Marine biogeography—the study of the distribution of marine organisms across the world’s oceans—is intimately linked to the dynamic history of Earth’s ocean currents and continental arrangements. A groundbreaking study led by Thomas A. Neubauer, a paleontologist at the Bavarian State Collection of Paleontology and Geology (SNSB-BSPG), sheds new light on how temperature regimes and the paleogeographic legacy of ocean currents intricately shape the global distribution patterns of modern benthic shallow-water mollusks. This detailed analysis, integrating over three million georeferenced mollusk occurrence records, reveals striking correlations between marine biodiversity, oceanographic structures, and the deep-time geological evolution of marine habitats.
The research emphasizes that the biogeographical distribution of marine mollusks—especially prevalent taxa such as bivalves and gastropods—aligns significantly with major ocean currents, which themselves are the product of complex tectonic events and climatological evolution. These large-scale current systems are not static but have evolved over millions of years, influenced heavily by the shifting positions of continents and the opening and closing of marine gateways such as straits and land bridges. Understanding mollusk distributions thus requires a multidisciplinary approach that encompasses oceanography, paleogeography, and evolutionary biology.
One of the most illustrative examples highlighted in the study is the closure of the Isthmus of Panama around 2.8 million years ago. This geologically recent event severed the marine connection between the tropical East Pacific and West Atlantic, yet biological similarity in mollusk faunas across these two regions persists due to their shared evolutionary history prior to the closure. In stark contrast, the faunas of the western and eastern Atlantic display pronounced divergence, a pattern attributable to the much older opening of the Atlantic Ocean more than 100 million years ago, allowing for extended periods of independent evolution and species turnover.
To construct the most comprehensive view of mollusk distribution patterns, Neubauer and colleagues synthesized an immense dataset combining global occurrence records from two major biodiversity data repositories: the Global Biodiversity Information Facility (GBIF) and the Ocean Biodiversity Information System (OBIS). By spatially correlating these species distribution points with contemporary sea surface temperature data and reconstructions of ancient ocean current pathways, the researchers developed quantitative models capturing the interplay between environmental parameters and evolutionary history.
The study reveals that temperature exerts a fundamental control on the distribution of benthic marine mollusks, influencing metabolic processes, reproductive cycles, and ultimately speciation events. However, temperature patterns themselves are a consequence of ocean current systems, which redistribute heat across vast marine expanses. Intriguingly, these currents are shaped not only by contemporary climate drivers such as wind and Earth’s rotation but also by the paleogeographic configuration of continents and seabed topography sculpted over millions of years.
By employing paleogeographic reconstructions, the research team could analyze how shifts in landmass positioning and seafloor morphology through geological epochs impacted ocean circulation patterns and, consequently, temperature gradients along continental shelves. Such insights reveal lasting ‘imprints’ that ancient oceanographic conditions leave on the present-day ecological niches of marine mollusks, accentuating the legacy of evolutionary constraints imposed by Earth’s geological past.
The implications of this work extend beyond academic curiosity. In the context of accelerating anthropogenic climate change, the delicate equilibrium between temperature regimes, ocean currents, and marine biodiversity is under unprecedented threat. Neubauer warns that rapid increases in global ocean temperatures are not merely shifting species ranges but are fundamentally altering the underlying oceanic circulation patterns. Such changes could disrupt established biogeographic patterns, driving species extinctions, altering community compositions, and jeopardizing ecosystem stability on a global scale.
Further compounding this concern is the fact that temperature influences key biological functions including mollusk metabolism and development. Disruptions in these areas can cascade through food webs, affecting fisheries and economies dependent on marine resources. Notably, the study highlights that changes in current patterns induced by warming may also decrease habitat connectivity, isolating populations and limiting gene flow, thereby affecting the resilience and adaptive potential of marine species.
This research also underscores the invaluable role of integrated biodiversity databases such as GBIF and OBIS in modern ecological and evolutionary studies. By pooling vast amounts of species distribution data that are globally sourced and taxonomically verified, these platforms enable the high-resolution spatial analyses necessary to tease apart complex biogeographic patterns. The collaborative effort involving institutions like the Natural History Museum in Vienna and the University of Malaga exemplifies the growing trend toward international, interdisciplinary research in marine science.
In essence, the study by Neubauer and colleagues presents a compelling narrative: the biogeography of marine organisms is the product of a multifaceted interplay between the physical environment, its historical transformations, and biological responses over evolutionary timescales. Such an integrative perspective is crucial for anticipating how marine biodiversity may respond to current environmental perturbations and for designing effective conservation strategies.
By revealing the significant influence of paleogeographic legacy alongside temperature and oceanographic factors on shallow-water mollusk distributions, this work opens new avenues for research into marine evolutionary ecology. It invites further exploration into how other marine taxa might exhibit similar distributional signatures reflecting Earth’s geological history, enriching our understanding of marine biodiversity patterns at a planetary scale.
Moreover, the findings illustrate how the often-overlooked drivers of biogeographic structure—such as shifting continents and ancient oceans—continue to shape living systems today. This recognition bridges deep time with present-day ecology, highlighting the evolutionary inertia contained within modern ecosystems.
In conclusion, this comprehensive study makes it clear that preservation of marine biodiversity hinges not only on mitigating contemporary climate impacts but also on appreciating the profound geological and oceanographic context within which marine life evolved. Efforts to safeguard marine ecosystems and their services must therefore incorporate long-term historical perspectives to effectively address the challenges posed by rapid environmental change.
Subject of Research: Animals
Article Title: Biogeographic patterns of modern benthic shallow-water molluscs and the roles of temperature and palaeogeographic legacy
News Publication Date: 1-Jul-2025
Web References: http://dx.doi.org/10.1038/s41598-025-06473-0
Image Credits: SNSB-ZSM, Sektion Mollusca
Keywords: Marine biogeography, shallow-water mollusks, ocean currents, paleogeography, temperature influence, evolutionary biology, climate change, marine biodiversity, species distribution, paleontological analysis
