21st century climate change: where has all the geomorphology gone?

This Commentary draws together recently published work relating to the relationship between climate change and geomorphology to address the surprising observation that geomorphic work seems to have had little impact upon the work of the Intergovernmental Panel for Climate Change. However, recent papers show that methodological innovation has allowed geomorphological reconstruction over timescales highly relevant to late 20th century and 21st century climate change. In turn, these and other developments are allowing links to be made between climatic variability and geomorphology, to begin to predict ‘geomorphic futures’ and also to appreciate the role that geomorphic processes play in the flux of carbon and the carbon cycle. Copyright © 2012 John Wiley & Sons, Ltd.     

Relative sea-level rising and its control strategy in coastal regions of China in the 21st century

Nearly 55% of Chinese GNP is out of and 70% of large-middle cities are located in the coastal regions, where there are vast plains and river-mouth deltas, covering 14% of the total land area and 40% of the nation抯 population. Since the 1980s, the coastal…     

Long-term Spatially Distributed Solutional Erosion: How Do We Put Solutes on the Map?

Much of the short-term solute process research in the last 20 years has focused on hydrochemical behaviour. This can help with the identification of solute source area type, but not the actual location of the solutional loss. The location and the spatial distribution of erosion are crucial to the identification of long-term landscale evolution. The way ahead lies in the fact that catchment budgeting and geochemical studies have been able to provide solute uptake rates. If these can be related to soil type, through a knowledge of soil mineralogy, reactive surface area and water flow rate, it may be possible to characterize the location and spatial distribution of solutional erosion through terrain analysis and soil maps in a geographical information system. © 1997 by John Wiley & Sons, Ltd.     

High-latitude coronal holes and polar faculae in the 21st–23rd solar activity cycles

The latitude-time evolution of large high-latitude coronal holes (CHs) and polar faculae (PF) during the period 1975–2010 has been studied. Their spatial distribution relative to each other has been considered. CHs and PF are shown to pass two significantly different phases in their evolution during an 11-year cycle. At phase I, i.e., during the period of an increase and maximum in the 11-year cycle, large CHs and PF exhibit a sequential motion from heliolatitudes of 40°–50° to the polar region and form a series of discrete chains with a periodicity of 1.25 ± 0.3 years in the 21st cycle. The magnetic field in CH chains corresponds to the trailing polarity of spot groups of this cycle. The anomaly of the 23rd cycle at high latitudes manifested itself in a break of the aforesaid periodicity in the N-hemisphere by the formation of a discontinuity between the second and third chains with a duration of three years. This shifted the beginning of the next 24th cycle by three years.     

Summit eruptions of Klyuchevskoi Volcano,Kamchatka in the early 21st century, 2003–2013

This paper is concerned with eruptions, seismicity, and deformation on Klyuchevskoi Volcano during the summit eruptions of 2012–2013, with the condition of the central crater during the eruptions, and with the effect that is exerted by the height of the lava in the crater on the start of the eruptions. The recurrence of eruptions in the North Volcanic Cluster (NVC), Kamchatka showed that all the four volcanoes in the cluster (Klyuchevskoi, Tolbachik, Shiveluch, and Bezymyannyi) become active during definite phases that were identified in the 18.6-year lunar cycle. This relationship of the NVC eruptions to the active phases in the 18.6-year lunar cycle, as well as the relationship to the 11-year solar activity, showed that eruptions can be predicted, yielding long-term estimates of activity for the NVC volcanoes. The short-term prediction of volcanic eruptions requires knowledge of seismicity and deformation that occur during the precursory period and during the occurrence of eruptions. Seismic activity during the summit eruptions of 2003–2013 took place in the depth range 20–25 km during repose periods of the volcano and at depths of 0–5 km in the volcanic edifice during the eruption. One notes an almost complete absence of any earthquakes at great depths during the summit eruptions. Volcanic tremor (VT) was recorded from the time that the eruptions began and continued to occur until the end. Geodetic measurements showed that the center of the magma pressure beneath the volcano during the parasitic and summit eruptions of 1979–1989 moved in the 4–17 km depth range, while during the summit eruptions of 2003–2013 the center moved in the 15–20 km range. These changes in the depth of the center of magma pressure may have been related to evacuation from shallow magma chambers.     

