February 17, 2017: The Southern California Stormwater Monitoring Coalition has completed a comprehensive analysis of the range of ecological condition scores obtained when engineered channels across coastal Southern California are scored using existing stream bioassessment tools.
The study, co-authored by SCCWRP and published in the SMC's 2015 annual report
, found that condition assessments based on multiple bioindicators are far more useful in engineered channels than assessments based on one indicator alone.
Specifically, using a benthic macroinvertebrate-based scoring tools together provided a more complete picture of stream health. The algae-based scoring tools, for example, generated a wider range of bioassessment scores than the benthic macroinvertebrate-based scoring tool, which typically generated bioassessment scores well below the threshold for healthy streams.
The SMC also shed light on why some engineered channels score better than others – insights that could help stream managers understand how best to direct resources to improve channel health. The study showed that bioassessment scores are influenced by habitat factors, including microhabitat diversity and shading, as well as by water quality, including specific conductivity and temperature.
The SMC study was conducted as California moves toward developing a biointegrity policy governing the condition of streams statewide. The SMC is evaluating the biological condition of engineered channels across California's South Coast region to understand how stream managers could be affected by this upcoming policy.
Engineered channels, which are streams that have been modified through installation of manmade features such as concrete lining, tend to score more poorly with bioassessment tools than their non-engineered counterparts, and might not be able to support the same biological communities. Engineered channels make up an estimated 40% of all stream-miles in the region.
The findings of the SMC study will inform ongoing discussions between regulators and permittees about appropriate biological objectives for engineered channels.
The Southern California Stormwater Monitoring Coalition's 2015 Report on the
SMC Regional Stream Survey, published in January, includes the findings of a study
shedding light on why some engineered channels in Southern California receive higher
ecological condition scores than others. The insights could help stream managers understand
how best to direct resources to improve the ecological health of engineered channels across
coastal Southern California.
February 10, 2017: SCCWRP and its partners will expose fish to flowing Los Angeles River water in real time this spring as part of an on-site study examining potential biological impacts to fish from exposure to contaminants of emerging concern (CECs).
The pilot project, which marks the first use of mobile exposure units for a Southern California water-quality study, will enable researchers to replicate environmental conditions more accurately than exposing the fish to a water sample in a laboratory setting. Mobile exposure units are set up along stream banks to pump water in real time through fish exposure chambers; the devices control for factors such as flow rate, food source, illumination and dissolved oxygen.
For the pilot study, scheduled to kick off in April, SCCWRP and the City of Los Angeles Bureau of Sanitation will set up mobile exposure units at two L.A. River sites – one just downstream of the L.A.-Glendale Water Reclamation Plant, and the other at a site in the Sepulveda Basin that receives urban runoff. Fathead minnows will be placed in exposure chambers for 15 days.
Researchers hope to learn whether CECs, which can be found in wastewater effluent and land-based runoff, trigger biological effects in fish, including changes in gene expression, tissue integrity and sex characteristics.
SCCWRP will analyze the fish using traditional toxicology tests and targeted chemical analysis, as well as use novel bioanalytical assays to link observed biological effects to CEC bioactivity levels.
In particular, endocrine-disruptive CECs such as nonylphenol, estrone, bisphenol A and galaxolide have been shown to affect sexual maturation and reproduction of fish in laboratory settings; these CECs have previously been detected in the L.A. River watershed.
The L.A. River flow-through study is being launched as water-quality regulators increasingly focus on understanding how CECs in freshwater systems could be affecting fish communities.
Over time, SCCWRP intends to use the mobile exposure units to conduct additional exposure studies in other watersheds. The goal is to gain a better understanding of what biological endpoints should be tracked to comprehensively assess CECs’ impacts on fish.
Mobile exposure units, which are set up along stream banks, pump water in real time
through exposure chambers that house fish to more accurately mimic real environmental
conditions. SCCWRP and its partners will use the technology for the first time this spring to
track how fathead minnows are impacted be CECs in Los Angeles River water.
February 03, 2017:
A 16-member expert panel convened to interpret bioassessment scores for wadeable streams statewide has reached consensus on how the scores correspond to various ranges of ecological condition.
The Biological Condition Gradient (BCG) expert panel, co-facilitated by SCCWRP and Tetra Tech, met at SCCWRP for four days in December and January to develop a BCG model for California wadeable streams using species composition data from more than 200 stream sites that represent a wide range of environmental conditions.
The BCG modeling approach defines for stream managers how stream condition scores relate to ecosystem function and services, enabling stream managers to more meaningfully interpret their stream bioassessment scores and make threshold decisions that protect a stream’s beneficial uses.
With the BCG interpretive framework, stream managers across California will gain an improved understanding of the consequences of losing various biological attributes of stream health as bioassessment scores fall in response to increasing stress.
