Spatial variation of ostracod (Crustacea, Ostracoda) egg banks in temporary lakes of a tropical flood plain

2021 ◽  
Vol 72 (1) ◽  
pp. 26
Author(s):  
Jonathan Rosa ◽  
Ramiro de Campos ◽  
Koen Martens ◽  
Janet Higuti
Keyword(s):  
Spatial Variation ◽  
Flood Plain ◽  
Resting Eggs ◽  
River Channels ◽  
Aquatic Communities ◽  
Lake Ecosystems ◽  
Flood Plains ◽  
Adverse Conditions ◽  
Egg Banks ◽  
Flood Pulses

Ostracods are microcrustaceans that produce resting eggs under adverse conditions. In this study we evaluated the spatial variation of ostracod resting eggs in different regions of temporary lakes in a Brazilian flood plain. Based on the homogenisation effect of flood pulses on aquatic communities in flood plains, we hypothesised that the composition and abundance of ostracod eggs in the centre of temporary lakes would be similar to those in edge regions. Samples were collected from the centre and edge regions of five temporary lakes. Sediment was oven dried, rehydrated and hatching was monitored in germinating chambers. Twelve ostracod species hatched from the egg banks during our experiments. The abundance and species composition were similar between the two regions of the lakes. Flood events may be responsible for the homogenisation of the egg banks as a result of the connection of lakes with principal river channels. During flooding, water masses powerfully enter lakes and can redistribute sediments. This study shows that egg banks have the potential to contribute to the maintenance of local biodiversity and the resilience of biodiversity of temporary lake ecosystems.

Showing the vegetation cover of flood-plains and river valleys on the Vegetation Map of Kazakhstan and middle Asia

1995 ◽  
pp. 58-66
Author(s):  
N. M. Kalibernova
Keyword(s):  
Plant Communities ◽  
Vegetation Cover ◽  
Flood Plain ◽  
Vegetation Map ◽  
Flood Plains ◽  
Additional Information ◽  
Ground Waters ◽  
The Matrix ◽  
River Valleys ◽  
Former Ussr

The fragment of the legend of the map concerning the vegetation of flood- plains and river-valleys in the subzones of northern and southern deserts is presented in the article. The map is compiled in Department of Vegetspon Geography and Cartography of Komarov Botanical Institute by a large team of botanists-geographers of the former USSR. The nature environments determining the development of vegetation of river-valleys in arid climate are conditioned by the intrazonal factors (alluvial and flood processes) at the background of natural zonal factors. Contrasts of environments and corresponding plant communities manifest themselves first of all. Mineralization of ground waters, salinity of soils, including the alluvial ones, are of essential importance. The practice of vegetation mapping of unstable habitats, to which floodplain landscapes belong, has shown that units of phytocoenological classification is of little use for this purpose. The heterogeneity of vegetation, consisting of short-term unstable serial communities generates a need for typification of space combinations of such phytocoenoses. For this purpose it is convenient to use generalized ecological-dinamic series, including plant communities of all levels within the limits of definite segment of valley. These series are the mapping units on the map. The vegetation of the first terrace is also nessecary to include in a single series with flood-plain vegetation because it has supplementary influence of ground waters. The higher divisions of the legend are based on zonal characters: vegetation of valleys in northern, middle and southern deserts. 13 numbers are used to show the vegetation cover of flood-plains and valleys. Additional 7 numbers are used for the out-of-valley meadow vegetation. The content is enriched by using of the letters by the numbers showing the geographic variants of series and ciphers for combination of series and out-of-series communities. The text legend is supplemented by the matrix (table), showing the subordination of subtitles, zonal position and geographic distribution of divisions. The types of series in the matrix are listed with indication of the main dominant species that gives the additional information on the legend divisions. The author's conclusion is that valley vegetation reveals clearly the zonal features, correlating with zonal (desert) vegetation.

scholarly journals Brief Communication: Analysis of the Fatalities and Socio-Economic Impacts Caused by Hurricane Florence

