Groundbreaking research from the University of Southampton is reshaping our understanding of evolutionary biology by offering an unprecedented day-by-day view into how prehistoric plankton adapted to their environments. By employing cutting-edge technologies, scientists have unlocked the minute details preserved within fossilized shells that date back millions of years, providing a vivid portrait of how individual organisms responded to environmental changes during their lifetimes. This methodological leap allows researchers to peer into the biological “chapters” of the past, rather than simply viewing entire volumes spanning millennia.
At the heart of this innovative study lies the use of high-resolution 3D computed tomography (CT) scanning combined with precise geochemical analysis via laser ablation. This hybrid approach enables the reconstruction of the growth patterns of foraminifera, single-celled planktonic organisms whose fossils are found in marine sediments worldwide. Their shell growth forms a spiraling series of chambers, each representing a snapshot of their development, much like the rings of a tree. By scanning these microscopic chambers in three dimensions, researchers are able to pinpoint subtle structural changes, while laser ablation reveals the chemical signatures embedded in the calcium carbonate.
What makes these findings particularly transformational is the temporal resolution achieved: rather than analyzing evolutionary changes over thousands or millions of years, the team has decoded environmental influences operating over mere days during the lifespan of individual creatures. This scale of analysis is unprecedented in paleontology, bridging a critical gap between modern ecological observations and deep-time fossil data. By tracking the growth and geochemical chemistry of each shell chamber, the scientists reconstructed fluctuations in temperature, water depth, and chemistry experienced by the plankton as they grew.
Foraminifera, colloquially called forams, serve as a vital proxy for oceanographic and climatic history because their shells record snapshots of their surrounding environment in exquisite detail. These organisms secrete calcium carbonate shells that accrete new chambers periodically, making their fossilized remains a natural archive of biological and environmental information. Understanding how these tiny marine organisms adapted to environmental shifts not only informs on their own evolutionary pathways but also sheds light on broader mechanisms underlying biodiversity and life’s resilience on Earth.
Dr. Anieke Brombacher, the lead researcher on the project, highlights the paradigm shift that this approach offers. Previously, fossil records provided evolutionary insight primarily at coarse temporal scales, masking the nuances of how individual entities reacted to environmental stressors. By contrast, this day-resolved analysis opens a window into developmental plasticity—the organism’s inherent flexibility to shift morphology or physiology in direct response to environmental cues. This newfound granularity amplifies our understanding of ‘nature versus nurture’ forces in evolution, pinpointing when an organism’s adaptations emerge within its own life rather than across multiple generations.
One of the pivotal discoveries of this research is that temperature plays a more pronounced role in governing foram growth rates than chronological age. Although all species studied exhibited similar growth patterns under cooler conditions, in warmer waters, some species accelerated their growth significantly without reaching larger overall sizes. This suggests that temperature not only influences metabolic rates but may also dictate habitat preferences and ecological niches, allowing plankton species to diversify their living strategies across thermal gradients in the ocean.
Moreover, comparative analysis of two species with similar environmental sensitivities revealed intriguing energetic trade-offs. One species managed to attain the same shell size but developed a thinner shell, potentially lowering the energetic cost of growth. This might indicate an adaptive evolutionary advantage, as lower resource investment for similar protective structures could enhance survival and reproduction success. Such insights reveal complex fitness landscapes where species balance growth dynamics, structural integrity, and metabolic expenditure.
Importantly, the technical approaches pioneered here are not limited to foraminifera. The same CT and laser techniques can be applied to other fossilized marine organisms like ammonoids, corals, and bivalves such as clams and oysters. Since these organisms also deposit growth layers that encapsulate environmental information at high resolution, expanding these methods offers vast potential for reexamining fossil records with newfound precision and reinterpret traditional evolutionary narratives.
Professor Thomas Ezard, supervising author on the study, emphasizes the interdisciplinary nature of the research. By bridging palaeontology, geochemistry, and advanced imaging technologies, the study exemplifies how collaborative science can tackle foundational biological questions previously beyond reach. Integrating expertise across these domains has enabled a leap forward in tracing adaptation mechanisms not just in theory but with real measurable proxies anchored in ancient life.
This research is part of a larger project aimed at scaling the sample size to thousands of foraminifera specimens. The goal is to elucidate if and how adaptive plasticity influences speciation events by providing some species with the flexibility to diversify and distinctively branch over evolutionary time. Unraveling whether such traits predispose lineages to speciation will have profound implications for understanding biodiversity generation and extinction trajectories.
The study itself, titled Detecting environmentally dependent developmental plasticity in fossilized individuals, was published in the Proceedings of the National Academy of Sciences and funded by the Natural Environment Research Council (NERC). It underscores the potential for fossil archives to deliver day-level resolution of evolutionary dynamics previously considered only accessible in living populations. As the resolution of paleontological techniques continues to sharpen, so too will our ability to tell life’s intricate stories etched into the mineralized remains left behind.
In essence, this research transforms the fossil record from a static timeline into an active biographical diary of ancient organisms. It marks a significant leap forward in how we interpret past biological responses to environmental variability, ultimately enriching our comprehension of the continuous interplay between organismal development and the changing Earth system. Such advances herald a new epoch in paleoscience where microscopic, time-resolved analyses unravel the fabric of evolutionary history with breathtaking detail.
Subject of Research: Prehistoric plankton (foraminifera) developmental plasticity and environmental adaptation
Article Title: Detecting environmentally dependent developmental plasticity in fossilized individuals
News Publication Date: 30 June 2025
Web References: http://dx.doi.org/10.1073/pnas.2421549122
Image Credits: University of Southampton
Keywords: Fossils; Evolutionary biology; Adaptive evolution; Marine life; Zooplankton
