Spanning six years and seven seaweed meadows along the California coast, the paper is published today from the University of California, Davis, and is the most comprehensive study yet of how seaweed can prevent ocean acidification.
The study, published today in the journal The Biology of Global Change, He found that these unknown ecosystems can dilute a lower pH, or more acid, for long periods of time, even at night in the absence of photosynthesis. And it found that the herbs can reduce local acidity by as much as 30 percent.
“This buffering temporarily returns seaweed environments to pre-industrial pH conditions, such as what the ocean may have experienced around 1750,” said co-author Tessa Hill, a UC Davis professor in the Department of Earth and Planetary Sciences and Bodega Marine Laboratory.
When photographing seaweed, you might think of sticky weeds touching your feet as you walk along the shoreline. But a closer look at these underwater meadows reveals an active and vibrant ecosystem full of surprises.
Sea turtles, bat rays, tiger sharks, fish, harbor seals, seahorses and colorful sea slugs are just some of the creatures that visit seagrass ecosystems for the food and habitat they provide. They are nursery areas for species like the Dungeness crab and the spiny lobster, and many birds visit Seaweed meadows Precisely for dinner it falls under a bobbing grass blade.
“It’s a marine forest without trees,” said lead author Aurora Ricart, who conducted the study as a postdoctoral researcher at UC Davis Bodega Marine Laboratory and currently at the Bigelow Oceanographic Laboratory in Maine. “The size of the forest is smaller, but all the biodiversity and life in that forest can be compared to what we have in terrestrial forests.”
Night and day
For the study, the scientists deployed sensors between 2014 and 2019 and collected millions of data points from seven seaweed meadows of eelgrass stretching from north to southern California. They include Bodega Harbor and three locations in Tomales Bay as well as Elkhorn Slough, Newport Bay and Mission Bay.
Buffering occurred on average 65 percent of the time across these locations, which ranged from nearly pristine reserves to operating ports, marinas and urban areas.
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Although of the same species, the behavior and patterns of eel grass changed from north to south, with some sites increasing pH better than others. The time of year was also an important factor, as more buffering occurred during the spring when the weeds were most productive.
Seaweed naturally absorbs carbon as it performs photosynthesis when the sun is outside, which drives this ability to buffer. However, the researchers wondered, could seaweed re-release this carbon when the sun goes down, eliminating buffering for that day? They tested this question and found a welcome and unique result:
“What shocks everyone who has seen this result is that we see the effects of improvement during the night as well as during the day, even in the absence of photosynthesis,” Riccart said. “We also see periods of high pH that last more than 24 hours and sometimes longer than weeks, which is very exciting.”
Bodega Port in Northern California and Tom’s Point in Tomales Bay have emerged as particularly good at reducing ocean acidification. Determining why and under what conditions it occurs across the diverse seascapes remains among the questions for further study.
Climate change, shellfish and ocean acidification
The study has implications for the management of, as well as on, the aquaculture Climate change Mitigation, Conservation and Restoration Efforts.
Globally, ocean acidification is increasing while seagrass ecosystems are degraded. As more carbon dioxide is emitted onto the planet, about a third is absorbed by the ocean. This alters the pH balance of the water and could directly hinder the shell formation of species such as oysters, abalone, and crabs.
Said co-author Melissa Ward, a researcher at UC Davis at the time of the study who is currently working as a postdoctoral researcher at San Diego State University. “This study shows another reason why conservation is so important. We now have evidence that outlines country directions for exploring these ideas for their improvement Ocean acidification It is a valuable topic that should be pursued and deserves more work. “
Source: University of California, Davis