Explore the vast range of titles available.

The Great Salt Lake is a closed basin lake in which level and volume fluctuate due to differences between inflows and outflows. The only outflow is evaporation, which depends directly on lake area and salinity, both of which depend on lake volume. The lake's level, volume, and area adjust to balance, on average, precipitation and streamflow inflows by evaporation. In this paper, we examine the sensitivity of lake volume changes to precipitation, streamflow, and evaporation and the interactions among these processes and lake area and salinity related to volume. A mass balance model is developed to generate representative realizations of future lake level from climate and streamflow inputs simulated using the k‐nearest‐neighbor method. Climate and salinity are used to estimate evaporation from the lake using a Penman model adjusted for the salinity‐dependent saturation vapor pressure. Our results show that fluctuation in streamflow is the dominant factor in lake level fluctuations, but fluctuations in lake area that modulate evaporation and precipitation directly on the lake are also important. The results also quantify the sensitivity of lake level to changes in streamflow and air temperature inputs. They predict that a 25% decrease in streamflow would reduce lake level by about 66 cm (2.2 feet), while a +4°C air temperature increase would reduce lake level by about 34 cm (1.1 feet) on average. This sensitivity is important in evaluating the impacts of climate change or streamflow change due to increased consumptive water use on the level of the lake. Key Points Quantifies relative role of closed basin lake inputs on lake level and volume Physically based approach to predict lake level sensitivity to input changes Uncertainty in level predictions quantified using stochastic simulations

Great Salt Lake (Utah, USA) is one of the world's largest hypersaline lakes, supporting many of the western U.S.'s migratory waterbirds. This unique ecosystem is threatened, but it and other large hypersaline lakes are not well understood. The ecosystem consists of two weakly linked food webs: one phytoplankton-based, the other organic particle/benthic algae-based. Seventeen years of data on the phytoplankton-based food web are presented: abundances of nutrients (N and P), phytoplankton (Chlorophyta, Bacillariophyta, Cyanophyta), brine shrimp ( Artemia franciscana ), corixids ( Trichocorixa verticalis ), and Eared Grebes ( Podiceps nigricollis ). Abundances of less common species, as well as brine fly larvae ( Ephydra cinerea and hians ) from the organic particle/benthic algae-based food web are also presented. Abiotic parameters were monitored: lake elevation, temperature, salinity, PAR, light penetration, and DO. We use these data to test hypotheses about the phytoplankton-based food web and its weak linkage with the organic particle/benthic algae-based food web via structural equation modeling. Counter to common perceptions, the phytoplankton-based food web is not limited by high salinity, but principally through phytoplankton production, which is limited by N and grazing by brine shrimp. Annual N abundance is highly variable and depends on lake volume, complex mixing given thermo- and chemo-clines, and recycling by brine shrimp. Brine shrimp are food-limited, and predation by corixids and Eared Grebes does not depress their numbers. Eared Grebe numbers appear to be limited by brine shrimp abundance. Finally, there is little interaction of brine fly larvae with brine shrimp through competition, or with corixids or grebes through predation, indicating that the lake's two food webs are weakly connected. Results are used to examine some general concepts regarding food web structure and dynamics, as well as the lake's future given expected anthropogenic impacts.

Terminal lakes in the Great Basin (GB) of the western US host critical wildlife habitat and food for migrating birds and can be associated with serious human health and economic consequences when they desiccate. Water levels have declined dramatically in the last 100+ years due to diversion of inflows, drought and climate change. Satellite‐derived environmental science data records (ESDRs) from the MODerate‐resolution Imaging Spectroradiometer (MODIS) (snow cover, evapotranspiration (ET) and land surface temperature (LST)), enable a unique approach to evaluate the effects of aridification on terminal lakes and to study their individual vulnerabilities. Surface and air temperatures in the GB are rising dramatically, with a sharp rise in the rate of increase observed beginning around 2011, while the number of days of snow cover is declining especially in the western mountainous part of the GB as exemplified in Mono Basin, California. Rising temperatures coincide with fewer days of snow cover, a decrease of inflow to the lakes and greater evaporation of water from the lakes. MODIS ESDRs show strong and statistically significant increasing surface temperature (LST) in the GB, a reduction in the number of days of snow cover, and mixed results in ET. ET declined slightly in the more arid parts of the GB due to greater moisture restrictions to evaporation from extended drought, while ET increased in the more‐vegetated, wetter, mountainous northeastern parts as temperatures have risen. Severe and costly ecological, human health and economic consequences are expected if the lakes continue to decline as predicted. Plain Language Summary Terminal lakes in the Great Basin (GB) of the western US host critical wildlife habitat and food sources for migrating birds and can be associated with costly human health and economic consequences when they desiccate. Toxic minerals in the expanding lakebeds may become airborne during windstorms, contributing to air pollution. Satellite data products (snow cover, evapotranspiration and surface temperature) have enabled a unique understanding of the dynamics of aridification in the GB and associated effects on terminal lakes which are usually saline. Surface temperature is rising dramatically, with a sharp rise in the rate of increase observed beginning around 2011, while snow cover is declining especially in the western mountainous part of the GB as exemplified in Mono Basin, California. Evapotranspiration has declined slightly in lower elevation parts of the GB likely due to a decrease in vegetation there, while it has increased in the wetter, mountainous eastern part as temperatures have risen. Though we recognize that 21 years is not adequate for assessing trends, it is clear that increasing temperatures, greater evaporation of lake water and decreasing number of days of snow cover are contributing to desiccation of terminal lakes, with severe environmental and human health consequences expected. Key Points MODerate‐resolution Imaging Spectroradiometer data products provide a unique way to assess individual vulnerabilities of terminal lakes as temperatures rise in the US West Surface and air temperatures in the Great Basin (GB) are rising dramatically, with a sharp rise in the rate of increase observed beginning ∼2011 ET is generally lower in the GB, exacerbated by drought restrictions on surface evaporation, likely reinforcing regional warming

