Vegetation, hydrology, and development of a coastal mire in Hokkaido, Japan, affected by flooding and tephra deposition

2001 ◽  
Vol 79 (3) ◽  
pp. 341-361 ◽  
Author(s):  
Stefan Hotes ◽  
Peter Poschlod ◽  
Hiroshige Sakai ◽  
Takashi Inoue
Keyword(s):  
Sea Water ◽  
Ionic Composition ◽  
Plant Macrofossils ◽  
Vegetation Pattern ◽  
Water Levels ◽  
Myrica Gale ◽  
Mineral Deposition ◽  
Volcanic Ejecta ◽  
Induced Changes ◽  
Flooding Events

Mires in coastal lowlands in Hokkaido, northern Japan, have repeatedly been affected by flooding events and tephra (aerially transported volcanic ejecta) deposition during their development. Vegetation, hydrology, and stratigraphy of Kiritappu Mire in eastern Hokkaido were investigated along two transects and are discussed in relation to disturbance by mineral deposition. The vegetation pattern showed little relation to past geologic events. Five plant communities, two of which (A and C) could be further divided into subgroups, were distinguished (A, Alnus japonica - Spiraea salicifolia community; B, Sasa chartacea community; C, Myrica gale var. tomentosa - Sphagnum fuscum community; D, Carex lyngbyei community; E, Carex subspathacea - Aster tripolium community). Water levels, pH, electric conductivity, and ionic composition of groundwater and surface water were measured in communities A-C. Mean water levels were similar in communities A and C; in community B, it was lower. The pH was higher in community A than in communities B and C. Ion concentrations were influenced by sea water at some sites. Plant macrofossils and ash contents of 31 cores were analysed. Sedge roots were the dominant peat component, often mixed with remains of Phragmites australis, Sphagnum spp., and Polytrichum juniperinum var. strictum. Ash contents were high, and up to nine different mineral layers consisting of tephra, sand, silt, and clay were detected. In some cases, mineral deposition induced changes in the macrofossil composition of the peat. However, in a greater number of cases, no changes in the macrofossil composition were found at the mineral layers, and most shifts were not related to mineral deposition.Key words: mire, vegetation, hydrology, disturbance, flooding, tephra.

scholarly journals Flooding in river mouths: human caused or natural events? Five centuries of flooding events in the SW Netherlands, 1500–2000

2015 ◽  
Vol 12 (1) ◽  
pp. 1437-1468 ◽  
Author(s):  
A. M. J. de Kraker
Keyword(s):  
Sea Water ◽  
Storm Surges ◽  
Water Levels ◽  
Defensive Strategies ◽  
Natural Feature ◽  
Flooding Event ◽  
Flooded Area ◽  
Flooding Events ◽  
River Mouths ◽  
Selection Of

Abstract. This paper looks into the flooding events of the past 500 years in the SW Netherlands addressing the issue what kind of flooding events have occurred and which ones have mainly natural causes and which ones are predominantly human induced. The flooding events are classified into two major categories: (a) flooding events that were caused during storm surges and (b) flooding events which happened during war fare. From both categories a selection of flooding events has been made. Each flooding event is discussed in terms time, location, extent of the flooded area and specific conditions. Among these conditions specific weather circumstances and how long they lasted, the highest water levels reached and dike maintenance are discussed as far as flooding events caused during storm surges are concerned. About the flooding events during war fare, offensive and defensive strategies are relevant. The paper demonstrates that although the strategic flooding events obviously were man-made, the natural feature, being the use of fresh water or sea water, of these events also played a major role. Flooding events caused during storm surge may have an obvious natural cause, but the extent of the flooding and damage it caused were largely determined by man.

scholarly journals Flooding in river mouths: human caused or natural events? Five centuries of flooding events in the SW Netherlands, 1500–2000

2015 ◽  
Vol 19 (6) ◽  
pp. 2673-2684 ◽  
Author(s):  
A. M. J. de Kraker
Keyword(s):  
Sea Water ◽  
Storm Surges ◽  
Water Levels ◽  
Flood Events ◽  
Defensive Strategies ◽  
Natural Feature ◽  
Flooded Area ◽  
Flooding Events ◽  
River Mouths ◽  
Selection Of

