Regional characterisation of hard‐bottom nursery habitat for juvenile Caribbean spiny lobster (Panulirus argus) using rapid assessment techniques     

Rodney D. Bertelsen  Mark J. Butler IV  William F. Herrnkind  John H. Hunt 《新西兰海洋与淡水研究杂志》2013,47(1):299-312

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Water contaminated by fresh tephra as a natural hazard factor: The 2008–2009 eruption of Koryakskii Volcano,Kamchatka     

I. V. Melekestsev  E. V. Kartasheva  T. P. Kirsanova  A. A. Kuz’mina 《Journal of Volcanology and Seismology》2011,5(1):17-30

This study is the first to show, using data from the eruption of Koryakskii Volcano, Kamchatka that began in December 2008 and continued through 2009 that the water in permanent and temporary streams that start on the slopes of the volcanic cone and in temporary lakes when contaminated with fresh tephra is a specific hazard factor related to long-continued hydrothermal-phreatic eruptions on that volcano. This water is characterized by increased acidity (pH 4.1–4.35) and large amounts (up to 50–100 cm³/liter) of solid suspension and is unfit for drinking and irrigation. When combined with tephra, it probably produced mass destruction of a number of animals who lived on the slopes and at the base of the volcano. The water contaminated with tephra is an important component of the atmospheric mud flows occurring on Koryakskii Volcano; for several future years it will be a potential source for enhancing the acidity of ground water in the volcanic edifice.  相似文献   

Eruptive history of Karymsky volcano,Kamchatka, USSR,based on tephra stratigraphy and 14C dating     

O A Braitseva  I V Melekestsev 《Bulletin of Volcanology》1991,53(3):195-206

Eruptions of the active Karymsky stratovolcano began about 5300 (6100 ¹⁴C) b.p. from within a pre-existing caldera which formed 7700 ¹⁴C b.p. As indicated by 32 ¹⁴C determinations on buried soils and charcoal, the volcano has gone through two major cycles of activity, separated by a 2300 year period of repose. The first cycle can be divided into two stages (6100–5100 and 4300–2800 b.p.). The earlier stage began with especially intense eruptions of basaltic andesite to dacite. The later stage was characterized by moderate-strength eruptions of andesite. The second cycle, which is characterized by weak to moderate intermittent eruptions of andesite, started 500 b.p. and continues to the present. Eruptive patterns suggest that this cycle may continue for at least another 200 years with an eruptive character similar to that of the recent past.  相似文献   

The importance of radiocarbon dates and tephra for developing chronologies of Holocene environmental changes from lake sediments,North Far East     

A. V. Lozhkin  T. A. Brown  P. M. Anderson  O. Yu. Glushkova  I. V. Melekestsev 《Russian Journal of Pacific Geology》2016,10(4):249-262

Developing continuous chronologies of paleoenvironmental change in northern areas of the Far East using ¹⁴C can be problematic because of the low organic content in lake sediments. However, Holocene age-models can be supplemented by widespread tephra deposits reported in the Magadan region. The best documented of these tephras has been correlated to the KO tephra from southern Kamchatka dated to 7600 BP. Although a key chronostratigraphic marker, no detailed compendium of the distribution of this tephra and its associated ¹⁴C dates has been available from sites in the northern Far East. We provide such a summary. Known locally as the Elikchan tephra, lake cores indicate an ash fall that extended ~1800 km north of the Kamchatkan caldera with a ~500 km wide trajectory in the Magadan region. Other Holocene tephras preserved in lake sediments have poorer age control and possibly date to ~2500 BP, ~2700 BP and ~6000 BP. These ashes seem to be restricted to coastal or near-coastal sites. A single record of a ~25,000 BP tephra has also been documented ~100 km to the northeast of Magadan.  相似文献   

Stable isotope analysis of Pacific salmon: insight into trophic status and oceanographic conditions over the last 30 years     

Franklin R. Satterfield  IV  Bruce P. Finney   《Progress in Oceanography》2002,53(2-4)

Food web interactions and the response of Pacific salmon to physical processes in the North Pacific Ocean over interannual and interdecadal timescales are explored using naturally occurring stable isotope ratios of carbon (¹³C/¹²C) and nitrogen (¹⁵N/¹⁴N). Stable isotope analyses of five species of sexually mature North Pacific salmon from Alaska (Oncorhynchus spp.) cluster into three groups: chinook salmon (O. tshawytscha) have the highest values, followed by coho (O. kisutch), with chum (O. keta), sockeye (O. nerka), and pink (O. gorbuscha) together having the lowest values. Although detailed isotopic data on salmon prey are lacking, there are limited data on relevant prey items from areas in which they are found in high abundance. These data suggest that the characteristics of the sockeye, pink and chum we have analyzed are compatible with their diets including open ocean squid and zooplankton, which are in general agreement with stomach content analyses. Isotope relationships between muscle and scale show consistent relationships for both δ¹³C (R²=0.98) and δ¹⁵N (R²=0.90). Thus, scales, which have been routinely archived for many systems, can be used for retrospective analyses. Archived sockeye salmon scales spanning 1966–1999 from Red Lake, Kodiak Island, Alaska were analyzed for their stable isotope ratios of carbon and nitrogen. The δ¹⁵N record displays a decreasing trend of ˜3‰ from 1969–1982 and an increasing trend of ˜3‰ from 1982–1992, while the variations in δ¹³C are relatively minor. These trends may result from factors such as shifts in trophic level of feeding and/or feeding location, or may originate at the base of the food web via changes in processes such as nutrient cycling or primary productivity. Detailed studies on prey isotopic variability and its controls are needed to distinguish between these factors, and thus to improve the use of stable isotope analysis as a tool to learn more about present and past ecosystem change in the North Pacific and its relation to climatic change.  相似文献   

