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Abiy, A. Z., & Melesse, A. M. (2017). Evaluation of watershed scale changes in groundwater and soil moisture storage with the application of GRACE satellite imagery data. Catena, 153, 50–60.
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Aiken, G. R., Spencer, R. G. M., Striegl, R. G., Schuster, P. F., & Raymond, P. A. (2014). Influences of glacier melt and permafrost thaw on the age of dissolved organic carbon in the Yukon River basin: DOC Age in the Yukon River Basin. Global Biogeochem. Cycles, 28(5), 525–537.
Abstract: Responses of near-surface permafrost and glacial ice to climate change are of particular significance for understanding long-term effects on global carbon cycling and carbon export by high-latitude northern rivers. Here we report 14C-dissolved organic carbon (DOC) values and dissolved organic matter optical data for the Yukon River, 15 tributaries of the Yukon River, glacial meltwater, and groundwater and soil water end-member sources draining to the Yukon River, with the goal of assessing mobilization of aged DOC within the watershed. Ancient DOC was associated with glacial meltwater and groundwater sources. In contrast, DOC from watersheds dominated by peat soils and underlain by permafrost was typically enriched in 14C indicating that degradation of ancient carbon stores is currently not occurring at large enough scales to quantitatively influence bulk DOC exports from those landscapes. On an annual basis, DOC exported was predominantly modern during the spring period throughout the Yukon River basin and became older through summer-fall and winter periods, suggesting that contributions of older DOC from soils, glacial meltwaters, and groundwater are significant during these months. Our data indicate that rapidly receding glaciers and increasing groundwater inputs will likely result in greater contributions of older DOC in the Yukon River and its tributaries in coming decades.
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Ajaz Ahmed, M. A., Abd-Elrahman, A., Escobedo, F. J., Cropper Jr., W. P., Martin, T. A., & Timilsina, N. (2017). Spatially-explicit modeling of multi-scale drivers of aboveground forest biomass and water yield in watersheds of the Southeastern United States. Journal of Environmental Management, 199, 158–171.
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Anandhi, A., & Kannan, N. (2018). Vulnerability assessment of water resources - Translating a theoretical concept to an operational framework using systems thinking approach in a changing climate: Case study in Ogallala Aquifer. Journal of Hydrology, 557, 460–474.
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Arias, M. E., Lee, E., Farinosi, F., Pereira, F. F., & Moorcroft, P. R. (2018). Decoupling the effects of deforestation and climate variability in the Tapajós river basin in the Brazilian Amazon. Hydrological Processes, 32(11), 1648–1663.
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Bekele, D., Alamirew, T., Kebede, A., Zeleke, G., & Melese, A. M. (2017). Analysis of rainfall trend and variability for agricultural water management in Awash River Basin, Ethiopia. J Water Climate Change, 8(1), 127–141.
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Burke, A., Present, T. M., Paris, G., Rae, E. C. M., Sandilands, B. H., Gaillardet, J., et al. (2018). Sulfur isotopes in rivers: Insights into global weathering budgets, pyrite oxidation, and the modern sulfur cycle. Earth and Planetary Science Letters, 496, 168–177.
Abstract: The biogeochemical sulfur cycle is intimately linked to the cycles of carbon, iron, and oxygen, and plays an important role in global climate via weathering reactions and aerosols. However, many aspects of the modern budget of the global sulfur cycle are not fully understood. We present new S measurements on sulfate from more than 160 river samples from different geographical and climatic regions—more than 46% of the world's freshwater flux to the ocean is accounted for in this estimate of the global riverine sulfur isotope budget. These measurements include major rivers and their tributaries, as well as time series, and are combined with previously published data to estimate the modern flux-weighted global riverine S as 4.4 ± 4.5‰ (V-CDT), and 4.8 ± 4.9‰ when the most polluted rivers are excluded. The sulfur isotope data, when combined with major anion and cation concentrations, allow us to tease apart the relative contributions of different processes to the modern riverine sulfur budget, resulting in new estimates of the flux of riverine sulfate due to the oxidative weathering of pyrites (1.3 ± 0.2 Tmol S/y) and the weathering of sedimentary sulfate minerals (1.5 ± 0.2 Tmol S/y). These data indicate that previous estimates of the global oxidative weathering of pyrite have been too low by a factor of two. As pyrite oxidation coupled to carbonate weathering can act as a source of CO2 to the atmosphere, this global pyrite weathering budget implies that the global CO2 weathering sink is overestimated. Furthermore, the large range of sulfur isotope ratios in modern rivers indicates that secular changes in the lithologies exposed to weathering through time could play a major role in driving past variations in the S value of seawater.
