Wetland dynamics at the transition between humid and semiarid environments of inland Brazil: São Francisco river morphodynamics and implications for the Pandeiros wetland.

Author(s):  
Diego Alves de Oliveira ◽  
Cristina Helena Ribeiro Rocha Augustin ◽  
Trevor Hoey ◽  
Cristina Persano

<p>The presence of wetlands as a result of local fluvial and hydrological conditions constitutes a frequently observed feature of such rivers. Therefore, they are important elements of the basin, because besides functioning as buffer zones for CO<sub>2</sub> and sediments they also house important ecosystems, playing an important role in the control of water circulation. Brazilian wetlands have different typologies and sizes, varying from huge swamplands such as the Pantanal do Mato Grosso, to flooded savannas called “veredas” or oxbow lakes. Their distribution in inland areas depends on the variety of flood pulses mainly linked to seasonality with the presence of distinct dry and wet seasons (Junk et al., 1989). This strong seasonality affects the São Francisco River (SFR), the 4<sup>th</sup> largest river in Brazil, which has frequent marginal lakes and swamps as it passes through five Brazilian states. This research aims to analyze the effect of the variation of the SFR level from 1925 to 2018, on the flow of the Pandeiros River which is one of many tributaries on the left side of SFR and on its wetland (“Pantanal Mineiro”). This wetland is hydrogeomorphologically linked to the SFR and receives water inputs during SFR flood periods. Measurements of the SFR water level performed once daily in the morning were obtained from gauging station n<sup>o</sup> 44200000 belonging to the Companhia de Pesquisa de Recursos Minerais (CPRM) [altitude 445 m; 15°56'57.84"S; 44°52'4.68"W. The hydrological year starts at the end of the dry season on October 1st. Time series analyses (level duration curve, Seasonal Trend Decomposition (STL) of the daily level data, monthly level, mean, maximum, minimum level for each day of the year) were conducted to describe the hydrological regime and to assess temporal changes of the SFR levels and how these affect the magnitude, frequency and duration of flooding of the Pandeiros’s River wetland. Field observations (March 14, 2018) show that when SFR, which is Pandeiro’s base level, reaches a level of 5.0 m this leads to flooding conditions of the Pandeiros River wetland. Over the full period of record (1925-2018) the average level of the SFR was 3.86 m, with a minimum annual average of 2.43 m during the dry season (winter) and maximum of 5.98 m during the wet season (summer), with an average annual range of 3.55 m between both seasons. The SFR was above the 5.0 m threshold flooding level for 20% of the time 1925-2018, which corresponds to an average of 77.8 days of flooding per year in the wetland. The longest period of inundation was 178 days in 1926, when the SFR reached its maximum recorded level, and the shortest was 1 day in 2015, when it reached its minimum. The number of days per year of inundation have decreased over the full record, but that this is mainly due to a significant decrease since 1985. Prior to this, cyclic differences between wetter (1925 and 1985) and drier periods (1925 to 1945, 1945 to 1965) are observed.</p>

2005 ◽  
Vol 21 (4) ◽  
pp. 451-460 ◽  
Author(s):  
Eduardo Jacusiel Miranda ◽  
George L. Vourlitis ◽  
Nicolau Priante Filho ◽  
Pedro Correto Priante ◽  
José Holanda Campelo ◽  
...  

The photosynthetic light response of Amazonian semi-deciduous forest trees of the rain forest–savanna transition near Sinop Mato Grosso, Brazil was measured between July 2000 and September 2003 to test the hypothesis that the photosynthetic capacity of trees acclimated to different growth light environments will decline during the dry season. Maximum photosynthesis (Amax) and stomatal conductance (gmax) were significantly higher during the wet season; however, the physiological response to drought was not a clear function of growth light environment. For some species, such as Psychotria sp. growing in the mid-canopy, internal leaf CO2 concentration (Ci) was >30% lower during the dry season suggesting that declines in Amax were caused in part by stomatal limitations to CO2 diffusion. For other species, such as Brosimum lactescens growing at the top of the canopy, Tovomita schomburgkii growing in the mid-canopy, and Dinizia excelsa growing in the understorey, dry season Ci declined by <20% suggesting that factors independent of CO2 diffusion were more important in limiting Amax. Dry-season declines in gmax appeared to be important for maintaining a more consistent leaf water potential for some species (T. schomburgkii and D. excelsa) but not others (Psychotria sp.). These results indicate that while seasonal drought exerts an important limitation on the physiological capacity of semi-deciduous Amazonian forest trees, the mechanism of this limitation may differ between species.


