Consulta: subjectFacets:"Tropical environment"
Registros recuperados: 14
Data/hora: 07/06/2024 05:26:00

Monomethylmercury sources in a tropical artificial reservoir
Provedor de dados: 5
Autores: Muresan, B; Cossa, Daniel; Richard, Sophie; Dominique, Y.
The distribution and speciation of mercury (Hg) in the water column, the inputs (wet deposition and tributaries) and the outputs (atmospheric evasion and outlet) of an artificial partially anoxic tropical lake (Petit-Sa-Lit reservoir, French Guiana) were investigated oil a seasonal basis in order to appraise the cycling and transformations of this metal. The total mercury (HgT) concentrations in the oxygenated epilimnetic waters averaged 5 +/- 3 pmol L-1 in the unfiltered samples (HgTUNF) and 4 +/- 2 pmol L-1 in the dissolved (HgTD) phase (&lt; 0.45 mu m). On average, the monomethylmercury (MMHg) constituted 8%, 40%, and 18% of the HgT in the dissolved phase, tile particulate suspended matter and in tile unfiltered samples, respectively. Covariant elevated...
Tipo: Text
Palavras-chave: Tropical environment; Artificial reservoir; Methylmercury; Mercury.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4198.pdf

Peculiarities of reproduction and generative production of tropical copepods
Provedor de dados: 5
Autores: Sazhina, L.
The aim of the present investigation consisted in revealing the regular natural changes of fecundity in mass pelagic copepods of the World Ocean tropical zone. Particular emphasis was placed on determination of the clutch size, duration of development, rate of generative production formation at both organism and population levels, and connection of these processes with environmental conditions. The major difficulty lay in the fact that most mass species of tropical copepods are laying eggs immediately into water thus complicating the determination of quantitative characteristics of reproduction.
Tipo: Text
Palavras-chave: Copepoda; Pelagic environment; Clutch; Environmental factors; Population density; Tropical environment; Fecundity; Biological production; Reproductive cycle.
Ano: 1984
URL: http://archimer.ifremer.fr/doc/1984/acte-1525.pdf

Virus diseases in temperate and tropical farming fish: State of current knowledge.
Provedor de dados: 5
Autores: Hill, B.
It is over 30 years since the development of fish tissue cultures led to the first confirmation of a viral infection in fish. Since that time, tissue cultures and, more usually, monolayer cell cultures, have been developed from a large number of fish species and have enabled the isolation from a large number of fish species and have enabled the isolation and study of 30 or so viral infections of fish, predominantly those of freshwater, catadromous and anadromous species, and particularly temperate species in the northern hemisphere. However, evidence for numerous other viral infections in fish has also been obtained without successful virus isolation through the visualisation of virus particles by electron microscopy or through experimental transmission of...
Tipo: Text
Palavras-chave: Tropical environment; Fish diseases; Fish culture.
Ano: 1989
URL: http://archimer.ifremer.fr/doc/1989/acte-1502.pdf

Questions sur la dynamique de l'exploitation halieutique
Provedor de dados: 5
Autores: Laloe, Francis; Rey, Hélène; Durand, Jean-louis.
Whether what is at stake is land-use management and stabilising the economy of the shoreline areas for a good number of developed countries or involvement in food self-sufficiency, contributing to the balance of payments and stabilising employment for developing countries, in every instance, the economic and/or political importance of fisheries management as a business sector is far from being marginal in most of the countries concerned. Thus, from the moment the question of the inexhaustibility of the resources was posed, the desire to manage them manifested itself by the emergence of social demand, peculiarly at around the same time as research, due to the involvement of the researchers in the decision-making bodies of land-use and business management...
Tipo: Text
Palavras-chave: Tropical environment; Artificial reservoir; Methymercury; Mercury; SEM.
Ano: 1993
URL: http://archimer.ifremer.fr/doc/2006/acte-2081.pdf

Accumulation of nine metals and one metalloid in the tropical scallop Comptopallium radula from coral reefs in New Caledonia
Provedor de dados: 5
Autores: Metian, M.; Bustamante, Paco; Hedouin, L.; Warnau, M.
Uptake of waterborne Cd, Co, Mn and Zn was determined in laboratory experiments using radiotracer techniques (Cd-109, Co-57, Mn-54 and Zn-65). Labelled Zn was mainly accumulated in the digestive gland (65%) and Co in kidneys (81%); Cd and Mn were similarly distributed in digestive gland and gills. In a complementary field study, Ag, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, and Zn were analysed in scallops collected at two stations showing different contamination levels. Digestive gland and kidneys displayed the highest concentrations. Ag, As, Cd, and Fe differed in soft tissues from the two stations, suggesting that Comptopallium radula could be a valuable local biomonitor species for these elements. Low Mn and Zn concentrations found in kidneys suggest that their...
Tipo: Text
Palavras-chave: Bioindicator species; Risk assessment; Pectinidae; Radiotracers; Arsenic; Trace elements; Tropical environment.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-6953.pdf

