Visual, spectral, and microchemical quantification of crystalline anomalies in otoliths of wild and cultured delta smelt

Nature Portfolio (Springer Nature) | December 1st, 2022

Developmental abnormalities in otoliths can impact growth and survival in teleost fishes. Here, we quantified the frequency and severity of developmental anomalies in oto

Developmental abnormalities in otoliths can impact growth and survival in teleost fishes. Here, we quantified the frequency and severity of developmental anomalies in otoliths of delta smelt (Hypomesus transpacificus), a critically endangered estuarine fish that is endemic to the San Francisco Estuary. Left–right asymmetry and anomalous crystalline polymorphs (i.e., vaterite) were quantified and compared between wild and cultured populations using digital image analysis. Visual estimates of vaterite were validated using X-ray diffraction, Raman spectroscopy, laser ablation ICPMS, and electron probe microanalysis. Results indicated that cultured delta smelt were 80 times more likely to contain a vateritic otolith and 18 times more likely to contain relatively large (≥ 15%) amounts of vaterite. Similarly, cultured fish exhibited 30% greater asymmetry than wild fish. These results indicate that cultured delta smelt exhibit a significantly higher frequency of vestibular abnormalities which are known to reduce fitness and survival. Such hatchery effects on otolith development could have important implications for captive culture practices and the supplementation of wild fish populations with cultured individuals.

Warming weakens the night-time barrier to global fire

Nature Portfolio (Springer Nature) | February 16th, 2022

Night-time provides a critical window for slowing or extinguishing fires owing to the lower temperature and the lower vapour pressure deficit (VPD). However, fire danger

Night-time provides a critical window for slowing or extinguishing fires owing to the lower temperature and the lower vapour pressure deficit (VPD). However, fire danger is most often assessed based on daytime conditions1,2, capturing what promotes fire spread rather than what impedes fire. Although it is well appreciated that changing daytime weather conditions are exacerbating fire, potential changes in night-time conditions—and their associated role as fire reducers—are less understood. Here we show that night-time fire intensity has increased, which is linked to hotter and drier nights. Our findings are based on global satellite observations of daytime and night-time fire detections and corresponding hourly climate data, from which we determine landcover-specific thresholds of VPD (VPDt), below which fire detections are very rare (less than 95 per cent modelled chance). Globally, daily minimum VPD increased by 25 per cent from 1979 to 2020. Across burnable lands, the annual number of flammable night-time hours—when VPD exceeds VPDt—increased by 110 hours, allowing five additional nights when flammability never ceases. Across nearly one-fifth of burnable lands, flammable nights increased by at least one week across this period. Globally, night fires have become 7.2 per cent more intense from 2003 to 2020, measured via a satellite record. These results reinforce the lack of night-time relief that wildfire suppression teams have experienced in recent years. We expect that continued night-time warming owing to anthropogenic climate change will promote more intense, longer-lasting and larger fires.

Water Ages Explain Tradeoffs Between Long-Term Evapotranspiration and Ecosystem Drought Resilience

American Geophysical Union (AGU) | May 23rd, 2023

Water is a master variable: Solving for resilience in the modern era

Water Security, Elsevier | November 21st, 2019

Resilience is increasingly recognized as an imperative for any prospect of sustainable development, as it relates to our ability to sustain human well-being and progress

Resilience is increasingly recognized as an imperative for any prospect of sustainable development, as it relates to our ability to sustain human well-being and progress under the planetary and societal changes that we face now and into the future. Yet, we are ill-prepared to meet this challenge. We neither fully understand nor manage consistently for resilience of the human and natural systems that we must steward through extraordinary change. A unifying approach and common currency would help us to understand and manage for resilience under uncertain futures. Water is an essential, defining element in human and natural systems. Human civilization and water systems have co-evolved as a coupled system, with the majority of natural freshwater systems transformed to meet our demands. Shifting patters of water availability in space and time will define key pathways and tipping points for our resilience, and thus requirements for water system resilience must guide the trajectories and boundaries of human development. Here, we consider the thesis that water offers a key to unlocking the complex challenge of designing and managing for the resilience of coupled human-natural systems. We examine what constitutes a resilient system, what drives freshwater resilience, and how pathways to human resilience may be charted and navigated through the medium of water. Our theoretical treatise frames a portfolio of research that tests this thesis, including modeling and applications to water and water-dependent systems.

