohio

Author Institution: International Minerals and Chemical Corp. ; Environmental Science and EngineeringLake and wind currents, temperature and transmissivity were monitored as part of a large-scale study involving monitoring of 2 dredged material disposal operations in Lake Erie near Ashtabula, Ohio. The study was carried out from June 1975 to September 1976. During this period at a location 4 km offshore the currents were found to generally flow parallel to the shore with average speeds of 12 cm/sec at 3 m and 5 cm/sec at one meter above lake bottom. The dominant periodic component of the velocity field was the first longitudinal mode of Lake Erie which had a period of approximately 14 hr, During the study currents were generally uniform over the entire study area. Changes in the local winds usually affected the established flow pattern but only after a lag time

Diversity and distribution of freshwater amphipod species in Switzerland (Crustacea: Amphipoda).

Amphipods are key organisms in many freshwater systems and contribute substantially to the diversity and functioning of macroinvertebrate communities. Furthermore, they are commonly used as bioindicators and for ecotoxicological tests. For many areas, however, diversity and distribution of amphipods is inadequately known, which limits their use in ecological and ecotoxicological studies and handicaps conservation initiatives. We studied the diversity and distribution of amphipods in Switzerland (Central Europe), covering four major drainage basins, an altitudinal gradient of>2,500 m, and various habitats (rivers, streams, lakes and groundwater). We provide the first provisional checklist and detailed information on the distribution and diversity of all amphipod species from Switzerland. In total, we found 29 amphipod species. This includes 16 native and 13 non-native species, one of the latter (Orchestia cavimana) reported here for the first time for Switzerland. The diversity is compared to neighboring countries. We specifically discuss species of the genus Niphargus, which are often receiving less attention. We also found evidence of an even higher level of hidden diversity, and the potential occurrence of further cryptic species. This diversity reflects the biogeographic past of Switzerland, and suggests that amphipods are ideally suited to address questions on endemism and adaptive radiations, post-glaciation re-colonization and invasion dynamics as well as biodiversity-ecosystem functioning relationships in aquatic systems

Thermodynamic Properties of a Quantum Group Boson Gas GLp,q(2)GL_{p,q}(2)

An approach is proposed enabling to effectively describe the behaviour of a bosonic system. The approach uses the quantum group $GL_{p,q}(2)$ formalism. In effect, considering a bosonic Hamiltonian in terms of the $GL_{p,q}(2)$ generators, it is shown that its thermodynamic properties are connected to deformation parameters $p$ and $q$. For instance, the average number of particles and the pressure have been computed. If $p$ is fixed to be the same value for $q$, our approach coincides perfectly with some results developed recently in this subject. The ordinary results, of the present system, can be found when we take the limit $p=q=1$.Comment: 13 pages, Late

Climate, immigration and speciation shape terrestrial and aquatic biodiversity in the European Alps

Quaternary climate fluctuations can affect speciation in regional biodiversity assembly in two non-mutually exclusive ways: a glacial species pump, where isolation in glacial refugia accelerates allopatric speciation, and adaptive radiation in underused adaptive zones during ice-free periods. We detected biogeographic and genetic signatures associated with both mechanisms in the assembly of the biota of the European Alps. Age distributions of endemic and widespread species within aquatic and terrestrial taxa (amphipods, fishes, amphibians, butterflies and flowering plants) revealed that endemic fish evolved only in lakes, are highly sympatric, and mainly of Holocene age, consistent with adaptive radiation. Endemic amphipods are ancient, suggesting preglacial radiation with limited range expansion and local Pleistocene survival, perhaps facilitated by a groundwater-dwelling lifestyle. Terrestrial endemics are mostly of Pleistocene age and are thus more consistent with the glacial species pump. The lack of evidence for Holocene adaptive radiation in the terrestrial biome is consistent with faster recolonization through range expansion of these taxa after glacial retreats. More stable and less seasonal ecological conditions in lakes during the Holocene may also have contributed to Holocene speciation in lakes. The high proportion of young, endemic species makes the Alpine biota vulnerable to climate change, but the mechanisms and consequences of species loss will likely differ between biomes because of their distinct evolutionary histories

Climate, immigration and speciation shape terrestrial and aquatic biodiversity in the European Alps.

Quaternary climate fluctuations can affect speciation in regional biodiversity assembly in two non-mutually exclusive ways: a glacial species pump, where isolation in glacial refugia accelerates allopatric speciation, and adaptive radiation in underused adaptive zones during ice-free periods. We detected biogeographic and genetic signatures associated with both mechanisms in the assembly of the biota of the European Alps. Age distributions of endemic and widespread species within aquatic and terrestrial taxa (amphipods, fishes, amphibians, butterflies and flowering plants) revealed that endemic fish evolved only in lakes, are highly sympatric, and mainly of Holocene age, consistent with adaptive radiation. Endemic amphipods are ancient, suggesting preglacial radiation with limited range expansion and local Pleistocene survival, perhaps facilitated by a groundwater-dwelling lifestyle. Terrestrial endemics are mostly of Pleistocene age and are thus more consistent with the glacial species pump. The lack of evidence for Holocene adaptive radiation in the terrestrial biome is consistent with faster recolonization through range expansion of these taxa after glacial retreats. More stable and less seasonal ecological conditions in lakes during the Holocene may also have contributed to Holocene speciation in lakes. The high proportion of young, endemic species makes the Alpine biota vulnerable to climate change, but the mechanisms and consequences of species loss will likely differ between biomes because of their distinct evolutionary histories