Abstract. This paper looks into flood events of the past 500 years in the SW Netherlands, addressing the issue of what kind of flooding events have occurred and which ones have mainly natural causes and which ones are predominantly human induced. The flood events are classified into two major categories: (a) flood events that were caused during storm surges and (b) flood events which happened during warfare. From both categories a selection of flood events has been made. Each flood event is discussed in terms of time, location, extent of the flooded area and specific conditions. Among these conditions, specific weather circumstances and how long they lasted, the highest water levels reached and dike maintenance are discussed as far as flood events caused during storm surges are concerned. Flood events during warfare as both offensive and defensive strategies are relevant; the paper demonstrates that although the strategic flood events obviously were man-made, the natural feature, being the use of fresh water or sea water, of these events also played a major role. Flood events caused during storm surge may have an obvious natural cause, but the extent of the flooding and damage it caused was largely determined by man.

SITE-SPECIFIC EQUATIONS OF STATE FOR COASTAL SEA AREAS AND INLAND WATER BODIES

2017 ◽  
Author(s):  
Natalia Andrulionis ◽  
Natalia Andrulionis ◽  
Ivan Zavialov ◽  
Ivan Zavialov ◽  
Elena Kovaleva ◽  
...  
Keyword(s):  
Equation Of State ◽  
Black Sea ◽  
Water Samples ◽  
Equations Of State ◽  
Sea Water ◽  
Ionic Composition ◽  
Water Bodies ◽  
Aral Sea ◽  
The Black Sea ◽  
Coastal Sea

This article presents a new method of laboratory density determination and construction equations of state for marine waters with various ionic compositions and salinities was developed. The validation of the method was performed using the Ocean Standard Seawater and the UNESCO thermodynamic equation of state (EOS-80). Density measurements of water samples from the Aral Sea, the Black Sea and the Issyk-Kul Lake were performed using a high-precision laboratory density meter. The obtained results were compared with the density values calculated for the considered water samples by the EOS-80 equation. It was shown that difference in ionic composition between Standard Seawater and the considered water bodies results in significant inaccuracies in determination of water density using the EOS-80 equation. Basing on the laboratory measurements of density under various salinity and temperature values we constructed a new equation of state for the Aral Sea and the Black Sea water samples and estimated errors for their coefficients.

Osmoregulation by the Prenatal Spiny Dogfish, Squalus Acanthias

1982 ◽  
Vol 101 (1) ◽  
pp. 295-305 ◽  
Author(s):  
DAVID H. EVANS ◽  
AIMO OIKARI ◽  
GREGG A. KORMANIK ◽  
LEIGH MANSBERGER
Keyword(s):  
Sea Water ◽  
Electrical Potential ◽  
Fluid Flows ◽  
Maternal Plasma ◽  
Water Levels ◽  
Squalus Acanthias ◽  
Rectal Gland ◽  
Na Efflux ◽  
Uterine Fluid ◽  
Electrochemical Equilibrium