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Cai, Y., Huang, W., Teng, F., & Gu, S. (2014). Effects of Changing Climate on Glacier Shrinkage and River Flow in the Upper Heihe River Basin, China. Journal of Coastal Research, 68, 121–128.
Abstract: Based on observed hydro-meteorological data and Remote Sensing images collected from 1990 to 2010, analysis has been conducted to investigate the effects of changing climate on glacier shrinkage and river flow in the upper Heihe River basin, an inland mountain river basin in China. Observed data indicates that the temperature in the study area shows the increase trend at the annual increase rate of 0.07 Celsius Degree/year. Spatial analysis of glacier coverage indicates that the glacier coverage area shrankby 52.93 km2 at the rate of approximately 2.65 km2/year from 1990 to 2010 due to the global climate change. Small glaciers with area less than 1 km2 account for over 87 % of the remaining glaciers in 2010, which will accelerate the recession of glaciers. Further analysis of river flows at Zhamashike Station shows the increase trend of the river flow at the 0.4 m3s−1/year. Through comparsion of variation characterisitcs of air temperatues, glaciers and runoff, the relationship between climate change, galciers shrinkage and runoff change is analyzed. It is indicated that the acute long-term loss of glacial storage will intensify water scarcity in the arid basin, notwithstanding the recent increase in runoff due to the melting of glaciers induced by global warming. It is urgent and important for the Heihe River basin to establish reasonable water resources management measures against glacier shrinkage and climate change.
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Catenazzi, A., & Kupferberg, S. J. (2018). Consequences of dam-altered thermal regimes for a riverine herbivore's digestive efficiency, growth and vulnerability to predation. Freshw Biol, 63(9), 1037–1048.
Abstract: Rivers around the world are undergoing shifts in thermal regime due to climate change and human appropriation of water resources. The local impacts of thermal regime change are challenging to predict because water temperature can influence aquatic organisms and communities at multiple levels simultaneously. For example, thermal change can influence the phenology of periphyton blooms, primary consumer physiology and behaviour, and interspecific interactions with predators. Using tadpoles of the threatened river-breeding foothill yellow-legged frog (Rana boylii, Ranidae), their algal foods and their invertebrate predators, we mimicked dam-induced changes in temperature and observed the outcome of consumer-resource interactions. In stream enclosures, we reared tadpoles across a gradient of cold to warm conditions, quantified the ash content of diet, digestive efficiency and growth rate, and assessed their vulnerability to hemipteran and odonate predators. Tadpoles reared in a cool stream (15.5 degrees C daily mean) digested epilithic periphyton poorly (6.60.4% assimilation efficiency). In contrast, average assimilation efficiency of tadpoles reared at 19 degrees C was 11.60.1%. Access to nutritious diatoms (i.e. dinitrogen-fixing Epithemia spp., Rhopalodiaceae) increased assimilation efficiency to 10.1 +/- 0.1% and 13.8 +/- 0.1% in the cool and warm treatments, respectively. Assimilation efficiency correlated positively with tadpole growth rate (R=0.66, p<.001). The effect of temperature on mortality due to predation was mediated by low tadpole growth rates at cool temperatures and not by the temperature of predator exposure. Non-lethal effects of predators on tadpole growth and tail injury, however, depended on both rearing temperature and exposure temperature. Contrary to the expectation that the cost of predator avoidance behaviours may be greater at warmer exposure temperatures because basal metabolic rates are higher, our results indicated that the energetic cost of foraging less was amplified at cool temperatures. Our results show that when thermal conditions impair digestion in a species' early life stages, recruitment bottlenecks are likely to arise due to the combined negative effects of cool temperatures on assimilation efficiency and growth, and increased predation by invertebrates.
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Chen, Y., Huang, W., & Xu, S. (2014). Frequency Analysis of Extreme Water Levels Affected by Sea-Level Rise in East and Southeast Coasts of China. Journal of Coastal Research, 68, 105–112.
