33 resultados para NOR-CLERODANE DITERPENE

em Aquatic Commons


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Three new acylic diterpenoids belonging to the class of phytol series have been isolated. They were obtained from the ethyl acetate soluble fractions of four siphonaceous green seaweeds, Bryopsis pennata Lamour., Caulerpa taxifolia (Vahl) C. Ag., Codium decorticatum (Woodw.) Howe and Valoniopsis pachynema (Mart.) Børg., collected from Karachi coast of Pakistan. Structures of these compounds were elucidated with the help of spectroscopic methods and confirmed by comparison with the known compounds. Even the known compounds are being reported for the first time from a green algal source. All the compounds were found to display a strong toxicity at all the three concentrations tested in the brine shrimp bioassay.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

One of the causes of lower artesian pressure, water waste and aquifer contamination is the misuse and insufficient care of artesian wells. In 1953, Senate Bill No. 57, entitled "An Act to Protect and Control the Artesian Waters of the State" (see Appendix) became a law. This law was passed through the efforts exerted by leading members of the Senate and the House of Representatives, who understood the need for a wise and controlled expenditure of our most valuable natural resource. The State Geologist and his authorized representatives were designated by this law to enforce this conservation measure; however, no financial provision was included for the 1953-55 biennium. The proposed program of the Florida Geological Survey for this biennium did not include the funds nor provide any full-time personnel for the enforcement of this statute. As a result, little actual work was accomplished during these two years, although much time was given to planning and discussion of the problem. Realizing that this program could provide additional basic data needed in the analysis of the water-supply problem, the State Geologist sought and was granted by the 1955 Legislature adequate funds with which to activate the first phase of the enforcement of Florida Statute No. 370.051-054. Enumerated below is a summary of the progress made on this investigation as outlined previously: 1. Data have been collected on 967 wildly flowing wells in 22 counties. 2. Chloride determinations have been run on 850 of the 967 wells. 3. Of the 967 wells, 554 have chlorides in excess of the 250 ppm, the upper limit assigned by the State Board of Health for public consumption. 4. Water escapes at the rate of 37, 762 gallons per minute from these 967 wells. This amounts to 54, 377, 280 gallons per day. The investigation is incomplete at this time; therefore, no final conclusions can be reached. However, from data already collected, the following recommendations are proposed: 1. That the present inventory of wildly flowing wells be completed for the entire State. 2. That the current inventory of wildly flowing wells be expanded at the conclusion of the present inventory to include all flowing wells. 3. That a complete statewide inventory program be established and conducted in cooperation with the Ground Water Branchof the U.S. Geological Survey. 4. That the enforcement functions as set down in Sections 370.051/.054, Florida Statutes, be separated from the program to collect water-resource data and that these functions be given to the Water Resources Department, if such is created (to be recommended by the Water Resources Study Commission in a water policy law presented to the 1957 Legislature). 5. That the research phase (well inventory) of the program remain under the direction of the Florida Geological Survey. (PDF contains 204 pages.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The word stress when applied to ecosystems is ambiguous. Stress may be low-level, with accompanying near-linear strain, or it may be of finite magnitude, with nonlinear response and possible disintegration of the system. Since there are practically no widely accepted definitions of ecosystem strain, classification of models of stressed systems is tenuous. Despite appearances, most ecosystem models seem to fall into the low-level linear response category. Although they sometimes simulate systems behavior well, they do not provide necessary and sufficient information about sudden structural changes nor structure after transition. Dynamic models of finiteamplitude response to stress are rare because of analytical difficulties. Some idea as to future transition states can be obtained by regarding the behavior of unperturbed functions under limiting strain conditions. Preliminary work shows that, since community variables do respond in a coherent manner to stress, macroscopic analyses of stressed ecosystems offer possible alternatives to compartmental models.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