Water Management Companion Plan (to the Statewide Wildlife Action Plan)

California Department of Fish and Wildlife (CDFW) | December 21st, 2016

The California State Wildlife Action Plan 2015 Update provides a vision and a framework for conserving California’s diverse natural heritage. SWAP 2015 also calls for t

The California State Wildlife Action Plan 2015 Update provides a vision and a framework for conserving California’s diverse natural heritage. SWAP 2015 also calls for the development of a collaborative framework to sustainably manage ecosystems across the state in balance with human uses of natural resources. To address the need for a collaborative framework, California Department of Fish and Wildlife (CDFW), Blue Earth Consultants, LLC (Blue Earth), and partner agencies and organizations undertook the preparation of companion plans for SWAP 2015. While this document reports on the progress made thus far on collaboration, the intent is to set a stage for achieving the state’s conservation priorities through continued partnerships and by mutually managing and conserving natural and cultural resources.

Water Quality Challenges in the San Francisco Bay/ Sacramento-San Joaquin Delta Estuary: EPA’s Action Plan

U.S. Environmental Protection Agency (EPA) | August 22nd, 2012

The U.S. Environmental Protection Agency (EPA) developed this Action Plan after assessing the effectiveness of current regulatory mechanisms designed to protect water qua

The U.S. Environmental Protection Agency (EPA) developed this Action Plan after assessing the effectiveness of current regulatory mechanisms designed to protect water quality in the San Francisco Bay Sacramento-San Joaquin Delta Estuary (Bay Delta Estuary) and its tributaries. EPA’s assessment concludes that Clean Water Act (CWA) programs currently are not adequately protecting aquatic resources of the Bay Delta Estuary. In this document, EPA recommends actions to restore water quality for aquatic species protection using existing EPA authorities and resources, as well as actions EPA believes are important and appropriate for the State Water Resources Control Board (State Water Board). EPA is one of more than 25 state and federal governmental agencies with responsibilities in the Bay Delta Estuary. EPA’s major statutory mission in the Estuary is to implement the CWA. EPA has delegated many CWA program authorities to the State Water Board while providing financial support,1 technical assistance, and oversight (including, in some cases, review and approval of State actions). Much of EPA's work in this Action Plan (as well as elsewhere in California) is done in support of and in partnership with the State. For example, water quality standards, which define water quality goals for our waterbodies, are typically developed and adopted by the State with EPA assistance, review, and ultimately, approval or disapproval. In the Bay Delta Estuary, EPA focuses on assuring that the many designated uses of the Estuary’s aquatic resources are protected. EPA emphasizes the CWA goals of maintaining and improving water quality – the chemical, physical, and biological integrity of the water – to ensure the Bay Delta Estuary can function as a vibrant, healthy estuary. About 90 species of fish are found in the Delta. The Delta’s channels serve as a migratory route and nursery area for Chinook salmon, striped bass, white and green sturgeon, American shad, and steelhead trout. These anadromous fish spend most of their adult lives either in the lower bays of the Estuary or in the ocean. Resident fish in the Estuary include delta smelt, longfin smelt, Sacramento splittail, catfish, largemouth bass, black bass, crappie, and bluegill. All Bay Delta Estuary waters are impaired by one or more contaminants. In addition, the reduction in the quantity and quality of estuarine habitat limits the Estuary’s ability to support aquatic species. EPA’s Action Plan describes a suite of activities to: 1. Strengthen water quality standards to protect estuarine habitat 2. Advance regional water quality monitoring and assessment 3. Accelerate water quality restoration through Total Maximum Daily Loads 4. Strengthen selenium water quality criteria 5. Prevent pesticide pollution 6. Restore aquatic habitats while managing methylmercury 7. Support the Bay Delta Conservation Plan Collectively, these activities will contribute to the restoration of the Bay Delta Estuary. Even if they are all successfully implemented, however, they are not sufficient to resolve the complex problems that have stressed the ecosystem to the point of collapse. Any solution to the ecological problems of the Bay Delta Estuary must be multi-faceted, including providing sufficient flows, physical habitat which is sufficiently large, connected, diverse, and self-sustaining, as well as a reduction of many types of stressors, such as contaminants, invasive species, and predation.

Water Right Decision 1485: Sacramento-San Joaquin Delta and Suisun Marsh

California State Water Resources Control Board (SWRCB) | August 16th, 1978

Water Supply and Habitat Resiliency for a Future Los Angeles River: Site-Specific Natural Enhancement Opportunities Informed by River Flow and Watershed-Wide Action

Nature Conservancy | December 15th, 2016

The mission of The Nature Conservancy is to conserve the lands and waters on which all life depends. As the Conservancy engages with the Los Angeles region, they are inve

