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| Chassot, Emmanuel; Bonhommeau, Sylvain; Dulvy, Nicholas K.; Melin, Frederic; Watson, Reg; Gascuel, Didier; Le Pape, Olivier. |
| Primary production must constrain the amount of fish and invertebrates available to expanding fisheries; however the degree of limitation has only been demonstrated at regional scales to date. Here we show that phytoplanktonic primary production, estimated from an ocean-colour satellite (SeaWiFS), is related to global fisheries catches at the scale of Large Marine Ecosystems, while accounting for temperature and ecological factors such as ecosystem size and type, species richness, animal body size, and the degree and nature of fisheries exploitation. Indeed we show that global fisheries catches since 1950 have been increasingly constrained by the amount of primary production. The primary production appropriated by current global fisheries is 17-112% higher... |
| Tipo: Text |
Palavras-chave: Bottom-up; Large Marine Ecosystem; Quantile regression; Sustainable fishing. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00002/11294/7836.pdf |
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| Heath, Michael R.; Speirs, Douglas C.; Steele, John H.. |
| Climate fluctuations and human exploitation are causing global changes in nutrient enrichment of terrestrial and aquatic ecosystems and declining abundances of apex predators. The resulting trophic cascades have had profound effects on food webs, leading to significant economic and societal consequences. However, the strength of cascades-that is the extent to which a disturbance is diminished as it propagates through a food web-varies widely between ecosystems, and there is no formal theory as to why this should be so. Some food chain models reproduce cascade effects seen in nature, but to what extent is this dependent on their formulation? We show that inclusion of processes represented mathematically as density-dependent regulation of either consumer... |
| Tipo: Text |
Palavras-chave: Bottom-up; Density dependence; Food chain; Food web; Harvesting; Model; Predator-prey; Simulation; Top-down. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00171/28249/26505.pdf |
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| Thingstad, T Frede; Browman, Howard. |
| In linear food chains, resource and predator control produce positive and negative correlations, respectively, between biomass at adjacent trophic levels. These simple relationships become more complex in food webs that contain alternative food chains of unequal lengths. We have used a “minimum” model for the microbial part of the pelagic food web that has three such food chains connecting free mineral nutrients to copepods: via diatoms, autotrophic flagellates, and heterotrophic bacteria. Trophic cascades from copepods strongly modulates the balance between the three pathways and, therefore, the functionality of the microbial food web in services such as food production for higher trophic levels, DOM degradation, and ocean carbon sequestration. The result... |
| Tipo: Text |
Palavras-chave: Arctic Ocean; Bottom-up; Mediterranean Sea; Microbial food web; Nansen Legacy; Top down; Trophic cascades. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00627/73958/73312.pdf |
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| Saraux, Claire; Van Beveren, Elisabeth; Brosset, Pablo; Queiros, Quentin; Bourdeix, Jean-herve; Dutto, Gilbert; Gasset, Eric; Jac, Cyrielle; Bonhommeau, Sylvain; Fromentin, Jean-marc. |
| Around 2008, an ecosystem shift occurred in the Gulf of Lions, highlighted by considerable changes in biomass and fish mean weight of its two main small pelagic fish stocks (European anchovy, Engraulis encrasicolus; European sardine, Sardina pilchardus). Surprisingly these changes did not appear to be mediated by a decrease in fish recruitment rates (which remained high) or by a high fishing pressure (exploitation rates being extremely low). Here, we review the current knowledge on the population's dynamics and its potential causes. We used an integrative ecosystem approach exploring alternative hypotheses, ranging from bottom-up to top-down control, not forgetting epizootic diseases. First, the study of multiple population characteristics highlighted a... |
| Tipo: Text |
Palavras-chave: Population dynamics; Top-down; Disease; Zooplankton; Exploited species; Bottom-up. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00427/53861/54903.pdf |
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| CHOVERT,ANGEL D.; ALONSO,MARCELO F.. |
| ABSTRACT In recent years, the majority of economic sectors in Brazil have gone through processes of development and transformation. These processes have led to increases in environmental pollution of all kinds; air pollution being one of the most adverse. The Brazilian transportation sector, which heavily affects the air quality, experienced a significant increase in its vehicle fleet thus provoking larger emissions of pollutant gases, mainly in regions with high population density such as the Metropolitan Region of Porto Alegre (MRPA). Within this research, considering mainly the ozone precursor species and Carbon Monoxide and using the year 2001 as a base year, scenarios are obtained for vehicular emissions of pollutant gases in the MRPA until the year... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Air pollution; Bottom-up; Emission scenarios; Vehicle fleet.. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652017000501971 |
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