On 15-16 January 2005, three offshore species of cetaceans (33 short-finned pilot whales, Globicephala macrorhynchus, one minke whale, Balaenoptera acutorostrata, and two dwarf sperm whales, Kogia sima) stranded alive on the beaches of North Carolina. The pilot whales stranded near Oregon Inlet, the minke whale in northern North Carolina, and the dwarf sperm whales near Cape Hatteras. Live strandings of three species in one weekend was unique in North Carolina and qualified as an Unusual Mortality Event. Gross necropsies were conducted on 16-17 January 2005 on 27 pilot whales, two dwarf sperm whales, and the minke whale. Samples were collected for clinical pathology, parasitology, gross pathology, histopathology, microbiology and serology. There was variation in the number of animals sampled for each collection type, however, due to carcasses washing off the beach or degradation in carcass condition during the course of the response. Comprehensive histologic examination was conducted on 16 pilot whales, both dwarf sperm whales, and the minke whale. Limited organ or only head tissue suites were obtained from nine pilot whales. Histologic examination of tissues began in February 2005 and concluded in December 2005 when final sampling was concluded. Neither the pilot whales nor dwarf sperm whales were emaciated although none had recently ingested prey in their stomachs. The minke whale was emaciated; it was likely a dependent calf that became separated from the female. Most serum biochemistry abnormalities appear to have resulted from the stranding and indicated deteriorating condition from being on land for an extended period. Three pilot whales had clinical evidence of pre-existing systemic inflammation, which was supported by histopathologic findings. Although gross and histologic lesions involving all organ systems were noted, consistent lesions were not observed across species. Verminous pterygoid sinusitis and healed fishery interactions were seen in pilot whales but neither of these changes were causes of debilitation or death. In three pilot whales and one dwarf sperm whale there was evidence of clinically significant disease in postcranial tissues which led to chronic debilitation. Cardiovascular disease was present in one pilot whale and one dwarf sperm whale; musculoskeletal disease and intra-abdominal granulomas were present in two pilot whales. These lesions were possible, but not definitive, causal factors in the stranding. Remaining lesions were incidental or post-stranding. The minke whale and three of five tested pilot whales had positive morbillivirus titers (≥1:8 with one at >1:256), but there was no histologic evidence of active viral infection. Parasites (nematodes, cestodes, and trematodes) were collected from 26 pilot whales and two dwarf sperm whales. Sites of collection included stomach, nasal/pterygoid, peribullar sinuses, blubber, and abdominal cavity. Parasite species, locations and loads were within normal limits for free-ranging cetaceans and were not considered causative for the stranding event. Gas emboli lesions which were considered consistent with or diagnostic of sonarassociated strandings of beaked whales or small cetaceans were not found in the whales stranded as part of UMESE0501Sp. Twenty-five heads were examined with nine specific anatomic locations of interest: extramandibular fat, intramandibular fat, auditory meatus, peribullar acoustic fat, peribullar soft tissue, peribullar sinus, pterygoid sinus, melon, and brain. The common finding in all examined heads was verminous pterygoid sinusitis. Intramandibular adipose tissue reddening, typically adjacent to the vascular plexus, was observed in some individuals and could represent localized hemorrhage resulting from vascular rete rupture, hypostatic congestion, or erythrocyte rupture during the freeze/thaw cycle. One cetacean had peracute to acute subdural hemorrhage that likely occurred from thrashing on the beach post-stranding, although its occurrence prior to stranding cannot be excluded. Information provided to NMFS by the U.S. Navy indicated routine tactical mid-frequency sonar operations from individual surface vessels over relatively short durations and small spatial scales within the area and time period investigated. No marine mammals were detected by marine mammal observers on operational vessels; standard operating procedure for surface naval vessels operating mid-frequency sonar is the use of trained visual lookouts using high-powered binoculars. Sound propagation modeling using information provided to NMFS indicated that acoustic conditions in the vicinity likely depended heavily on position of the receivers (e.g., range, bearing, depth) relative to that of the sources. Absent explicit information on the location of animals meant that it was not possible to estimate received acoustic exposures from active sonar transmissions. Nonetheless, the event was associated in time and space with naval activity using mid-frequency active sonar. It also had a number of features in common (e.g., the “atypical” distribution of strandings involving multiple offshore species, all stranding alive, and without evidence of common infectious or other disease process) with other sonar-related cetacean mass stranding events. Given that this event was the only stranding of offshore species to occur within a 2-3 day period in the region on record (i.e., a very rare event), and given the occurrence of the event simultaneously in time and space with a naval exercise using active sonar, the association between the naval sonar activity and the location and timing of the event could be a causal rather than a coincidental relationship. However, evidence supporting a definitive association is lacking, and, in particular, there are differences in operational/environmental characteristics between this event and previous events where