Claims of paleodata periodicity are many and controversial, so that, for example, superimposing Phanerozoic (0–541 My) mass-extinction periods renders life on Earth impossible. This period hunt coincided with the modernization of geochronology, which now ties geological timescales to orbital frequencies. Such tuneup simplifies energy-band (variance-) stratification of information contents, enabling the separation of astronomical signals from harmonics, e.g., using variance-based spectral analysis. I thus show on diverse data (geomagnetic polarity, cratering, extinction episodes) as a proxy of planetary paleodynamics that many-body subharmonic entrainment induces a resonant response of the Earth to astronomical forcing so that the 2π-phase-shifted axial precession p=26 ky, and its Pi=2πp/i; i=1,…,n harmonics, get resonantly responsible for virtually all paleodata periods. This resonantly quasiperiodic nature of strata is co-triggered by a p'/4-lockstep to the p'=41-ky obliquity (also 2π-phase-shifted, to P'=3.5-My superperiod). For verification, residuals analysis after suppressing 2πp (and thus Pi, too) in the current polarity-reversals GPTS-95 timescale’s calibration extending to end-Campanian (0–83 My) successfully detected weak signals of Earth-Mars planetary resonances, reported previously from older epochs. The significant intrinsic residual signal is 26.5-My Rampino period — the carrier wave of crushing deflections co-responsible for transformative polarity reversals. While the (2πp, Pi) resonant response of the Earth to orbital forcing is the long-sought energy transfer mechanism of the Milankovitch theory, fundamental system properties — 2π-phase-shift, ¼ lockstep to a forcer, and the discrete time translation symmetry (multiplied or halved periods) — previously thought confined to (quantum) time crystal, here appear macroscopic, rendering the concept of time crystal unremarkable. In turn, such a surprising cross-scale outcome has confirmed the main result: that of planetary precession being a cataclysmic geodynamic phenomenon as claimed in the past, e.g., as the mechanism for Earth expansion; then a time crystal in quantum dynamics could be due to particle entrainment, such as the collisions resulting in Feshbach resonances.
Stable carbon (δ¹³C) and oxygen (δ¹⁸O) isotope measurements in lacustrine ostracodes are widely used to infer past climatic conditions. Previous work has used individual ostracode valves to resolve seasonal and subdecadal climate signals, yet environmental controls on geochemical variability within co-occurring specimens from modern samples are poorly constrained. Here we focus on individual ostracode valves in modern-aged Lake Turkana sediments, an alkaline desert lake in tropical East Africa. We present individual ostracode valve analyses (IOVA) of δ¹³C and δ¹⁸O measurements (n = 329) of extant species Sclerocypris clavularis from 17 sites spanning the entire lake (n-avg ~19 specimens per site). We demonstrate that the pooled statistics of individual valve measurements at each site overcome inter-specimen isotopic variance and are driven by hydrological variability in the lake. Mean IOVA-δ¹³C and -δ¹⁸O across the sites exhibit strong spatial trends with higher values at more southerly latitudes, modulated by distance from the inflow of the Omo River. Whereas the latitudinal δ¹³C gradient reflects low riverine δ¹³C and decreasing lacustrine productivity towards the southern part of the lake, the δ¹⁸O gradient is controlled by evaporation superimposed on the waning influence of low-δ¹⁸O Omo River waters, sourced from the Ethiopian highlands. We show that ostracode δ¹⁸Oproximal to Omo River inflow is deposited under near-equilibrium conditions and that inter-specimen δ¹⁸O variability across the basin is consistent with observed temperature and lake water δ¹⁸O variability. IOVA can provide skillful constraints on high-frequency paleoenvironmental signals and, in Omo-Turkana sediments, yield quantitative insights into East African paleohydrology.