Biodiversity and sustainable management of a tropical wetland lake ecosystem: A case study of Lake Kanyaboli, Kenya
Provedor de dados: 20
Autores: Rasowo, J.O.; Abila, R.; Manyala, J.
Lake Kanyaboli and the surrounding Yala swamp wetland has been recognized as an important biodiversity hotspot. Recent population genetic and phylogenetic studies confirm the evolutionary importance of Lake Kanyaboli (Kenya) in preserving the cichlid fish fauna of Lake Victoria. The adjoining Yala swamp harbours the endangered swamp antelope Sitatunga (Tragecephalus spekii) and several papyrus endemic birds. The lake and adjoining swamp play a critical role in the livelihood of the local communities who heavily depend on the wetland resources. Current ongoing large scale land use changes within the swamp threaten the ecological integrity and functioning of this highly dynamic wetland ecosystem. It is therefore imperative that proper management and...
Tipo: Proceedings Paper
Palavras-chave: Wetlands; Biodiversity; Resource conservation; Inland waters; Ecosystem management; Ecological crisis; Tropical environment; Population genetics; Phylogenetics; Lake fisheries; Freshwater fish; Aquatic birds; Land use.
Ano: 2006
URL: http://hdl.handle.net/1834/2126

Report of the first session of the IOTC Working Party on Tropical Tunas.
Provedor de dados: 20
The emphasis of the meeting was placed on bigeye tuna (Thunnus obesus), but a number of the conclusions and recommendations reached apply equally to all tropical tunas. A review of fisheries and available data confirmed that both longline and purse seine fisheries for bigeye tuna have been expanding rapidly over the current decade. There are however major gaps in catch and effort data available, in particular major longline fleets operating from Indonesia and several eastern Indian Ocean ports and some which are engaged in illegal, unregulated and unreported (IUU) fishing. Furthermore, size data for most longline fisheries are generally missing or of doubtful quality. A number of recommendations on research were formulated, dealing with improvements in...
Tipo: Working Paper
Palavras-chave: Fishery statistics; Tuna fisheries; Fishery data; Stock assessment; Tropical environment.
Ano: 1999
URL: http://hdl.handle.net/1834/118

Das abnorme Dickenwachstum von Haematoxylon brasiletto Karsten
Provedor de dados: 20
Autores: Mägdefrau, K.
Las ramas de la Cesalpiniácea Haematoxylon brasiletto Karsten tienen en sus macroblastos tres filas de braquiblastos. En las zonas de los braquiblastos, la actividad del cámbium es reprimido, mientras en las zonas entre éllas se forma mucho leño secundario. Por eso macroblastos más viejos muestran un corte  transversal redondeado-triangular.
Tipo: Journal Contribution
Palavras-chave: Tropical environment.
Ano: 1970
URL: http://hdl.handle.net/1834/3279

Vertical distribution and structure of copepod (Arthropoda: Copepoda) assemblages in two different seasons down to 1,200 m in the tropical Southwestern Atlantic
Provedor de dados: 103
Autores: Dias,Cristina de Oliveira; Araujo,Adriana Valente de; Bonecker,Sérgio Luiz Costa.
ABSTRACT The vertical distribution of copepod assemblages, ascertained from the surface down to 1,200 m, was investigated during two sampling periods (rainy and dry seasons), at four depths, in the oligotrophic waters of the southwestern Atlantic Ocean. Total density, diversity, and richness differed among sampling depths. Copepod density decreased with depth in the two sampling periods, with a maximum at 1 m and a slight decrease at 800 m. Higher diversities were observed at 250 m and 1,200 m during the rainy season and at 1 m and 1,200 m during the dry season. The maximum number of species was found at 1,200 m during the rainy season and at 1 m during the dry season. Various copepod assemblages were delimited in the water column in the two sampling...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Mesozooplanktonic copepod; Southeastern Brazil; Tropical environment.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702018000100320

Evaluation of thermal stress indexes for dairy cows in tropical regions
Provedor de dados: 96
Autores: Silva,Roberto Gomes da; Morais,Débora Andréa Evangelista Façanha; Guilhermino,Magda Maria.
Data from 359 Holstein and 54 Jersey cows (total of 1359 observations) collected in commercial herds in the northeast of Brazil were used to evaluate six environmental stress indexes. The selection criterion was the correlation between the index value with the rectal temperature (RT) and the respiratory rate (RR) of cows. Both Temperature-Humidity Index (THI) and Black Globe-Humidity Index (BGHI) had the lowest correlations with animal RT and RR. The selected indexes were the Equivalent Temperature Index (r = 0.293 and 0.520 with RT and RR, respectively) and the Heat Load Index (0.286 and 0.542, respectively).
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Dairy cattle; Thermal comfort index; Tropical environment.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982007000500028