sonar has apparently played a role in marine mammal strandings. This does not preclude behavorial avoidance of noise exposure. No harmful algal blooms were present along the Atlantic coast south of the Chesapeake Bay during the months prior to the event. Environmental conditions, including strong winds, changes in upwelling- to downwelling-favorable conditions, and gently sloping bathymetry, were consistent with conditions which have been correlated with other mass strandings. In summary, we did not find commonality in gross and histologic lesions that would indicate a single cause for this stranding event. Three pilot whales and one dwarf sperm whale had debilitating conditions identified that could have contributed to stranding, one pilot whale had a debilitating condition (subdural hemorrhage) that could have been present prior to or resulting from stranding. While the pilot and dwarf sperm whale strandings may have had a common cause, the minke whale stranding was probably just coincidental. On the basis of examination of physical evidence in the affected whales, however, we cannot definitively conclude that there was or was not a causal link between anthropogenic sonar activity or environmental conditions (or a combination of these factors) and the strandings. Overall, the cause of UMESE0501Sp in North Carolina is not and likely will not be definitively known. (PDF contains 240 pages)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The mission of the National Oceanic and Atmospheric Administration (NOAA) is to understand and predict changes in the Earth’s environment and conserve and manage coastal and marine resources to meet our nation’s economic, social and environmental needs (NOAA, 2004). In meeting its marine stewardship responsibilities, NOAA seeks to ensure the sustainable use of resources and balance competing uses of coastal and marine ecosystems, recognizing both their human and natural components (NOAA, 2004). Authorities for executing these responsibilities come from over 90 separate pieces of Federal legislation, each with unique requirements and responsibilities. Few of these laws explicitly mandate an ecosystem approach to management (EAM) or supporting science. However, resource managers, the science community, and increasingly, the public, are recognizing that significantly greater connectedness among the scientific disciplines is needed to support management and stewardship responsibilities (Browman and Stergiou, 2004; 2005). Neither NOAA nor any other science agency can meet the increasing demand for ecosystem science products addressing each of its mandates individually. Even if it was possible, doing so would not provide the integration necessary to solve the increasingly complex array of management issues. This focus on the integration of science and management responsibilities into an ecosystem view is one of the centerpieces of the U.S. Commission on Ocean Policy’s report (USCOP, 2004), and the Administration’s response to that report in the U.S. Ocean Action Plan (CEQ, 2004). (PDF contains 100 pages)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The names: bachelor, campbellite, white bass, camp lighter, sac-a-lait, silver crappie, speckled bass, tinmouth, bar fish, Oswego bass, razorback, grassback, shiner, john demon, calico bass, strawberry bass and "crap'pee," along with 10-20 others, all refer to two rather than one species of fish. Most Maryland fishermen when applying these time honored names do not realize they are referring to two distinct species of fish. These species are the black crappie, Pornoxis nigromaculatus, and the white crappie, Pornoxis annulars. Contrary to common belief, the white crappie does not change into a black crappie during parts of the year nor are these two fish just color phases of one species. Crappies are members of the freshwater sunfish family of fishes, Centrarchidae. (PDF contains 4 pages)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Since the early years of the 21st century, and in particular since 2007, the U.S. has been awakening rapidly to the fact that climate change is underway and that even if stringent efforts are undertaken to mitigate greenhouse gas emissions, adaptation to the unavoidable impacts from the existing commitment to climate change is still needed and needs to be begun now. This report provides an historical overview of the public, political, and scientific concern with adaptation in the United States. It begins by briefly distinguishing ongoing, historical adaptation to environmental circumstances from deliberate adaptation to human‐induced climate change. It then describes the shift from the early concerns with climate change and adaptation to the more recent awakening to the need for a comprehensive approach to managing the risks from climate change. Ranging from the treatment of the topic in the news media to the drafting of bills in Congress, to state and local government activities with considerable engagement of NGOs, scientists and consultants, it is apparent that adaptation has finally, and explosively, emerged on the political agenda as a legitimate and needed subject for debate. At the same time, the current policy rush is not underlain by widespread public engagement and mobilization nor does it rest on a solid research foundation. Funding for vulnerability and adaptation research, establishing