scholarly journals Sedimentação de Longo e Curto Período na Lagoa dos Patos, Sul do Brasil

2006 ◽  
Vol 33 (2) ◽  
pp. 79 ◽  
Author(s):  
ELÍRIO TOLDO JR ◽  
SERGIO DILLENBURG ◽  
IRAN CORRÊA ◽  
LUIZ ALMEIDA ◽  
JAIR WESCHENFELDER ◽  
...  
Keyword(s):  
Coastal Plain ◽  
Average Rate ◽  
Stratigraphic Correlation ◽  
Sedimentation Rates ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Short Term ◽  
European Colonization ◽  
Reflecting Surface

Lagoa dos Patos in southern Brazil is part of the largest lagoonal system in South America. The Holocene lagoonal sediments of the Lagoa dos Patos, mostly muds, have an average thickness of about 6 m as determined by 297 km of 7.0 kHz echograms. Holocene muddy sedimentation developed over a probable Upper Pleistocene coastal plain, whose surface has a subbottom reflector that could not be penetrated by the energy of a 7.0 kHz seismic wave. The characteristics of this reflecting surface suggest indurated Pleistocene muds and/or sediments that are coarser than the overlying muddy deposits of Holocene lagoon. Based on stratigraphic correlation and the local sea level curve, we estimate that Holocene sedimentation started about 8.0 ka ago. This yields an average deposition rate of 0.75 mm/yr. A broadly comparable average rate of 0.52 ± mm/yr was obtained for cored intervals between 14C samples from the upper part of these muddy Holocene lagoon deposits. These long-term sedimentation rates are much slower than rates based on two determinations of 210Pb for surface muds deposits in the last 150 years, which yielded values of 3.5 and 8.3 mm/yr. Quite possibly the high short-term rates may be the result of more rapid lagoonal sedimentation related to deforestation of the watershed of the lagoon and other impact types related with human activities during the 150 years of European colonization in the Rio Grande do Sul state. Also, the aim of this study is to identify present and possible future environmental problems related with high lagoonal sedimentation rates such as the water quality, port dredge and the presence of mud deposits on the oceanic beach.

Molecular Detection of Trypanosoma kaiowa in Tabanus triangulum (Diptera: Tabanidae) from the Coastal Plain of Rio Grande do Sul, Southern Brazil

2021 ◽  
Author(s):  
Gratchela D. Rodrigues ◽  
Eduardo Blodorn ◽  
Ândrio Zafalon-Silva ◽  
William Domingues ◽  
Roberta Marques ◽  
...  
Keyword(s):  
Coastal Plain ◽  
Molecular Detection ◽  
Rio Grande ◽  
Southern Brazil ◽  
Rio Grande Do Sul

scholarly journals Long- to short-term denudation rates in the southern Apennines: geomorphological markers and chronological constraints

2011 ◽  
Vol 62 (1) ◽  
pp. 27-41 ◽  
Author(s):  
Dario Gioia ◽  
Claudio Martino ◽  
Marcello Schiattarella
Keyword(s):  
Sediment Accumulation ◽  
Radiometric Dating ◽  
Sedimentation Rates ◽  
Southern Apennines ◽  
Short Term ◽  
Small Catchment ◽  
Fluvial Terraces ◽  
Denudation Rates ◽  
Land Surfaces

