Appearance and disappearance rates of Phanerozoic marine animal paleocommunities

Ecological observations and paleontological data show that communities of organisms recur in space and time. Various observations suggest that communities largely disappear in extinction events and appear during radiations. This hypothesis, however, has not been tested on a large scale due to a lack of methods for analyzing fossil data, identifying communities, and quantifying their turnover. We demonstrate an approach for quantifying turnover of communities over the Phanerozoic Eon. Using network analysis of fossil occurrence data, we provide the first estimates of appearance and disappearance rates for marine animal paleocommunities in the 100 stages of the Phanerozoic record. Our analysis of 124,605 fossil collections (representing 25,749 living and extinct marine animal genera) shows that paleocommunity disappearance and appearance rates are generally highest in mass extinctions and recovery intervals, respectively, with rates three times greater than background levels. Although taxonomic change is, in general, a fair predictor of ecologic reorganization, the variance is high, and ecologic and taxonomic changes were episodically decoupled at times in the past. Extinction rate, therefore, is an imperfect proxy for ecologic change. The paleocommunity turnover rates suggest that efforts to assess the ecological consequences of the present-day biodiversity crisis should focus on the selectivity of extinctions and changes in the prevalence of biological interactions.

Lithospheric plate tectonics and mass extinctions of biological species

The merging of lithospheric plates and the formation of supercontinents are considered to be the main causes of global species extinctions within the Earth’s biosphere. Under those conditions, the factor of geographic isolation is diminished and interspecies competition is accelerated, allowing for the survival of the best-adapted species. The divergence of lithospheric plates triggers a new spurt of speciation that surpasses the previous one, as it involves the participation of the winning species.

r-Process Radioisotopes from Near-Earth Supernovae and Kilonovae

The astrophysical sites where r-process elements are synthesized remain mysterious: it is clear that neutron star mergers (kilonovae (KNe)) contribute, and some classes of core-collapse supernovae (SNe) are also possible sources of at least the lighter r-process species. The discovery of 60Fe on the Earth and Moon implies that one or more astrophysical explosions have occurred near the Earth within the last few million years, probably SNe. Intriguingly, 244Pu has now been detected, mostly overlapping with 60Fe pulses. However, the 244Pu flux may extend to before 12 Myr ago, pointing to a different origin. Motivated by these observations and difficulties for r-process nucleosynthesis in SN models, we propose that ejecta from a KN enriched the giant molecular cloud that gave rise to the Local Bubble, where the Sun resides. Accelerator mass spectrometry (AMS) measurements of 244Pu and searches for other live isotopes could probe the origins of the r-process and the history of the solar neighborhood, including triggers for mass extinctions, e.g., that at the end of the Devonian epoch, motivating the calculations of the abundances of live r-process radioisotopes produced in SNe and KNe that we present here. Given the presence of 244Pu, other r-process species such as 93Zr, 107Pd, 129I, 135Cs, 182Hf, 236U, 237Np, and 247Cm should be present. Their abundances and well-resolved time histories could distinguish between the SN and KN scenarios, and we discuss prospects for their detection in deep-ocean deposits and the lunar regolith. We show that AMS 129I measurements in Fe–Mn crusts already constrain a possible nearby KN scenario.

Accelerated mass extinction in an isolated biota during Late Devonian climate changes

The fossil record can illuminate factors that contribute to extinction risk during times of global environmental disturbance; for example, inferred thermal tolerance was an important predictor of extinction during several mass extinctions that corresponded with climate change. Additionally, members of geographically isolated biotas may face higher risk because they have less opportunity to migrate to suitable climate refugia during environmental disturbances. Here, we investigate how different types of risk intersect in the well-preserved brachiopod fauna of the Appalachian Foreland Basin during the two pulses of the Frasnian–Famennian mass extinction (Late Devonian, ~ 372 Ma). The selectivity of extinction is consistent with climate change (cooling) as a primary kill mechanism in this fauna. Overall, the extinction was mild relative to other regions, despite the many endemic species. However, vulnerable taxa went extinct more rapidly, during the first extinction pulse, such that the second pulse was insignificant. These results suggest that vulnerable taxa in geographically isolated biotas face heightened extinction risk at the initiation of environmental stress, but that taxa in other regions may eventually see elevated extinction risk if environmental stress repeats or intensifies.

An overview of the plumbing systems of Large Igneous Provinces and their significance

Identification of large volume, short duration mafic magmatic events of intraplate affinity in both continental and oceanic settings on the Earth and other planets provides invaluable clues for understanding several vital geological issues of current concern. Of particular importance is understanding the assembly and dispersal of supercontinents through Earth's history, dramatic climate change events including mass extinctions, and processes that have produced a wide range of LIP-related resources such as Ni-Cu-PGE, Au, U, base metals, and petroleum. This current volume presents some of the latest developments and new information on the temporal and spatial distribution of LIPs in both the Precambrian and Phanerozoic, their origin, the plumbing system of mafic dyke swarms, sill provinces, and layered inrusions, and links to mantle plumes/superplumes events, supercontinent reconstructions and associated metallogeny.

