Synthesis is central to the Delta Science Program‘s mission, as outlined in the Delta Reform Act, which mandates providing unbiased science to guide water and environmental decisions in the Delta. To advance this, the program partnered with the National Center for Ecological Analysis and Synthesis (NCEAS) in 2021, offering training in reproducible research and open-source tools. These efforts reflect the program’s dedication to open science and informed decision-making.
At the June meeting of the Delta Stewardship Council, Henry DeBey, Deputy Executive Officer for Science at the Delta Stewardship Council, and Maggie Chrisman, Program Manager for the Science Communication and Synthesis Unit, highlighted the importance of synthesis in addressing complex ecological challenges and shared updates on the program’s ongoing efforts to integrate data, foster collaboration, and advance open science principles in the Delta.
WHAT IS SYNTHESIS?
Synthesis involves integrating and analyzing diverse scientific data to answer specific questions or build a comprehensive understanding of a topic. It’s about weaving individual pieces of knowledge into a clearer, more cohesive picture—like assembling a puzzle. In the Delta, most of these “puzzle pieces” come from fish monitoring surveys.
The California Department of Fish and Wildlife conducts various surveys in the Delta to monitor fish populations, crustaceans, zooplankton, and the overall health of the ecosystem. These studies track key species, including smelt, striped bass, sturgeon, and other pelagic fish, while also examining their food resources, such as zooplankton. The fish surveys sample at dozens of locations across the Delta, with some conducted biweekly, monthly, or seasonally, depending on the study’s focus. Some have been conducted since the 1990s.
“So if you think of that survey being that one puzzle piece and all the data that comes with that survey, it’s a lot of data that tells you about what fish were caught, when, and under what conditions,” said Mr. DeBey. “It turns out there are 156 puzzle pieces of monitoring data in the Delta on everything from fish to subsidence to water quality. Each puzzle piece represents vast amounts of data collected over decades. So the power of synthesis is to connect this data to see the bigger picture.”
PUTTING THE PIECES TOGETHER
Synthesis was key to solving the Pelagic Organism Decline (POD), which refers to a significant drop in the populations of several fish species in the Delta in the early 2000s. This decline was most pronounced in the Delta smelt, but also affected other pelagic fish like longfin smelt, splittail, and threadfin shad. The decline was concerning because it happened despite moderate water flows and investments in habitat restoration.
“So these scientists combined five different puzzle pieces of survey data in the Delta,” said Mr. DeBey. “Of course, that’s easier said than done, because a lot of the time the data isn’t apples to apples. It’s in different formats; it’s collected at different times of day, in different places, and it’s not stored in the same location. So it takes knowledge of these surveys, expertise, statistics, and data science to integrate this data in an accurate and meaningful way.”
The scientists used data from the five surveys, each of which targets native Delta fish at different life stages. What the scientists found is that it wasn’t just the Delta smelt that were declining; it was other native fish, like longfin smelt, striped bass, and threadfin shad,” said Mr. DeBey. “These concurrent declines came to be known as the pelagic organism decline, and these declines were ultimately attributed to changes in food availability for these fish because of the introduction of invasive clams that were sucking up a lot of the potential fish food in the water. This synthesis ultimately helped inform efforts to make more fish food through restoration and changes to water operations.”
“But importantly, this effort really demonstrated to the science community across the Delta, the tremendous value of synthesis, and how, if you don’t do it, you really can miss that bigger picture. That is part of the reason that the legislature called out synthesis as a core function for the Delta Science Program in the Delta Reform Act.”
OPEN SCIENCE PRINCIPLES UNDERLIE SYNTHESIS
Open Science principles form the backbone of the synthesis work at the Delta Science Program. Open Science is a global movement aimed at making every aspect of the research process—data, methods, publications, and outputs—transparent, accessible, and available for all to use and review.
The three core principles of Open Science are:
- Accessibility: Ensuring that data and information are easy to find, openly available, and ready for use by anyone.
- Reproducibility: Sharing data, methods, and code transparently so others can replicate research. This fosters trust, encourages collaboration, and promotes shared use of techniques within the research community.
- Inclusivity: Emphasizing open collaboration by involving participants from diverse backgrounds, perspectives, disciplines, and ways of knowing to enrich the research process.
The broader adoption of open science principles in recent years has significantly enhanced the power of synthesis, particularly with the ever-increasing amounts of data and information available. However, open science is not without its challenges. It requires scientists to continually learn new software, techniques, and workflows to stay at the forefront of these activities.
NURTURING SYNTHESIS SKILLS
Recognizing this, the Delta Science Program initiated a partnership with the National Center for Ecological Analysis and Synthesis (NCEAS) to foster collaboration and develop open science skills, and provide participants with the dedicated time, resources, and collaborative structure necessary to address ecological challenges in the Bay-Delta.
NCEAS, established in 1995, is a globally recognized institution for synthesis science. NCEAS has three primary areas of focus: developing advanced techniques in data science and research methods for synthesis, conducting research that leverages data analytics and synthesis techniques, and training scientists to perform this work. NCEAS facilitates synthesis working groups, which come together to analyze data and address big picture issues for their region.