Long- to short-term denudation rates in the southern Apennines: geomorphological markers and chronological constraints Age constraints of geomorphological markers and consequent estimates of long- to short-term denudation rates from southern Italy are given here. Geomorphic analysis of the valley of the Tanagro River combined with apatite fission track data and radiometric dating provided useful information on the ages and evolution of some significant morphotectonic markers such as regional planated landscapes, erosional land surfaces and fluvial terraces. Reconstruction of paleotopography and estimation of the eroded volumes were perfomed starting from the plano-altimetric distribution of several orders of erosional land surfaces surveyed in the study area. Additional data about denudation rates related to the recent and/or active geomorphological system have been obtained by estimating the amount of suspended sediment yield at the outlet of some catchments using empirical relationships based on the hierarchical arrangement of the drainage network. Denudation rates obtained through these methods have been compared with the sedimentation rates calculated for two adjacent basins (the Pantano di San Gregorio and the Vallo di Diano), on the basis of published tephrochronological constraints. These rates have also been compared with those calculated for the historical sediment accumulation in a small catchment located to the north of the study area, with long-term exhumation data from thermochronometry, and with uplift rates from the study area. Long- and short-term denudation rates are included between 0.1 and 0.2 mm/yr, in good agreement with regional data and long-term sedimentation rates from the Vallo di Diano and the Pantano di San Gregorio Magno basins. On the other hand, higher values of exhumation rates from thermochronometry suggest the existence of past erosional processes faster than the recent and present-day exogenic dismantling. Finally, the comparison between uplift and denudation rates indicates that the fluvial erosion did not match the tectonic uplift during the Quaternary in this sector of the chain. The axial zone of the southern Apennines should therefore be regarded as a landscape in conditions of geomorphological disequilibrium.

ESR dating of Pleistocene mammals and marine shells from the coastal plain of Rio Grande do Sul state, southern Brazil

2014 ◽  
Vol 352 ◽  
pp. 124-134 ◽  
Author(s):  
Renato P. Lopes ◽  
Angela Kinoshita ◽  
Oswaldo Baffa ◽  
Ana Maria Graciano Figueiredo ◽  
Sérgio Rebello Dillenburg ◽  
...  
Keyword(s):  
Coastal Plain ◽  
Rio Grande ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Esr Dating ◽  
Pleistocene Mammals

scholarly journals Rapid retreat of permafrost coastline observed with aerial drone photogrammetry

2019 ◽  
Vol 13 (5) ◽  
pp. 1513-1528 ◽  
Author(s):  
Andrew M. Cunliffe ◽  
George Tanski ◽  
Boris Radosavljevic ◽  
William F. Palmer ◽  
Torsten Sachs ◽  
...  
Keyword(s):  
Coastal Erosion ◽  
Average Rate ◽  
Temporal Frequency ◽  
Shoreline Change ◽  
Yukon Territory ◽  
Aerial Photographs ◽  
The Arctic ◽  
Storm Events ◽  
Short Term

Abstract. Permafrost landscapes are changing around the Arctic in response to climate warming, with coastal erosion being one of the most prominent and hazardous features. Using drone platforms, satellite images, and historic aerial photographs, we observed the rapid retreat of a permafrost coastline on Qikiqtaruk – Herschel Island, Yukon Territory, in the Canadian Beaufort Sea. This coastline is adjacent to a gravel spit accommodating several culturally significant sites and is the logistical base for the Qikiqtaruk – Herschel Island Territorial Park operations. In this study we sought to (i) assess short-term coastal erosion dynamics over fine temporal resolution, (ii) evaluate short-term shoreline change in the context of long-term observations, and (iii) demonstrate the potential of low-cost lightweight unmanned aerial vehicles (“drones”) to inform coastline studies and management decisions. We resurveyed a 500 m permafrost coastal reach at high temporal frequency (seven surveys over 40 d in 2017). Intra-seasonal shoreline changes were related to meteorological and oceanographic variables to understand controls on intra-seasonal erosion patterns. To put our short-term observations into historical context, we combined our analysis of shoreline positions in 2016 and 2017 with historical observations from 1952, 1970, 2000, and 2011. In just the summer of 2017, we observed coastal retreat of 14.5 m, more than 6 times faster than the long-term average rate of 2.2±0.1 m a−1 (1952–2017). Coastline retreat rates exceeded 1.0±0.1 m d−1 over a single 4 d period. Over 40 d, we estimated removal of ca. 0.96 m3 m−1 d−1. These findings highlight the episodic nature of shoreline change and the important role of storm events, which are poorly understood along permafrost coastlines. We found drone surveys combined with image-based modelling yield fine spatial resolution and accurately geolocated observations that are highly suitable to observe intra-seasonal erosion dynamics in rapidly changing Arctic landscapes.

