Biology subjects

Kiessling, W.

Publications and source records attributed to Kiessling, W..

7 recordsLinked to original sources

bioRxiv2025

Asymmetric leading vs. trailing edge shifts since the Last Glacial Maximum underpin the modern bimodal latitudinal diversity gradient in planktonic foraminifera

AimThe modern latitudinal diversity gradient of planktonic foraminifera is bimodal with a distinct depression near the equator, surrounded by mid-latitude diversity peaks. This pattern emerged after the Last Glacial Maximum, but it is unclear how species spatial dynamics contributed to its formation. Here, we investigate how species range dynamics, i.e., trailing-edge contractions (extirpations) and leading-edge expansions (colonisations), shaped the modern bimodal pattern, and how global biodiversity patterns arise from local patterns. LocationGlobal open ocean, with basin-specific analyses in the Atlantic and Pacific Oceans. Time periodLast Glacial Maximum (19 - 23 ka) (LGM) and the Pre-Industrial (modern) Major taxa studiedPlanktonic foraminifera (unicellular eukaryotes) MethodsWe analysed taxonomically standardized LGM and modern foraminiferal assemblage datasets to characterize changes in species richness at multiple spatial scales: global ocean, basin-wide, and within basin. We quantified species range shifts by comparing their trailing- and leading-edge movements. We estimated temporal turnover locally, and the net imbalance between colonisations and extirpations (NICE) within sites, and tested whether species thermal preferences correlate with their extirpation risk. ResultsWe found no evidence of systematic trailing edge contractions, indicating that equatorial extirpations did not drive the bimodal LDG pattern. In the Atlantic, leading-edge expansions generated a coherent increase in species richness in the mid-latitudes, whereas the Pacific exhibited highly spatially heterogeneous responses, including extirpation hotspots in the western tropical Pacific and colonisation zones in the eastern and southern Pacific. Species thermal optima weakly predicted extirpations, with species adapted to lower temperatures more at risk of extirpation, consistent with the general warming trend since the last ice age. Main conclusionsThe modern bimodal LDG of planktonic foraminifera arises primarily from mid-latitude colonisations rather than equatorial extirpations. Colonisations were particularly frequent in the North Atlantic. Localized extirpations in the western Pacific highlight small-scale patches of vulnerability, that spatially aggregated richness metrics mask. Our results underscore the need to distinguish between trailing and leading processes in climate-induced range shifts, and to consider spatial variability in monitoring and protection of marine biodiversity.

ecology↗

bioRxiv2025

Unique fingerprint of marine ectotherm body size change during hyperthermal crises

The term Lilliput Effect describes a substantial decrease in the average body size of fossil assemblages during major environmental perturbations in Earths history, which is reported in many paleontological studies. The limited regional, temporal and taxonomic focus of most studies, however, has sparked discussions concerning its generality. Additionally, even though a negative relationship between warming and body size has been established in recent marine ectotherms, the environmental and mechanistic drivers of the Lilliput effect are still debated. We compiled close to 9000 body size changes from fossil, historical and modern body size studies, to show that a decrease in body size is indeed a general response of marine ectotherms to environmental crises. The magnitude and temporal variability of size changes at the species-level are significantly higher during hyperthermal than non-hyperthermal events, suggesting differing mechanisms of body size decrease depending on the environmental stressor. Our results further show that ancient environmental perturbations with a higher magnitude of warming were associated with a greater dwarfing. This implies that warming was a major driver of body size decreases during hyperthermal events throughout the Phanerozoic, and future warming will impact current trajectories of body size reduction in modern marine ectotherms. Significance StatementDwarfing is a common response of marine ectotherms to both anthropogenic warming and similar environmental crises throughout Earths history. However, the underlying mechanisms and parallels between fossil and modern observations are still debated. We show, using newly compiled data from fossil, historical and modern studies, that warming events elicit especially strong species body size changes, suggesting similar mechanisms linking modern and fossil body size reductions to warming stress. A correlation between the magnitude of warming during ancient crises and the observed dwarfing indicates that trajectories of body size reduction can be projected into the future depending on climate-change scenarios.

paleontology↗

bioRxiv2025

Reefal regions were biodiversity hotspots throughout the Phanerozoic

Reefs are important hotspots of marine biodiversity today, and acted as cradles of diversification in the geological past. However, we know little about how the diversity of reef-supporting regions varied through deep time, and how this differed from other regions. We quantified regional diversity patterns in reef-supporting and non-reef-supporting regions in the fossil record of Phanerozoic marine invertebrates. Diversity in reef-supporting regions is on average two- to three-fold higher than in non-reef-supporting regions, and has been remarkably stable over timescales of tens to hundreds of millions of years. This signal is present in both reefal and non-reefal facies within reef-supporting regions, suggesting that reefs enriched diversity in surrounding environments. Sepkoskis Modern Fauna, an assemblage of higher taxa that includes gastropods, bivalves and echinoids, has been a key component of reef-supporting regions since the Paleozoic, contrasting with its later rise to dominance in non-reef-supporting regions during the later Mesozoic-Cenozoic. One-Sentence SummaryRegions of the globe that supported reefal environments have been key hotspots of marine animal diversity for over 400 million years.

paleontology↗

bioRxiv2024

Spatially heterogeneous responses of planktonic foraminifera assemblages over 700,000 years of climate change