2016 ◽  
Vol 9 (3) ◽  
pp. 175
Author(s):  
Huda Bachtiar ◽  
Franto Novico ◽  
Fitri Riandini

Model numerik MIKE 21 modul transport sedimen digunakan untuk mengetahui respon pergerakan lumpur Sidoarjo pada saat musim hujan dan musim kemarau dan pengaruh tanggul yang berada di muara Sungai Porong. Data yang digunakan adalah pasang surut muka air laut, kedalaman air, debit sungai, arus dan konsentrasi sedimen. Simulasi dilakukan dengan membuat dua skenario, yaitu pada saat kondisi musim hujan dan pada saat musim kemarau. Hasil simulasi model hidrodinamika di verifikasi dengan data lapangan untuk mendapatkan nilai korelasi. Verifikasi meliputi data muka air dan kecepatan arus baik arah –x maupun –y. Berdasarkan hasil verifikasi didapatkan nilai korelasi muka air sebesar 0.8641 sementara arus bernilai 0.1493 untuk sumbu –x dan 0.1917 untuk sumbu –y. Selanjutnya hasil simulasi model menunjukkan konsentrasi sedimen pada tanggal 27 November 2007 merupakan puncak tertinggi dengan nilai 3.2x10-3 kg/m3 untuk musim hujan sementara untuk musim kemarau konsentrasi sedimen bernilai 0.0x10-3 kg/m3. Kata kunci : Model Numerik, Pergerakan Lumpur, Sungai Porong. Numerical model of MIKE 21 sediment transport module was applied to recognize the response of mud flow respective in rainy and dry season and also to get information of dike effect at the river mouth. Data that used in this simulation was tide, water depth, river discharge, current and sediment concentration. The simulations were created for two scenarios, therefore dry season and wet season. The result of the simulation model verified with observation data to see the correlation value. The verification are covering water level data and current magnitude of –x and –y axis. Based on the verification result, the correlation value of water level has a value 0.8641 meanwhile for the current the correlation value have magnitude 0.1493 of x-axis and 0.1917of y-axis. Moreover, the maximum value of sediment concentration could be seen at November 27th 2007 with 3.2x10-3 kg/m3 at the wet season and 0.0x10-3 kg/m3 for dry season. Keywords: Numerical Model, Mud Movement, Porong River


2020 ◽  
Vol 46 (1) ◽  
pp. e10168
Author(s):  
Lúcia Yamazaki ◽  
Vanessa França Vindica ◽  
Marinêz Isaac Marques ◽  
Leandro Dênis Battirola

Studies on arthropods associated with tropical rainforest canopies contribute to a further understanding of forest canopy community dynamics and their relationship to the structure and function of this ecosystem. This study evaluated arthropod community composition in monodominant Callisthene fasciculata forest canopy throughout the high water and dry periods in the northern region of the Pantanal in Mato Grosso, Brazil, as a part of a project about arboreal canopy arthropods associated with monodominant areas in this region. Sampling was conducted on 12 individuals of C. fasciculata, six from the high-water season (2010) and six from the dry season (2011), using insecticide fogging. A total of 28,197 arthropods were collected. Hymenoptera (the majority being Formicidae), Diptera, Acari, Thysanoptera, Hemiptera and Coleoptera, were the most representative groups. Although the analysis did not show variation in the abundance of individuals between the high water and dry seasons, the arthropod community varied significantly in taxa composition. Opiliones, Embioptera, Ephemeroptera and Scorpiones occurred only during the high-water period, with Polyxenida and Strepsiptera occurring only in the dry season. Thysanoptera was more abundant in the dry season, showing a relationship with the beginning of the C. fasciculata flowering period. In general, the high water and dry seasons maintain distinct communities in this habitat, illustrating how the temporal variation in the phenology of C. fasciculata imposed by the Pantanal’s hydrological regime alters the composition of the associated arthropod communities in the canopy of these monodominant formations in the Pantanal of Mato Grosso.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
P. H. D. Cançado ◽  
J. L. H. Faccini ◽  
H. M. Herrera ◽  
L. E. R. Tavares ◽  
G. M. Mourão ◽  
...  

Feral pigs (S. scrofa) were introduced to the Pantanal region around 200 years ago and the population appears to be in expansion. Its eradication is considered to be impossible. The population of feral pigs in the Pantanal wetlands is currently estimated at one million. Two scientific excursions were organized. The first was conducted during the dry season, when 21 feral pigs were captured and the second was during the wet season, when 23 feral pigs were captured. Ticks were collected and the oviposition and hatching process were studied to confirm the biological success of each tick species. Three tick species were found to be feeding on feral pigs: Amblyomma cajennense, A. parvum, and Ornithodoros rostratus. During the dry season, 178 adult A. cajennense were collected, contrasting with 127 A. cajennense specimens in the wet season. This suggests that the seasonality of these ticks in the Brazilian Pantanal wetlands could be different from other regions. The results indicate that A. parvum and A. cajennense are biologically successful parasites in relation to feral pigs. A. cajennense appears to have adapted to this tick-host relationship, as well as the areas where feral pigs are abundant, and could play a role in the amplification of this tick population.


Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 206
Author(s):  
Camila C. Braun-Cruz ◽  
Hans Mario Tritico ◽  
Renato Leandro Beregula ◽  
Pierre Girard ◽  
Peter Zeilhofer ◽  
...  

This work aims to evaluate the hydrologic changes caused by a small hydropower plant on the watercourse in which it is installed. Since hydrologic research with data of temporal frequencies less than a day is less common than daily measurements, there are few indicators and methodologies capable of treating such records. For this reason, 17 indicators are proposed which describe the magnitude, duration, frequency and rate of changes in hydrologic conditions occurring in a watercourse at a sub-daily frequency. These 17 indicators were used to assess changes in the flow regimes at sub-daily scales across the Itiquira hydroelectric facility in Mato Grosso, Brazil. During the dry season the river was more susceptible to hydroelectric operations than during the wet season. Eighty-eight percent of the proposed indicators were significantly altered during the dry season compared to 71% during the rainy season. In addition to the number of indicators that changed between the seasons, the magnitude of the change was different. During the dry season, 53% of the magnitudes of the proposed indicators were classified as having a high magnitude of change, while in the rainy season only 6% of the indicators were characterized as having a high magnitude of change.


2014 ◽  
Vol 18 (12) ◽  
pp. 5377-5397 ◽  
Author(s):  
K. E. Clark ◽  
M. A. Torres ◽  
A. J. West ◽  
R. G. Hilton ◽  
M. New ◽  
...  

Abstract. The hydrology of tropical mountain catchments plays a central role in ecological function, geochemical and biogeochemical cycles, erosion and sediment production, and water supply in globally important environments. There have been few studies quantifying the seasonal and annual water budgets in the montane tropics, particularly in cloud forests. We investigated the water balance and hydrologic regime of the Kosñipata catchment (basin area: 164.4 km2) over the period 2010–2011. The catchment spans over 2500 m in elevation in the eastern Peruvian Andes and is dominated by tropical montane cloud forest with some high-elevation puna grasslands. Catchment-wide rainfall was 3112 ± 414 mm yr−1, calculated by calibrating Tropical Rainfall Measuring Mission (TRMM) 3B43 rainfall with rainfall data from nine meteorological stations in the catchment. Cloud water input to streamflow was 316 ± 116 mm yr−1 (9.2% of total inputs), calculated from an isotopic mixing model using deuterium excess (Dxs) and δD of waters. Field streamflow was measured in 2010 by recording height and calibrating to discharge. River run-off was estimated to be 2796 ± 126 mm yr−1. Actual evapotranspiration (AET) was 688 ± 138 mm yr−1, determined using the Priestley and Taylor–Jet Propulsion Laboratory (PT-JPL) model. The overall water budget was balanced within 1.6 ± 13.7%. Relationships between monthly rainfall and river run-off follow an anticlockwise hysteresis through the year, with a persistence of high run-off after the end of the wet season. The size of the soil and shallow groundwater reservoir is most likely insufficient to explain sustained dry-season flow. Thus, the observed hysteresis in rainfall–run-off relationships is best explained by sustained groundwater flow in the dry season, which is consistent with the water isotope results that suggest persistent wet-season sources to streamflow throughout the year. These results demonstrate the importance of transient groundwater storage in stabilising the annual hydrograph in this region of the Andes.


2014 ◽  
Vol 11 (7) ◽  
pp. 8603-8650 ◽  
Author(s):  
K. E. Clark ◽  
M. A. Torres ◽  
A. J. West ◽  
R. G. Hilton ◽  
M. New ◽  
...  

Abstract. The hydrology of tropical mountain catchments plays a central role in ecological function, geochemical and biogeochemical cycles, erosion and sediment production, and water supply in globally important environments. There have been few studies quantifying the seasonal and annual water budgets in the montane tropics, particularly in cloud forests. We investigated the water balance and hydrologic regime of the Kosñipata Valley (basin area 164.4 km2) over the period 2010–2011. The valley spans over 2500 m in elevation in the eastern Peruvian Andes and is dominated by tropical montane cloud forest with some high elevation puna grasslands. Catchment wide rainfall was 3028 ± 414 mm yr−1, calculated by calibrating Tropical Rainfall Measuring Mission (TRMM) 3B43 rainfall with rainfall data from 9 meteorological stations in the valley. Cloud water input to streamflow was 316 ± 116 mm yr−1 (~10% of total inputs), calculated from an isotopic mixing model using deuterium excess (Dxs) and δD of waters. Field stream flow was measured in 2010 by recording height and calibrating to discharge. River runoff was estimated to be 2796 ± 126 mm yr−1. Actual evapotranspiration (AET) was 909 ± 182 mm yr−1, determined using the Priestley and Taylor – Jet Propulsion Laboratory (PT-JPL) model. The overall water budget was balanced within 10%. Relationships between monthly rainfall and river runoff follow an anti-clockwise hysteresis through the year, with a persistence of high runoff after the end of the wet season. The size of the soil- and shallow ground-water reservoir is most likely insufficient to explain sustained dry season flow. Thus, the observed hysteresis in rainfall-runoff relationships is best explained by sustained groundwater flow in the dry season, which is consistent with the water isotope results that suggest persistent wet season sources to stream flow throughout the year. These results demonstrate the importance of transient groundwater storage in stabilizing the annual hydrograph in this region of the Andes.


BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xue Zhu ◽  
Jiyue Qin ◽  
Chongyang Tan ◽  
Kang Ning

Abstract Background Most studies investigating human gut microbiome dynamics are conducted on humans living in an urban setting. However, few studies have researched the gut microbiome of the populations living traditional lifestyles. These understudied populations are arguably better subjects in answering human-gut microbiome evolution because of their lower exposure to antibiotics and higher dependence on natural resources. Hadza hunter-gatherers in Tanzania have exhibited high biodiversity and seasonal patterns in their gut microbiome composition at the family level, where some taxa disappear in one season and reappear later. Such seasonal changes have been profiled, but the nucleotide changes remain unexplored at the genome level. Thus, it is still elusive how microbial communities change with seasonal changes at the genome level. Results In this study, we performed a strain-level single nucleotide polymorphism (SNP) analysis on 40 Hadza fecal metagenome samples spanning three seasons. With more SNP presented in the wet season, eight prevalent species have significant SNP enrichment with the increasing number of SNP calling by VarScan2, among which only three species have relatively high abundances. Eighty-three genes have the most SNP distributions between the wet season and dry season. Many of these genes are derived from Ruminococcus obeum, and mainly participated in metabolic pathways including carbon metabolism, pyruvate metabolism, and glycolysis. Conclusions Eight prevalent species have significant SNP enrichments with the increasing number of SNP, among which only Eubacterium biforme, Eubacterium hallii and Ruminococcus obeum have relatively high species abundances. Many genes in the microbiomes also presented characteristic SNP distributions between the wet season and the dry season. This implies that the seasonal changes might indirectly impact the mutation patterns for specific species and functions for the gut microbiome of the population that lives in traditional lifestyles through changing the diet in wet and dry seasons, indicating the role of these variants in these species’ adaptation to the changing environment and diets.


Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 319
Author(s):  
Cristian Pérez-Granados ◽  
Karl-L. Schuchmann

Climatic conditions represent one of the main constraints that influence avian calling behavior. Here, we monitored the daily calling activity of the Undulated Tinamou (Crypturellus undulatus) and the Chaco Chachalaca (Ortalis canicollis) during the dry and wet seasons in the Brazilian Pantanal. We aimed to assess the effects of climate predictors on the vocal activity of these focal species and evaluate whether these effects may vary among seasons. Air temperature was positively associated with the daily calling activity of both species during the dry season. However, the vocal activity of both species was unrelated to air temperature during the wet season, when higher temperatures occur. Daily rainfall was positively related to the daily calling activity of both species during the dry season, when rainfall events are scarce and seem to act as a trigger for breeding phenology of the focal species. Nonetheless, air temperature was negatively associated with the daily calling activity of the Undulated Tinamou during the wet season, when rainfall was abundant. This study improves our understanding of the vocal behavior of tropical birds and their relationships with climate, but further research is needed to elucidate the mechanisms behind the associations found in our study.


Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 320
Author(s):  
Qianyao Si ◽  
Mary G. Lusk ◽  
Patrick W. Inglett

Stormwater infiltration basins (SIBs) are vegetated depressions that collect stormwater and allow it to infiltrate to underlying groundwater. Their pollutant removal efficiency is affected by the properties of the soils in which they are constructed. We assessed the soil nitrogen (N) cycle processes that produce and remove inorganic N in two urban SIBs, with the goal of further understanding the mechanisms that control N removal efficiency. We measured net N mineralization, nitrification, and potential denitrification in wet and dry seasons along a sedimentation gradient in two SIBs in the subtropical Tampa, Florida urban area. Net N mineralization was higher in the wet season than in the dry season; however, nitrification was higher in the dry season, providing a pool of highly mobile nitrate that would be susceptible to leaching during periodic dry season storms or with the onset of the following wet season. Denitrification decreased along the sediment gradient from the runoff inlet zone (up to 5.2 μg N/g h) to the outermost zone (up to 3.5 μg N/g h), providing significant spatial variation in inorganic N removal for the SIBs. Sediment accumulating around the inflow areas likely provided a carbon source, as well as maintained stable anaerobic conditions, which would enhance N removal.


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