Cas historique de sédimentation du barrage Péligre, Haïti

1982 ◽  
Vol 9 (2) ◽  
pp. 206-223
Author(s):  
M. Frenette ◽  
J. P. Tournier ◽  
T. J. Nzakimuena
Keyword(s):  
Average Rate ◽  
Sedimentation Rates ◽  
Average Increase ◽  
Physical Processes ◽  
Straight Line ◽  
Average Sedimentation Rate ◽  
The Future ◽  
Reservoir Geometry ◽  
Consolidation Effect

The Péligre Dam in Haïti, on the Artibonite River, was built in 1956 for an expected life of about 180 years. Based on sedimentation data collected in 1925 and 1926, the average rate of silting in the reservoir was estimated at 3.45 × 106 m3/year. In 1979, however, an average sedimentation rate of 9.6 × 106 m3/year was established.Systematic observations were undertaken in 1961, 1977, and 1979 to explain the phenomenon and to predict the future rate of silting in the reservoir. The studies led to simulation, by means of a mathematical model, of the processes involved and have permitted reconstruction of the hydro-sedimentological events since 1956 as well as prediction of the future rate of sedimentation.In order to develop a methodology that has widespread applicability for predicting the rate of sedimentation, the main physical processes responsible for the patterns of deposition were used as common denominators: degradation of watershed and rivers, effects of deforestation, urbanisation, and agriculture, effects of flocculation and consolidation, effect of the reservoir geometry, expected sediment inflow, water inflow versus outflow, etc.On the whole, the model indicates very well the acceleration of the silting rate with an average increase of about 18% per year. The study thus shows that the sediment inflow took the form of a quadratic or exponential growth curve instead of a straight line. After 23 years the average silting is three times that of the design. The results show in conclusion how we must be careful in predicting long-term sedimentation rates in a reservoir since the lifetime of the dam is notably reduced. Keywords: erosion, sedimentation, reservoir, lifetime, simulation, degradation, watershed, design.

Cladocera (Crustacea, Branchiopoda) in coastal temporary environments in southern Brazil

Zootaxa ◽  
2019 ◽  
Vol 4701 (5) ◽  
pp. 473-480
Author(s):  
KAROLINE PEREIRA MARTINS ◽  
MAIBY GLORIZE DA SILVA BANDEIRA ◽  
CLEBER PALMA-SILVA ◽  
EDÉLTI FARIA ALBERTONI
Keyword(s):  
Coastal Plain ◽  
Coastal Region ◽  
Rio Grande ◽  
Aquatic Environments ◽  
Species Accumulation Curve ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Accumulation Curve ◽  
Species Accumulation ◽  
Number Of Species

The coastal plain of Rio Grande do Sul state, southern Brazil, presents as characteristic large expanses of wetlands. Some of these environments are of a temporary nature, and thus have a community adapted to periods with water and periods of drought. Among these communities we can highlight the Cladocera, which have the capacity to form structures of dormancy, and due to this adaptation are effective at colonizing these environments. This study aims to identify the Cladocera species present in the temporary aquatic environments of the southern coastal region of Brazil. Samples were collected in 14 temporary aquatic environments using a classical filtering methodology. As results we obtained 64 Cladocera taxa, representing 54% of the total number of species described in Brazil. The number of taxa was high, the species accumulation curve showed a tendency to stabilization, demonstrating that this region possesses a greater richness.