Snow in the Great Salt Lake Basin is a vital resource for regional agriculture, municipal water use, and the Great Salt Lake. Accumulation of light absorbing particles (LAPs) on mountain snowpacks results in lower albedos and earlier melt compared to clean snow. Though snow darkening is linked to dust events and varies spatially, snowmelt impacts have primarily been studied at the point scale. To address this gap, a spatially distributed process‐based snow model (iSnobal) was used to simulate the snowpack under different albedos: a “baseline” estimate uninfluenced by episodic LAP variability, and an “observed” scenario where MODIS snow albedo retrievals informed darkened snow conditions. Shifts in snow disappearance date (SDD) between scenarios were used to quantify the cumulative impact of snow darkening on melt over contrasting water years (WYs). The SDD shifts were greater in WY 2022, with snow disappearing 23–29 days earlier, attributed to sunny weather and darker snow. In WY 2023, SDD shifts were moderate with melt advancing 11–16 days, despite similar melt season albedos to WY 2022. Frequent storms in WY 2023 delayed darkening until later in the season, when melt progressed suddenly due to rapid albedo declines and weak longwave losses. In both years, SDD shifts were pronounced at subalpine elevations (∼2,300–2,900 m), potentially related to snow albedo declines coinciding with high solar irradiance and snowfall patterns. These findings suggest that melt sensitivity to snow darkening shows consistent spatial patterns, but the magnitude of snowmelt impacts is controlled by seasonal variability in meteorology.

With the desiccation of saline lakes around the globe, it is increasingly important to quantify the impacts of playa dust on downwind urban areas and mountain snowpack. In this study, we used 87Sr/86Sr ratios of carbonate minerals to trace dust from playas to urban areas and mountain snowpack. We focused on dust contributions from Great Salt Lake (GSL), in northern Utah, USA, which recently reached historic lows in water levels exposing large areas of dry lakebed. We measured 87Sr/86Sr ratios in dust from GSL, Sevier Dry Lake (SDL), and other playas across western Utah and compared them to 87Sr/86Sr ratios in dust across the urban Wasatch Front and mountain snowpack collected seasonally from 2015-2018. Dust from GSL had unique 87Sr/86Sr ratios (∼0.715) relative to SDL (∼0.710) and other playas (∼0.711 to 0.712), providing a potentially powerful tool for tracing GSL dust to downwind areas. Dust deposition had 87Sr/86Sr ratios ranging from ∼0.710 to ∼0.712 in the urban area and snowpack, within the range of playa dust sources. Using a simple two-endmember mixing model considering only GSL and SDL as sources, GSL contributed 5% of the dust flux to the southern Wasatch Front (Provo) and between 30%-34% of the dust flux to the northern Wasatch Front (Salt Lake City, Ogden, and Logan). For mountain snowpack, GSL contributed 11% of the dust flux to the Uinta Mountains and 22% of the dust flux to the Wasatch Mountains. Dust transport modeling could be combined with 87Sr/86Sr fingerprints for source apportionment in northern Utah and other areas that are impacted by regional playa dust.

Seasonal snowmelt from the Wasatch Mountains of northern Utah, USA, is a primary control on water availability for the metropolitan Wasatch Front, surrounding agricultural valleys, and the Great Salt Lake (GSL). Prolonged drought, increased evaporation due to warming temperatures, and sustained agricultural and domestic water consumption have caused GSL water levels to reach record low stands in 2021 and 2022, resulting in increased exposure of dry lakebed sediment. When dust emitted from the GSL dry lakebed is deposited on the adjacent Wasatch snowpack, the snow is darkened, and snowmelt is accelerated. Regular observations of dust-on-snow (DOS) began in the Wasatch Mountains in 2009, and the 2022 season was notable for both having the most dust deposition events and the highest snowpack dust concentrations. To understand if record high DOS concentrations were linked to record low GSL levels, dust source regions for each dust event were identified through a backward trajectory model analysis combined with aerosol measurements and field observations. Backward trajectories indicated that the exposed lakebed of the GSL contributed 23% of total dust deposition and had the highest dust emissions per surface area. The other potential primary contributors were the GSL Desert (45%) and the Sevier +Tule dry lakebeds (17%), both with lower per-area emissions. The impact on snowmelt, quantified by mass and energy balance modeling in the presence and absence of snow darkening by dust, was over 2 weeks (17 d) earlier. The impact of dust on snowmelt could have been more dramatic if the spring had been drier, but frequent snowfall buried dust layers, delaying dust-accelerated snowmelt later into the melt season.