Abstract: Qiantang bore as well as the storm surge are great disasters for river bank protection at the estuary of Qiantang River. Pearl River estuary is also frequently attacked by strong typhoon storm surge. The risk of damage from storm surge is expected to increase in both estuaries, exacerbated by sea level rise (SLR) and possible climate-induced increases in typhoon intensity and frequency. Adequate estimation on extreme water level will be essential to the coastal flood mitigation for both estuary areas with the effect of climate change. In this study, the popular frequency models Weibull, Lognormal, Gumbel, P-III and GEV are compared on Ganpu station located at the estuary of Qiantang River and Denglongshan station in Guangdong province, the optimal GEV model is recommended. For the risky analysis and management concern induced by the shortage of studied data, the estimated 50 year and 100 year extreme water levels respectively at Ganpu and Denglongshan stations are recommended in this study. Both studied stations located at different estuaries are all type II GEV model as the parameter of GEV distribution are higher than 0. The difference of the parameter and the reason causes the difference in the studied stations are analyzed and discussed in this paper. Furthermore, with the estimated 2.9mm/yr SLR by sea level bulletin of China, effect of SLR in frequency analysis on Denglongshan station is discussed.
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Fang, Y., Ceola, S., Paik, K., McGrath, G., Rao, P. S. C., Montanari, A., et al. (2018). Globally Universal Fractal Pattern of Human Settlements in River Networks. Earth's Future, 6(8), 1134–1145.
Abstract: River networks play a key role in the spatial organization of human settlements. Both river networks and human settlements have been found to exhibit regular self-similar patterns, but little is known about the generalized spatial patterns of human settlements embedded within river networks. Here based on night light data, we find a universal fractal structure at the global scale, with both robust Hortonian scaling relationships with the extent of human settlements and statistically significant power law scaling of the power spectra of human area functions. Globally, we find consistent patterns of power law preferential downstream clustering of human settlements across all six populated continents, typically up to 40% of the maximum flow length. This downstream clustering suggests an optimum distribution of humans in large river basins for trade, transport, and natural resource utilization but with attendant implications for human impacts on rivers. Recognition of such spatial patterns helps generalize assessments of human impacts on rivers, with direct implications for management of water quality and biological diversity in river networks.
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Feller, I. C., Dangremond, E. M., Devlin, D. J., Lovelock, C. E., Proffitt, C. E., & Rodriguez, W. (2015). Nutrient enrichment intensifies hurricane impact in scrub mangrove ecosystems in the Indian River Lagoon, Florida, USA. Ecology, 96(11), 2960–2972.
Abstract: Mangroves are an ecological assemblage of trees and shrubs adapted to grow in intertidal environments along tropical, subtropical, and warm temperate coasts. Despite repeated demonstrations of their ecologic and economic value, multiple stressors including nutrient over-enrichment threaten these and other coastal wetlands globally. These ecosystems will be further stressed if tropical storm intensity and frequency increase in response to global climate changes. These stressors will likely interact, but the outcome of that interaction is uncertain. Here, we examined potential interaction between nutrient over-enrichment and the September 2004 hurricanes. Hurricanes Frances and Jeanne made landfall along Florida's Indian River Lagoon and caused extensive damage to a long-term fertilization experiment in a mangrove forest, which previously revealed that productivity was nitrogen (N) limited across the forest and, in particular, that N enrichment dramatically increased growth rates and aboveground biomass of stunted Avicennia germinans trees in the interior scrub zone. During the hurricanes, these trees experienced significant defoliation with three to four times greater reduction in leaf area index (LAI) than control trees. Over the long term, the +N scrub trees took four years to recover compared to two years for controls. In the adjacent fringe and transition zones, LAI was reduced by >70%, but with no differences based on zone or fertilization treatment. Despite continued delayed mortality for at least five years after the storms, LAI in the fringe and transition returned to pre-hurricane conditions in two years. Thus, nutrient over-enrichment of the coastal zone will increase the productivity of scrub mangroves, which dominate much of the mangrove landscape in Florida and the Caribbean; however, that benefit is offset by a decrease in their resistance and resilience to hurricane damage that has the potential to destabilize the system.