A major project in the age of the environment: Out of controversy,complexity, and challenge     

Nathaniel D. McClure IV 《Environmental Geology》1985,7(1-2):15-24

The recently completed Tennessee-Tombigbee Waterway (Tenn-Tom) survived many challenges from all three branches of the federal government A brief overview of these challenges over the past 40 years is presented Central among the challenges was the litigation involving allegations under the National Environmental Policy Act (NEPA) The response of the U S Army Corps of Engineers to NEPA and its influence on the Tenn-Tom are presented A summarization of the principal environmental issues related to the Tenn-Tom is provided to describe the wide spectrum of concerns and controversies associated with the development of this major waterway The Tenn-Tom met the test in all forums The measures taken to respond in a meaningful way to NEPA and other environmental statutes are a model that could well be followed in the development of other major projects  相似文献   

Quaternary calderas of Kamchatka     

E. N. Erlich  I. V. Melekestsev  A. A. Tarakanovsky  M. I. Zubin 《Bulletin of Volcanology》1972,36(1):222-237

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Evolution stages and petrology of the Kekuknai volcanic massif as reflecting the magmatism in Backarc zone of Kuril-Kamchatka island arc system. Part 1. Geological position and geochemistry of volcanic rocks     

A. V. Koloskov  G. B. Flerov  A. B. Perepelov  I. V. Melekestsev  M. Yu. Puzankov  T. M. Filosofova 《Journal of Volcanology and Seismology》2011,5(5):312-334

The evolution of the Quaternary Kekuknai volcanic massif (the western flank of the Sredinnyi Range in Kamchatka) has been subdivided into five stages: (1) the pre-caldera trachybasaltbasaltic andesite, (2) the extrusive trachyandesite-trachydacite, (3) the early trachybasalt, (4) the middle hawaiitemugearite (with occasional occurrences of basaltic andesites), and (5) the late trachybasalt-hawaiitemugearite (with occasional andesites) of areal volcanism. On the basis of petrologic data we identified the island arc and the intraplate geochemical types of rocks in the massif. The leading part in petrogenesis was played by dynamics of the fluid phase with a subordinated role of fractional crystallization and hybridism. Successive saturation of rocks with the fluid phase in the course of melt evolution stopped at the time of caldera generation when most fluid mobile elements and silica had been extracted. The geological and petrologic data attest to the formation of the massif in the environment of a backarc volcanic basin during the beginning of rifting with active participation of mantle plume components.  相似文献   

Environmental restoration measures on the Tennessee–Tombigbee Waterway – an update     

N. D. McClure IV  N. L. Connell Sr. 《Environmental Geology》2001,40(4-5):566-570

 The Tennessee–Tombigbee Waterway (Tenn–Tom) was one of the first and largest water resources projects constructed after the enactment of the National Environmental Policy Act of 1969. This highly controversial project was in litigation for 9 of the 13 years it was under construction. Substantial and innovative measures were incorporated into the project design to minimize environmental damage and to promote environmental protection. Additionally, a wide variety of environmental mitigation measures, including the acquisition and management of 35,614 ha of wildlife habitat to compensate for unavoidable impacts. This paper, which updates a paper published by the American Society of Civil Engineers in 1996, presents an update of the environmental and restorative measures incorporated into the design, construction, operation, and management of the Tenn–Tom some 15 years after it was opened for navigation. The paper examines the accuracy of selected predicted impacts, waterway utilization, and the effectiveness of environmental measures. Received: 13 March 2000 · Accepted: 12 June 2000  相似文献   

Molecular models of a hydrated calcite mineral surface     

Thomas D. Perry IV  Randall T. Cygan 《Geochimica et cosmochimica acta》2007,71(24):5876-5887

Hydrated mineral surfaces play an important role in many processes in biological, geological, and industrial applications. An energy force field was developed for molecular mechanics and molecular dynamics simulations of hydrated carbonate minerals and was applied to investigate the behavior of water on the calcite surface. The force field is a significant development for large-scale molecular simulations of these systems, and provides good agreement with experimental and previous modeling results. Simulations indicate that water molecules are significantly ordered near the calcite surface. The predominant surface configuration (75-80%) results from coordination of a water molecule with a single calcium cation-carbonate anion pair, while the less common situation involves water coordination with two ion pairs. Surface restructuring and variation in coordination in the water layers results in distinct distances for water oxygens above the calcite surface—a two-component first monolayer (2.3 and 3.0 Å) and a secondary monolayer (5.0 Å). The different coordinations also alter lateral displacement, hydrogen bonding, and surface-normal orientation of the water molecules. The ordering of water molecules and the formation of a unique hydrogen bonding network at the calcite surface influence the physical properties of the interfacial water. Surface exchange of water molecules is observed by molecular dynamics simulation to occur at a rate of one exchange per 10 ps. Diffusion coefficients derived from mean square displacement analysis of atomic trajectories indicate a dependence of water transport based on the distance of the water molecules from the calcite surface.  相似文献