Severe climatic and environmental changes are far more prevalent in Earth history than major extinction events, and the relationship between environmental change and extinction severity has important ...implications for the outcome of the ongoing anthropogenic extinction event. The response of mineralized marine plankton to environmental change offers an interesting contrast to the overall record of marine biota, which is dominated by benthic invertebrates. Here, we summarize changes in the species diversity of planktic foraminifera and calcareous nannoplankton over the Mesozoic-Cenozoic and that of radiolarians and diatoms over the Cenozoic. We find that, aside from the Triassic-Jurassic and Cretaceous-Paleogene mass extinction events, extinction in the plankton is decoupled from that in the benthos. Extinction in the plankton appears to be driven primarily by majorclimatic shifts affecting water column stratification, temperature, and, perhaps, chemistry. Changes that strongly affect the benthos, such as acidification and anoxia, have little effect on the plankton or are associated with radiation.
Fossilizing marine plankton provide some of the most highly temporally and taxonomically resolved records of biodiversity since the Mesozoic.
The record of extinction and origination in the plankton differs from the overall marine biodiversity record in revealing ways.
Changes to water column stratification and global circulation are the main drivers of plankton diversity.
Anoxia, acidification, and eutrophication (which strongly influence total marine fossil diversity) are less important in the plankton.
Planktic foraminifera are an abundant component of deep-sea sediment and are critical to geohistorical research, primarily because as a biological and geochemical system they are sensitive to coupled ...bio-hydro-lithosphere interactions. They are also well sampled and studied throughout their evolutionary history. Here, we combine a synoptic global compilation of planktic foraminifera with a stochastic null model of taxonomic turnover to identify statistically significant increases in macroevolutionary rates. There are three taxonomic diversifications and two distinct extinctions in the history of the group. The well-known Cretaceous-Paleogene extinction is of unprecedented magnitude and abruptness and is linked to rapid environmental perturbations associated with bolide impact. The Eocene-Oligocene boundary extinction occurs due to a combination of factors related to a major reorganization of the global climate system. Changes in ocean stratification, seawater chemistry, and global climate recur as primary determinants of both macroevolutionary turnover in planktic foraminifera and spatiotemporal patterns of deep-sea sedimentation over the past 130 Myr.
The geographic ranges of marine organisms, including planktonic foraminifera
, diatoms, dinoflagellates
, copepods
and fish
, are shifting polewards owing to anthropogenic climate change
. However, ...the extent to which species will move and whether these poleward range shifts represent precursor signals that lead to extinction is unclear
. Understanding the development of marine biodiversity patterns over geological time and the factors that influence them are key to contextualizing these current trends. The fossil record of the macroperforate planktonic foraminifera provides a rich and phylogenetically resolved dataset that provides unique opportunities for understanding marine biogeography dynamics and how species distributions have responded to ancient climate changes. Here we apply a bipartite network approach to quantify group diversity, latitudinal specialization and latitudinal equitability for planktonic foraminifera over the past eight million years using Triton, a recently developed high-resolution global dataset of planktonic foraminiferal occurrences
. The results depict a global, clade-wide shift towards the Equator in ecological and morphological community equitability over the past eight million years in response to temperature changes during the late Cenozoic bipolar ice sheet formation. Collectively, the Triton data indicate the presence of a latitudinal equitability gradient among planktonic foraminiferal functional groups which is coupled to the latitudinal biodiversity gradient only through the geologically recent past (the past two million years). Before this time, latitudinal equitability gradients indicate that higher latitudes promoted community equitability across ecological and morphological groups. Observed range shifts among marine planktonic microorganisms
in the recent and geological past suggest substantial poleward expansion of marine communities even under the most conservative future global warming scenarios.
In palaeontological studies, groups with consistent ecological and morphological traits across a clade's history (functional groups)
afford different perspectives on biodiversity dynamics than do ...species and genera
, which are evolutionarily ephemeral. Here we analyse Triton, a global dataset of Cenozoic macroperforate planktonic foraminiferal occurrences
, to contextualize changes in latitudinal equitability gradients
, functional diversity, palaeolatitudinal specialization and community equitability. We identify: global morphological communities becoming less specialized preceding the richness increase after the Cretaceous-Palaeogene extinction; ecological specialization during the Early Eocene Climatic Optimum, suggesting inhibitive equatorial temperatures during the peak of the Cenozoic hothouse; increased specialization due to circulation changes across the Eocene-Oligocene transition, preceding the loss of morphological diversity; changes in morphological specialization and richness about 19 million years ago, coeval with pelagic shark extinctions
; delayed onset of changing functional group richness and specialization between hemispheres during the mid-Miocene plankton diversification. The detailed nature of the Triton dataset permits a unique spatiotemporal view of Cenozoic pelagic macroevolution, in which global biogeographic responses of functional communities and richness are decoupled during Cenozoic climate events. The global response of functional groups to similar abiotic selection pressures may depend on the background climatic state (greenhouse or icehouse) to which a group is adapted.
For over 50 years, cores recovered from ocean basins have generated fossil, lithologic, and chemical archives that have revolutionized fields within the earth sciences. Although scientific ocean ...drilling (SOD) data are openly available following each expedition, the 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 Findable, Accessible, Interoperable, and Reusable (FAIR) Data Principles and the establishment of community‐led 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 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 data sets that were never deposited in a database; these were manually transcribed from original reports. This compiled data set contains over 79,899 lithological units from 1,125 drilling holes from 422 sites. Over 26,000 fossil‐bearing samples, with 5,378 taxonomic entries from 13 biological groups, are placed within this lithologic spatiotemporal framework. All information is available via GitHub and Macrostrat's application programming interface, which renders data retrievable by a variety of parameters, including age, site, and lithology.