Features and Factors of Hydrological and Morphological Changes in the Agrakhan Bay at the Mouth of the Terek River in the 20th–Early 21st Centuries

Water Resources - The Agrakhan Bay of the Caspian Sea is a unique hydrographic and environmentally valuable object at the mouth of the Terek River. At the beginning of the 20th century, it was a...     

Annual Beech (Fagus sylvatica) Growth Rings and Solar-Related Climate Variations in the Central and Western Balkans in the 18th–21st Centuries

Geomagnetism and Aeronomy - Abstract—This work analyzes a time series of annual growth ring widths for beech trees (Fagus sylvatica) in the western and central Balkans (Stara Planina,...     

Do biological soil crusts determine vegetation changes in sandy deserts? Implications for managing artificial vegetation

Biological soil crusts (BSCs), which are widespread in arid and semiarid regions, such as sandy deserts, strongly influence terrestrial ecosystems. Once sand‐binding vegetation has been established on sand dunes, BSCs are colonized and gradually develop from cyanobacteria dominated crusts to lichen and moss dominated crusts on dune surfaces. We conducted this study to determine if the occurrence and development of BSCs in the Tengger Desert could be used to determine sand‐binding vegetation changes via altering soil moisture and water cycling using long‐term monitoring data and field experimental observation. BSCs changed the spatiotemporal pattern of soil moisture and re‐allocation by decreasing rainfall infiltration, increasing topsoil water‐holding capacity and altering evaporation. Changes in the soil moisture pattern induced shifting of sand‐binding vegetation from xerophytic shrub communities with higher coverage (35%) to complex communities dominated by shallow‐rooted herbaceous species with low shrub coverage (9%). These results imply that BSCs can be a major factor controlling floristic and structural changes in sand‐binding vegetation and suggest that the hydrological effects of BSCs must be considered when implementing large‐scale revegetation projects in sandy deserts. Copyright © 2010 John Wiley & Sons, Ltd.     

Getting it right for the North Atlantic right whale (Eubalaenaglacialis): A last opportunity for effective marine spatial planning?

The North Atlantic right whale (Eubalaena glacialis) faces increasing pressure from commercial shipping traffic and proposed marine renewable energy developments. Drawing upon the successful Stellwagen Bank National Marine Sanctuary model, we propose a multi-stakeholder marine spatial planning process that considers both appropriate positioning of offshore wind farms and redefining commercial shipping lanes relative to whale migration routes: placement of wind turbines within certain right whale habitats may prove beneficial for the species. To that end, it may be advisable to initially relocate the shipping lanes for the benefit of the whales prior to selecting wind energy areas. The optimal end-state is the commercial viability of renewable energy, as well as a safe shipping infrastructure, with minimal risk of collision and exposure to shipping noise for the whales. This opportunity to manage impacts on right whales could serve as a model for other problematic interactions between marine life and commercial activities.     

Sampling VOCs with Porous Suction Samplers in the Presence of Ethanol: How Much Are We Losing?

Porous suction samplers have been widely used to obtain ground water samples from the vadose zone. However, previous studies identified different mechanisms that may compromise the sample's representativeness, such as volatilization and sorption. This issue is particularly important when dealing with volatile organic compounds (VOCs) as in gasoline spills. Ethanol is common in modern fuels and so may be present in ground water contamination from fuel releases. The objective of this work was to evaluate the losses of VOCs in the presence of ethanol when using porous suction samplers. Laboratory experiments were performed using a ceramic porous suction sampler to sample test solution containing benzene, toluene, xylenes, trimethylbenzenes, naphthalene, and different volumetric fractions of ethanol. Significant losses were found up to 30% for ethylbenzene. Ethanol was found to affect the accuracy of the readings by two main mechanisms: first, negatively, by increasing the headspace in the sampling tube, and second, positively, increasing partition to the aqueous phase due to the cosolvent effect and therefore decreasing the mass loss by volatilization. As a consequence, the highest losses of VOCs were found at intermediate ethanol volume fractions: 10% and 20% (v/v). The losses can be anticipated by measuring the ratio of gas to water in the sampling line and then by applying simple partition models considering cosolvency by ethanol. The importance of adequate purging when using porous suction samplers was also shown.     

Does the complexity in temporal precipitation disaggregation matter for a lumped hydrological model?