Comparison of Hydrology of Two Atlantic Coastal Plain Forests

2019 ◽  
Vol 62 (6) ◽  
pp. 1509-1529 ◽  
Author(s):  
Devendra M. Amatya ◽  
Thomas M. Williams ◽  
Jami E. Nettles ◽  
Richard W. Skaggs ◽  
Carl C. Trettin
Keyword(s):  
Soil Water ◽  
Water Table ◽  
Coastal Plain ◽  
Atlantic Coastal Plain ◽  
Soil Water Storage ◽  
Coastal Forests ◽  
Short Term ◽  
Atlantic Coastal ◽  
Term Monitoring

Abstract. This article compares the short-term and long-term hydrology of two typical forests in the humid Atlantic Coastal Plain, including a relatively undisturbed forest with natural drainage in South Carolina (SC) and a drained pine plantation in North Carolina (NC), using monitoring and modeling approaches. Highly dynamic outflow (O) from both of these systems is driven by the water table (WT) position, as influenced by rainfall (R) and evapotranspiration (ET). The annual runoff coefficient (ROC) varied from 5% in dry years to 56% in wet years, depending on the soil water storage (SWS), with a significantly higher average value for the NC site despite its deeper WT, on average, than the SC site. Although both sites behaved similarly in extreme climate conditions, the change in SWS above the WT influenced the annual RO, ROC, and ET. The 17-year average annual ET of 1114 mm (R – O, assuming annual balanced SWS) for the SC site was significantly higher (p = 0.014) than the ET of the drained NC site (997 mm) despite the SC site’s lower mean annual R of 1370 mm, compared to 1520 mm for the NC site. This may be due to both the higher potential ET (PET) and soil water-holding capacity of the SC site. The SC site had higher frequency and duration of WT near the surface during winter, deeper summer WT, and higher correlation of annual ET to annual R (r2 = 0.90 vs. 0.15), suggesting that the SC site was often moisture-limited, particularly during the growing season. Most of the streamflow in these systems occurred during winter, with low ET demands. However, summer periods with tropical storms also resulted in large RO events, generally with higher frequency and longer durations at the drained NC site. These results are similar to an earlier short-term comparison with an unstable behavior period at the SC site after Hurricane Hugo (1989). This study highlighted (1) the differences in hydrology between coastal forests drained for silvicultural production and undrained natural forests managed only for restoration, (2) the importance of long-term monitoring and the effects of regeneration as well as vegetation management on flow regime, and (3) the application and limitations of two widely used models (MIKESHE and DRAINMOD) in describing the hydrology of these forests. Long-term studies can be a basis for testing new hypotheses on water yield, stormwater management, wetland hydrology, vegetation restoration, bioenergy production, and climate change, in addition to applications of proper models for assessing the eco-hydrologic impacts of land use and climate change on freshwater coastal forests linked with downstream riparian rivers and estuaries affected by tidal fluxes and sea level rise.HighlightsOutflow, driven by water table position on these forest systems, is highly variable, depending on its soil water storage.The hydrologic responses of both forest sites were similar during extreme climatic events or disturbances.Effect of forestry drainage on runoff was obscured by its large interannual differences.Long-term monitoring provides better insights on climate and vegetation management effects on flow regime and model validation Keywords: Drainage, Evapotranspiration, Hydrologic models, Pine forest, Poorly drained soils, Runoff coefficient, Water table.

scholarly journals The conservation status of the tuco-tucos, genus Ctenomys (Rodentia: Ctenomyidae), in southern Brazil

2007 ◽  
Vol 67 (4 suppl) ◽  
pp. 839-847 ◽  
Author(s):  
FA. Fernandes ◽  
GP. Fernández-Stolz ◽  
CM. Lopes ◽  
TRO. Freitas
Keyword(s):  
Conservation Biology ◽  
Coastal Plain ◽  
Conservation Status ◽  
Southeastern Brazil ◽  
Subterranean Rodents ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Ecological Processes ◽  
Risk Of Extinction ◽  
History Of

The goal of conservation biology should be related to the preservation of species and also to the evolutionary and ecological processes that were responsible to form them and that are still acting. We review the conservation status of the species of tuco-tuco (Ctenomys torquatus, C. lami, C. minutus, and C. flamarioni) from southern Brazil, and relate these data to the geological history of a particular area in that region, the Coastal Plain of the States of Rio Grande do Sul and Santa Catarina. The implications of the data on these species from the Southeastern Brazil are also discussed in relation to the evolution and risk of extinction of these subterranean rodents.

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