South Coast

Exposure history determines pteropod vulnerability to ocean acidification along the US West Coast

Nature Portfolio (Springer Nature) | July 3rd, 2017

The pteropod Limacina helicina frequently experiences seasonal exposure to corrosive conditions (Ωar  < 1) along the US West Coast and is recognized as

The pteropod Limacina helicina frequently experiences seasonal exposure to corrosive conditions (Ωar  < 1) along the US West Coast and is recognized as one of the species most susceptible to ocean acidification (OA). Yet, little is known about their capacity to acclimatize to such conditions. We collected pteropods in the California Current Ecosystem (CCE) that differed in the severity of exposure to Ωar conditions in the natural environment. Combining field observations, high-CO2 perturbation experiment results, and retrospective ocean transport simulations, we investigated biological responses based on histories of magnitude and duration of exposure to Ωar < 1. Our results suggest that both exposure magnitude and duration affect pteropod responses in the natural environment. However, observed declines in calcification performance and survival probability under high CO2 experimental conditions do not show acclimatization capacity or physiological tolerance related to history of exposure to corrosive conditions. Pteropods from the coastal CCE appear to be at or near the limit of their physiological capacity, and consequently, are already at extinction risk under projected acceleration of OA over the next 30 years. Our results demonstrate that Ωar exposure history largely determines pteropod response to experimental conditions and is essential to the interpretation of biological observations and experimental results.

Extreme California Rains During Winter 2015/16: A Change in El Niño Teleconnection?

American Meteorological Society (AMS) | January 25th, 2018

This is a story of two extreme events—one that was expected but failed to occur and the other that actually did occur but was not anticipated. The one that failed was

This is a story of two extreme events—one that was expected but failed to occur and the other that actually did occur but was not anticipated. The one that failed was extreme wetness over Southern California (SCAL) during winter 2015/16, which was predicted by seasonal forecasts. The extreme event that did occur was dryness whose considerable magnitude exacerbated one of the worst droughts on record over SCAL. *Chapter 10,  Explaining Extreme Events of 2016 from a Climate Perspective, Herring, S. C., N. Christidis, A. Hoell, J. P. Kossin, C. J. Schreck III, and P. A. Stott, Eds., 2018: Bull. Amer. Meteor. Soc., 99 (1), S1–S157.

Extreme hydrological changes in the southwestern US drive reductions in water supply to Southern California by mid century

Environmental Research Letters (IOP) | September 21st, 2016

The Southwestern United States has a greater vulnerability to climate change impacts on water security due to a reliance on snowmelt driven imported water. The State of C

The Southwestern United States has a greater vulnerability to climate change impacts on water security due to a reliance on snowmelt driven imported water. The State of California, which is the most populous and agriculturally productive in the United States, depends on an extensive arti cial water storage and conveyance system primarily for irrigated agriculture, municipal and industrial supply and hydropower generation. Here we take an integrative high-resolution ensemble modeling approach to examine near term climate change impacts on all imported and local sources of water supply to Southern California. While annual precipitation is projected to remain the same or slightly increase, rising temperatures result in a shift towards more rainfall, reduced cold season snowpack and earlier snowmelt. Associated with these hydrological changes are substantial increases in the frequency and the intensity of both drier conditions and ooding events. The 50 year extreme daily maximum precipitation and runoff events are 1.5–6 times more likely to occur depending on the water supply basin. Simultaneously, a clear de cit in total annual runoff over mountainous snow generating regions like the Sierra Nevada is projected. On one hand, the greater probability of drought decreases imported water supply availability. On the other hand, earlier snowmelt and signicantly stronger winter precipitation events pose increased flood risk requiring water releases from control reservoirs, which may potentially decrease water availability outside of the wet season. Lack of timely local water resource expansion coupled with projected climate changes and population increases may leave the area in extended periods of shortages.

Extreme Precipitation-Temperature Scaling in California: The Role of Atmospheric Rivers

American Geophysical Union (AGU) | July 25th, 2023

Extremophile hotspots linked to containerized industrial waste dumping in a deep-sea basin

Oxford University Press (OUP) | September 9th, 2025

Decaying barrels on the seafloor linked to DDT contamination have raised concerns about the public health implications of decades old industrial waste dumped off the coas

Decaying barrels on the seafloor linked to DDT contamination have raised concerns about the public health implications of decades old industrial waste dumped off the coast of Los Angeles. To explore their contents, we collected sediment cores perpendicular to five deepsea barrels. The concentration of DDT and its breakdown products were highly elevated relative to control sites yet did not vary with distance from the barrels, suggesting that they were not associated with the contamination. Sediment cores collected through white halos surrounding three barrels were enriched in calcite and had elevated pH. The associated microbial communities were low diversity and dominated by alkalophilic bacteria with metagenome-assembled genomes adapted to high pH. A solid concretion sampled between a white halo and barrel was composed of brucite, a magnesium hydroxide mineral that forms at high pH. Based on these findings, we postulate that leakage of containerized alkaline waste triggered the formation of mineral concretions that are slowly dissolving and raising the pH of the surrounding sediment pore water. This selects for taxa adapted to extreme alkalinity and drives the precipitation of “anthropogenic” carbonates forming white halos, which serve as a visual identifier of barrels that contained alkaline waste. Remarkably, containerized alkaline waste discarded >50 years ago represents a persistent pollutant creating localized mineral formations and microbial communities that resemble those observed at some hydrothermal systems. These formations were observed at one-third of the visually identified barrels in the San Pedro Basin and have unforeseen, long-term consequences for benthic communities in the region.

