| 1. |
- Phillips, Helen R. P., et al.
(författare)
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Global distribution of earthworm diversity
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 366:6464, s. 480-
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Tidskriftsartikel (refereegranskat)abstract
- Soil organisms, including earthworms, are a key component of terrestrial ecosystems. However, little is known about their diversity, their distribution, and the threats affecting them. We compiled a global dataset of sampled earthworm communities from 6928 sites in 57 countries as a basis for predicting patterns in earthworm diversity, abundance, and biomass. We found that local species richness and abundance typically peaked at higher latitudes, displaying patterns opposite to those observed in aboveground organisms. However, high species dissimilarity across tropical locations may cause diversity across the entirety of the tropics to be higher than elsewhere. Climate variables were found to be more important in shaping earthworm communities than soil properties or habitat cover. These findings suggest that climate change may have serious implications for earthworm communities and for the functions they provide.
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| 2. |
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| 3. |
- Brussaard, Lijbert, et al.
(författare)
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Biodiversity and ecosystem functioning in soil
- 1997
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Ingår i: Ambio: a Journal of Human Environment. - 0044-7447. ; 26:8, s. 563-570
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Tidskriftsartikel (refereegranskat)abstract
- We review the current knowledge on biodiversity in soils, its role in ecosystem processes, its importance for human purposes, and its resilience against stress and disturbance. The number of existing species is vastly higher than the number described, even in the macroscopically visible taxa, and biogeographical syntheses are largely lacking. A major effort in taxonomy and the training of a new generation of systematists is imperative. This effort has to be focussed on the groups of soil organisms that, to the best of our knowledge, play key roles in ecosystem functioning. To identify such groups, spheres of influence (SOI) of soil biota - such as the root biota, the shredders of organic matter and the soil bioturbators - are recognized that presumably control ecosystem processes, for example, through interactions with plants. Within those SOI, functional groups of soil organisms are recognized. Research questions of the highest urgency are the assignment of species to functional groups and determining the redundancy of species within functional groups. These priorities follow from the need to address the extent of any loss of functioning in soils, associated with intensive agriculture, forest disturbance, pollution of the environment, and global environmental change. The soil biota considered at present to be most at risk are species-poor functional groups among macrofaunal shredders of organic matter, bioturbators of soil, specialized bacteria like nitrifiers and nitrogen fixers, and fungiforming mycorrhizas. An experimental approach in addressing these research priorities is needed, using longterm and large-scale field experiments and modern methods of geostatistics and geographic information systems.
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| 4. |
- Costa, Denis Duda, et al.
(författare)
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Long-term relationships between climate oscillation and basin-scale hydrological variability during rainy season in eastern Northeast Brazil
- 2018
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Ingår i: Hydrological Sciences Journal. - : Informa UK Limited. - 0262-6667 .- 2150-3435. ; 63:11, s. 1636-1652
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Tidskriftsartikel (refereegranskat)abstract
- The high variability in the hydrological regime of the Eastern Hydrological Region (EHR) of Northeast Brazil often results in floods and droughts, leading to serious socio-economic issues. Therefore, this work aimed to investigate connections between spatiotemporal hydrological variability of the EHR and large-scale climate phenomena. Multivariate statistical techniques were applied to relate climate indices with hydrological variables within two representative river basins in the EHR. The results indicated a multi-annual relationship between the state of the sea surface temperature of the Atlantic and Pacific oceans and anomalous hydrological variability in the basins. In addition, the northern Tropical Atlantic conditions were shown to play an important role in modulating the long-term variability of the hydrological response of the basins, whilst only extreme ENSO anomalies seemed to affect the rainy season. This knowledge is an important step towards long-term prediction of hydrological conditions and contributes to the improvement of water resources planning and management in the EHR.
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| 5. |
- de Brito, Almir Nunes, et al.
(författare)
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Tidal exchange in a choked coastal lagoon : A study of Mundaú Lagoon in northeastern Brazil
- 2018
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Ingår i: Regional Studies in Marine Science. - : Elsevier BV. - 2352-4855. ; 17, s. 133-142
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Tidskriftsartikel (refereegranskat)abstract
- Changes in the inlet morphology of choked coastal lagoons often restrict the water exchange with the sea, making them vulnerable to pollution events and eutrophication processes. In this study, the importance of tides for the water exchange was investigated in Mundaú Lagoon, which is a choked lagoon located in northeastern Brazil that has a very dynamic inlet and channel system. The analysis was carried out for critical scenarios during the dry season when the river flow to the lagoon decreases markedly. The concepts of integrated flushing time and spatially distributed residence time scales were applied using a Lagrangian particle tracking approach coupled with a hydrodynamic model. The flushing time of Mundaú Lagoon was estimated to be 12.6 days during neap tide and 5.7 days during spring tide, including a return flow factor. Employing an e-folding form, the corresponding value was calculated to be 64 and 54 days for particles allowed and not allowed to return to the lagoon, respectively. The spring tides were responsible for the most pronounced water exchange in the Mundaú Lagoon. Different particles release times displayed the effect of the initial tidal conditions on the flushing time; lower exchange times were estimated for releases during ebb tides and spring tides. The integrated estimation of the water exchange when imposing a scenario of most frequent wind conditions indicated a considerable delay caused by this forcing, increasing the flushing time up to 23 days. Another observed effect of the wind was a spatial redistribution of the tidal exchange in the lagoon into different zones with similar residence time.