The mission of The Nature Conservancy is to conserve the lands and waters on which all life depends. As the Conservancy engages with the Los Angeles region, they are investigating what it means to carry out this mission in the highly urbanized Los Angeles River ecosystem. As a starting point, it is known that the basic ecological principles of science apply to all environmental systems, regardless of their location. Therefore, the Conservancy is testing these principles by applying them in the Elysian Valley of the Los Angeles River and identifying habitat enhancement requirements, opportunities, and constraints. As a basic principle of ecological systems, a watershed’s hydrology determines the flow characteristics of its river system. These flows define what the biological characteristics of that river will be, which in turn determine what kinds of habitat enhancement projects will succeed at various locations along a river. The study of the Elysian Valley included one full year of multi-taxa biological surveys, a historical ecology investigation of the Elysian Valley, and a review of historic and existing hydrological and hydraulic conditions. Major findings of this study are: Multiple Flow Scenarios = Uncertainty: There are currently multiple visions for the flow characteristics of the Los Angeles River as a whole due to differing management priorities of the agencies and stakeholders that have governance over different aspects of this hydrologic system. Bringing the various hydrologic plans and possibilities for the watershed into a single integrated vision of system flow characteristics will allow certainty and clarity at the site level for the design of habitat projects anywhere in the River system, including the Conservancy’s study area. Flows Drive Biology: The study area currently has higher flood and much higher dry weather flow rates than its historic condition. These high flow rates are supporting and encouraging non-native and invasive species. This leads to a lower level of biological diversity and resiliency than what would exist under lower flow rates, particularly during dry weather conditions. Prioritize Complementary Habitats: Enhancing and increasing the amount of perennial riparian habitat in-stream alone will not create as much biological value as identifying complementary enhancement opportunities outside of the River channel in adjacent upper terrace floodplain and upland habitats (e.g. alluvial scrub, mulefat scrub, willow scrub, oak-sycamore woodland, sage scrub, and grassland). River Adjacent Land Use: Land uses adjacent to the River and throughout the watershed are a part of the solution and part of the Los Angeles River’s biological and hydrologic system. The landscaping and hydrology of these areas should be designed to provide a value-added role to the habitat functions of the Los Angeles River ecosystem. Next steps for advancing the discussion of habitat enhancement include working with local stakeholders and agencies to find consensus on a flow condition for the River and its Watershed as a whole. In the study area itself there are six complementary project opportunities that could be implemented in the near term to advance understanding of habitat enhancement for the Los Angeles River. These smaller, localized projects can be used as pilot projects for the complicated jurisdictional and regulatory processes that all future habitat projects will have to navigate. They will provide a manageable and controlled process that will bring the necessary agencies together to identify the most effective processes for future projects throughout the Los Angeles River ecosystem.

Water-Resources Data for the Devils Hole Area, Nye County, Nevada, July 1978 - September 1988

U.S. Geological Survey (USGS) | July 1st, 1993

Data on water levels, spring discharge, and consumption of electric power by irrigation pumps collected at Devils Hole and vicinity from July 1978 through September 1988

Data on water levels, spring discharge, and consumption of electric power by irrigation pumps collected at Devils Hole and vicinity from July 1978 through September 1988 are reported herein. These data were collected to document the effects of irrigation pumping on the pool level at Devils Hole and the recovery following cessation of irrigation pumping in August 1982. The pool contains the endangered species of pupfish, Cyprinodon diabolis. Data on fluctuations in water level and springflow are presented in graphic form. Data on consumption of electric power by pumps in irrigation wells, useful as an index of the pumpage, are presented in tabular form.

Waterline responses to climate forcing along the North American West Coast

Nature Portfolio (Springer Nature) | June 7th, 2025

Understanding waterline variability at seasonal to interannual timescales is crucial for predicting coastal responses to climate forcing. However, relationships between l

Understanding waterline variability at seasonal to interannual timescales is crucial for predicting coastal responses to climate forcing. However, relationships between large-scale climate variability and coastal morphodynamics remain underexplored beyond intensively monitored sites. This study leverages a newly developed 25-year (1997–2022) satellite-derived waterline dataset along the North American West Coast. Our results reveal distinct latitudinal patterns in seasonal waterline change, with excursions exceeding 25 m in the Pacific Northwest, decreasing to less than 10 m in Southern California and farther south. Waterline fluctuations strongly follow wave power in the Pacific Northwest (R = −0.78), northern California (R = −0.75), and Baja California (R = −0.62), while Baja California Sur aligns more with sea-level variations (R = −0.42). Interannually, waterline change exhibits latitudinal dependence: south of southern California, variability is low, with major erosion confined to strong El Niño-Southern Oscillation (ENSO) events, while northern regions show mixed responses. ENSO-driven storm track shifts modulate winter wave climate, resulting in enhanced (attenuated) erosion from southern California to Baja California Sur during El Niño (La Niña). However, further north, ENSO impacts are less consistent, reflecting a complex interplay of storm track displacement and intensification. These findings highlight the spatial complexity of ENSO-driven morphodynamics and provide a framework for assessing climate-induced coastal vulnerability.