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Feng, L., Hu, C., Chen, X., & Song, Q. (2014). Influence of the Three Gorges Dam on total suspended matters in the Yangtze Estuary and its adjacent coastal waters: Observations from MODIS. Remote Sensing of Environment, 140, 779–788.
Abstract: Several studies showed the linkage of the Three Gorges Dam to the downstream coastal ecosystem in the East China Sea, yet its potential influence on the total suspended matters (TSM) in the Yangtze Estuary and its adjacent coastal waters has not been reported, possibly due to technical difficulties in obtaining statistically meaningful results. Here, a new remote sensing algorithm was established to estimate TSM from MODIS observations over the Yangtze Estuary and its adjacent coastal waters. The algorithm was based on a piecewise regression between TSM and surface reflectance at 645 and 869 nm, leading to RMS uncertainties of only 20–30% for TSM between 2 mg L− 1 and 1762 mg L− 1. The algorithm was applied to MODIS data to derive TSM distribution maps from 2000 to 2010 at 250 m resolution, which revealed significant spatial and temporal (seasonal and inter-annual) variability. Mean TSM in the Yangtze Estuary increased from 44.4 ± 34.1 mg L− 1 in May to 96.0 ± 58.0 mg L− 1 in October, while much higher TSM was found in the nearby Hangzhou Bay (between 100.3 ± 51.6 mg L− 1 in August and 290.2 ± 120.0 mg L− 1 in February). Two regions showed significantly out-of-phase seasonality: region A1 in the Yangtze Estuary driven by sediment discharge from the Yangtze River and region A2 in offshore waters and part of Hangzhou Bay driven by winds. The annual mean TSM in region A1 showed significantly decreasing trend in the 11-year period (− 2.8 mg L− 1/yr), which appeared to be caused by the construction of the TGD. The study also has established a TSM environmental data record (EDR) to assess future TSM in the ecologically and economically important Yangtze Estuary and Hangzhou Bay.
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Guerra-Chanis, G. E., Reyes-Merlo, M. Á., Díez-Minguito, M., & Valle-Levinson, A. (2019). Saltwater intrusion in a subtropical estuary. Estuarine, Coastal and Shelf Science, 217, 28–36.
Abstract: River discharge, precipitation, wind, water level and salinity measurements were used to investigate saltwater intrusion in a subtropical estuary. The upstream limit of saltwater intrusion was defined by the position of the 2 g/kg isohaline (X-2) as it changed each tidal cycle. Observations were obtained from November 2014 to November 2015 along the Suwannee River, at Florida's Big Bend. Observations provided information to construct a first-order autoregressive Markov-chain model and predict X-2. The model predicts from its position in the previous tidal cycle, from river discharge, from water level, from precipitation and from wind velocity. In order to capture the seasonality of the Suwannee River discharge, the analysis was done separately for high and low river discharge regimes. The high discharge regime for the particular year of observations coincided with the cold season and had a mean value of 360 m(3)/s. The low discharge regime overlapped with the warm season and had a mean of 198 m(3)/s. As expected, saltwater intrusion was inversely related to river discharge. Values of X-2 were 0.4 km for a discharge of 377 m(3)/s, and 6 km for a discharge of 195 m(3)/s. The autoregressive model was able to reproduce the observed seasonality of saltwater intrusion in the Suwannee River. The model was then used to project values of X-2 for different scenarios of climate change as represented by possible combinations of river discharge and water levels.
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Hu, M., Ren, H., Ren, P., Li, J., Wilson, B. J., & Tong, C. (2017). Response of gaseous carbon emissions to low-level salinity increase in tidal marsh ecosystem of the Min River estuary, southeastern China. Journal of Environmental Sciences, 52, 210–222.
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Kharel, G., & Kirilenko, A. (2018). Comparing CMIP-3 and CMIP-5 climate projections on flooding estimation of Devils Lake of North Dakota, USA. PeerJ, 6, e4711.
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Kuang, C., Chen, W., Gu, J., Su, T. - C., Song, H., Ma, Y., et al. (2017). River discharge contribution to sea-level rise in the Yangtze River Estuary, China. Continental Shelf Research, 134, 63–75.
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Liu, Y., Wu, J., Liu, Y., Hu, B. X., Hao, Y., Huo, X., et al. (2015). Analyzing effects of climate change on streamflow in a glacier mountain catchment using an ARMA model. Quaternary International, 358, 137–145.