ABSTRACT

Flood peaks and volumes are essential design variables and can be simulated by precipitation–runoff (P–R) modelling. The high-resolution precipitation time series that are often required for this purpose can be generated by various temporal disaggregation methods. Here, we compare a simple method (M1, one parameter), focusing on the effective precipitation duration for flood simulations, with a multiplicative cascade model (M2, 32/36 parameters). While M2 aims at generating realistic characteristics of precipitation time series, M1 aims only at accurately reproducing flood variables by P–R modelling. Both disaggregation methods were tested on precipitation time series of nine Swiss mesoscale catchments. The generated high-resolution time series served as input for P–R modelling using a lumped HBV model. The results indicate that differences identified in precipitation characteristics of disaggregated time series vanish when introduced into the lumped hydrological model. Moreover, flood peaks were more sensitive than flood volumes to the choice of disaggregation method.     

Do model parameters change under changing climate and land use in the upstream of the Lancang River Basin,China?

ABSTRACT

Hydrological model parameters may vary under the impacts of climate and land-use change. This study proposes a hydrological modelling framework based on the Soil and Water Assessment Tool (SWAT) to investigate the variability of model parameters in three different experiments and to assess the impacts of climate and/or land-use change on these parameters in the upstream of the Lancang River Basin, China. In Experiment 1 (E1), most parameters show clear temporal trends under changing climate and land use, implying that model parameters are strongly influenced by their combined effects. Experiments 2 (E2) and 3 (E3) investigate the separate impacts of land-use change and climate change, respectively. Due to the almost invisible changes in land use in E2, there is no change detected in the model parameters. Temporal trends are found in most parameters in E3 and over half of them show consistent trends with E1, which indicates that climate change has greater impacts on model parameter variability. The simulated extreme streamflow and sediment fluxes vary substantially with time-variant parameters, implying that the variations in model parameters do matter for hydrological prediction.     

Characteristic Features of Solar Cosmic Rays in the 21st–24th Solar-Activity Cycles According to Data from Catalogs of Solar Proton Events

Geomagnetism and Aeronomy - Homogeneous series of solar cosmic-ray events for four solar-activity cycles against the background of decreased activity in cycles 23 and 24 are considered. The number...     

Are steroids really the cause for fish feminization? A mini-review of in vitro and in vivo guided TIEs

Feminization of fish has been reported throughout the world in freshwater and marine systems. While the population impacts are conflictive, enough negative effects warrant additional research into causation. In order to ascertain the identities of specific feminizing agents, variants of toxicity identification evaluations (TIEs) have been employed. The majority of these evaluations have utilized in vitro estrogen receptor-based cell-lines to identify chromatographic fractions that possess biological activity from predominately wastewater derived from municipal treatment facilities and have concluded that synthetic and natural estrogens are the primary cause for feminization of fish. This paper will focus on three aquatic systems impacted by wastewater originating from purely domestic, and industrial/domestic secondary treatment systems. Wastewater and sediment extracts were evaluated by in vitro and in vivo biological responses in a TIE fractionation design. While in vitro responses tended to mirror in vivo responses in purely domestic wastewater systems, in vitro responses tended to severely underestimate in vivo estrogenic activity when normalized to estradiol equivalents in more complex systems. TIE fractionation schemes using in vivo biological responses failed to indicate any relationship to steroids in either wastewater or sediment extractions. These data consistently support the view that mechanisms other than direct ER binding and activation by toxicants may be important in the feminization of fish particularly residing in habitats that receive complex wastewater or agricultural effluents.     

Are steroids really the cause for fish feminization? A mini-review of in vitro and in vivo guided TIEs

Feminization of fish has been reported throughout the world in freshwater and marine systems. While the population impacts are conflictive, enough negative effects warrant additional research into causation. In order to ascertain the identities of specific feminizing agents, variants of toxicity identification evaluations (TIEs) have been employed. The majority of these evaluations have utilized in vitro estrogen receptor-based cell-lines to identify chromatographic fractions that possess biological activity from predominately wastewater derived from municipal treatment facilities and have concluded that synthetic and natural estrogens are the primary cause for feminization of fish. This paper will focus on three aquatic systems impacted by wastewater originating from purely domestic, and industrial/domestic secondary treatment systems. Wastewater and sediment extracts were evaluated by in vitro and in vivo biological responses in a TIE fractionation design. While in vitro responses tended to mirror in vivo responses in purely domestic wastewater systems, in vitro responses tended to severely underestimate in vivo estrogenic activity when normalized to estradiol equivalents in more complex systems. TIE fractionation schemes using in vivo biological responses failed to indicate any relationship to steroids in either wastewater or sediment extractions. These data consistently support the view that mechanisms other than direct ER binding and activation by toxicants may be important in the feminization of fish particularly residing in habitats that receive complex wastewater or agricultural effluents.     