The BCG model is a centerpiece of a State Water Board plan to use bioassessment scoring tools – namely, the California Stream Condition Index, which uses benthic invertebrates as bioindicators of ecological condition, and its algae-based counterpart, the Algal Stream Condition Index – as the basis for crafting a combined statewide biointegrity and biostimulatory (nutrient) policy to govern the health of California wadeable streams.
The State Water Board could adopt the policy as early as 2019, pending completion of science and policy elements.
During the BCG modeling workshops, the 16 experts, which were selected from across the nation, created six categories, or bins, of ecological stream condition and worked towards consensus in assigning each of the 200+ stream sites to one of the bins, based on the types of benthic invertebrate and algal species observed at the site.
SCCWRP and TetraTech will use these classifications to quantify the ranges of bioassessment index scores that correspond to each bin.
The BCG expert panel will present its findings to the State Water Board and other stakeholders this spring; a written report will be released this fall.
The Santa Clara River near Los Angeles County-Ventura County line is an example
of an urbanized stream that has experienced ecological degradation. Its condition
was evaluated by an expert panel as part of a Biological Condition Gradient modeling project.
The minimally disturbed North Fork of the San Gabriel River in Los Angeles County,
left, and channelized Forrester Creek in San Diego County are among the stream sites
placed into ecological condition categories by a 16-member expert panel convened by
SCCWRP to develop a Biological Condition Gradient model for wadeable streams statewide.
November 21, 2016:
SCCWRP and its partners have completed a comprehensive investigation into how sediment contamination is transferred through Southern California marine food webs, a study that has enabled scientists to close key data gaps and build more accurate models for estimating health risks to wildlife and humans across coastal California.
The three-year study, which was finalized in October, was conducted in San Diego Bay; it already is being used to refine and calibrate a standardized sediment assessment framework under development for California’s coastal embayments to extend greater protections to human health. The statewide Sediment Quality Objective (SQO) for protection of human health – which relies on bioaccumulation models to explain how contaminants travel through food webs – will help inform sediment clean-up targets and other management actions for embayments.
The study involved linking major contaminants found in San Diego Bay sediment – including PCBs, pesticides and trace metals – to the contaminants that were found to be bioaccumulating in organisms throughout the marine food web, from sediment-dwelling organisms to seabirds. Sediment contaminants are transferred through food webs by each successive predator that consumes its prey.
The study found that all types of sportfish examined had contamination levels that exceeded statewide safe-eating guidelines for humans, and seabirds also were potentially at risk from eating fish that had mercury and PCB contamination.
However, the health risks from sediment contamination were low, and conditions have improved in recent years, according to the study. For example, PCB contamination in seafood has dropped two- to five-fold over the past 15 years.
San Diego Bay environmental managers will use the study’s findings to take more effective, targeted actions to continue to improve the bay’s sediment quality.
In early 2017, the State Water Board is expected to release a draft of the California SQO assessment framework for protection of human health; the framework has been improved using data obtained from the San Diego Bay bioaccumulation study and other case studies. The counterpart to the SQO human health framework – the SQO assessment framework for the protection of sediment-dwelling aquatic life – was co-developed by SCCWRP and adopted by the State Water Board in 2009.
A researcher collects abandoned bird eggs from the California least tern in South
San Diego Bay's Salt Works area. Field sampling was conducted for organisms at multiple
levels of the marine food web for a San Diego Bay contaminant bioaccumulation study.
(Courtesy of Lea Squires)
The San Diego Bay bioaccumulation study analyzed 209 tissue samples (plotted on map)
from across San Diego Bay 64 sediment samples. The study was done in partnership
with the Southern California Bight 2013 Regional Monitoring Program, San Diego
Regional Harbor Monitoring Program, and City of San Diego.
Researchers collected abandoned eggs from the California least tern and other
bird species during a bioaccumulation study in San Diego Bay.
November 14, 2016:
SCCWRP in September helped kick-start a wide-ranging discussion with California water-quality and natural resource managers about how to more effectively manage a common type of coastal estuary known as a bar-built estuary that is periodically cut off from the open ocean through the natural build-up of sandy barriers.
The intermittently open phenomenon, which affects about 90% of the state’s 400-plus coastal estuaries, is intrinsic to bar-built estuaries, but the hydrologic isolation makes them particularly vulnerable to the impacts of land-based pollution and global climate change. Anytime that bar-built estuaries are shut off from dynamically mixing with the open ocean for extended periods, they can experience a precipitous decline in water quality that threatens the health of their inhabitants.
Water-quality managers commonly breach the sandy berms of bar-built estuaries to flush out these systems and boost water quality, but this strategy is at odds with efforts to restore and maintain bar-built estuaries in a more ecologically natural state. The endangered tidewater goby, for example, is a fish that depends on the periodic closing of bar-built estuaries to complete their lifecycle.