Geosciences ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 58 ◽  
Author(s):  
Srikanto Paul ◽  
Dawit Ghebreyesus ◽  
Hatim Sharif
Keyword(s):  
Flood Hazard ◽  
Coal Ash ◽  
Flood Plain ◽  
Communication Analysis ◽  
Mortality And Morbidity ◽  
Flood Plains ◽  
The Public ◽  
Hog Manure ◽  
Torrential Rainfall ◽  
Cape Fear

Florence made landfall on the southeastern coast of North Carolina (NC) generating torrential rainfall and severe flooding that led to 53 fatalities in three states (NC, SC, and VA) and $16–$40 billion in damage. Seventy-seven percent (77%) of the fatalities occurred in the rural flood plains of NC with Duplin county reporting a high of eight deaths. Approximately 50% of the total number of hurricane-related fatalities across the three states were vehicle-related. The predominant demographic at risk were males over the age of 50 years. The type of property damage was in line with other major hurricanes and predominantly affected residential structures (93% of the total number of damaged buildings). Florence is among the top 10 costliest hurricanes in U.S. history with approximately 50% of the damage projected as uninsured losses due to residential flooding. The cumulative 5-day rainfall resulted in major flooding along the Cape Fear, Lumberton, and Neuse rivers where many industrial waste sites (hog manure lagoons and coal ash pits) are located. Several of these waste sites located in the flood plain were breached and have likely cross-contaminated the waterways and water treatment operations. The observed extent of the flooding, environmental contamination, and impact to public health caused by Florence will add to the long-term disaster related mortality and morbidity rates and suggests an expansion of the 100-yr flood hazard zone to communicate the expanded risk to the public.

Role of environmental and spatial processes structuring fish assemblages in streams of the eastern Amazon

2018 ◽  
Vol 69 (2) ◽  
pp. 243 ◽  
Author(s):  
N. L. Benone ◽  
R. Ligeiro ◽  
L. Juen ◽  
L. F. A. Montag
Keyword(s):  
Environmental Factors ◽  
Environmental Variables ◽  
Fish Assemblages ◽  
Flood Plain ◽  
Habitat Isolation ◽  
Flood Plains ◽  
Β Diversity ◽  
Flood Period ◽  
Stream Fish Assemblages ◽  
Stream Biota

Considering the increasing importance of analysing spatial structure in ecological studies, the aims of the present study were to test whether fluvial distances and environmental factors are important drivers of the β-diversity of stream fish assemblages, and whether β-diversity is different in distinct hydrological periods. Specimens were sampled at 33 stream sites in the eastern Amazon. Eight environmental variables were measured at each site and fluvial distances between pairs of stream sites were determined. Environmental variables were the main factors structuring fish assemblages in both periods. However, fluvial distances were important only during the flood period. This can be related to the formation of extensive flood plains in this period, which increases connectivity between streams, breaking habitat isolation and increasing the regional signal for fish species. The higher correlation of β-diversity with environmental variables during the flood period may be related to decreased dispersal limitations and intermediate dispersal. Finally, β-diversity was higher during the flood period, highlighting the importance of the heterogeneity of the flood plain to stream biota. The results of the present study indicate that spatial and environmental factors play complementary roles in structuring fish assemblages in Amazon streams, and that β-diversity was affected by changes in the habitat connectivity experienced in different hydrological periods.

Daphnia laevis ephippia cemetery in the sediment of a permanent tropical lake

2019 ◽  
Vol 193 (2) ◽  
pp. 185-194 ◽  
Author(s):  
Luciana Pena Mello Brandão ◽  
Marina Isabela Bessa Silva ◽  
Déborah Oliveira ◽  
Diego Pujoni ◽  
Thécia Alfenas Paes ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Resting Eggs ◽  
Tropical Lake ◽  
Sediment Depth ◽  
Egg Bank ◽  
Egg Banks ◽  
Active Population ◽  
Temporal Dispersion ◽  
Hatching Rates