Sexual harassment in STEM continues to be a pervasive barrier to women’s full participation in the sciences. Many studies conclude that workplace culture and lack of clear policies and practices exacerbate the risks of sexual harassment. Remote research environments, such as field stations and ocean platforms, bring additional risk to researchers. Participants already face acute safety concerns related to the remoteness of the field station or oceanographic vessels, fewer and less clear policies and enforcement regulations are in place, and multiple institutions bear responsibility, leading to a challenging environment for preventing and handling incidents. This workshop explored the factors that permit sexual harassment in remote research, and aimed to develop practices to prevent and respond to harassment in the field. The California State University Desert Studies Center and the Center for Ocean Leadership convened workshop in March, 2021 to address sexual harassment in field science. Over three days, field and ocean science leadership and practitioners came together with leadership from professional societies and academia, and experts in sociology, policy, and social justice. The goals were to: 1) open a dialogue between sexual harassment experts and the field research community to develop best practices and recommendations; 2) build coordination and consistency in policy setting and enforcement across field stations and oceanographic platforms; 3) develop processes to monitor the reporting of sexual harassment instances occurring at remote field locations; and 4) promote a safe culture for scientists conducting research at remote field stations and on oceanographic vessels. The workshop compiled and developed best practices and recommendations in four key areas: 1) culture change, 2) policy, 3) accountability, and 4) reporting. These recommendations were targeted at all facets of field and ocean sciences, from academic and research institutions, professional societies, and funding agencies, to departments and field research crews. Here we will give an overview of the workshop findings, with particular focus on the recommendations for research leadership.
To assess zonal temperature and biogeographical patterns in the Paleogene of the Southern Ocean, we present new multi-proxy air and sea surface temperature data for the latest Paleocene (~57–56 Ma) and the Paleocene-Eocene Thermal Maximum (PETM; ~56 Ma) from the northern margin of the Australo-Antarctic Gulf (AAG). The various proxies document the well-known late Paleocene gradual warming and, superimposed, two late Paleocene pre-cursor warming events, hundreds of kyrs prior to the PETM. Remarkably, however, air and sea surface temperature reconstructions for the AAG and SW Pacific during the latest Paleocene, PETM and Early Eocene Climatic Optimum (~53–49 Ma) show similar trends and, within proxies, similar absolute temperatures. The record implies that the exceptional warmth previously recorded in the SW Pacific extended westward into the AAG. This contrasts with the modeled circulation and temperature patterns. We suggest that simulations of ocean circulation underestimate heat transport in the SW Pacific due insufficient resolution, not allowing for mesoscale eddy-related heat transport. We argue for a systematic approach to tackle model and proxy biases in marginal marine settings, including assessment of underexplored factors as high-latitude proxy mechanisms to confidently assess temperature in these non-analogue climates.
In the face of ongoing marine deoxygenation, understanding timescales and drivers of past oxygenation change is of critical importance. Marine sediment cores from tiered silled basins provide a natural laboratory to constrain timing and implications of oxygenation changes across multiple depths. Here, we reconstruct oxygenation and environmental change over time using benthic foraminiferal assemblages from sediment cores from three basins across the Southern California Borderlands: Tanner Basin (EW9504-09PC, 1194 m water depth), San Nicolas Basin (EW9504-08PC, 1442 m), and San Clemente Basin (EW9504-05PC ,1818 m). We utilize indicator taxa, community ecology, and an oxygenation transfer function to reconstruct past oxygenation, and we directly compare reconstructed dissolved oxygen to modern measured dissolved oxygen. We generate new, higher resolution carbon and oxygen isotope records from planktic (Globigerina bulloides) and benthic foraminifera (Cibicides mckannai) from Tanner Basin. Geochemical and assemblage data indicate limited ecological and environmental change through time in each basin across the intervals studied. Early to mid-Holocene (11.0-4.7 ka) oxygenation below 1400 m (San Clemente and San Nicolas) was relatively stable and reduced relative to modern. San Nicolas Basin experienced a multi-centennial oxygenation episode from 4.7-4.3 ka and oxygenation increased in Tanner Basin gradually from 1.7-0.8 ka. Yet across all three depths and time intervals studied, dissolved oxygen is consistently within a range of intermediate hypoxia (0.5-1.5 ml L-1 [O2]). Variance in reconstructed dissolved oxygen was similar to decadal variance in modern dissolved oxygen and reduced relative to Holocene-scale changes in shallower basins.