Late in gestation of the ovoviviparous dogfish, Squalus acanthias, the uterine fluids are essentially sea water, while the plasma of the ‘pup’ is similar to that of the female, i.e. isotonic to sea water/uterine fluids, with significantly less Na and Cl, and substantial concentrations of urea. Early ‘candle’ embryos are bathed in ‘candle’ fluid and uterine fluid which contains Na and Cl concentrations intermediate between maternal plasma and sea water levels, K concentrations above sea water levels, and urea concentrations slightly below those found in the maternal plasma. Both fluids are isotonic to sea water and maternal plasma. Incubation of ‘candles’ with associated embryos in sea water for 4–6 days resulted in significant increases in ‘candle’ fluid Na and Cl concentrations, and a decline in ‘candle’ fluid K and urea levels. However, under these conditions, the ‘candle’ embryo is still able to regulate plasma Na, Cl, K and urea concentrations. The efflux of Cl is approximately 5 times the efflux of Na from the prenatal ‘pup’; however, both effluxes are equivalent to those described for adult elasmobranchs. The transepithelial electrical potential (TEP) across the ‘pup’ is −4.4 mV in sea water, which indicates that both Na and Cl are maintained out of electrochemical equilibrium. Cloacal fluid flows vary diurnally with Na and Cl concentrations significantly above those of the plasma. Rectal gland efflux can account for 50–100% of the Na efflux, but less than 25% of the Cl efflux. Removal of the rectal gland resulted in an increase in plasma Na and Cl concentrations 48 or 72 h after the operation, but in both cases it appears that some extra rectal gland excretory system balances at least some of the net influx of both salts. Our results demonstrate that even very young ‘candle’ embryos of S. acanthias are capable of osmoregulation, and that older embryos (‘pups') osmoregulate against sea water intra-utero and display the major hallmarks of elasmobranch osmoregulation, including a reduced ionic permeability and a functional rectal gland for net extrusion of NaCl. In addition, it appears that other pathways exist for salt extrusion in addition to the rectal gland. Note:

A 6000-year record of ecological and hydrological changes from Laguna de la Leche, north coastal Cuba

2007 ◽  
Vol 67 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Matthew C. Peros ◽  
Eduard G. Reinhardt ◽  
Anthony M. Davis
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Plant Macrofossils ◽  
Water Levels ◽  
Loss On Ignition ◽  
Coastal Lake ◽  
Freshwater Gastropods ◽  
Level Increase ◽  
Pollen Rain ◽  
Calcareous Microfossils

AbstractLaguna de la Leche, north coastal Cuba, is a shallow (≤ 3 m), oligohaline (∼ 2.0–4.5‰) coastal lake surrounded by mangroves and cattail stands. A 227-cm core was studied using loss-on-ignition, pollen, calcareous microfossils, and plant macrofossils. From ∼6200 to ∼ 4800 cal yr BP, the area was an oligohaline lake. The period from ∼ 4800 to ∼ 4200 cal yr BP saw higher water levels and a freshened system; these changes are indicated by an increase in the regional pollen rain, as well as by the presence of charophyte oogonia and an increase in freshwater gastropods (Hydrobiidae). By ∼ 4000 cal yr BP, an open mesohaline lagoon had formed; an increase in salt-tolerant foraminifers suggests that water level increase was driven by relative sea level rise. The initiation of Laguna de la Leche correlates with a shift to wetter conditions as indicated in pollen records from the southeastern United States (e.g., Lake Tulane). This synchronicity suggests that sea level rise caused middle Holocene environmental change region-wide. Two other cores sampled from mangrove swamps in the vicinity of Laguna de la Leche indicate that a major expansion of mangroves was underway by ∼ 1700 cal yr BP.

The Environmental Relations of Vegetation Pattern on Chenier Beach Ridges on Bathurst Island, Northern Territory

1993 ◽  
Vol 41 (3) ◽  
pp. 275 ◽  
Author(s):  
RJ Fensham
Keyword(s):  
Sea Water ◽  
Acid Soils ◽  
Soil Nutrient ◽  
Vegetation Pattern ◽  
High Concentration ◽  
Radiocarbon Dates ◽  
Beach Ridges ◽  
Nutrient Levels ◽  
Environmental Relations ◽  
Monsoon Rainforest

Radiocarbon dates confirm a chronological sequence for late Holocene beach ridges at Wangiti Beach on Bathurst Island. The vegetation on these beach ridges can be clearly related to topography and distance from the sea. Monsoon rainforest occurs on the fore-dunes where the nutrient levels of the young sediments are relatively high. The mid-dunes support woodland dominated by Melalueca viridiflora and have nutrient-poor acid soils. Vegetation with a high component of monsoon rainforest species occupies the rear dunes, which have a high concentration of seawater macronutrient cations despite their older age than more seaward dunes. The relatively low elevation of the rear dunes supports the suggestion that soil nutrient levels are enriched by sea water or marine sediments during infrequent inundation events such as those during cyclones.

