Consulta: subjectFacets:"Pelagic environment"
Registros recuperados: 8
Data/hora: 09/06/2024 01:21:38

Productivity in tropical upwelling areas considered by a new method of analysis and determination.
Provedor de dados: 5
Autores: Minas, H; Minas, M; Packard, T.
When in frontal zones of upwelling areas, a two-component mixing of nutrient rich upwelled water and oligotrophic offshore waters occurs, the amounts of nutrient consumed (- Delta N) and oxygen produced (+ Delta O2) can be evaluated by a detailed analysis of diagrams, in which salinity is the conservative parameter. By this same method, the corresponding T-S diagram allows a determination of the net heat gain of the upwelling water body during its offshore transport, and consequently the corresponding residence time in the photic zone. By integrating the nutrient consumption over the whole upwelling area, it is possible to obtain a more realistic average value of the productivity than with direct measurements of photosynthetic activity (14C and other...
Tipo: Text
Palavras-chave: Primary production; Dynamical oceanography; T/S diagrams; Fertility; Biomass; Upwelling; Pelagic environment; Analytical techniques; Biological production.
Ano: 1984
URL: http://archimer.ifremer.fr/doc/1984/acte-1527.pdf

Utilisation du submersible Cyana pour l'etude du macroplancton fragile
Provedor de dados: 5
Autores: Laval, P.
The gelatinous macroplanktonic organisms living in the deep sea can only be studied with manned submersibles. There is presently in increasing interest in the study of the role of this part of the pelagic ecosystem, because they are strongly involved in the transformation of the particulate organic matter. Their transparency, small size and mobility present technical challenges, unanticipated by the designers of the first submersibles, aimed at the sea bottom observation. Despite these limitations, the use of conventional submersibles has brought very interesting results. It is hoped that engineers will take into account the requirements of pelagic observations in the design of future submersibles.
Tipo: Text
Palavras-chave: Pelagic environment; Zooplankton; Ecosystems; Deep water; Manned vehicles.
Ano: 1990
URL: http://archimer.ifremer.fr/doc/1990/acte-1152.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

Southern elephant seals from Kerguelen Islands confronted by Antarctic Sea ice. Changes in movements and in diving behaviour
Provedor de dados: 5
Autores: Bailleul, Frédéric; Charrassin, Jean-benoit; Ezraty, Robert; Ardhuin, Fanny; Mcmahon, Clive R.; Field, Iain C.; Guinet, Christophe.
The behaviour of southern elephant seals from Kerguelen Island (4950&amp;#8242;S, 7030&amp;#8242;E) was investigated in relation to the oceanographic regions of the Southern Ocean. The oceanographic and the seal behaviour data, including location and diving activity, were collected using a new generation of satellite-relayed devices measuring and transmitting pressure, temperature, and salinity along with locations. Dive duration, maximum diving depth, time spent at the bottom of the dives, and shape of dive profiles were compared between male and female seals, and were related to the oceanographic characteristics of areas prospected by the seals. Most animals travelled to the Antarctic shelf. However, during winter, adult females travelled away from the...
Tipo: Text
Palavras-chave: Mirounga leonina; Diving Behaviour; Pelagic environment; Benthic environment; Temperature profiles; Marine ecology.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2500.pdf

Climate Change-Induced Emergence of Novel Biogeochemical Provinces
Provedor de dados: 5
Autores: Reygondeau, Gabriel; Cheung, William W. L.; Wabnitz, Colette C. C.; Lam, Vicky W. Y.; Frölicher, Thomas; Maury, Olivier.
The global ocean is commonly partitioned into 4 biomes subdivided into 56 biogeochemical provinces (BGCPs) following the accepted division proposed by Longhurst in 1998. Each province corresponds to a unique regional environment that shapes biodiversity and constrains ecosystem structure and functions. Biogeochemical provinces are dynamic entities that change their spatial extent and position with climate and are expected to be perturbated in the near future by global climate change. Here, we characterize the changes in spatial distribution of BGCPs from 1950 to 2100 using three earth system models under two representative concentration pathways (RCP 2.6 and 8.5). We project a reorganization of the current distribution of BGCPs driven mostly by a poleward...
Tipo: Text
Palavras-chave: Physical oceanography; Marine biogeography; Pelagic environment; Novel ocean climate; Environmental niche model.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00654/76611/77762.pdf

Contribution au suivi contrôle et surveillance des pêches au Sénégal
Provedor de dados: 20
Autores: Diarra, B.
La gestion des ressources humaines constituent une priorité de la DPSP. Pour la formation des actions ont été faites dans le cadre du projet Appui à une gestion durable et paritaire du secteur de la pêche au Sénégal.
Tipo: Book
Palavras-chave: Pelagic environment; Factory ships; Zonal distribution; Sailing ships; Safety regulations; Pelagic environment; Factory ships; Http://aims.fao.org/aos/agrovoc/c_5658; Http://aims.fao.org/aos/agrovoc/c_10732.
Ano: 2002
URL: http://hdl.handle.net/1834/1481

Characterizing and Comparing the Spawning Habitats of Sardine (Sardinops sagax) and Anchovy (Engraulis encrasicolus) in the Northern Benguela Region
Provedor de dados: 20
Autores: Tjizoo,Mbeurora Beau.
Spawning habitats of sardine and anchovy in eastern boundary current systems are characterized in an attempt to understand the fluctuations observed in their abundance. The northern Benguela, as an eastern boundary current system, is characterized by turbulent conditions that seem to govern the variability observed in the abundance of these species. Sardine and anchovy have developed mechanisms that enable them to maximize productivity. In the northern Benguela, spawning intensity is historically known to be high in periods and vicinities where turbulence is reduced. However, it is believed that selection of conditions for spawning by these species may change withfluctuations in abundance of fish.
Tipo: Theses and Dissertations
Palavras-chave: Sardine fisheries; Spawning; Anchovy fisheries; Habitat; Ecosystems; Sea surface temperature; Salinity; Spatial distribution; Climatic changes; Anthropogenic factors; Pelagic environment; Circulation; Coastlines.
Ano: 2008
URL: http://hdl.handle.net/1834/5231

The abundance, biomass and composition of pelagic ciliates in East African lakes of different salinity and trophy
Provedor de dados: 20
Autores: Yasindi, A. W.; Taylor, W. D.
Planktonic ciliates were studied in 17 tropical East African lakes of different salinity and trophic status. Oligotrichs (e.g., Strombidium, Strobilidium and Halteria) and scuticociliates (e.g., Cyclidium, Pleuronema, Cristigera), dominated the ciliate communities. Conductivity and trophic status were the most important environmental variables influencing the distribution of ciliate species in East African lakes. Herbivorous oligotrichs were important in oligotrophic and mesotrophic lakes, as they are in temperate and subtropical lakes, but their importance decreased with increasing chlorophyll a concentration and conductivity. On the other hand, the importance of scuticociliates (primarily bacterivores) increased with increasing chlorophyll a and...
Tipo: Proceedings Paper
Palavras-chave: Freshwater lakes; Abundance; Biomass; Pelagic environment; Salinity; Plankton; Community composition; Oligotrophic lakes; Aquatic communities; Regression analysis; Tropical lakes; Species diversity; Plankton; Freshwater.
Ano: 2006
URL: http://hdl.handle.net/1834/5311