Meteorites that produce K-feldspar-rich ejecta blankets correspond to mass extinctions

Meteorite impacts load the atmosphere with dust and cover the Earth's surface with debris. They have long been debated as a trigger of mass extinctions through Earth's history. Impact winters generally last <100 years, whereas ejecta blankets persist for 103-105 years. Here we show that only meteorite impacts that emplaced ejecta blankets rich in K-feldspar (Kfs) correlate to Earth system crises (n=11, p<0.000005). Kfs is a powerful ice-nucleating aerosol yet is normally rare in atmospheric dust mineralogy. Ice nucleation plays an important role in cloud microphysics, which modulates global albedo. A conceptual model is proposed whereby the anomalous prevalence of Kfs is posited to have two key effects on cloud dynamics: 1) reducing the average albedo of mixed-phase cloud, which effected a hotter climate; 2) weakening of the cloud albedo feedback, which increased climate sensitivity. These mechanisms offer an explanation as to why this otherwise benign mineral is correlated so strongly with mass extinction events: every K-feldspar-rich ejecta blanket corresponds to a severe extinction episode over the past 600 Myr. This model may also explain why many kill mechanisms only variably correlate with extinction events through geological time: they coincide with these rare periods of climate destabilization by atmospheric Kfs.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5690646

Preface

It is a great honor for us, Faculty of Forestry of Hasanuddin University, to host the 2nd Biennial Conference of Tropical Biodiversity 2021 (BCTB) 2021 on August 4th - 5th, 2021, in Makassar City of South Sulawesi Province, Indonesia. This conference is a series of international scientific seminars held by the Faculty of Agriculture, Universitas Hasanuddin, Makassar, Indonesia, held biennially since 2018. In addition, The proceedings of BCTB have been published in the IOP conference series: Earth and Environmental Science (EES). Biodiversity is evenly distributed and varies widely across the world and within regions, the diversity of which is highly dependent on environmental factors such as temperature, rainfall, altitude, soil geography, and the presence of other species. Biodiversity is also essential in supporting ecosystem services, including air quality, climate, carbon dioxide absorption, water purification, pollination, and erosion prevention. Rapid environmental changes have led to many mass extinctions of species. Therefore, protecting its existence has become one of the most significant challenges humanity has to face. The Biennial Conference of Tropical Biodiversity is a scientific forum to enhance science and technology, together with researchers, scientists, practitioners, and scholars to anticipate the impacts of climate change in biodiversity. This is also conducted to promote Sustainable Development Goals (SDGs). Hence, this conference chose an SDGs-related theme, namely “Managing Challenges in Biodiversity Conservation During The Pandemic to Achieve Sustainable Development Goals for Better Environment” with six sub-themes: 1. Assessment of global biodiversity: the impact of a pandemic to biodiversity. 2. The existence of genetic diversity to maintain biodiversity. 3. Community partnership for biodiversity conservation. 4. Biodiversity and utilization. 5. The conservation of tropical biodiversity: current challenges for the management. 6. Ecological risk and natural disaster. The Biennial Conference of Tropical Biodiversity will be held every two years. The first was in 2018, and the second should be in 2019. Due to the Covid-19 outbreak, the conference was postponed to be this year (2021). Hence, the conference model has performed with a virtual conference instead of a live meeting. This conference presents keynote speakers from 5 countries, namely Prof. Enrico Bonello from Ohio State University, USA, Dr. Doan Nainggolan from Aarhus University-Denmark, Prof. Erin P. Riley from San Diego State University-USA, Dr. Ida Ayu Pradnya Resosudarmo from Australian National University-Australia, and Prof. Supratman from Hasanuddin University-Indonesia. The plenary session and discussion for all speakers were for 3 hours. Participant presentations (oral and video presentations) were held in 3 sessions, and each session was divided into ten rooms. The number of participants per room was 15-20 participants with an allocation of presentations for 5 minutes/participant conducted in parallel as many as three parallel sessions. Discussions sessions were held in parallel in each parallel session with an allocation of 3 minutes per participant. The Virtual BCTB conference implementation applied the zoom meeting application provided by the Faculty of Forestry, Universitas Hasanuddin. List of Conference Committee & Reviewer BCTB 2021 are available in this pdf.

Post-extinction recovery of the Phanerozoic oceans and the rise of biodiversity hotspots

The fossil record of marine invertebrates has long fueled the debate on whether or not there are limits to global diversity in the sea1–4⁠. Ecological theory states that as diversity grows and ecological niches are filled, the strengthening of biological interactions imposes limits on diversity5–7⁠. However, the extent to which biological interactions have constrained the growth of diversity over evolutionary time remains an open question1–4,8–12⁠, largely because of the incompleteness and spatial heterogeneity of the fossil record13–15⁠. Here we present a regional diversification model that reproduces surprisingly well the Phanerozoic trends in the global diversity of marine invertebrates after imposing mass extinctions. We find that the dynamics of global diversity is best described by a diversification model that operates broadly within the exponential growth regime of a logistic function. A spatially resolved analysis of the diversity-to-carrying capacity ratio reveals that only < 2% of the global flooded continental area exhibits diversity levels approaching ecological saturation. We attribute the overall increase in global diversity during the Late Mesozoic and Cenozoic to the development of diversity hotspots under prolonged conditions of Earth system stability and maximum continental fragmentation. We call this the "diversity hotspots hypothesis", which is proposed as a non-mutually exclusive alternative to the hypothesis that the Mesozoic marine revolution led this macroevolutionary trend16,17.