semiarid ecosystem
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Trees ◽  
2021 ◽  
Author(s):  
Eduardo Chimal-Sánchez ◽  
Noé Manuel Montaño ◽  
Sara Lucía Camargo-Ricalde ◽  
Rosalva García-Sánchez ◽  
Laura Verónica Hernández Cuevas

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2402
Author(s):  
Fernando Morgado ◽  
Ruy M. A. L. Santos ◽  
Daniela Sampaio ◽  
Luiz Drude de Lacerda ◽  
Amadeu M. V. M. Soares ◽  
...  

Due to global warming, in the northeastern semiarid coastal regions of Brazil, regional and global drivers are responsible for decreasing continental runoff and increasing estuarine water residence time, which promotes a greater mobilization of bioavailable mercury (Hg) and allows increasing fluxes and/or bioavailability of this toxic trace element and an acceleration of biogeochemical transformation of Hg. In this work, an application of dendrochemistry analysis (annular tree rings analysis) was developed for the reconstruction of the historical pattern of mercury contamination in a contaminated area, quantifying chronological Hg contamination trends in a tropical semiarid ecosystem (Ceará River Estuary, northeastern coast of Brazil) through registration of mercury concentration on growth rings in specimens of Rhizophora mangle L. and using the assessment in sediments as a support for the comparison of profiles of contamination. The comparison with sediments from the same place lends credibility to this type of analysis, as well as the relationship to the historical profile of contamination in the region, when compared with local data about industries and ecological situation of sampling sites. In order to evaluate the consequences of the described increase in Hg bioavailability and bioaccumulation in aquatic biota, and to assess the biological significance of Hg concentrations in sediments to fish and wildlife, muscle and liver from a bioindicator fish species, S. testudineus, were also analyzed. The results of this work reinforce the indicators previously described in the semiarid NE region of Brazil, which showed that global climate change and some anthropogenic factors are key drivers of Hg exposure and biomagnification for wildlife and humans. Considering the Hg concentration present in the top layers of sediment (~20 cm around 15 to 20 years) with the outer layers in the tree ring cores and in the sediment’s cores from Pacoti estuary and the Ceará estuary, overall the data indicate an increase in mercury in recent years in the Hg surface sediments, especially associated with the fine sediment fraction, mainly due to the increased capacity of small particles to adsorb Hg. There was revealed a positive and significant correlation (p < 0.05) between Hg trends in sediments and Hg trends in annular tree rings. This shared Hg pattern reflects local environmental conditions. The Hg concentration values in S. testudineus from both study areas are not restrictive to human consumption, being below the legislated European limit for Hg in foodstuffs. The results from S. testudineus muscles analysis suggest a significant and linear increase in Hg burden with increasing fish length, indicating that the specimens are accumulating Hg as they grow. The results from both rivers show an increase in BSAF with fish growth. The [Hg] liver/[Hg] muscles ratio >1, which indicates that the S. testudineus from both study areas are experiencing an increase in Hg bioavailability. Possible climate-induced shifts in these aquatic systems processes are inducing a greater mobilization of bioavailable Hg, which could allow an acceleration of the biogeochemical transformation of Hg.


Ecology ◽  
2021 ◽  
Author(s):  
Jennifer L. Funk ◽  
Julie E. Larson ◽  
Joni Ricks‐Oddie

2021 ◽  
Vol 51 ◽  
pp. e1370
Author(s):  
Sara Lucía Camargo-Ricalde ◽  
Noé Manuel Montaño ◽  
Susana A. Montaño-Arias ◽  
Claudia Janette De la Rosa-Mera ◽  
Eduardo Chimal-Sánchez

Background: Arbuscular mycorrhizal fungi (AMF) and biocrusts (BC), occur inside and outside Mimosa luisana resource islands (M. luisana-RI) at the Tehuacán-Cuicatlán Valley, Puebla-Oaxaca, Mexico. Objectives: To determine: 1) Whether there are AMF within biocrusts, 2) The abundance and richness of AMF, and 3) The potential of AMF propagation in BC and soil below BC inside (BC-RI, soil-BC-RI) and outside (BC-ORI, soil-BC-ORI) M. luisana-RI, and open areas (OA), in the rainy (September 2011) and dry (May 2012) seasons. Methods: AMF were extracted of biocrusts and soil samples collected inside and outside M. luisana-RI and OA, in both seasons. Spore abundance and species richness, as well as potential propagation of AMF were determined in laboratory and greenhouse. Results and Conclusions: Biocrusts inside and outside M. luisana-RI form reservoirs of AMF spores and species richness (12 spp.), and act as “shields” protecting AMF compared with OA (5 spp.). Seasonal changes in the AMF composition within the biocrusts and the soil suggest that the availability of water drives AMF assemblages. The AM fungal spores in BC-RI and BC-ORI have a high potential of propagation; however, the BC-ORI by buffering the loss of AMF in soil-BC-ORI, they form mycorrhizal inocula within the soil.


Author(s):  
Justine E.C. Missik ◽  
Heping Liu ◽  
Zhongming Gao ◽  
Maoyi Huang ◽  
Xingyuan Chen ◽  
...  

Author(s):  
Andri Wibowo

Paddy field is an old agriculture practice that very common especially in Asia. The earliest paddy field found dated back to 4330 BC. Most paddy fields in the world are having rectangular shapes. Whereas, in Flores island, indigenous people have developed a spider web or circular paddy field instead of regular rectangular shape and this driven by culture and local wisdom. In here, the objectives of this study are to assess the characteristic, ecology and fertility of circular paddy field compared to common rectangular shape. Fertility values were assessed using Landsat 8 remote sensing with RGB combination of NIR, SWIR 1 and blue. The study site was paddy field within Flores island. The result shows that spider web paddy field appeared in many sizes, number, altitude, ecosystem and terrain. Remote sensing result confirms that the fertility of circular paddy field is similar to the rectangular shape. Likewise, circular field has higher NDVI than rectangular field. Considering semiarid environment, limited labor and resources in Flores island, circular paddy field shape can allow the use of pivot irrigation that more efficient.


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