Increased adoption and improved methodology in carbonate clumped isotope thermometry has greatly enhanced our ability to interrogate a suite of Earth-system processes. However, interlaboratory discrepancies in quantifying Increased use and improved methodology of carbonate clumped isotope thermometry has greatly enhanced our ability to interrogate a suite of Earth-system processes. However, inter-laboratory discrepancies in quantifying carbonate clumped isotope (Δ47) measurements persist, and their specific sources remain unclear. To address inter-laboratory differences, we first provide consensus values from the clumped isotope community for four carbonate standards relative to heated and equilibrated gases with 1,819 individual analyses from 10 laboratories. Then we analyzed the four carbonate standards along with three additional standards, spanning a broad range of δ47 and Δ47 compositions, for a total of 5,329 analyses on 25 individual mass spectrometers from 22 different laboratories. Treating three of the materials as known standards and the other four as unknowns, we find that the use of carbonate reference materials is a robust method for standardization that yields inter-laboratory discrepancies entirely consistent with in-laboratory analytical uncertainties. Carbonate reference materials, along with measurement and data processing practices described herein, provide the carbonate clumped isotope community with a robust approach to achieve inter-laboratory agreement as we continue to use and improve this powerful geochemical tool. We propose that carbonate clumped isotope data normalized to the carbonate reference materials described in this publication should be reported as Δ47 (I-CDES) for Intercarb-Carbon Dioxide Equilibrium Scale.
Recent satellite mapping and coring of the peatland complex of the Congo Basin’s Couvette Centrale region underscores the global significance of this area. Freshwater tropical peatlands in the Congo Basin make up one of Earth’s largest terrestrial carbon sinks which forms an important nexus between global climate, biogeochemical cycling, and biodiversity. These peatlands are also a unique record of past climates, containing microfossil and geochemical proxies documenting past climatic and hydrological conditions in the region, yet there are no published studies of these peatland deposits south of the Congo River in the Democratic Republic of Congo (DRC). Recent coring and radiocarbon dating of peatland core sequences collected from the Couvette Centrale and Mai Ndombe regions of DRC provides new data on the timing of peatland establishment in the Congo Basin. Furthermore, preliminary results of palynological and isotope geochemical analysis shed light on the spatial and temporal variability in regional rainfall regimes for these regions.
Hydrogen isotope ratios of sedimentary leaf waxes (δ2HWax values) are increasingly used to reconstruct past hydroclimate. Here, we add δ2HWax values from 19 lakes and four swamps on 15 tropical Pacific islands to an updated global compilation of published data from surface sediments and soils. Globally, there is a strong positive linear correlation between δ2H values of mean annual precipitation (δ2HP values) and the leaf waxes n-C29-alkane (R2 = 0.74, n = 665) and n-C28-acid (R2 = 0.74, n = 242). Tropical Pacific δ2HWax values fall within the predicted range of values based on the global calibration, and the largest residuals from the global regression line are no greater than those observed elsewhere, despite large uncertainties in δ2HP values at some Pacific sites. However, tropical Pacific δ2HWax values in isolation are not correlated with estimated δ2HP values from isoscapes or from isotope-enabled general circulation models. Palynological analyses from these same Pacific sediment samples suggest no systematic relationship between any particular type of pollen distribution and deviations from the global calibration line. Rather, the poor correlations observed in the tropical Pacific are likely a function of the small range of δ2HP values relative to the typical residuals around the global calibration line. Our results suggest that δ2HWax values are currently most suitable for use in detecting large changes in precipitation in the tropical Pacific and elsewhere, but that ample room for improving this threshold exits in both improved understanding of δ2H variability in plants, as well as in precipitation.