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| 6. |
- Duda Costa, Denis, et al.
(författare)
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Understanding drought dynamics during dry season in Eastern Northeast Brazil
- 2016
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Ingår i: Frontiers in Earth Science. - : Frontiers Media SA. - 2296-6463. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Eastern Northeast Brazil (ENEB) generally experiences a high variability in precipitation in the dry season, with amplitudes that can overcome 500mm. The understanding of this variability can help in mitigating the socio-economic issues related to the planning and management of water resources this region, which is highly vulnerable to drought. This work aims to assess spatio-temporal variability of precipitation during the dry season and investigate the relationships between climate phenomena and drought events in the ENEB, using univariate (Spearman correlation) and multivariate statistical techniques, such as Principal Component Analysis, Cluster Analysis, and Maximum Covariance Analysis. The results indicate that the variability of precipitation in the dry season can be explained mainly (62%) by local physical conditions and climate conditions have a secondary contribution. Further analysis of the larger anomalous events suggests that the state of Atlantic and Pacific oceans can govern the occurrence of those events, and the conditions of Atlantic Ocean can be considered a potential modulator of anomalous phenomena of precipitation in ENEB.
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| 7. |
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| 8. |
- Nunes, Almir, et al.
(författare)
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Morphological modeling of long-term inlet channel evolution with an application to the Mundaú Lagoon inlet, Brazil
- 2020
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Ingår i: Estuarine, Coastal and Shelf Science. - : Elsevier BV. - 0272-7714. ; 235
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, a morphological model based on the main governing processes of inlet channels was developed for application in long-term simulations, requiring minimum data on forcing and only key information on the inlet geometry. The model considers the balance between the inlet sand transport due to tides and river flows and the longshore transport due to breaking waves. The resulting equations were numerically implemented and validated first through schematic simulations and then through an application to a real inlet. For the schematic simulations, the sediment transport rates in the inlet and alongshore were maintained constant and the behavior during evolution towards equilibrium was investigated and qualitatively assessed. Then, the model was applied to Mundaú Lagoon inlet (Brazil), a natural inlet sheltered by reefs and with a marked seasonality in river runoff. Thus, the model performance was validated for a complex setting over time scales of decades through comparisons with the observed inlet evolution determined from satellite images. The calculated results of inlet channel morphological evolution exhibited satisfactory agreement with observations. The computational efforts were low making the model suitable for long-term simulations where many alternative scenarios may be explored in a probabilistic manner. In conclusion, the developed model yielded robust and reliable simulation results having the potential for use in the assessment of long-term inlet channel evolution.
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| 9. |
- Nunes De Brito Junior, Almir, et al.
(författare)
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A STUDY ON THE WATER EXCHANGE IN MUNDAÚ LAGOON, NORTHEASTERN BRAZIL DURING THE DRY SEASON
- 2017. - 2017
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Ingår i: Proceedings of Coastal Dynamics 2017. ; , s. 1251-1260
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Konferensbidrag (refereegranskat)abstract
- Changes in the inlet morphology of choked coastal lagoons often restrict the water exchange with the sea, making them vulnerable to pollution release and eutrophication processes. In this study, the role of tides for the water exchange was investigated in a choked lagoon for critical scenarios during the low river flow season. Both an integrated and spatially distributed approach were employed using Lagrangian tracking of particles. The spring tides were responsible for the most pronounced water exchange and the spatially distributed approach identified different zones with similar water exchange characteristics. The tide action was primarily limited to the southern portion of the lagoon presenting a zone with rapid exchange times, whereas the other parts involved lower exchange and consequently long renewal times making it a more vulnerable area to different types of pollution releases.
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| 10. |
- Nunes De Brito Junior, Almir, et al.
(författare)
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MORPHOLOGICAL MODELING OF TIDAL INLET EVOLUTION: AN APPLICATION TO MUNDAÚ INLET, BRAZIL
- 2019
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Ingår i: Coastal Sediments 2019. - : WORLD SCIENTIFIC. - 9789811204494
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this study was to develop a morphological model for long-term inlet evolution to be applied using a minimum amount of input data and requiring low computational costs. The model was implemented numerically and then validated for a real inlet application: Mundaú inlet (northeastern Brazil), a dynamic inlet with a marked freshwater seasonality and alongshore sand transport, reduced by reef sheltering. The model performance was verified, over a total period of 11 years, comparing the simulated inlet width with Landsat and Google Earth images. The simulated inlet channel morphology presented a satisfactory agreement with observations. With the low computational costs, the developed model represented a reliable approach with demonstrated potential to be applied in the quantitative assessment of inlet evolution over long time periods.
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