Abstract: Impacts of the climate change on streamflow have been of great concern over recent decades. The streamflow from a glacier mountain in an arid or semiarid region, in particular, plays a vital role in ecological, social and economic developments of the region. In this study, a long-term climate and runoff data were collected from an upstream glacier mountain area in the Ürümqi River basin, China. An autoregressive-moving-average model (ARMA) was used to quantitatively analyze the influence of the air temperature and the precipitation on the streamflow that originated from mountain glaciers. We used the differences between two consecutive years in the monthly air temperature and the monthly precipitation over a period of 48 years (from January 1959 to December 2006) as our climate change indexes. Similarly, the corresponding differences of monthly runoff were treated in the same way to derive the streamflow response indicator time series. These three new time series (temperature, precipitation, and runoff) were then transformed by removing their seasonal trends to construct three stationary time series. The ARMA model was subsequently applied to analyze the transformed time series. Results of this analysis indicated that the runoff was related to the temperature and the precipitation at any given time and that the precipitation was more important than the temperature in controlling the streamflow. The runoff in the upstream of the Ürümqi River increased approximately 1 m3/s every 10 years due to the climate change.
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Melesse, A., Abtew, W., & Setegn, S. G. (2014). Nile River Basin: Ecohydrological Challenges, Climate Change and Hydropolitics. Springer.
Abstract: The book provides a comprehensive overview of the hydrology of the Nile River, especially the ecohydrological degradation and challenges the basin is facing, the impact of climate change on water availability and the transboundary water management issues. The book includes analysis and approaches that will help provide different insights into the hydrology of this complex basin, which covers 11 countries and is home to over 300 million people. The need for water-sharing agreements that reflect the current situations of riparian countries and are based on equitable water- sharing principles is stressed in many chapters.
This book explores water resource availability and quality and their trends in the basin, soil erosion and watershed degradation at different scales, water and health, land use and climate change impact, transboundary issues and water management, dams, reservoirs and lakes. The link between watershed and river water quantity and quality is discussed pointing out the importance of watershed protection for better water resource management, water accessibility, institutional set-up and policy, water demand and management. The book also presents the water sharing sticking points in relation to historical treaties and the emerging water demands of the upstream riparian countries. The need for collaboration and identification of common ground to resolve the transboundary water management issues and secure a win-win is also indicated.
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Miloslavich, P., Bax, N. J., Simmons, S. E., Klein, E., Appeltans, W., Aburto-Oropeza, O., et al. (2018). Essential ocean variables for global sustained observations of biodiversity and ecosystem changes. Glob Chang Biol, 24(6), 2416–2433.
Abstract: Sustained observations of marine biodiversity and ecosystems focused on specific conservation and management problems are needed around the world to effectively mitigate or manage changes resulting from anthropogenic pressures. These observations, while complex and expensive, are required by the international scientific, governance and policy communities to provide baselines against which the effects of human pressures and climate change may be measured and reported, and resources allocated to implement solutions. To identify biological and ecological essential ocean variables (EOVs) for implementation within a global ocean observing system that is relevant for science, informs society, and technologically feasible, we used a driver-pressure-state-impact-response (DPSIR) model. We (1) examined relevant international agreements to identify societal drivers and pressures on marine resources and ecosystems, (2) evaluated the temporal and spatial scales of variables measured by 100+ observing programs, and (3) analysed the impact and scalability of these variables and how they contribute to address societal and scientific issues. EOVs were related to the status of ecosystem components (phytoplankton and zooplankton biomass and diversity, and abundance and distribution of fish, marine turtles, birds and mammals), and to the extent and health of ecosystems (cover and composition of hard coral, seagrass, mangrove and macroalgal canopy). Benthic invertebrate abundance and distribution and microbe diversity and biomass were identified as emerging EOVs to be developed based on emerging requirements and new technologies. The temporal scale at which any shifts in biological systems will be detected will vary across the EOVs, the properties being monitored and the length of the existing time-series. Global implementation to deliver useful products will require collaboration of the scientific and policy sectors and a significant commitment to improve human and infrastructure capacity across the globe, including the development of new, more automated observing technologies, and encouraging the application of international standards and best practices.
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