Committees touch nearly every facet in the science, technology, engineering, and mathematics (STEM) research enterprise. However, the role of gatekeeping through committee work has received little attention in Earth and space sciences. We propose a novel concept called, “regenerative gatekeeping” to challenge institutional inertia, cultivate belonging, accessibility, justice, diversity, equity, and inclusion in committee work. Three examples, a hiring committee process, a seminar series innovation, and an awards committee, highlight the need to self-assess policies and practices, ask critical questions and engage in generative conflict. Rethinking committee work can activate distributed mechanisms needed to promote change.
The end-Permian mass extinction event resulted in the loss of approximately 80% to 90% of marine animal species due to drastic changes in climate. Because warming was a major factor in the extinction, it has been theorized the organisms that did survive were able to do so because they moved to higher latitudes and this hypothesis is consistent with tetrapod data. We hypothesized that this relationship holds true for marine mollusks and arthropods as well. Using Changhsingian (Late Permian) and Induan (Early Triassic) data from the Paleobiology Database, we extracted occurrences of classes Bivalvia, Cephalopoda, Gastropoda, and Ostracoda, which had 2433, 395, 379, and 1717 genus occurrences, respectively. Then, we used the paleolatitude data for each genus occurrence to characterize the latitude distribution of each class before and after the Permian/Triassic transition. We compared the paleolatitude medians before and after the mass extinction for each class to quantify the latitude shift for each class: 23.18° for Bivalvia, 37.45° for Cephalopoda, 29.82° for Gastropoda, and 6.29° for Ostracoda. This finding indicates that each individual class had a different latitudinal shift, with all classes exhibiting a poleward shift north. We also conducted Welch t-tests to compare the differences in latitudinal ranges and found that they were significant (Bivalvia: p < 2.2e-16, Cephalopoda: p = 3.83e-6, Gastropoda: p < 2.2e-16, Ostracoda: p = 0.0030). In addition, we ran multiple randomized models to compare them with our original results and found a significant difference between them via the Kolmogorov-Smirnov test, which means that the northward migration could be a biological response. Moreover, the results of our study show that the overall latitudinal range of most classes contracted after the extinction event, with the exception of the Cephalopoda class.
Birds are some of the most diverse organisms on Earth, with species inhabiting nearly every conceivable niche in every major biome. As such, birds are vital to our understanding of modern ecosystems. Unfortunately, this is hampered by knowledge gaps relating to the origin of this modern diversity and its role in ecosystems. A crucial part of addressing these shortcomings is improving our understanding of the earliest birds, the non-avian avialans i.e. non-crown birds. The diet of non-avian avialans has been a matter of substantial debate, partly related to some of the ambiguous qualitative approaches that have been used to reconstruct it. Here we review the methods of determining diet in both modern avians and fossil avian and non-avian theropods, and comment on their usefulness when applied to non-avian avialans. We use this to propose a set of comparable, quantitative approaches to ascertain fossil bird diet and on this basis provide a consensus of what we currently know about fossil bird diet. While no single approach can precisely predict diet in birds, each can exclude some diets and narrow the dietary possibilities. We recommend combining  dental microwear,  landmark-based muscular reconstruction,  stable isotope geochemistry,  body mass estimations,  traditional and/or geometric morphometric analysis, and  finite element analysis to accurately reconstruct fossil bird diet. Our review provides specific methodologies to implement each approach and discusses complications future researchers should keep in mind. On this basis we report the current state of knowledge of non-avian avialan diet which remains very incomplete. The ancestral dietary condition in non-avian avialans remains unclear due to a scarcity of data and contradictory evidence in Archaeopteryx. Among early non-avian pygostylians, Confuciusornis has finite element analysis and mechanical advantage evidence pointing to herbivory, whilst Sapeornis only has mechanical advantage evidence indicating granivory, which agrees with fossilised ingested material known for this taxon. The enantiornithine ornithothoracine Shenqiornis has mechanical advantage and pedal morphometric evidence pointing to carnivory. In the hongshanornithid ornithuromorph Hongshanornis, only mechanical advantage evidence indicates granivory, but this is congruent with evidence of fossilised ingested material in this taxon. The same is true for the songlingornithid ornithuromorph Yanornis and its inferred carnivorous diet. Due to the sparsity of robust dietary assignments, no clear trends in non-avian avialan dietary evolution have yet emerged. Dietary diversity may seem to increase through time, but this is a preservational bias associated with a predominance of data from the Early Cretaceous Jehol Lagerstatte. With this new framework and our current synthesis of current knowledge of non-avian non-avialan diet, we expect dietary knowledge and evolutionary trends to become much clearer[…]
