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The Texas A&M-led team is creating the first global map of seafloor biodiversity activity

Seabed sediments burrowed and churned by invertebrates, which new research shows play an important role in protecting marine ecosystems.

Seabed sediments burrowed and churned by invertebrates, which new research shows play an important role in protecting marine ecosystems.


Thanks to Dr. Martin Solan, University of Southampton

A groundbreaking study has used extensive global datasets and machine learning to map the activities of seafloor invertebrates, including worms, mussels and shrimp, across the ocean, revealing critical factors for the first time that support and maintain the health of marine ecosystems.

The international team, led by Texas A&M University and including researchers from Yale University and the University of Southampton, focused specifically on the unsung but crucial role that burrowing animals play as “ecosystem engineers” in shaping nutrient cycling and ecosystem health – and in turn maritime economies and food security – across the oceans. The researchers used machine learning to paint a global picture of these animals’ activities and the environmental conditions that drive them.

Marine sediments cover most of the Earth’s surface and are very diverse. By shaking up and stirring the seafloor – a process known as bioturbation – seafloor invertebrates play an important role in regulating global carbon, nutrient and biogeochemical cycles, explains Assistant Professor Dr. Shuang Zhang, principal investigator and first author from the Texas A&M Department of Oceanography, said. study, which will be published May 22 in the journal Cell Press Current biology.

The first global maps of burrowing animal activity in today's oceans, created by Dr.  Shuang Zhang and collaborators using global dispersion predictions of the intensity (top) and depth (bottom) of their seafloor-sediment mixing efforts, as generated by the Random Machine learning model for forestry.

The first global maps of burrowing animal activity in today’s oceans, created by Dr. Shuang Zhang and collaborators using global dispersion predictions of the intensity (top) and depth (bottom) of their seafloor-sediment mixing efforts, as generated by the Random Machine learning model for forestry.


Dr. Shuang Zhang/Texas A&M University

“By knowing how bioturbation relates to other aspects of the environment, we are now better equipped to predict how these systems may change in response to climate change,” said Zhang, who is also a member of the CARbon Cycle and Earth Environment ( CACEE). Laboratory at Texas A&M.

Working with trained models and global bioturbation datasets, the team took into account seawater depth, primary productivity, sediment type and other criteria to investigate how the ocean environment these animals live in affects how intensively and deeply mixed the seabed all over the world.

“Through our analysis, we found that not just one, but multiple environmental factors jointly influence seafloor bioturbation and the ecosystem services these animals provide,” said Dr. Lidya Tarhan, assistant professor in Yale’s Department of Earth and Planetary Sciences. “This includes factors that directly impact food supplies and underlie the complex relationships that sustain marine life both today and in Earth’s past.”

Protection of seabed processes

In addition to showing that current efforts to protect marine ecosystems have fallen short by not targeting these animals, the researchers note that their research has important implications for how we protect and conserve the ocean.

“We have known for some time that ocean sediments are extremely diverse and play a fundamental role in mediating ocean health, but only now do we understand where and to what extent these communities contribute,” says Dr. Martin. Solan, professor of marine ecology at Southampton. “For example, the way these communities influence important aspects of ocean ecosystems is very different between coastlines and the deep sea.”

Tarhan says the ability to anticipate these changes is essential for developing strategies to combat habitat degradation and protect marine biodiversity.

“Our analysis suggests that the current global network of marine protected areas does not adequately protect these important seafloor processes, indicating the need for better consideration of conservation measures to promote ecosystem health,” she added.

According to Zhang, the team is already planning their next joint collaboration, building on the findings of the current study. Despite having a clearer picture of the geographic patterns in bioturbation, he says there are still big questions about how it translates into the many ecosystem services society relies on, such as food security, climate regulation and biogeochemical cycles. Ultimately, Zhang argues that researchers must determine how to best protect seafloor communities and anticipate how these communities respond to a changing climate.

“Addressing these really big questions is critical, but as we have found here, it will take an international team with a diversity of expertise to fully address these issues,” Zhang added. “By working together as we have done here, we expect even more exciting findings soon.”

The team’s research was funded in part by the Natural Environment Research Council and Yale, where Zhang received his Ph.D. in 2017. Their paper, ‘Global distribution and Environmental correlates of marine bioturbation’, can be viewed online, along with related figures and captions.

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