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| Registros recuperados: 473 | |
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| Hamon, Pierre-yves; Tournier, Henri. |
| Since 1980, the IFREMER research laboratory "Resources Aquacoles", Sete (France), follows during the summer period, the evolution of the commercial stocks of molluscs (mussels and oysters) reared in Thau Lagoon. The data for this estimation are collected, on one hand, by surface observations and, on the other hand, by diving observations. During the years 1980 to 1984, the authors noticed an increase of oyster biomass, during the same period the mussel biomass decreased. The different simulations used to know the total filtration and the biodeposit, have shown that the impact of the increase of the total biomass is not so important as it could be feared. |
| Tipo: Text |
Palavras-chave: Bivalvia; Marine mollusks; Stock assessment; Population density; Biomass. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/publication-1787.pdf |
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| Gerard, Denis. |
| The quantity of mussels cultivated on wooden poles called « bouchots », in Mont Saint-Michel bay, has been estimated in april 2002, by volume, number and weight. To do so, a sampling strategy has been conceived, operated and then optimized, taking into account the spatial distribution of this stock and the material and human constraints (especially the amount of persons and working days available). The sampling plan uses procedures of stratification, degrees, regression, so as to reach the optimum precision related to cost. The operation took a great advantage of the efficient help of mussel farmers. During the first day, the task consisted to estimate the number and position of poles occupied by mussels, with the help of 5 persons on boat. The following 2... |
| Tipo: Text |
Palavras-chave: Mont Saint Michel; Sampling; Biomass; Stock; Mussels; Mont Saint Michel; Échantillonnage; Biomasse; Bouchot; Stock; Moules. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/2002/rapport-5304.pdf |
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| Sagan, G; Thouzeau, G. |
| Microphytobenthic biomass was estimated in the Bay of Brest (1994) and the western English Channel (Trezen Vraz, 1993) using spectrophotometry. Best results (42 % difference) were obtained with an instantaneous extraction procedure at room temperature, compared with the cold extraction procedure. Chlorophyll biomass in sediment was higher in the western English Channel (65-215 mg Chl a m(-2)) than in the Bay of Brest (10-113 mg Chl a m(-2)), in contrast to total pigment biomass (Chl a + pheo a : 88-254 mg m(-2) at Trezen Vraz vs. 131-934 mg m(-2) in the Bay of Brest). This study emphasized decreasing pigment biomass from the estuary to the open sea. Low benthic pigment biomass in the Bay, compared to eutrophic ecosystems, agrees with previous studies on... |
| Tipo: Text |
Palavras-chave: Microphytobenthos; Biomasse; Écosystèmes côtiers; Forçage physique; Microphytobenthos; Biomass; Coastal ecosystems; Physical forcing. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/00325/43651/43242.pdf |
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| Galeron, Joelle; Sibuet, Myriam; Mahaut, Ml; Dinet, A. |
| Three major size classes of the benthic metazoan communities (megafauna, macrofauna and meiofauna) were investigated simultaneously at 3 sites in the tropical Northeast Atlantic. The sites varied in their level of surface primary productivity (eutrophic, mesotrophic and oligotrophic). Results for 3 cruises in 3 seasons (Eumeli 2, winter 1991; Eumeli 3, autumn 1991; Eumeli 4, spring 1992) are given for each size class in terms of taxonomic composition, density and biomass. The benthic communities did not exhibit evidence of seasonal variation, but there were substantial differences in the quantitative structure of the metazoan communities between the 3 sites. Total metazoan density and biomass, as well as density and biomass of each size class, decreased... |
| Tipo: Text |
Palavras-chave: Deep sea; Tropical Atlantic; Meiofauna; Macrofauna; Megafauna; Taxonomic composition; Density; Biomass; Environmental conditions. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00000/10519/7602.pdf |
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| Caumette, P. |
| In the deepest parts of the estuarine region of Ebrie Lagoon (Abidjan Africa, (5 degree N, 4 degree W) stratified conditions have been observed during the rainy season (May to Nov.), owing to salinity differences between oxic and anoxic layers. At the interface, 3-4 m depth, phototrophic bacteria (Chromatium, Chlorobium and Pelodictyon ) developed, forming a brown layer due to their different pigments. Their production has been estimated at 41% of the total photosynthetic production during high stratification (Sep. 1981) and their biomass was used by the copepod population for 40 to 60% of its diet. During the dry season, the water column became homogeneous and oxygen was detected to 6m depth. The brown layer of phototrophic bacteria disappeared, as well... |