“It’s NCEAS leadership and experience in these programs that drew our attention and led us to the idea of coming together to partner with them to organize our own synthesis working groups,” said Ms. Chrisman.
The partnership with NCEAS for Delta working groups began about five years ago. “First and foremost, these groups come together and are provided high-quality training led by NCEAS experts in data science and statistical techniques. It includes research from researchers from all across the Bay Delta. We then support those participants in projects where they can directly apply those new skills to produce meaningful outputs and advance our state of knowledge. These are spaces we’re creating to enhance collaboration. We’re making partnerships and building bridges across different state and federal agencies, other organizations, and academia.”
Each cohort has about 18 participants. Participants are selected who are early in their careers and represent a diverse range of agencies, backgrounds, and expertise, allowing questions to be answered across environmental, physical, and social science disciplines.
The Science Program staff selects a theme for the trainings and invites participants, while NCEAS designs a tailored curriculum to address those questions using synthesis techniques. The workgroups begin with an intensive three-week training, but the effort extends well beyond that. Participants are expected to continue their research for one to two years, depending on the complexity of the questions.
Throughout this period, the workgroups reconvene regularly to collaborate and produce meaningful outputs. Data collected during the process is integrated into shared datasets and made openly accessible for others to use. Publications and findings are also shared to further advance knowledge and collaboration.
The Science Program has a limited capacity for participants in the training. However, the curriculum compiled by NCEAS is recorded and posted on the Delta Science Program website, making it accessible to anyone who wants to run through the training modules themselves.
2021 WORKGROUP: DRIVERS OF ESTUARINE FOOD SUPPLY
The first workgroup launched in 2021 and focused on drivers of the estuarine food supply. The working group’s goal was to generate insights that informed decision-making for restoration, the protection of endangered fish species, and the management of flow actions.
The group compiled and utilized datasets relevant to food webs, including primary productivity, contaminants, connectivity, climate change, growth, floodplains, zooplankton, food web linkages, forecasting, and hydrodynamics, combining 40 years of information into a single dataset. The single, integrated dataset produced through this effort has enabled researchers to model the estuary’s food web in ways that were not previously possible.
A publication in the Journal of Ecology entitled “Evaluating top-down, bottom-up, and environmental drivers of pelagic food web dynamics along an estuarine gradient” (Rogers et al. 2024) was produced through this work.
“Essentially, they were able to see, based on data, that there are similar effects on some of our important fish in the estuary that are being driven by environmental factors like flows, water temperature, and turbidity, as well as by food availability,” said Ms. Chrisman. “This allowed us, for the first time, to look at food webs and answer certain questions that we’d never been able to do based on data in the past.”
2023 WORKGROUP: Managing the Delta as a social-ecological system
The second synthesis working group, convened in 2023, focused on integrating social, economic, and environmental data to better understand the human-environment interface in the San Francisco Estuary. 16 participants with backgrounds in economics, social sciences, and environmental sciences participated in the cohort.
Two groups were formed during the training workshops: one focused on analyzing the social benefits and impacts of restoration projects in the Bay-Delta, and the other evaluated the social, economic, and ecological costs and benefits of levee infrastructure within the Delta.
Following the training workshops, NCEAS supported both groups in building reproducible and well-documented workflows for their projects, which are accessible through the Delta Stewardship Council’s GitHub account. To date, both groups have produced interactive dashboards to share data and results of their synthesis projects. Additional analyses and publications are in progress.
“The work is still underway, so it’s more about the progress they’ve made,” said Ms. Chrisman. “The teams are currently scraping through project proposals and project descriptions to understand what social benefits exist in these projects or they’re being called for, and then, how are these projects actually spatially arranged, and how are they filling social equity needs and gaps in our system. So stay tuned for more information coming out of this.”
BENEFITS GO BEYOND
While the focus a lot of times is on the products of the working groups, such as datasets, reports, or dashboards, Ms. Chrisman pointed out there is a less tangible component that’s critically important.
“We’re already seeing impacts of this work,” she said. “One of the big goals of this work is enhancing the capacity in our system to do synthesis science. These people who are participating in the training are going back to their regular jobs and applying those skills right away. And we’re seeing impacts of that. We’re addressing or making progress on some key knowledge gaps, and we’re seeing some of these collaborative networks being built and strengthened.”
The word cloud on the slide shows the survey responses from participants to the question, ‘Share the most valuable thing you learned from this training.’ “These quotes from surveys show how impactful participating in these working groups has been for them,” said Ms. Chrisman. “My personal favorite one is the one at the top: ‘I wish everyone who worked with scientific data could take this course.’ And I took one of the NCEAS courses about six years ago, and that’s how I felt, which is partly why we’re doing these things today.”
NEW COHORT FORMING
The next cohort is forming now. The Delta Science Program has released an open call for participants and topic submissions. Submissions should consider how existing data can be used to address emerging challenges or management-relevant questions in the Bay-Delta and must clearly describe how an idea aligns with the 2022–2026 Science Action Agenda or other priority management needs. Selected ideas will help shape both the working group curriculum and the focus areas for working group projects during and after the workshops. More information about these opportunities is available on the Delta Science Program’s DSP-NCEAS website.