Aiming to evaluate the importance of egg banks from a tropical lake for the active Daphnia laevis dynamics, we investigated ephippia down to a 28-cm sediment depth, and used data obtained by traps to compare with the in situ production and hatching rates of fresh ephippia. All the ephippia from the sediment were opened for inspection of the presence of resting eggs, and those found were incubated to verify hatching. Ephippia density degradation rate was tested by putting isolated ephippia immersed in the sediment lake for 75 days, and found to exponentially decrease with increasing sediment depth. Higher densities were recorded in 2017 (maximum of 1.43 ephippia per cm2) than in 2016 (maximum of 0.8 ephippia per cm2). The empty ephippia rates were high in all sediment depths ranging from 83% to 100%. In contrast, the hatching rates in situ of fresh ephippia were high, suggesting that those that sink are mostly unviable or empty, forming an unusual egg bank in the sediment. In the laboratory, ephippia degradation signs were observed as early as the fifteenth day after contact with sediment. We conclude that the egg bank is not able to support an active population since most of the ephippia are empty and also rapidly degrade in sediment. Our results contribute to the current understanding of diapause in tropical cladocerans, demonstrating that the presence of Daphnia ephippia in the sediment of permanent lakes do not always correspond to an egg bank for temporal dispersion.

LATE CRETACEOUS WOODY DICOTS FROM THE AGUJA AND JAVELINA FORMATIONS, BIG BEND NATIONAL PARK, TEXAS, USA

IAWA Journal ◽  
2000 ◽  
Vol 21 (1) ◽  
pp. 83-120 ◽  
Author(s):  
E. A. Wheeler ◽  
T. M. Lehman
Keyword(s):  
Late Cretaceous ◽  
National Park ◽  
Sedimentary Facies ◽  
Flood Plain ◽  
Big Bend National Park ◽  
Flood Plains ◽  
Big Bend ◽  
Stratigraphic Succession ◽  
Subordinate Role

Angiosperm woods occur throughout Upper Cretaceous (84–66 million years old) continental strata of Big Bend National Park, Texas, USA. Vertebrate remains occur along the same stratigraphic levels, providing a rare opportunity to reconstruct associations of sedimentary facies, wood remains, and vertebrate remains. The wood collection sites span a vertical stratigraphic succession that corresponds to an environmental transect from poorly-drained coastal salt- or brackish water swamps to progressively better drained freshwater flood-plains lying at increasingly greater distance from the shoreline of the inland Cretaceous sea and at higher elevations. The eight dicot wood types of the Aguja Formation differ from the five types of the Javelina Formation, paralleling a change from a fauna dominated by duckbill and horned dinosaurs to a fauna dominated by the large sauropod, Alamosaurus. These woods increase the known diversity of Cretaceous woods, and include the earliest example of wood with characteristics of the Malvales. The lower part of the upper shale member of the Aguja contains numerous narrow axes, some seemingly in growth position, of the platanoid/ icacinoid type, and of another wood that has a suite of features considered primitive in the Baileyan sense. Duckbill dinosaur remains are common in the facies with these woods. In contrast to other Cretaceous localities with dicot wood, Paraphyllanthoxylon is not common. Dicotyledonous trees are most abundant at the top of the Aguja and the lower part of the Javelina Formations in sediments indicating well-drained inland fluvial flood-plain environments. One locality has logs and insitu stumps, with an average spacing of 12–13 metres between each tree, and trees nearly 1 metre in diameter. To our knowledge this is the first report of anatomically preserved in situ Cretaceous dicot trees. Javelinoxylon wood occurs at all levels where remains of the giant sauropod Alamosaurus occur. The vertebrate faunas of the late Cretaceous of New Mexico and Texas are said to comprise a ʻsouthernʼ fauna distinct from the ʻnorthern faunaʼ of Alberta and Montana. The wood remains are consistent with such provincialism. It has been suggested that dicots were not commonly trees in the late Cretaceous of the northern part of the western interior of North America. The Big Bend woods provide direct evidence for dicot trees having more than a subordinate role in Cretaceous vegetation at lower latitudes. Most of the dicot wood types of Big Bend are characterized by high proportions of parenchyma, over 50% in one type. Whether these high proportions of parenchyma are correlated with the higher CO2 levels of the Cretaceous and /or the pressures exerted by aggressive browsing by large dinosaur herbivores is unknown.