Should the Three Gorges Dam be blamed for the extremely low water levels in the middle–lower Yangtze River?

Extremely low water level events have frequently occurred in the middle–lower Yangtze River (MLYR) in recent years (2006–2011). Most of these drought events coincided with the initial operation of the Three Gorges Dam (TGD). The TGD was therefore the focus of controversy about the causes of the hydrological droughts of the rivers and lakes of the region. We quantified the effects of the TGD's operation on water levels from 2006 to 2011 using a newly developed hydrodynamic model. The operation of the TGD significantly exacerbated the severe hydrological droughts that occurred in late September to November because of water impoundment, but it increased water levels from April to early June in the MLYR because of the drawdown of TGD water levels. Evidence suggests that the recent extremely low water levels were mainly because of the remarkable decline in inflows to the MLYR resulting from precipitation changes and possible human activities. Nevertheless, it should be noted that the effects of the TGD on downstream rivers and lakes will be intensified in the foreseeable future. Copyright © 2013 John Wiley & Sons, Ltd.     

The 2010–2012 eruption of Kizimen Volcano: The greatest output (from the data of remote-sensing observations) for eruptions in Kamchatka in the early 21st century part I. The November 11, 2010 to December 11, 2011 phase

This paper presents the results from the detailed analysis of aerial photographs and space images for the Kizimen area, which characterize the geologic and geomorphologic effects of the ongoing eruption over the 2010–2011 period. It is shown that the total volume (>0.5 km³) and total mass (>10⁹ t) of the discharged (resurgent plus juvenile) material makes this eruption the most productive in Kamchatka for the first 12 years of the 21st century. The dominant component (>90%) is juvenile material with andesitic composition. The pyroclastics (tephra, deposits of the juvenile pyroclastic avalanches and incandescent debris avalanches) comprise >0.3 km³and >0.45× 10⁹ t, the lava (a very thick block lava flow 3.052 km long and 2.163 km² in area) occupies about 0.195 km³ and 0.45 × 10⁹ t. With the exception of the tephra, which fell over an area of about 100000 km², the rest of the material was accumulated on the Kizimen cone and at its base. The mean discharge rate of juvenile ejecta was about 15 m³/s (29 t/s) for 13 months (November 11, 2010 to December 11, 2011). Appreciable changes also occurred at the near-summit part of the volcano’s cone.     

Is correlation dimension a reliable proxy for the number of dominant influencing variables for modeling risk of arsenic contamination in groundwater?

The correlation dimension (CD) of a time series provides information on the number of dominant variables present in the evolution of the underlying system dynamics. In this study, we explore, using logistic regression (LR), possible physical connections between the CD and the mathematical modeling of risk of arsenic contamination in groundwater. Our database comprises a large-scale arsenic survey conducted in Bangladesh. Following the recommendation by Hossain and Sivakumar (Stoch Environ Res Risk Assess 20(1–2):66–76, 2006), who reported CD values ranging from 8 to 11 for this database, 11 variables are considered herein as indicators of the aquifer’s geochemical regime with potential influence on the arsenic concentration in groundwater. A total of 2,048 possible combinations of influencing variables are considered as candidate LR risk models to delineate the impact of the number of variables on the prediction accuracy of the model. We find that the uncertainty associated with prediction of wells as safe and unsafe by LR risk model declines systematically as the total number of influencing variables increases from 7 to 11. The sensitivity of the mean predictive performance also increases noticeably for this range. The consistent reduction in predictive uncertainty coupled with the increased sensitivity of the mean predictive behavior within the universal sample space exemplify the ability of CD to function as a proxy for the number of dominant influencing variables. Such a rapid proxy, based on non-linear dynamic concepts, appears to have considerable merit for application in current management strategies on arsenic contamination in developing countries, where both time and resources are very limited.