adequate decision support institutions, as well as the building of the necessary capacity in science, the consulting world, and in government agencies, lags far behind the need. (PDF contains 42 pages)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Cod, haddock, whiting, saithe, plaice, sole and Norway lobster are 7 main target species of the demersal mixed fisheries in the North Sea, Skagerrak and Eastern Channel. Gadoids and Norway lobsters are mainly taken in the nor-thern North Sea by towed gears except beam trawls while the flatfish fisheries are conducted in the southern North Sea mainly using beam trawls. Recently, the central North Sea appears less fished by demersal gears. Towed nets including seines and beam trawls equipped with meshes of more than 100 mm resp. more than 80 mm were identified as the main gears effecting the depleted cod and reduced plaice stocks. The saithe sector, using towed nets with meshes of more than110 mm, longlines, gill nets and others, appears to affect the 7 species to a lesser extend. These results support the interim effort limitations by gear types, vessel and month as enforced by the European Commission since 2003. TAC regulations alone are considered inefficient to sustainably harvest stocks by mixed fisheries. A fleet-effort management method is developed estimating the fleets’ effects based on the sum of partial exploitation rates of the species in mixed fisheries weighted by the ratio of the precautionary reference Bpa and the actual SSB size as ecological quality objective. Applying such fleet effort management could result in increased catch possibilities of some stocks by fleets selecting mainly few and non-overexploited stocks while respecting precautionary management constraints in minimum SSB or maximum exploitation rates at the same time.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Three groups of Sarotherodon niloticus fry were fed for 8 weeks on diets either treated with 17- & methyltestosterone (MT), alcohol (CA), or untreated (CO). Growth rate and food utilization in the different groups were compared. Results indicate that the best growth, Feed Conversion Ratio (FCR), Protein Efficiency Ratio (PER) and Mean Growth Rate (MGR) were obtained with the MT diet. There was no significant difference (P 0.05) in growth and food utilization of the CA and CO fry, nor in the mortality rate of the 3 treatments. The androgen, methyltestosterone promotes growth and protein anabolism without producing toxic effects in S. niloticus

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Diploid meiotic gynogenesis was induced in African catfish, Heterobranchus longifilis by injection of 0.5ml/kg ovaprim on the breeders, followed by application of UV light irradiation on the spermatozoa and temperature shocking of activated eggs. Diploidy was restored by shocking haploid activated eggs at 5 degree C for 40 minutes. The normal control spermatozoa did not receive any UV irradiation nor temperature shock, while the haploid control spermatozoa were irradiated, but did not receive cold shock. The percentage hatchability in the treated group was 25%, while in the control it was 53%. Less than 15 fingerlings had morphological aberrations. After two weeks of indoor rearing, the survival percentage of the treated group was 45% in the control experiment. Cytogenetic analysis of chromosomes revealed 25 chromosomes in the haploid embryo and 50 chromosomes each in diploid gynogenesis and normal diploid control

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The management of Lake Victoria is a high priority to the riparian countries that benefit directly from its resources. Management regulations have been formulated and implemented with the aim of maintaining the lake's ecological quality as well as sustaining fisheries exploitation for economic gain. Results indicate, however, that the regulations have not been successful in maintaining the state of the lake's ecosystem nor the fisheries. There has been a continuing decline in fish catches as well as declining biodiversity. Currently, the riparian countries are considering the introduction of a co-management regime as an alternative managerial strategy to address the lake's problems. In this paper it is argued that the failure of the former management regulations was because ownership of the lake was not clearly defined. It is further argued that even if co-management were to be successfully instituted, it will yield very minimal results if the problem of ownership is not properly addressed. This paper explores the ownership status of the lake based on data collected in Tanzania, and examines the relationship between, and significance of, ownership and co-management. The research makes recommendations for how these concepts can contribute to an integrated management of the lake