Hypersaline Great Salt Lake’s (GSL: Utah, USA) pelagic food web is dominated by the herbivore, Artemia franciscana . Artemia demographic responses (survival, developmental transition, and reproduction) to GSL salinities, temperatures, common phytoplankton and yeast, and food levels were examined by factorial experiment. Survival across developmental stages was best at 90 ppt salinity, and decreased as temperature increased. Transition between life stages was best at 45 ppt salinity, and increased as temperature increased. Food was most important with both survival and transitioning responding similarly to food types and increasing with amount of food. Artemia reproduce in two ways (diapausing cysts – oviparity, live young – ovoviviparity): ovoviviparous and total reproduction were greatest at 90 ppt salinity and 20 °C, while oviparous reproduction was weakly affected by salinity and greatest at 20 °C. Oviparity was greatest at low food availability, while ovoviviparity and total reproduction increased with food availability, so reproduction shifted from oviparity to ovoviviparity as food increased. Maternal effects were observed for cyst hatchability, and ovoviviparous nauplii survival and transitioning to the juvenile stage. Combinations of salinity, temperature, food taxa and food amount strongly affect demography, making single factor studies of limited value. Results explain Artemia abundance in different parts of GSL and among years.

Climate change and water diversions are putting the Great Salt Lake (GSL) at risk. Projections indicate a continued decrease in the GSL water surface elevation (WSE) would lead to several catastrophic consequences. An aspect of the GSL dynamics gaining importance, and not addressed in past studies, is how resilient the lake WSE will be to increasing diversions from contributing rivers, intensifying drought conditions, and more frequent hydrologic deficits caused by climate change. The objectives of the present study were to: (1) examine the impacts of historical drought and development on the GSL resilience and (2) determine future WSE resilience under a range of hydroclimate and development scenarios. The historical resilience was analyzed considering three periods with different development conditions: (1) less developed (1901–1950); (2) moderately developed (1951–2000); (3) highly developed (2001–2020). Furthermore, a range of hydroclimate and development conditions were introduced into a system dynamics-based water management model to simulate the future GSL WSE and corresponding resilience. The historical analysis showed a significant decline in resilience (45.4%) during the highly developed period compared with the moderately developed period. Future scenarios of climate change and development revealed that the mean GSL WSE for the 2021–2050 period may drop by 0.93 m, while the resilience reduces by 30%, and 38% using RCP4.5 and RCP8.5 scenarios when compared to the less and medium developed historical periods respectively. This research provides insight for the State of Utah Department of Natural Resources and stakeholders to inform water management policies and GSL adaptive management strategies.

Grazing experiments were conducted for the zooplankton Artemia franciscana on three of its most common Great Salt Lake (Utah: USA) phytoplankton species (> 80–90% of phytoplankton biovolume: a chlorophyte, Dunaliella viridis ; a cyanobacterium, Euhalothece sp., and a bacillariophyte, the pennate diatom Nitzschia epithemioides ). For each Artemia developmental stage (nauplii, juveniles and adults), grazing rates (same phytoplankton abundances, temperatures, and salinities) are reported along with grazing preferences for the phytoplankton species in mixes of species pairs and all three species together. Each Artemia developmental stage exhibited different preferences for the phytoplankton species. Preferences measured for each species pair were consistent with preferences when all three species were together and were correlated with the phytoplankton’s survival value for each Artemia developmental stage. Survival values were positively related to the ingestion rate for each phytoplankton species (biovolume/individual/h), likely a function of cell size, and its nutritional quality treated as a function of phytoplankton N:P relative to Artemia developmental stage N:P.

Covering a large swath of the American West, the Great Basin, centered in Nevada and including parts of California, Utah, and Oregon, is named for the unusual fact that none of its rivers or streams flow into the sea. This fascinating illustrated journey through deep time is the definitive environmental and human history of this beautiful and little traveled region, home to Death Valley, the Great Salt Lake, Lake Tahoe, and the Bonneville Salt Flats. Donald K. Grayson synthesizes what we now know about the past 25,000 years in the Great Basin—its climate, lakes, glaciers, plants, animals, and peoples—based on information gleaned from the region’s exquisite natural archives in such repositories as lake cores, packrat middens, tree rings, and archaeological sites. A perfect guide for students, scholars, travelers, and general readers alike, the book weaves together history, archaeology, botany, geology, biogeography, and other disciplines into one compelling panorama across a truly unique American landscape.