| Tipo: Text |
Palavras-chave: Chlorobium; Chromatium; Primary production; Photosynthesis; Estuaries; Seasonal variations; Plankton; Stratification; Vertical distribution; Bacteria; Coastal lagoons; Trophic relationships; Biomass. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-957.pdf |
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| Herlory, Olivier; Blanchard, G; Planche, S; Huet, V; Richard, Pierre. |
| Many scientists consider that the top centimetre of the sediment on intertidal mudflats contains the photosynthetic competent biomass (PCB). Part of this biomass migrates upward to the surface of the sediment during diurnal emersion periods to form a temporary biofilm: the photosynthetic active biomass (PAB). The present study tests the hypothesis that the size of the biofilm (PAB) is functionally dependent on PCB. Therefore, we have plotted PAB as a function of PCB for a range of different environmental conditions: 3 seasons and 5 tidal situations, representing a total of 600 cores. This investigation points out that, in spring and autumn, there was a simple linear relationship between PAB and PCB, thus indicating that the maximum size of the biofilm... |
| Tipo: Text |
Palavras-chave: Functional relationship; Biofilm; Biomass; Intertidal mudflat; Microphytobenthos. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-3622.pdf |
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| Migne, A; Davoult, D. |
| Because of strong tidal currents, the bottom of the Dover Strait consists of coarse sediment which is colonized by a pebble community. A quantitative study, based on 0.1 m(2) quadrat samples taken by divers, was conducted on this community to establish the richness of benthic macrofauna (in terms of biomass and diversity) and to provide conclusive data on global community structure (spatial and temporal heterogeneity, trophic structure). Eight samples were taken between June 1992 and June 1993, eight replicates being taken on each sampling visit. One hundred and one species were identified, in 10 zoological groups, and a mean biomass of 281 g.m(-2) (ash free dry weight) was calculated. The Shannon diversity index was low (H' = 1.24) because of the strong... |
| Tipo: Text |
Palavras-chave: Macrobenthos; Biomass; Trophic structure; Diversity; Spatial heterogeneity. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20409/18076.pdf |
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| Leclerc, Jean-charles; Riera, Pascal; Laurans, Martial; Leroux, Cedric; Leveque, Laurent; Davoult, Dominique. |
| Worldwide kelp forests have been the focus of several studies concerning ecosystems dysfunction in the past decades. Multifactorial kelp threats have been described and include deforestation due to human impact, cascading effects and climate change. Here, we compared community and trophic structure in two contrasting kelp forests off the coasts of Brittany. One has been harvested five years before sampling and shelters abundant omnivorous predators, almost absent from the other, which has been treated as preserved from kelp harvest. δ15N analyses conducted on the overall communities were linked to the tropho-functional structure of different strata featuring these forests (stipe and holdfast of canopy kelp and rock). Our results yielded site-to-site... |
| Tipo: Text |
Palavras-chave: Laminaria hyperborea; Community cascade; Stable isotopes; Biomass; Suspension-feeders; Omnivorous predators. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00226/33747/32161.pdf |
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| Gobert, S; Kyramarios, M; Lepoint, G; Pergent-martini, C; Bouquegneau, Jm. |
| The biometric parameters (shoot density, length and width of leaves, leaf and epiphyte biomasses, leaf surface) of the P. oceanica meadow present a significant spatial variability at the mesoscale level (100m(2)). All the parameters studied, excepting the number of leaves, decrease according to the depth. The horizontal spatial variations (centrifuge and centripetal distributions) reach a maximum in the shallower areas. The analysis of the microstructures (m(2)) of the meadow has not allowed a relationship to be established between the spatial variations of the biometric parameters and the environmental factors in the sediment (pH, water and organic matter content, red-ox potential, nutrient content). The heterogeneity of the meadow in the Revellata Bay... |
| Tipo: Text |
Palavras-chave: Posidonia oceanica; Distribution spatiale; Biomasse; Sédiment; Phanérogame; Méditerranée; Posidonia oceanica; Spatial distribution; Biomass; Sediment; Seagrass; Mediterranean Sea. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00322/43277/43009.pdf |
