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Plankton help predict ocean biodiversity losses

Marine plankton, particularly the single-celled organisms known as foraminifera, have populated the oceans for hundreds of millions of years. These microscopic, hard-shelled creatures are more than just tiny specks in the vast ocean; they are fundamental to the marine food chain and serve as a historical archive that helps scientists predict changes in global biodiversity related to our warming climate.

Plankton predicting biodiversity changes

Recently, an extensive study utilizing a high-resolution global dataset of planktonic foraminifera fossils – one of the richest biological archives available – has revealed crucial insights.

Researchers have discovered that major environmental stresses leading to mass extinctions were consistently preceded by subtle changes in the composition of these marine communities. These shifts act as an early warning system for potential future extinctions.

The study was led by Anshuman Swain, a researcher in the Harvard Society of Fellows, who is also affiliated with the Museum of Comparative Zoology.

Swain, initially trained as a physicist, applies network analysis to biological and paleontological data. Collaborating with co-first author Adam Woodhouse at the University of Bristol, Swain investigated the ancient global community structure of marine plankton to develop predictions for the future of ocean life.

Harnessing the past to protect our future

Swain emphasized the importance of historical data in understanding contemporary challenges. “Can we leverage the past to understand what might happen in the future, in the context of global change?”

He noted that his previous work on the impact of polar ice cap formations on marine plankton over the last 15 million years provides valuable context for how biodiversity responds to global climatic shifts, particularly during periods of global warmth, which mirror projections for future warming.

Plankton population and biodiversity

Using the Triton database, crafted by Woodhouse, the team analyzed how the composition of foraminifera plankton communities evolved over extensive periods, far longer than those typically studied.

The focus was the Early Eocene Climatic Optimum, a significant phase of high global temperatures that occurred after the age of dinosaurs. This period is comparable to modern worst-case global warming scenarios.

The researchers found that prior to an extinction event around 34 million years ago, marine communities across the globe became highly specialized – except in southern high latitudes.

This suggests a mass migration of micro-plankton to cooler, higher latitudes and away from the tropics. The pattern is indicative of significant ecological shifts detectable in the fossil records well before actual biodiversity extinctions took place.

Paleoinformatics and future biodiversity

The importance of monitoring biological community structures to predict future extinctions cannot be overstated. The insights gleaned from plankton studies pave the way for broader biodiversity research on other marine organisms, including sharks and even insects.

This burgeoning field, known as paleoinformatics, harnesses large, spatiotemporally resolved databases of fossil records to offer new perspectives on Earth’s future.

By studying the past with sophisticated tools and databases, scientists like Swain and Woodhouse are not only uncovering the secrets of ancient marine ecosystems but are also providing essential tools to anticipate and potentially mitigate future biodiversity losses due to climate change.

Their work underscores the critical role of historical ecological data in environmental conservation efforts and the broader understanding of our planet’s complex climate system.

Marine plankton biodiversity

Marine plankton biodiversity encompasses a vast range of microscopic organisms that play crucial roles in ocean ecosystems. Here are a few key aspects:

Types of plankton

There are two main groups of marine plankton: phytoplankton and zooplankton. Phytoplankton, like algae, are photosynthetic and form the base of the marine food web. Zooplankton, which include foraminifera, are often tiny animals or protists that eat phytoplankton and other small particles.

Ecological importance

Phytoplankton produce about half of the oxygen we breathe and absorb carbon dioxide from the atmosphere, helping to regulate the climate. Zooplankton, including krill and copepods, are a vital food source for larger marine animals such as fish, whales, and seabirds.

Impact on biogeochemical cycles

Plankton are central to biogeochemical cycles. They help cycle nutrients through the ocean by breaking down and redistributing organic and inorganic matter. This includes the carbon cycle, where plankton influence carbon storage and release in the oceans.

Indicators of environmental change

The diversity and distribution of plankton can indicate changes in the environment, such as water temperature, salinity, and pollution levels. Shifts in plankton populations often reflect broader ecological changes that can impact fisheries, water quality, and global climate patterns.

Research and monitoring

Scientists study marine plankton to monitor the health of marine ecosystems and predict ecological shifts due to factors like climate change. Advanced technologies, such as remote sensing and automated underwater vehicles, are used to collect data on plankton populations over large areas and extended periods.

Understanding the biodiversity of marine plankton is critical, as these organisms are foundational to marine ecosystems and global environmental health.

The study is published in the journal Nature.


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