Kelp forests, though temporary and ever-changing, serve as critical ecological anchors in coastal marine environments. According to a recent study led by Kyle Emery of UC Santa Barbara’s Marine Science Institute and published in Communications Biology, these underwater forests also play a vital role in supporting nearby beach ecosystems.

The research highlights how kelp fronds, after detaching due to seasonal shifts, storms, and wave activity, wash ashore and become essential components of beach food webs. These kelp fragments, also known as kelp wrack, nourish invertebrates and help sustain broader biodiversity along the shoreline.

While the existence of a link between offshore kelp forests and beach ecosystems has long been recognized, the UCSB team aimed to better understand the scale and strength of that connection. Using years of ecological data from the Santa Barbara Coastal Long-Term Ecological Research (SBC LTER) program, along with satellite imagery, the researchers examined how much kelp makes its way from the ocean to the shore—and how far this influence extends.
Their analysis found that the ecological connection is highly localized. Beaches within approximately 10 kilometers of kelp forests receive the most benefit from this natural subsidy, especially in winter months when storm-driven waves increase kelp deposition. This suggests that both the condition and proximity of kelp forests are critical to the health of adjacent beach habitats.

“This has important implications for beach conservation,” Emery noted. “We can start to identify beaches that are likely to serve as biodiversity hotspots simply due to their location near kelp forests.”

The findings are also relevant to discussions around “blue carbon”—the concept of using marine vegetation like kelp to capture and store atmospheric carbon. Understanding the fate of dislodged kelp, including where it ends up, is essential for carbon accounting and ecosystem management strategies.

This work, which involved collaboration with researchers Jenifer E. Dugan, Robert J. Miller, David M. Hubbard, and Jessica R. Madden of UCSB, as well as Kyle Cavanaugh of UCLA, offers new insights into the dynamic relationship between ocean and shoreline systems. Ongoing research will delve even deeper, including tracking individual pieces of kelp to better map their journey from sea to sand.

Adapted from original reporting by Sonia Fernandez, “Kelp forests are connected to local beach ecosystems,” The Current, UC Santa Barbara, 2025.