A recent study conducted by Stanford researchers has provided new insights into the historical changes in ocean life abundance over the past 500 million years. This research marks the first time long-term trends in total biomass have been calculated, offering a fresh perspective on biodiversity and ecosystem health.
The study revealed that the overall mass of marine organisms has generally increased over this extensive period, despite setbacks from major extinction events. These findings suggest an evolutionary link between biomass and biodiversity, reinforcing the importance of conserving biodiversity for both human and planetary health.
Pulkit Singh, a postdoctoral scholar at Stanford Doerr School of Sustainability and lead author of the study, explained the significance of understanding biomass: “Understanding the amount of biomass is important because it represents key traits about an ecosystem that are not captured by the number of species or even the number of niches that they fill.” Singh noted that previous measurements of historical biomass were limited, prompting this investigation to fill a crucial gap in biological history.
The research involved analyzing thousands of rock samples containing skeletal remains to assess biomass across different geological intervals. The team used petrographic point-counting methods to determine shell content in these samples, providing insights into ecosystem productivity and health.
Jonathan Payne, senior study author and professor at Stanford, praised Singh’s efforts: “The first quantitative effort to document and graph biodiversity across geological time was made in 1860, but until Pulkit’s paper, there’s never been a corresponding biomass-across-time paper.”
The results showed variations in shell content over time, with significant increases during periods such as the Cambrian Explosion. Notable decreases occurred during mass extinction events like the Late Devonian and Permian-Triassic extinctions. Despite these fluctuations, biomass has generally risen throughout Earth’s history.
To ensure accuracy, researchers cross-checked their findings against various ecological factors and sample biases. Singh stated: “The more tests we did and the more we divided our dataset, we realized that these big biological patterns we were seeing stayed over time.”
This increase in marine life abundance is attributed to greater diversity among marine organisms allowing for enhanced nutrient recycling within ecosystems. However, modern human activities pose potential threats to this trend through impacts like overfishing and ocean acidification.
Payne emphasized the relevance of these findings today: “Our findings show that overall biomass is linked to biodiversity and that losses in biodiversity may suppress productivity for geologically meaningful intervals.” He stressed that conserving biodiversity is vital for maintaining ecosystem productivity.
Co-authors from various institutions contributed to this research supported by a grant from the U.S. National Science Foundation. The full study was published on June 25th in Current Biology.