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In June 1994 and 1995 stations in the North, Irish, Celtic Seas and the Channel were studied for the occurrence of Myxobolus aeglefini in whiting (Merlangius merlangus). The disease was visible externally as either white nodules of a few millimeters diameter in the upper mouth cavity, gill arches and the basis of pelvic fins and in severe cases also on the lower jaws or in the cornea and sclera of the eye. It was verified morphometrically in histological sections of infected eyes by size and shape of spores. Myxobolus aeglefini was present in low prevalences at two North Sea stations and high prevalences of up to 49 % in the Irish Sea (Solway Firth) during both cruises. Whiting between 23 and 55 cm were found to be infected. Neither length-age prevalences nor condition factors and gonado, spleen, liver somatic indices differed in diseased and healthy fishes.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A decade-long time series recorded in southern Monterey Bay, California demonstrates that the shallow, near-shore environment (17 m depth) is regularly inundated with pulses of cold, hypoxic and low pH water. During these episodes, oxygen can drop to biologically threatening levels, and pH levels were lower than expected. Weekly water chemistry monitoring revealed that the saturation state of aragonite (the more soluble form of calcium carbonate) was often below saturation and had a moderate positive relationship with pH, however, analytical and human error could be high. Pulses of hypoxia and low pH water with the greatest intensity arise at the onset of the spring upwelling season, and fluctuations are strongly semidurnal (tidal) and diurnal. Arrival of cold, hypoxic water on the inner shelf typically occurs 3 days after the arrival of a strong upwelling event and appears to be driven by upwelling modulated by internal tidal fluctuations. I found no relationship between the timing of low-oxygen events and the diel solar cycle nor with terrestrial nutrient input. These observations are consistent with advection of hypoxic water from the deep, offshore environment where water masses experience a general decline of temperature, oxygen and pH with depth, and inconsistent with biochemical forcing. Comparisons with concurrent temperature and oxygen time series taken ~20 km away at the head of the Monterey Canyon show similar patterns but even more intense hypoxic events due to stronger semidiurnal forcing there. Analysis of the durations of exposure to low oxygen levels establishes a framework for assessing the ecological relevance of these events. Increasing oceanic hypoxia and acidification of both surface and deep waters may increase the number, intensity, duration and spatial extent of future intrusions along the Pacific coast. Evaluation of the resiliency of nearshore ecosystems such as kelp forests, rocky reefs and sandy habitats, will require consideration of these events.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

ENGLISH: The population structure and production of Pacific yellowfin tuna, Thunnus albacares, were examined by studying most of the basic data available on stock assessment, as well as other data, for the period 1965 to 1972. The data were obtained mainly from the Japanese longline fishery in the Pacific Ocean east of about 1200E and from the purse-seine fishery in the eastern Pacific east of about 140oW. Data from genetic studies of subpopulations were not used due to their preliminary nature. It was concluded that the concept of "semi-independent" subpopulations proposed by Kamimura and Honma (1963) and Royce (1964) defines the population structure of Pacific yellowfin. At least three stocks (i.e. western, central and eastern), relatively independent of each other, are thought to exist, but the actual number and location of subpopulations is still unclear. Possible north-south separations, indicated to some extent by genetic studies and tagging, could be neither substantiated nor rejected on the basis of this study. Finally, unless some major change in the fishing technology occurs, it is doubtful if any significant sustainable increase in yellowfin production from the Pacific is possible. The greatest potential for increase, if any, appears to be based on changing the size structure of yellowfin in the catch from the central Pacific. SPANISH: Se examino la estructura de la población y la producción del atún aleta amarilla del Pacifico Thunnus albacares para estudiar la mayoría de los datos básicos que se tenían sobre el avalúo de la población, como también otra información correspondiente al periodo de 1965·1972. Los datos fueron obtenidos principalmente de las pescas palangreros japonesas del Océano Pacifico al este de los 1200 E y de las pescas con redes de cerco del Pacifico oriental, al este de los 140oW. No se emplearon los datos de estudios genéticos de las subpoblaciones porque eran mas bien preliminares. Se concluyo que el concepto propuesto por Kamimura y Honma (1963) y Royce (1964) de subpoblaciones "semiindependientes" define la estructura de la población del aleta amarilla en el Pacifico. Se cree que existen por 10 menos tres existencias (e.d. la occidental, central y oriental), relativamente independientes la una de la otra, pero no se conoce con certeza cuantas subpoblaciones hay y donde se encuentran. La posible separación norte-sur, indicada, hasta cierto punto, por los análisis genéticos y del marcado, no puede ni confirmarse ni rechazarse basados en este estudio. Finalmente, a no ser que ocurra algún gran cambio en la tecnología pesquera es dudoso que sea posible obtener un aumento constante e importante en la producción del aleta amarilla del Pacifico. El potencial mayor de aumento, si es que existe alguno, parece que se basa en el cambio de la estructura de talla en la captura del aleta amarilla del Pacifico central. (PDF contains 169 pages.)