Reconstructions of Common-Era sea level are informative of relationships between sea level and natural climate variation, and the uniqueness of modern sea-level rise. Kench et al. recently reconstructed Common-Era sea level in the Maldives, Indian Ocean, using coral microatolls. They reported periods of 150-500 yr when sea level fell and rose at average rates of 2.7-4.3 mm/yr. These periods coincided with intervals of cooling and warming inferred from proxy reconstructions of sea-surface temperature (SST) and radiative forcing (ref. 2, Fig. 2). Kench et al. reasoned that these 0.6-1.4-m centennial-scale sea-level fluctuations were driven by climate, specifically thermal contraction and expansion of seawater. In contrast to previous studies, Kench et al. argued that modern rates and magnitudes of sea-level rise caused by climate change have precedent during the Common Era. We use principles of sea-level physics to argue that pre-industrial radiative forcing and SST changes were insufficient to cause thermosteric sea-level (TSL) trends as large as reported for the Maldives.
For over fifty years, cores recovered from ocean basins have generated extensive fossil, lithologic, and chemical archives that have revolutionized the fields of plate tectonics and oceanography, and significantly improved our understanding of climate change. Although scientific ocean drilling (SOD) data are openly available after each expedition, formats for these data are heterogeneous. Furthermore, lithological, chronological, and paleobiological data are typically separated into different repositories, limiting researchers’ abilities to discover and analyze integrated SOD data sets. Emphasis within Earth Sciences on adhering to FAIR Data Principles and the establishment of community-lead databases provide a pathway to unite SOD data and further harness the scientific potential of the investments made in offshore drilling. Here, we describe a workflow for compiling, cleaning, and standardizing key SOD records, and importing them into the Paleobiology Database (PBDB) and Macrostrat, systems with versatile, open data distribution mechanisms. These efforts are being carried out by the extending Ocean Drilling Pursuits (eODP) project. eODP has processed all of the lithological, chronological, and paleobiological data from one SOD repository, along with numerous other datasets that were never deposited in a database; these were manually transcribed from original reports. This compiled dataset contains over 78,000 lithological units from 1,048 drilling holes from 390 sites. Over 26,000 fossil-bearing samples, with 5,280 taxonomic entries from 13 biological groups, are placed within this lithologic spatiotemporal framework. Information is available via the PBDB and Macrostrat application programming interfaces, which render data retrievable by a variety of parameters, including age, taxon, site, and lithology.
It is now understood that if life had ever erose on Mars, it might have been preserved in the simplest form. Therefore, studying the traces of simple life forms from the rock records of various Earth environments and climatic conditions perhaps helps to narrow down the region of interest while searching for life on the red planet. The Precambrian era covered almost 80% of Earth’s geologic history, witnessed the appearance of life on Earth and experienced prolonged extreme climatic events that delayed biological evolution. During this extreme period, primitive lifeforms such as microbial mats had a strong influence on sedimentation, and they facilitated the formation of a variety of mat-induced sedimentary structures (MISS) in siliciclastic and carbonate sedimentary environments. In the last two decades MISS have been identified from several Precambrian successions of India for example, Vindhyan, Marwar, Chhattisgarh and, Cuddapah Supergroup. In this study we tried to provide an updated catalogue based on the chronologic, stratigraphic and paleoenvironmental occurrences of MISS from the Indian Precambrian successions. We further explore their potential in understanding extreme habitability, searching biomarkers and biosignatures on Mars and propose a few potential sites for astrobiological research.
