Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Relationship between bio-optical characteristics and photoinhibition of phytoplankton

15 páginas, 5 figuras, 2 tablas.The relationship between the bio-optical properties of different microalgae and photoinhibition after short-term exposure (15 and 30 min) to solar radiation was analyzed. Photoinhibition was determined as the decrease in oxygen production and in the in vivo-induced chlorophyll fluorescence. Microalgae with different chlorophyll concentrations, cell size and volume were used. Both photoinhibition and recovery of oxygen production and quantum yield were higher after 30 than after 15 min exposure to solar radiation. Photoinhibition was reduced when UV-A and UV-B radiations were eliminated from the solar radiation. The decrease of effective quantum yield and oxygen production was not dependent on cell size, biovolume or chlorophyll concentration in the algal cultures. It was, however, related to the bio-optical property of the cultures, manifested as the specific attenuation coefficient (Kc). As a general response, the inhibition of effective quantum yield slightly decreased with the increase in Kc. Recovery of yield and oxygen production in darkness after exposure to solar radiation was also clearly related to Kc. The relation between the recovery of the yield and Kc followed a parabolic function. It was also found that the recovery of the inhibition of the yield was higher in phytoplankton with active xanthophyll cycle but that it was not dependent on the concentration of total carotenoids.This work was financed by the Spanish Ministry of Education and Science project AMB 94-0684 CO2 to F.L.F. and L.M.L, by the Acción Integrada Hispano-Alemana 133-B to F.L.F. and D.-P.H., by DADD (322-AI-e-dr) to D.P.-H. and by the European Union (Environment programme, ENV-5V-CT94-0425; DG XII)to D.-P.H.Peer reviewe

Relationship between bio-optical characteristics and photoinhibition of phytoplankton

15 páginas, 5 figuras, 2 tablas.The relationship between the bio-optical properties of different microalgae and photoinhibition after short-term exposure (15 and 30 min) to solar radiation was analyzed. Photoinhibition was determined as the decrease in oxygen production and in the in vivo-induced chlorophyll fluorescence. Microalgae with different chlorophyll concentrations, cell size and volume were used. Both photoinhibition and recovery of oxygen production and quantum yield were higher after 30 than after 15 min exposure to solar radiation. Photoinhibition was reduced when UV-A and UV-B radiations were eliminated from the solar radiation. The decrease of effective quantum yield and oxygen production was not dependent on cell size, biovolume or chlorophyll concentration in the algal cultures. It was, however, related to the bio-optical property of the cultures, manifested as the specific attenuation coefficient (Kc). As a general response, the inhibition of effective quantum yield slightly decreased with the increase in Kc. Recovery of yield and oxygen production in darkness after exposure to solar radiation was also clearly related to Kc. The relation between the recovery of the yield and Kc followed a parabolic function. It was also found that the recovery of the inhibition of the yield was higher in phytoplankton with active xanthophyll cycle but that it was not dependent on the concentration of total carotenoids.This work was financed by the Spanish Ministry of Education and Science project AMB 94-0684 CO2 to F.L.F. and L.M.L, by the Acción Integrada Hispano-Alemana 133-B to F.L.F. and D.-P.H., by DADD (322-AI-e-dr) to D.P.-H. and by the European Union (Environment programme, ENV-5V-CT94-0425; DG XII)to D.-P.H.Peer reviewe