Anual variation of morphologic traits and hair coat surface temperature of Holstein cows in semi-arid environment
Provedor de dados: 96
Autores: Façanha,Débora Andréa Evangelista; Silva,Roberto Gomes da; Maia,Alex Sandro Campos; Guilhermino,Magda Maria; Vasconcelos,Angela Maria de.
This work aimed to study the annual variation of temperature of the coat surface and other traits of coat in Holstein cows managed in a tropical environment by separately considering black coat and white coat. It was measured the coat thickness (mm) characteristic, hair length (mm), hair number (hair/cm²) and coat surface temperature on 191 crossbred cows with 7/8 and 31/32 Holstein composition distributed in 3 herds in a semi-arid environment. Less dense coats with shorter, flattened hair occurred predominantly in March, a time coinciding to high levels of solar radiation. This type of coat shows low resistance to the flux of latent and sensitive heat through the skin, thus favoring heat loss. The black coat surface temperature was on average 4ºC higher...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Adaptation; Dairy cattle; Hair coat; Tropical environment.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982010000400020

Latent heat loss of Holstein cows in a tropical environment: a prediction model
Provedor de dados: 96
Autores: Maia,Alex Sandro Campos; Silva,Roberto Gomes da; Loureiro,Cintia Maria Battiston.
Nine lactating Holstein cows with average 526 ± 5 kg of BW, five predominantly black and four predominantly white, bred in a tropical region and managed in open pasture were observed to measure cutaneous and respiratory evaporation rates under different environmental conditions. Cows were separated in three weight class: 1 (&lt;450 kg), 2 (450-500 kg) and 3 (&gt;500 kg). Latent heat loss from cutaneous surface was measured using a ventilated capsule; evaporation in the respiratory system was measured using a facial mask. The results showed that heaviest cows (2 and 3 classes) presented the least evaporation rates. When air temperature increased from 10 to 36ºC the relative humidity decreased from 90 to 30%. In these conditions the heat loss by respiratory...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Evaporation rate; Holstein cows; Tropical environment.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982008001000018

Distribution, diversity, and habitat partitioning of Scolecitrichidae species (Copepoda: Calanoida) down to 1,200 m in the Southwestern Atlantic Ocean
Provedor de dados: 42
Autores: DIAS,CRISTINA O.; ARAUJO,ADRIANA V. DE; BONECKER,SÉRGIO L.C.
In this study, we analyzed the main distributional features of Scolecitrichidae species in the Southwestern Atlantic Ocean (northern region of Rio de Janeiro State) and determined and described their habitat partitioning, based on a night series of stratified samplings down to a depth of 1,200 m. A total of 18 species from seven genera were identified and grouped according to their depth distribution. Distinct vertical patterns of total density, richness, diversity, and evenness were observed, with a decrease in density and an increase in diversity and richness with increasing depth. The total scolecitrichid abundance was dominated by a few epipelagic migrant species (Scolecithrix danae, Scolecithricella minor, Amallothrix tenuiserrata, and Lophothrix...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Copepoda; Scolecitrichid; Deep waters; Southwestern Atlantic Ocean; Tropical environment.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652019000100611

Seasonal and spatial distribution of Bacterioplankton in a fluvial-lagunar system of a tropical region: density, biomass, cellular volume and morphologic variation
Provedor de dados: 52
Autores: Araújo,Magnólia Fernandes Florêncio de; Godinho,Mirna Januária Leal.
The temporal and spatial fluctuations of Bacterioplankton in a fluvial-lagunar system of a tropical region (Pitimbu River and Jiqui Lake, RN) were studied during the dry and the rainy periods. The bacterial abundance varied from 2.67 to 5.1 Cells10(7)mL-1 and did not show a typical temporal variation, presenting only small oscillations between the rainy and the dry periods. The bacterial biomass varied from 123 µgC L-1 to 269 µgC L-1 in the sampling sites and the average cellular volume varied from 0.12 to 0.54µm³, showing a predominance of the rods. The temperature showed a positive correlation with the cellular volume of the rods (R=0.55; p=0.02) and vibrio (R=0.53; p=0.03). Significant spatial differences of biomass (Mann Whitney: p=0.01) and cellular...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bacterioplankton; Biomass; Morphologic variation; Tropical environment.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132008000100024