Model simulations of past climates are increasingly found to compare well with proxy data at a global scale, but regional discrepancies remain. A persistent issue in modeling past greenhouse climates has been the temperature difference between equatorial and (sub-)polar regions, which is typically much larger in simulations than proxy data suggest. Particularly in the Eocene, multiple temperature proxies suggest extreme warmth in the southwest Pacific Ocean, where model simulations consistently suggest temperate conditions. Here we present new global ocean model simulations at 0.1° horizontal resolution for the middle-late Eocene. The eddies in the high-resolution model affect poleward heat transport and local time-mean flow in critical regions compared to the non-eddying flow in the standard low-resolution simulations. As a result, the high-resolution simulations produce higher surface temperatures near Antarctica and lower surface temperatures near the equator compared to the low-resolution simulations, leading to better correspondence with proxy reconstructions. Crucially, the high-resolution simulations are also much more consistent with biogeographic patterns in endemic-Antarctic and low-latitude-derived plankton, and thus resolve the long-standing discrepancy of warm subpolar ocean temperatures and isolating polar gyre circulation. The results imply that strongly eddying model simulations are required to reconcile discrepancies between regional proxy data and models, and demonstrate the importance of accurate regional paleobathymetry for proxy-model comparisons.
The Shuram excursion, an extremely negative and prolonged carbonate δ13C anomaly, is recorded globally in late Ediacaran shallow-water marine sedimentary sequences and coincided with a time of increasing ocean oxygenation. Marine planktonic microorganisms with organic cell walls, known as acritarchs, were common in the Ediacaran Period. The onset of the Shuram excursion occurred during a time of rapid acritarch cell wall diversification, and the excursion’s resolution was followed by the appearance of macroscopic calcium carbonate biomineralizing metazoans in the late Ediacaran. Accordingly, I consider that the Shuram excursion may be attributed to sedimentary accumulations of material sourced from weakly calcified acritarchs, which primitively biomineralized their cell walls by precipitating 13C-enriched marine carbonate onto 13C-depleted organic carbon. Decay of this organic carbon to authigenic carbonate after burial may have produced the low δ13Ccarb values. The carbon isotope mass balance of global carbon cycle reservoirs permits this effect to produce a Shuram excursion of any duration. An initial organic fraction of ~0.6 is required in the acritarch-derived phase, in agreement with fossil evidence that the earliest biomineralized structures contained a major fraction of organic carbon. I will discuss how fossil, petrographic and geochemical observations are consistent with this hypothesis. During the excursion, a peak globally averaged organic carbon burial fraction of ~0.4 is predicted. Burial sequestration of organic carbon in organic-rich biomineralized calcium carbonate could account for the rise in oxygen associated with the Shuram excursion.
The research data repository of the Environmental Data Initiative (EDI) is a signatory of the FAIR Data Principles. Building on over 30 years of data curation research and experience in the NSF-funded US Long-Term Ecological Research program (LTER), it provides mature functionalities, well established workflows, and support for ‘long-tail’ environmental data publication. High quality scientific metadata are enforced through automatic checks against community developed rules and the Ecological Metadata Language (EML) standard. Although the EDI repository is far along the continuum of making its data FAIR, representatives from EDI and the LTER Information Management community have recently been developing best practices for the edge cases in environmental data publishing. Here we discuss and seek feedback on how to best handle the publication of these ‘long-tail’ data when extensive additional data are available along with e.g., genomics data, physical specimens, or flux tower data. While these latter data are better handled in other discipline-specific repositories such as NCBI, iDigBio, and AmeriFlux, they are frequently associated with other data collected at the same time and location, or even from the same samples. This is particularly relevant across the LTER Network, where sites represent integrative research projects. Questions we address (and seek community input from) include: How to archive documents and images when they are data, e.g., field notebooks, or time-lapse photographs of plant phenology? How to deal with data from Unmanned Vehicle (e.g., drones and underwater gliders), acoustic data, or model outputs, which may be several terabytes in size? How should processing scripts or modeling code be associated with data? Overall, these best practices address issues of Findability and Accessibility of data as well as greater transparency of the research process.