Key Points
Scientific ocean drilling has produced vast amounts of data; however, they are not archived in a way that meets the Findable, Accessible, Interoperable, and Reusable data principles
The extending Ocean Drilling Pursuits project standardizes lithology, paleontology, and age data across decades of drilling programs
This project has migrated data sets to existing, open‐access, searchable databases to enable scientific research
Microfossils have a ubiquitous and well‐studied fossil record with temporally and spatially fluctuating diversity, but how this arises and how major events affect speciation and extinction is ...uncertain. We present one of the first applications of PyRate to a micropalaeontological global occurrence dataset, reconstructing diversification rates within a Bayesian framework from the Mesozoic to the Neogene in four microfossil groups: planktic foraminiferans, calcareous nannofossils, radiolarians and diatoms. Calcareous and siliceous groups demonstrate opposed but inconsistent responses in diversification. Radiolarian origination increases from c. 104 Ma, maintaining high rates into the Cenozoic. Calcareous microfossil diversification rates significantly declines across the Cretaceous–Palaeogene boundary, while rates in siliceous microfossil groups remain stable until the Paleocene–Eocene transition. Diversification rates in the Cenozoic are largely stable in calcareous groups, whereas the Palaeogene is a turbulent time for diatoms. Diversification fluctuations are driven by climate change and fluctuations in sea surface temperatures, leading to different responses in the groups generating calcareous or siliceous microfossils. Extinctions are apparently induced by changes in anoxia, acidification and stratification; speciation tends to be associated with upwelling, productivity and ocean circulation. These results invite further micropalaeontological quantitative analysis and study of the effects of major transitions in the fossil record. Despite extensive occurrence data, regional diversification events were not recovered; neither were some global events. These unexpected results show the need to consider multiple spatiotemporal levels of diversity and diversification analyses and imply that occurrence datasets of different clades may be more appropriate for testing some hypotheses than others.
Understanding the links between long-term biological evolution, the ocean-atmosphere system and plate tectonics is a central goal of Earth science. Although environmental perturbations of many ...different kinds are known to have affected long-term biological evolution, particularly during major mass extinction events, the relative importance of physical environmental factors versus biological interactions in governing rates of extinction and origination through geological time remains unknown. Here we use macrostratigraphic data from the Atlantic Ocean basin to show that changes in global species diversity and rates of extinction among planktonic foraminifera have been linked to tectonically and climatically forced changes in ocean circulation and chemistry from the Jurassic period to the present. Transient environmental perturbations, such as those that occurred after the asteroid impact at the end of the Cretaceous period approximately 66 million years ago, and the Eocene/Oligocene greenhouse-icehouse transition approximately 34 million years ago, are superimposed on this general long-term relationship. Rates of species origination, by contrast, are not correlated with corresponding macrostratigraphic quantities, indicating that physiochemical changes in the ocean-atmosphere system affect evolution principally by driving the synchronous extinction of lineages that originated owing to more protracted and complex interactions between biological and environmental factors.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The Kuroshio Current Extension (KCE) is the major western boundary current of the North Pacific Subtropical Gyre. To better understand how the KCE behaved under elevated CO2 conditions and how it ...came into its modern configuration, we use stable isotopic analyses from mixed‐layer planktic foraminifera from three Ocean Drilling Program sites that lie to the north, underneath of, and south of the present day KCE. Our data support previous hypotheses suggesting that the KCE played a significant role in delivering moisture to the high latitudes and contributed to extensive ice growth. Samples span from 5 to 2.5 Ma and cover three tectonic and climate events. In response to constriction of the Central American Seaway, the KCE region warmed then cooled, with a potential equatorward shift of the current and intensification of the North Pacific Subtropical Gyre. During the mid‐Piacenzian Warm Period, we define the mid‐Piacenzian 1 and 2 events, which were times when the KCE warmed and subsequently developed a strong temperature/salinity gradient between the two northernmost sites. Northern Hemisphere ice growth at ∼2.9 Ma brought the KCE into its modern‐day configuration. Paradoxically, the southernmost Hole 1209A appears coolest through the study interval. This paradox is resolved by invoking seasonal preferences of the species analyzed, a finding that highlights the need to consider seasonal and ecological preferences of plankton when interpreting geochemical records in midlatitude regions. We propose several hypotheses for drivers of KCE behavior that require further testing using higher‐resolution proxy data tied to additional regional and global records.
Key Points
The Kuroshio Current Extension (KCE) was sensitive to changes in temperature, salinity, and wind strength during the Pliocene
The KCE came into its modern‐like configuration with Northern Hemisphere glaciation around 2.9 Ma
Planktic foraminiferal seasonality affects geochemical records within midlatitude regions
Using temperature gradients measured in 10 holes at 6 sites, we generate the first high fidelity heat flow measurements from Integrated Ocean Drilling Program drill holes across the northern and ...central Lesser Antilles arc and back arc Grenada basin. The implied heat flow, after correcting for bathymetry and sedimentation effects, ranges from about 0.1 W/m2 on the crest of the arc, midway between the volcanic islands of Montserrat and Guadeloupe, to <0.07 W/m2 at distances >15 km from the crest in the back arc direction. Combined with previous measurements, we find that the magnitude and spatial pattern of heat flow are similar to those at continental arcs. The heat flow in the Grenada basin to the west of the active arc is 0.06 W/m2, a factor of 2 lower than that found in the previous and most recent study. There is no thermal evidence for significant shallow fluid advection at any of these sites. Present‐day volcanism is confined to the region with the highest heat flow.
Key Points
Heat flow in the Lesser Antilles is similar to other volcanic arcs
No evidence for subsurface fluid flow
Volcanism is confined to the region with high heat flow
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