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81.
Variations of the abundance and nucleic acid content of heterotrophic bacteria in Beaufort Shelf waters during winter and spring 总被引:1,自引:0,他引:1
Claude Belzile Sonia Brugel Christian Nozais Yves Gratton Serge Demers 《Journal of Marine Systems》2008,74(3-4):946
Depth profiles of heterotrophic bacteria abundance were measured weekly over a 6-month period from December to May in Franklin Bay, a 230 m-deep coastal Arctic Ocean site of the southeastern Beaufort Sea. Total bacteria, low nucleic acid (LNA) and high nucleic acid (HNA) bacteria abundances were measured using flow cytometry after SYBR Green I staining. The HNA bacteria abundance in surface waters started to increase 5–6 weeks after phytoplankton growth resumed in spring, increasing from 1 × 105 to 3 × 105 cells mL− 1 over an 8-week period, with a net growth rate of 0.018 d− 1. LNA bacteria response was delayed by more than two months relative to the beginning of the phytoplankton biomass accumulation and had a lower net growth rate of 0.013 d− 1. The marked increase in bacterial abundance occurred before any significant increase in organic matter input from river discharge (as indicated by the unchanged surface water salinity and DOC concentrations), and in the absence of water temperature increase. The abundance of bacteria below the halocline was relatively high until January (up to 5 × 105 cells mL− 1) but then decreased to values close to 2 × 105 cells mL− 1. The three-fold bacterial abundance increase observed in surface waters in spring was mostly due to HNA bacteria, supporting the idea that these cells are the most active. 相似文献
82.
Masahiko Ozaki Junichi Minamiura Yoshinori Kitajima Shuji Mizokami Kazuhisa Takeuchi Katsunori Hatakenaka 《Journal of Marine Science and Technology》2001,6(2):51-58
Ocean sequestration of the CO2 captured from fossil-fuel burning is a possible option to mitigate the increase in CO2 concentration in the atmosphere. It can isolate huge amounts of CO2 from the atmosphere for a long time at relatively low cost, if it is acceptable from the viewpoint of the environmental impact
on the ocean. The concept of CO2 dispersion in the ocean depths by ships is a promising method for efficient dilution. That is, liquefied CO2 is delivered to the site and injected into the ocean at depths of 1000–2500 m with a suspended pipe towed by a slowly moving
ship. In addition to the horizontal movement of the release point, the vertical journey of CO2 droplets until they disappear by dissolution is effective for the dilution of CO2 in seawater. In this paper, the possibility of the generation of relatively large-sized droplets from a moving nozzle is
investigated experimentally. In addition, the terminal velocity of CO2 droplets in deep-sea circumstances is measured in a large high-pressure tank to investigate the influence of the hydrate
film formed on the surface of the droplet. Finally, it is shown by simulation that an initial dilution ratio of one to some
ten thousandths is possible on a realistic engineering scale in the moving ship type of CO2 ocean sequestration.
Received: August 7, 2001 / Accepted: September 13, 2001 相似文献
83.
Military ocean patrol vessels (OPVs) are today an increasingly common type of naval ship. To facilitate the wide range of tasks with small crews, OPVs represent several ship design compromises between, for example, survivability, redundancy and technical endurance, and some of these compromises are new to military ships.The aim of this study is to examine how the design risk control-options in relation to survivability, redundancy and technical endurance can be linked to the operational risk in a patrol and surveillance scenario. The ship operation for a generic OPV, including the actions of the threat, is modelled with a Bayesian network describing the scenario and the dependency among different influences.The scenario is described with expert data collected from subject matter experts. The approach includes an analysis of uncertainty using Monte Carlo analysis and numerical derivative analysis.The results show that it is possible to link the performance of specific ship design features to the operational risk. Being able to propagate the epistemic uncertainties through the model is important to understand how the uncertainty in the input affects the output and the output uncertainty for the studied case is small relative to the input uncertainty. The study shows that linking different ship design features for aspects such as survivability, redundancy and technical endurance to the operational risk gives important information for the ship design decision-making process. 相似文献
84.
Emilie Springer 《Coastal management》2013,41(4):455-465
This article has two goals: (1) to consider the underlying semantic confusion surrounding the promotion of “social science” in the design and establishment of marine protected areas and (2) to demonstrate the successful community processes that led to the designation of Sitka, Alaska's Local Area Management Plan (LAMP) for halibut fishing in the vicinity of Sitka. Uniting a collection of diverse “social” issues creates ambiguity in actual problem solving—extensive generalization can not resolve a specific issue. The Sitka LAMP is a specific case with clear details and a traceable history of success, designed to sustain the healthy status of Sitka's local halibut resource. The development of the Sitka LAMP designation demonstrates the importance of community collaboration and exhibits methods that could potentially be modeled in other locations. 相似文献
85.
This article is part of a special issue that provides insight into global conservation science by analyzing a 5-year, $12.5 million global marine conservation science and policy program. In this article, we summarize the development of the program in Belize, which concentrated its effort in the southern portion of the country. The marine managed areas that developed in Belize took a variety of different forms, and involved a number of different government and private sector agencies and organizations. 相似文献
86.
This article is part of a special issue that provides insight into global conservation science by analyzing a 5-year, $12.5 million global marine conservation science and policy program. In this article, we summarize the development of the program in Coiba Island in the Gulf of Chiriquí Panama, and the Galapagos islands of Ecuador, both part of the Eastern Tropical Pacific Seascape. In Panama, the history of Coiba island as a federal penal colony shaped the process and outcome of the program. In the Galapagos, the unique science history of the islands and subsequent international recognition influenced the outcomes of regional marine managed areas. 相似文献
87.
88.
本文介绍了知识经济的基本特征,结合讨论我国目前的现状,提出我国发展知识经济的必然性及近期发展策略。 相似文献
89.
Samiul Hasan Satish V. Ukkusuri 《Transportation Research Part B: Methodological》2011,45(10):1590-1605
Individual evacuation decisions are often characterized by the influence of one’s social network. In this paper a threshold model of social contagion, originally proposed in the network science literature, is presented to characterize this social influence in the evacuation decision making process. Initiated by a single agent, the condition of a cascade when a portion of the population decides to evacuate has been derived from the model. Simulation models are also developed to investigate the effects of community mixing patterns and the initial seed on cascade propagation and the effect of previous time-steps considered by the agents and the strength of ties on average cascade size. Insights related to social influence include the significant role of mixing patterns among communities in the network and the role of the initial seed on cascade propagation. Specifically, faster propagation of warning is observed in community networks with greater inter-community connections. 相似文献
90.