Xem 1-20 trên 22 kết quả Aquatic species
  • Fish are aquatic vertebrates with fins for appendages. They "breathe" by means of gills. Fish make up the largest of the vertebrate groups with over 20,000 species. They can be found in a great variety of lakes, streams, oceans and estuaries. Fish are divided into two groups based on the composition of their skeletons. The sharks, skates and rays are cartilaginous fish. Their skeletons are made of cartilage, the same flexible material in your ear lobes and nose. The majority of fish have skeletons made of bone and are called bony fish....

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  • Aquatic scientists have always been intrigued with concepts of scale. This interest perhaps stems from the nature of ßuid dynamics in oceans and lakes — energy cascades from spatial scales of kilometers down to viscous scales at centimeters or less. Turbulent processes affect not only an organism’s perception of, and response to, the physical environment, but also the interaction between species, both within and across trophic levels.

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  • Much new material has been added to this second edition. Besides a totally new chapter on radionuclides, the text has been reorganized and updated with separate chapters on metals, light nonaqueous phase liquids (LNAPLs), dense nonaqueous phase liquids (DNAPLs), and biodegradation. Also, some end-of-chapter exercises have been added. The dictionary of inorganic pollutants has been enlarged and some important organic pollutants added.

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  • The object of aquaculture is not the same requirements for the size of food at an early stage larvae. rotifer is a live feed after the first important microalgae for them. rotifer but sometimes can not be used for some species of fish larvae that have a small mouth size. So rotifer size is the same in all species, and size change within the lifetime of them?

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  • Aquaculture is a general term for the resource, giving the human animal from the environment and human exploitation, aquaculture harvest used for food, raw materials or sold on the market. In the aquatic species, most commonly used fishing activities, aquaculture and exploitation of fish.

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  • The long-term approach to achieving protection is “ecological separation.” A true ecological separation is defined as no inter-basin transfer of aquatic organisms via the Chicago Waterway System at any time – 100% effectiveness. Ecological separation prohibits the movement or interbasin transfer of aquatic organisms between the Mississippi and Great Lakes basins via the CWS. Once established, the impacts of invasive species on ecosystem health are permanent and irreversible.

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  • By all accounts, Marine Ornamentals 2001: Collection, Culture and Conservation, was a highly successful meeting. The November 2001 gathering in Orlando, Florida, was attended by more than 300 individuals from 23 countries, representing a broad cross-section of interests in the marine ornamental fish and invertebrate industry, including scientists, hobbyists, students, commercial collectors, and representatives of government agencies.

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  • Urban ecology in Berlin has been developing over the past 350 years, from garden floras and wild floras of castles and ruins to the Graduate Research Training Group 780 “Perspectives in Urban Ecology”. This program has brought together universities and scientific institutes from all over Berlin. Since the beginning, urban ecology in Berlin has included approaches from biology and geography, leading to the current interdisciplinary work documented in this summarizing publication.

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  • The report describes the environmental status of the water bodies in 2004 as well as the trend in environmental quality over the period 1989–2004 in relation to changes in the pressures. In addition it de- scribes the monitoring of terrestrial natural habitats and species, in- cluding the first results of this monitoring, which was initiated in 2004.

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  • Decreases in pH and ANC are often paral- leled by changes in element concentrations including increases in Al +3 concentrations and decreases in Ca +2 . High dissolved Al +3 concen- trations can have toxic effects on many types of aquatic biota, and at extreme levels few aquatic species can survive (Table 1). Organic forms of Al +3 are much less toxic than inorganic forms. Emerging research suggests that Ca +2 concentra- tions in streamwater are also an important bio- logical indicator.

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  • The rising incidence of invasive species displacing endemics and altering water chemistry and local foodwebs increasingly affects freshwater systems and should be considered a water quality problem (Carr and Neary 2008). Aquatic species have in many cases been introduced deliberately into distant ecosystems for recreational, economic, or other purposes. In many instances, these introductions have decimated endemic fish and other aquatic organisms, and they can also degrade local watersheds.

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  • Human activities may seriously affect the quality of aquatic ecosystems. Pathogen organisms, nutrients, heavy metals, toxic elements, pesticides, pharmaceuticals and various other organic micropollutants enter to aquatic environment through a range of point and diffuse sources. The presence of these compounds has adverse impacts on aquatic biota. It is well recognised that the distribution and the abundance of various species in aquatic systems are directly related to the water quality and hydrological conditions....

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  • Order Anura - Frogs: Adults lack tails and have four legs, Body size ranges from 2-3 up to about 15 cm, Aquatic larvae usually present, Larvae are basically herbivorous, Adults are never herbivorous, 5 Families known from Cat Tien, 0-40 species known from Cat Tien

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  • Bird characteristics: Body always covered with feathers; feet (toes and usually tarsometatarsus) covered with scales (thickened skin). Aquatic birds have webbed toes. No teeth; horny beak. Lightweight skeleton in flying birds (many hollow bones), with keel on sternum for attachment of flight muscles (pectoral muscles). No keel in large flightless birds (ostrich, emu, rhea). Completely bony ribs (no rib cartilage). Clavicles fused into single bone, the furculum (wishbone). Numerous neck vertebrae (number varies by species) provide great neck flexibility.

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  • Plant species that invade an alien area and outgrow the native vegetation, establishing and increasing their own territory, often lead to negative economic, environmental, and social impacts. Even native species can behave like invasive species by their exponential spread. Similarly, not all non-native species are invasive. Many alien invasive species, however, do threaten the health and integrity of our terrestrial and aquatic ecosystems.

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  • This book addresses the significant environmental changes experienced by high latitude and high altitude ecosystems at the beginning of the 21st century. Increased temperatures and precipitation, reduction in sea ice and glacier ice, the increased levels of UV-radiation and the long-range transported contaminants in arctic and alpine regions are stress factors that challenge terrestrial and aquatic ecosystems.

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  • The culture of striped catfish, Pangasianodon hypophthalmus (Sauvage), or “ca tra” in Vietnamese in the Mekong Delta of Vietnam, can be considered as a unique aquatic farming system in many ways. Production is the fastest growth recorded in any aquaculture sector, ever, based on a single species, superseding the production per unit for any form of primary production. Stripped catfish aquaculture now need to be improved in many aspects and environmental issues need to be paid more attention to ensure the sustainable development.

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  • A variety of organisms have been investigated to evaluate their potential as biological indicators of different forms of pollution in the aquatic environment (e.g. review by Gunkel 1994). Certain species have been identified as being highly sensitive either in their physiological response to aquatic contaminants or in their ability to accumulate particular toxins in a dose-time dependent manner.

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  • VNU Journal of Science, Natural Sciences and Technology 27 (2011) 9-13 In the present study, faunistic data on water bugs from urban area of Hanoi has been catalogued for the first time. From our surveys, we have identified a total of 23 species of 12 genera and nine families of aquatic bugs (Nepomorpha) and semi-aquatic bugs (Gerromorpha) from the studied area. The water bug fauna in Hanoi is of a typical lowland fauna in Southeast Asia mainland, comprising many species with wide distribution. ...

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  • Early attempts to look at the link between air pollution and wildlife focused mainly on the so- called "charismatic megafauna", ie on large and "colourful" species of animals. In fact, the most widely affected species - in terms of both number of species suffering damage from air pollution and also sensitivity of individual species to pollution - are amongst the lower life forms. In particular, lichens, bryophytes, fungi, and soft-bodied aquatic invertebrates are likely to be at risk.

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