Elkhorn Slough Hester Marsh (US-EKH) is the 500th site to publish BASE data in the AmeriFlux Network!!!!! A major milestone that hopefully all flux enthusiasts celebrate with us! Many people contributed to this success in countless ways – including the 499 sites that came before!
We talked with the US-EKH site team to learn more about this site. This blog post reflects conversations with PI Adina Paytan, site tech J.J. Jabuka, and data manager Sylvain Labedens, from the University of California, Santa Cruz.
Celebrating 500 sites with BASE data product published! 🥳🥳🥳
Tell me about this site – what are the questions that you are studying? What do you like about working here?
The Paytan Biogeochemistry Lab is studying wetland ecosystems to learn more about how they store and release carbon. This tower is part of a set of five study sites at the Elkhorn Slough near Monterey, California (check out US-EKH, US-EKN, US-EKP, US-EKY, and US-MCP). Elkhorn Slough is the third largest estuarine wetland in California (readers, can you guess #1 and 2?). This important ecosystem provides the opportunity to study a range of conditions within a short distance. We find polluted and pristine parts, different levels of tidal influence and inundation in close proximity.
Saltwater marshes are teeming with life, providing nursery space for fish, sustaining bird populations, sequestering carbon and filtering water. In California alone, 90% of tidal marshes habitat area is lost.
The tower site at Hester Marsh provides beautiful views, you get there by walking across another marsh and over a hill, which is lovely. It is located closest to the entrance of the slough, so it is a very dynamic site with strong tidal influences. It is also the windiest site out of the cluster! We see a lot of exciting birdlife, sting rays, bat rays and the occasional otter in the Hester channel. Elkhorn Slough itself is a big otter sanctuary – if you want to see them from a kayak or catamaran, this is the place to go!
The Hester Marsh has been restored in 2018, from a previously diked off, low lying area, and raised about 3 feet in elevation, through a large conservation effort described on this page by the Elkhorn Slough Reserve. This marsh and the entire Elkhorn Slough are a pivotal site for wetland and tidal research, also studied by Elkhorn Slough National Estuarine Research Reserve, Monterey Bay Aquarium Research Institute, and CSU Monterey Bay, among others. The cluster of flux towers is one pillar of the University of California Coastal Wetland Restoration project.
What variables are you measuring at this site?
The eddy covariance setup captures H2O, CO2, and CH4. The site also collects Phenocam data and NDVI. To learn more about how carbon is stored in the soil, we collect soil samples at different times of the year, studying soil properties, pore-water chemistry and microbiology. We also collect surface water and ground water samples. The Elkhorn Slough Reserve also conducts a variety of observations to portray the restoration of this habitat for a variety of species.
When did you start this tower and what are some things you learned from establishing the site to publishing your first batch of data?
This tower was established in December 2022, together with a tower at nearby Yampah salt marsh (undisturbed) and another tower further upland, in diked Porter marsh. In 2023, we added two more towers. Hester marsh and Porter marsh are both publishing data for the first time now, and it’s been a long road! Our team is new at the eddy flux game, and this site comes with many challenges. A levee on the Pajaro river broke, drowning the tower; winds tipping over two of our towers. The physical maintenance on these towers is intense, particularly due to the erosion of materials due to constant salt spray. The effect of salt on the infrastructure cannot be understated! Wildlife also leaves their traces on the tower, be it birds, raccoons or spiders.
Photo of US-EKH tower site after it fell over in a wind storm.
So it has taken a village to get these data cleaned up and ready to publish. The whole team is really proud of this, and also very grateful for the assistance we have received from colleagues. Anyone who is starting out: don’t be shy reaching out to AmeriFlux Management Project, and to your local colleagues! We received a lot of support from the the AmeriFlux Tech team, and Joe Verfaille and Daphne Szutu from the UC Berkeley Biomet lab have been with us every step of the way, lending their many years of expertise. We couldn’t have done it without them!
Can you give us a sneak peek about the insights you are finding in the data?
Something that may be surprising is that very quickly after the restoration effort, this site turned into a pretty decent carbon sink! In contrast to many wetlands, this site has only a muted methane flux signal, compared to natural wetlands. Two important factors here are the limited availability of organic matter due to the site history, and the large grain size of the soil which is allowing seawater circulation, so you have less oxygen depletion.
At this point, the carbon sink is not as big as in sites with fully healthy vegetation, and we hope that Hester marsh will eventually reach a stage of fully restored pickleweed and other important species that we see in Yampah marsh across the hill. This will take some time as the marshland is intentionally set at higher elevation, to withstand expected sea level rise in the next century.
But it’s really wonderful to see the immediate effect of the wetland restoration here in terms of carbon drawdown.
What is next for US-EKH? What else is happening at Elkhorn Slough?
Visitors on US-EKH tower.
Currently, we are working on our own data pipeline and storage system, and hopefully will soon have a dynamic dashboard that we can use to quickly review our data and spot issues in real time.
Be sure to stop by the Visitor Center at the Elkhorn Slough Reserve, where you can see an interactive educational display that the Paytan Lab put together about this project. We have funding through the Coastal Wetland Restoration project to run the cluster of towers for one more year, and are hoping to find funding to keep it going beyond that.
Data from this cluster will be really important to understand tidal estuarine wetlands better, which have such enormous ecological benefits (not just for carbon sequestration!), but they are very complex and closing the carbon budget for these systems is a major challenge. We hope that our insights can inform further research projects and wetland restoration projects!
Data from US-EKH are available under the CC-BY-4.0 data use license. Find them together with BASE data from 73 other wetland sites in our site search.
If you are setting up a new site, do tap into the AmeriFlux community to find advice and support! Start with our Onboarding page, but don’t hesitate to reach out to flux practitioners in your area or ecosystem.
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