AimTo determine the degree to which assemblages of planktonic foraminifera track thermal conditions. LocationThe worlds oceans. Time periodThe last 700,000 years of glacial-interglacial cycles. Major taxa studiedPlanktonic foraminifera. MethodsWe investigate assemblage dynamics in planktonic foraminifera in response to temperature changes using a global dataset of Quaternary planktonic foraminifera, together with a coupled Atmosphere-Ocean General Circulation Model (AOGCM) at 8,000-year resolution. We use thermal deviance to assess assemblage responses to climate change, defined as the difference between the temperature at a given location and the bio-indicated temperature (i.e., the abundance-weighted average of estimated temperature optima for the species present). ResultsAssemblages generally tracked annual mean temperature changes through compositional turnover, but large thermal deviances are evident under certain conditions. The coldest-adapted species persisted in polar regions during warming but were not joined by additional immigrants, resulting in decreased assemblage turnover with warming. The warmest-adapted species persisted in equatorial regions during cooling. Assemblages at mid latitudes closely tracked temperature cooling and showed a modest increase in thermal deviance with warming. Main conclusionsPlanktonic foraminiferal assemblages were generally able to track or endure temperature changes: as climate warmed or cooled, bio-indicated temperature also became warmer or cooler, although to a variable degree. At polar sites under warming and at equatorial sites under cooling, the change in temperature predicted from assemblage composition was less than, or even opposite to, expectations based on estimated environmental change. Nevertheless, all species survived the accumulation of thermal deviance--a result that highlights the resilience and inertia of planktonic foraminifera on an assemblage level to the last 700,000 years of climate change, which might be facilitated by broad thermal tolerances or depth shifts.

paleontology↗

bioRxiv2023

Response of siliceous marine organisms to the Permian-Triassic climate crisis based on new findings from central Spitsbergen, Svalbard

Siliceous marine ecosystems play a critical role on the Earths climate system through its influence on organic carbon burial and rates of marine authigenic clay formation (i.e. reverse weathering). The ecological demise of silicifying organisms associated with the Permian-Triassic mass extinction is postulated to have elevated rates of marine authigenic clay formation, resulting in a prolonged greenhouse climate during the Early Triassic. Yet, our understanding of the response of siliceous marine organisms during this critical interval is poor. Whilst radiolarians experienced the strongest diversity loss in their evolutionary history and perhaps also the greatest population decline of silica-secreting organisms during this event, only a small number of Griesbachian (post-extinction) localities that record siliceous organisms are known. Here, we report newly discovered latest Changhsingian to early Griesbachian (Clarkina meishanensis - Hindeodus parvus Zone) radiolarians and siliceous sponge spicules from Svalbard. This fauna documents the survival of a low-diversity radiolarian assemblage alongside stem-group hexactinellid sponges making this the first described account of post-extinction silica-secreting organisms from the Permian/Triassic boundary in a shallow marine shelf environment and a mid-northern palaeolatitudinal setting. Our findings indicate that latitudinal diversity gradients for silica-secreting organisms following the mass extinction were significantly altered, and that silica productivity was restricted to high latitude and deep water thermal refugia. This result has potential to further shape our understanding of changes to marine porewater and seawater dissolved silica levels and in turn rates of reverse weathering, with implications for our understanding of carbon cycle dynamics during this interval. This also suggests that the export of organic carbon to the deep ocean was not as severely impacted at non-equatorial latitudes. Key PointsO_LIWe document the first occurrence of siliceous sponge spicules and radiolarians (biogenic silica) from a mid-northern paleolatitude following the mass extinction event C_LIO_LIHoldover radiolarian species show poleward range shifts C_LIO_LIThe ecological composition and the restriction to shallow water oxygenated facies suggests a shallow mid-latitude refuge for siliceous marine organisms C_LIO_LIThis result has potential to further shape our understanding of changes to marine dissolved silica levels and in turn rates of reverse weathering, with implications for our understanding of Permian-Triassic carbon cycle dynamics. C_LI

evolutionary biology↗

bioRxiv2020

The rise and fall of novel ecological communities

Local and global environmental change is transforming ecological assemblages into new configurations, resulting in ecosystems with novel communities. Here we develop a robust methodology for the identification of novel communities, examine patterns in their natural chance of occurrence, and quantify the probability of local extinction, emigration, local origination and immigration in transitions to and from novel communities. Using a global dataset of Cenozoic marine plankton communities, we found the probability of local extinction, origination and emigration during transitions to a novel community increased up to four times that of background community changes, with the probability of species loss about equal to that of species gain. Although rare, once a novel community state emerged, the chance of shifting into another novel community state was five times greater than expected by chance. Thus, for marine planktonic communities at 100K year time scales, novel communities are particularly sensitive to further extinctions and community shift. One Sentence SummaryOnce developed, novel ecological communities face increased susceptibility to further shifts in species composition, with heightened extinction risk.

ecology↗

bioRxiv2018

The R package divDyn for quantifying diversity dynamics using fossil sampling data

O_LIUnbiased time series of diversity dynamics are vital for quantifying the grand history of life. Applications include identifying ancient mass extinctions and inferring both biotic and abiotic controls on diversification rates.\nC_LIO_LIWe introduce divDyn, a new R package that facilitates the calculation of taxonomic richness, extinction and origination rates from time-binned fossil sampling data. State-of-the-art sampling completeness metrics, counting protocols, and sampling standardisation functions permit the reconstruction of biologically meaningful time series. Additional functions permit the partitioning of turnover rates by trait and environmental affinity.\nC_LIO_LIWe display Phanerozoic-scale diversity dynamics of marine invertebrates using the divDyn package. Using the core function and standard subsampling options, we revisit earlier assessments of declining extinction and origination rates over time and of equilibrial diversity dynamics to assess their methodological dependency.\nC_LIO_LIThe modular and fast implementation of published methods ensures traceability, reproducibility, and comparability of future studies.\nC_LI

paleontology↗