Dead Sea Water Levels Analysis Using Artificial Neural Networks and Firefly Algorithm

2022 ◽  
pp. 1118-1129
Author(s):  
Nawaf N. Hamadneh
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Water Level ◽  
Firefly Algorithm ◽  
Sea Water ◽  
Dead Sea ◽  
Water Levels ◽  
Artificial Neural ◽  
The Dead ◽  
Predicted Values

In this study, the performance of adaptive multilayer perceptron neural network (MLPNN) for predicting the Dead Sea water level is discussed. Firefly Algorithm (FFA), as an optimization algorithm is used for training the neural networks. To propose the MLPNN-FFA model, Dead Sea water levels over the period 1810–2005 are applied to train MLPNN. Statistical tests evaluate the accuracy of the hybrid MLPNN-FFA model. The predicted values of the proposed model were compared with the results obtained by another method. The results reveal that the artificial neural network (ANN) models exhibit high accuracy and reliability for the prediction of the Dead Sea water levels. The results also reveal that the Dead Sea water level would be around -450 until 2050.

scholarly journals An ensemble study of extreme storm surge related water levels in the North Sea in a changing climate

Ocean Science ◽  
2009 ◽  
Vol 5 (3) ◽  
pp. 369-378 ◽  
Author(s):  
A. Sterl ◽  
H. van den Brink ◽  
H. de Vries ◽  
R. Haarsma ◽  
E. van Meijgaard
Keyword(s):  
North Sea ◽  
Climate Model ◽  
Sea Water ◽  
Global Climate ◽  
Global Climate Model ◽  
Storm Surges ◽  
Water Levels ◽  
The North ◽  
Extreme Storm ◽  
The North Sea

Abstract. The height of storm surges is extremely important for a low-lying country like The Netherlands. By law, part of the coastal defence system has to withstand a water level that on average occurs only once every 10 000 years. The question then arises whether and how climate change affects the heights of extreme storm surges. Published research points to only small changes. However, due to the limited amount of data available results are usually limited to relatively frequent extremes like the annual 99%-ile. We here report on results from a 17-member ensemble of North Sea water levels spaning the period 1950–2100. It was created by forcing a surge model of the North Sea with meteorological output from a state-of-the-art global climate model which has been driven by greenhouse gas emissions following the SRES A1b scenario. The large ensemble size enables us to calculate 10 000 year return water levels with a low statistical uncertainty. In the one model used in this study, we find no statistically significant change in the 10 000 year return values of surge heights along the Dutch during the 21st century. Also a higher sea level resulting from global warming does not impact the height of the storm surges. As a side effect of our simulations we also obtain results on the interplay between surge and tide.

Observations on the Physical Properties of Sea-Ice at Hopedale, Labrador

ARCTIC ◽  
1958 ◽  
Vol 11 (3) ◽  
pp. 134 ◽  
Author(s):  
Wilford F. Weeks ◽  
Owen S. Lee
Keyword(s):  
Sea Ice ◽  
Physical Properties ◽  
Air Force ◽  
Sea Water ◽  
Field Studies ◽  
Water Levels ◽  
Cambridge Research ◽  
Freezing Period ◽  
Before And After ◽  
General Physical

Preliminary results are reported of field studies 1955-56 by the U.S. Air Force Cambridge Research Center, the Hydrographic Office and SIPRE on the general physical properties of sea ice; methods of measurement are described. Characteristics of sea water during the freezing period are outlined: formation, structure, and salinity of the initial ice cover, formation and characteristics of infiltrated snow-ice, growth of the ice and influencing factors, density of the ice at various periods, and crack formation are discussed. Data on the salinity of sea ice formed during during wave action and that of sheet-ice, hourly averages of air and ice temperatures at various levels, snow and slush density and thickness, observed slush levels and theoretical water levels are shown. Salinity of ice before and after the slush layer froze, and that of deteriorating ice , salinity of ice vs. ice thickness, thickness of ice versus degree-days, the density of the ice, and measured ice densities vs. theoretical density of air-free sea ice at -15 C are figured and discussed. The orientation of sea ice c-axes and of infiltrated snow-ice c-axes are diagrammed.--From SIPRE.

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