scholarly journals Flood Insurance as a Component of Land Use Management

1976 ◽  
Vol 8 (1) ◽  
pp. 175-180
Author(s):  
Ronald D. Lacewell ◽  
John G. McNeely
Keyword(s):  
Land Use ◽  
Flood Control ◽  
Flood Hazard ◽  
Flood Plain ◽  
Flood Insurance ◽  
Land Use Management ◽  
Flood Plains ◽  
Long Run ◽  
Relief Operations ◽  
Rescue And Relief

Floods will continue to cause damage as long as development continues upon flood-prone lands. Inevitably, flooding occurs, damage ensues and there is personal suffering and loss. A burden of rescue and relief operations falls on all taxpayers.Flood control projects cannot protect against all damage, and not all flood hazard areas are amenable to flood control projects. An alternative to continued construction of engineering works for flood protection is flood plain management. To be effective, this must be brought about through political and legal means. Its purposes are to minimize the consequences of flooding and to achieve, in the long run, an optimum use of the flood plains.

Facies characteristics and cyclicity of Lower Siwalik sediments, Jammu area: a new perspective

2001 ◽  
Vol 138 (4) ◽  
pp. 455-470 ◽  
Author(s):  
SHIKHA SHARMA ◽  
MANEESH SHARMA ◽  
INDRA BIR SINGH
Keyword(s):  
Statistical Model ◽  
Flood Plain ◽  
River Channel ◽  
River Channels ◽  
Natural Levee ◽  
Major River ◽  
New Perspective

The Lower Siwalik succession of the Jammu area has been distinguished into three major lithofacies associations: a sand-dominant association, a sandy-mud-dominant association, and a silty-heterolithic association. The sand-dominant association is made up of three lithofacies: cross-bedded sandstone, rippled silty sandstone and bioturbated sandy siltstone, which are organized in multi-storeyed sandbodies representing deposition in major river channels. The sandy-mud-dominant association is made up of two lithofacies, mottled clayey siltstone and interbedded sandstone, siltstone and mudstone, representing deposition in overbank areas of flood-plain and natural levee-crevasse splays. The sand-dominant association and sandy-mud-dominant association are grouped together as a channel-related succession and are products of processes in the river channel. The silty-heterolithic association consists of four lithofacies: mottled siltstone, mottled silty sandstone, bedded calcrete and mottled mudstone. They are considered to be deposits of Doab (upland interfluve) areas operating independently of present-day major river channels. These deposits have been formed in minor channels, sloping surfaces, and lakes and ponds of the interfluve regions. The cyclicity of both successions (channel-related and Doab-related) has been determined using a partial-independence statistical model.

Incidence on Polypogon monspeliensis of Clavibacter toxicus and Anguina sp., the organisms associated with 'flood plain staggers' in South Australia

1995 ◽  
Vol 35 (5) ◽  
pp. 567 ◽  
Author(s):  
T Bertozzi ◽  
AC McKay
Keyword(s):  
South Australia ◽  
Flood Plain ◽  
Survey Area ◽  
The South ◽  
Flood Plains ◽  
Murray River ◽  
Flood Prone Areas

During 1991-92, a survey was conducted in South Australia to determine the distribution of the nematode Anguina sp. and bacterium Clavibacter toxicus associated with 'flood plain staggers'. Polypogon monspeliensis (annual beardgrass) was examined at 265 sites in flood-prone areas in the South East. Seed-galls produced by Anguina sp. were observed at 96 sites, and at 78 of these, seed heads infected with C. toxicus were observed. Infected sites were observed throughout the survey area, with the greatest concentration between Naracoorte and Kingston. No infected Agrostis avenacea (annual blowngrass) was found in the South East or along the flood plains of the Murray River.

Sign in / Sign up

Export Citation Format

Share Document