During the workshop, held in September at SCCWRP, participants agreed that the inherent tension between water-quality goals and preservation goals for bar-built estuaries will intensify in the coming decades. Climate change is expected to trigger prolonged drought and more frequent storm surges, which will tend to strengthen the sandy berms of bar-built estuaries and keep them shut off from the open ocean for longer periods of time.
To enable managers to take a “climate-ready” approach to bar-built estuary management, workshop participants emphasized the need for improved science to inform management decisions. In particular, more ecologically relevant water quality indicators and targets are needed.
Already, researchers have begun developing the science to help bar-built estuary managers balance water-quality and preservation goals.
At the workshop, SCCWRP presented the findings of a recent study that found that bar-built estuary managers aren’t using ecologically relevant thresholds for dissolved oxygen levels in their decision-making. In fact, SCCWRP and its partners found that bar-built estuaries in reference condition failed to meet existing objectives for dissolved oxygen (DO) 26% to 60% of the time, signaling that existing DO objectives require updating to be useful in guiding management decision-making.
SCCWRP also highlighted its recently completed effort to develop macroalgal numeric targets for bar-built estuaries – an example of a more ecologically relevant indicator.
Workshop participants agreed that researchers should continue down this path, including improving on existing tools for bottom-dwelling estuarine organisms to measure overall ecological health, and using innovative modeling and conceptual frameworks to adaptively manage bar-built estuaries.
Researchers’ long-term goal is to develop a full suite of assessment tools that can help managers make science-informed decisions about how best to protect both water quality and habitat condition in intermittently open estuaries, especially in light of climate change. This management toolbox will be modeled after the robust, multi-pronged approaches developed in recent years to improve management of California streams.
Malibu Lagoon in Los Angeles County is a bar-built estuary that is periodically cut off
from the ocean by the natural build-up of a sandy barrier at its mouth. This hydrologic
isolation makes it particularly vulnerable to the impacts of land-based pollution and climate change.
Coastal estuaries like San Mateo Lagoon in San Diego County that are cut off from
the ocean by naturally forming sand barriers often face water-quality challenges.
Although artificially breaching the estuary mouth can restore water quality, this
management strategy is at odds with goals to restore and maintain the site in a more
ecologically natural state. Improved science can help bar-built estuary managers make
better decisions about the management of these ecologically sensitive systems.
November 07, 2016:
Scientists and coastal managers from across the West Coast began laying the groundwork for the development of ecologically relevant criteria for coastal ocean acidification during a two-day workshop in October at Stanford University.
At the workshop, titled An Uncommon Dialogue: Ocean Acidification: Setting Water Quality Goals
, participants sought to develop consensus around how to apply ocean acidification science to improve management of the coastal ocean, as well as what research is most needed to support development of management criteria. The October 17-18 workshop was hosted by Stanford University’s Woods Institute for the Environment, the Center for Ocean Solutions, the California Ocean Protection Council and SCCWRP.
In particular, workshop participants stressed the need for improved understanding of how the chemical indicators of ocean acidification (e.g., carbonate saturation state, pH) relate to how biological communities respond to acidification (e.g., free-swimming pteropods, or sea snails).
The pH-based criteria that West Coast managers have been using for decades to protect ocean health are based on outdated science, with marine communities harmed at pH thresholds that fall within the criteria’s range.
Furthermore, because development of ocean acidification criteria to manage coastal waters is still years into the future, participants discussed how they could advance acidification science to a point where West Coast managers could use it to improve their monitoring and management practices in the short term. For example, participants explored how to use observational acidification data in tandem with a West Coast-wide ocean acidification modeling effort to help quantify natural variability in ocean state.
The timely workshop follows on the heels of two new state laws (SB 1363
and AB 2139
) that direct the California Ocean Protection Council and other state agencies to implement the recommendations of a 20-member West Coast advisory panel of leading ocean scientists. The West Coast Ocean Acidification and Hypoxia Science Panel
released a series of short- and long-term management actions for combatting ocean acidification in April; SCCWRP’s Dr. Steve Weisberg and Dr. Martha Sutula were among the panelists.
Already, the California Ocean Protection Council has responded to the new legislative directive by announcing funding for a broad suite of acidification-related initiatives, including a SCCWRP-led effort to develop a synthesis of existing science regarding ocean acidification indicators and their response thresholds, and an expansion of the ongoing West Coast acidification modeling effort. The West Coast acidification model, which is being co-developed by SCCWRP, seeks to understand which marine habitats are most vulnerable to acidification and to what extent local, land-based sources of pollution are exacerbating acidification.
Acidification of West Coast ocean waters is making it harder for marine organisms
like the pteropod, or sea snail, above, to maintain its calcium carbonate shell. The shell
of a healthy pteropod, top, looks visibly different from a pteropod that's been stressed
by acidification, bottom.