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| Wasof, Safaa; Lenoir, Jonathan; Hattab, Tarek; Jamoneau, Aurelien; Gallet-moron, Emilie; Ampoorter, Evy; Saguez, Robert; Bennsadek, Lamine; Bertrand, Romain; Valdes, Alicia; Verheyen, Kris; Decocq, Guillaume. |
| Questions How does plant community diversity influence variation in plant biomass? There are two competing hypotheses: the ‘biomass‐ratio hypothesis’, where biomass is influenced by the abundance and traits of the most dominant species, and the ‘diversity hypothesis’, where the diversity of organisms influences biomass through mechanisms such as niche complementarity. However, no studies have tested which one of these two hypotheses better explains the variation in plant biomass in the forest understorey. Location Temperate deciduous forests in Northern France. Methods For the forest understorey, we assessed species diversity and biomass as well as soil and light conditions in 133 forest plots of 100m² each. Using mixed‐effect models and after controlling... |
| Tipo: Text |
Palavras-chave: Biodiversity; Biomass; Biomass ratio hypothesis; Forest understorey; Functional diversity; Ivy; Phylogeny; Production. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00433/54441/55799.pdf |
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| Quevedo, M; Anadon, R. |
| Microzooplankton abundance, biomass and composition were investigated in the coastal waters of Asturias (southern Bay of Biscay) in May 1996. Abundance ranged from 0.7 x 10(3) to 8.5 x 10(3) cell.L-1 The protists community was dominated by aloricate ciliates averaging 82 % of microheterotrophs. Small aloricate ciliates, below 20 mu m in size, contributed 63 % to total ciliate abundance. Carbon biomass ranged from 2.4 to 15.4 mgC.m(-3), averaging 23 % of phytoplankton biomass. Aloricate ciliates were also the dominant component of biomass (56.2 %), but the importance of copepod nauplii increased in terms of carbon, averaging 28.5 % of total biomass. Microzooplankton biomass was significantly correlated with Chi a concentration in the water column.... |
| Tipo: Text |
Palavras-chave: Microzooplancton; Ciliés; Biomasse; Broutage; Golfe de Gascogne; Microzooplankton; Ciliates; Biomass; Grazing; Southern Bay of Biscay. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00324/43564/44061.pdf |
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| Bodoy, A; Geiaron, P; Garnier, Jacqueline; Heurtebise, S. |
| Two different biomasses (100 g multiplied by m super(-2) and 1 kg multiplied by m super(-2)) of oysters were put in identical sea-water ponds, thus leading to different trophic conditions, corresponding to rearing techniques. Changes in growth, biochemical composition and sexual maturation were recorded for two age groups. The first one included 9 month-old oysters and the second one 21 month-old oysters, at the beginning of the experiment. For both age groups, significant differences were observed in growth and biochemical composition. Lipids were accumulated faster for the lower biomass. However, the only difference concerning glycogen was observed on the older oysters. They showed a peak at the lowest biomass and a decrease at the larger biomass. Sexual... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Bivalvia; Sea water; Oyster culture; Glycogen; Age; Chemical composition; Lipids; Biochemistry; Sexual maturity; Rearing; Pond culture; Biomass; Growth; Density. |
| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/1992/acte-916.pdf |
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| Araújo, Rita; Vázquez Calderón, Fatima; Sánchez López, Javier; Azevedo, Isabel Costa; Bruhn, Annette; Fluch, Silvia; Garcia Tasende, Manuel; Ghaderiardakani, Fatemeh; Ilmjärv, Tanel; Laurans, Martial; Mac Monagail, Micheal; Mangini, Silvio; Peteiro, César; Rebours, Céline; Stefansson, Tryggvi; Ullmann, Jörg. |
| The EU Bioeconomy Strategy aims to support the sustainable growth and development of the EU bio-based sectors while creating jobs, innovation and services. Despite the recognized potential of the algae biomass value chain, significant knowledge gaps still exist regarding the dimension, capability, organization and structure of the algae production in Europe. This study presents and analyses the results of a comprehensive mapping and detailed characterization of the algae production at the European scale, encompassing macroalgae, microalgae, and the cyanobacteria Spirulina. This work mapped 447 algae and Spirulina production units spread between 23 countries, which represents an important addition to the reported number of algae producing countries. More... |
| Tipo: Text |
Palavras-chave: Blue growth; Seaweed; Bioeconomy; Biomass; Production; Algae. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00677/78923/81291.pdf |
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| Registros recuperados: 473 | |
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