Facing the Climate Gap: How Environmental Justice Communities are Leading the Way to a More Sustainable and Equitable California

University of Southern California (USC) | October 31st, 2012

California has traditionally led the nation in protecting and preserving the environment – and we have proudly continued the trend with the 2006 passage and ong

California has traditionally led the nation in protecting and preserving the environment – and we have proudly continued the trend with the 2006 passage and ongoing implementation of the California Global Warming Solutions Act (AB 32). Aimed at reducing greenhouse gas emissions (GHGs) and slowing climate change, AB 32 came under political attack in 2010 when an initiative, funded largely by oil refiners, sought to delay application of the legislation’s rules. Fortunately, voters soundly rejected that effort, but many observers have worried that California’s concerns about climate could wane, particularly since the actual impacts of climate change can seem abstract and far-off. Against this backdrop, a wide range of community-based organizations have been working to “make it real” by connecting the dots between global warming and human impacts, and by helping residents adapt now and not later. In what might be a surprise to some observers, many of these organizations are working with low-income communities of color – those often stereotyped as the least concerned about climate change.

Federal Reserved Water Rights and Groundwater: Quantity, Quality, and Pore Space

Congressional Research Service (CRS) | February 8th, 2018

Tribal rights to groundwater have not been legally established to the same extent as rights to other natural resources (e.g., surface water, timber, minerals). A March 2

Tribal rights to groundwater have not been legally established to the same extent as rights to other natural resources (e.g., surface water, timber, minerals). A March 2017 decision of the U.S. Court of Appeals for the Ninth Circuit upheld the rights of a California Indian tribe (the Agua Caliente band of Cahuilla Indians) to groundwater beneath the tribe's reservation in the Coachella Valley. In November 2017, the U.S. Supreme Court declined to review the decision; the case now proceeds to other phases that may partially shape this ruling's significance. This is the first case in which an appellate court has held that a tribe's "reserved" rights under the Winters doctrine apply to groundwater. Pursuant to Winters, when Congress reserves land for a reservation, it also reserves a right to water necessary to accomplish the purposes for which the reservation was created. For decades, tribal reserved rights for surface water have been established and have required settlements between the federal government (as authorized by Congress), tribes, and nonfederal users. Thus, some have raised concerns about the implications of interpreting Winters rights to include groundwater. This Insight explores three aspects of groundwater relevant to Agua Caliente: quantity, quality, and "pore space." The legal outcome may affect how groundwater is allocated among tribal and nontribal interests and may influence groundwater allocations at other federal reservations. The Supreme Court has not declared outright that groundwater is subject to the Winters doctrine, but declining to review the Ninth Circuit decision essentially upheld phase one of the three-phase case: a federally reserved right to the groundwater resource for the tribe. Phase two will address whether the tribe has the right to receive groundwater of a certain quality from the aquifer and whether it owns the pore space beneath tribal lands. Phase three will determine the quantity of groundwater to which the tribe is entitled, pursuant to its reserved rights. The outcome of phases two and three could have implications for expanding the scope of federal preemption of state water law. It also could affect how much groundwater is available for nontribal water agencies and water districts and those entities' ability to store water in an aquifer beneath federally reserved lands. Congress has authority over federal water law and could influence this legal framework.

Fillmore Basin Groundwater Sustainability Plan

Fillmore and Piru Basins Groundwater Sustainability Agency | December 16th, 2021

The Fillmore Basin (the Basin) is managed (along with the upslope Piru Basin) by the Fillmore and Piru Basins Groundwater Sustainability Agency (the Agency). The Basin is

The Fillmore Basin (the Basin) is managed (along with the upslope Piru Basin) by the Fillmore and Piru Basins Groundwater Sustainability Agency (the Agency). The Basin is planned to remain sustainable over the Sustainable Groundwater Management Act (SGMA) implementation and sustainability period based on the current understanding of historical, current (2019), and projected (2022 through 2072) groundwater conditions in relation to the sustainability indicators specified in SGMA. A sustainability indicator refers to any of the effects caused by groundwater conditions occurring throughout the basin that, when significant and unreasonable, cause undesirable results. The Agency, with consideration of feedback from active stakeholder engagement, has identified and planned for the prevention of significant and unreasonable undesirable results.

Final Environmental Impact Report for Adoption of a Regulation for the Hexavalent Chromium Maximum Contaminant Level

California State Water Resources Control Board (SWRCB) | April 17th, 2024

As the lead agency in accordance with sections 15089 and 15132 of the California Environmental Quality Act (CEQA) Guidelines (Cal. Code Regs., tit. 14, § 15000 et seq.),

As the lead agency in accordance with sections 15089 and 15132 of the California Environmental Quality Act (CEQA) Guidelines (Cal. Code Regs., tit. 14, § 15000 et seq.), this document is the Final Environmental Impact Report (Final EIR) for the adoption of statewide regulations setting the maximum contaminant level (MCL) for hexavalent chromium (Proposed Regulations). The Proposed Regulations include a maximum contaminant level (MCL) of 10 μg/L for hexavalent chromium. (Cal. Code Regs. tit. 22, § 64431 Table 64431-A.) The Proposed Regulations also include a compliance schedule based on public water system size, by adding subdivision (p) and Table 64432-B to section 64432 of title 22 of the California Code of Regulations, identifies a detection limit for purposes of reporting, sets monitoring and reporting requirements and public notice requirements for violations of the MCL, and establishes the Best Available Technologies (BAT) for treating hexavalent chromium in drinking water. California State Water Resources Control Board (SWRCB) Chrom VI MCL rulemaking chronology.

Final Groundwater Assessment Study: A Status Report on the Use of Groundwater in the Service Area of the Metropolitan Water District of Southern California

Metropolitan Water District of Southern California (MWD) | September 3rd, 2007