Preprints
Filtering by Subject: Life Sciences
A focus on different types of organic matter particles and their significance in the open ocean carbon cycle
Published: 2023-02-15
Subjects: Life Sciences
Marine particles are key to the cycling of major elements on Earth and play an important role in the balance of nutrients in the ocean. Three main categories ofmarine particles link the different parts of the open ocean by shaping carbon distribution: (i) sinking; (ii) suspended, and (iii) ascending. Atmospheric carboncaptured by phytoplankton in the surface water, is partly sequestered by [...]
Clumped isotopes in globally distributed Holocene coccoliths reveal their habitat depth
Published: 2023-02-06
Subjects: Life Sciences, Physical Sciences and Mathematics
Reliable temperature reconstructions are necessary to improve climate reconstructions and comparisons with paleoclimate model simulations. Most existing paleotemperature proxies are based on organic and inorganic remains of marine organisms. Despite the evidence that the habitat depth of coccolithophores and other phytoplankton depend on their ability to balance light, nutrients, and grazing [...]
Reading the sediment archive of the Eastern Campeche Bank (southern Gulf of Mexico): From the aftermath of the Chicxulub impact to Loop Current variability
Published: 2023-02-04
Subjects: Life Sciences
This is the first high-resolution seismic study showing how the Chicxulub impact shaped the eastern slope of the Campeche Bank in the south-eastern Gulf of Mexico. The induced shock wave fractured Cretaceous strata causing the collapse of the upper slope and shelf over a length of ca. 200 km. Failed material was either transported downslope or remained in parts on the accommodation space created [...]
Non-perennial stream networks as directed acyclic graphs: The R-package streamDAG
Published: 2023-01-11
Subjects: Life Sciences, Physical Sciences and Mathematics
Many conventional stream network metrics are time-invariant and/or do not consider the importance of individual stream locations to network functionality. As a result, they are not well-suited to non-perennial streams, in which hydrologic status (flowing vs. pooled vs. dry) can vary substantially in space and time. To help address this issue, we consider non-perennial streams as directed acyclic [...]
The Communication Distance of Non-Perennial Streams
Published: 2023-01-11
Subjects: Life Sciences, Physical Sciences and Mathematics
We developed Bayesian statistical approaches to assess non-perennial stream network connectivity. Our new methods allow: 1) consideration of changes to both local (stream segment) and global (stream network) connectivity over time, 2) incorporation of prior information from different data sources, and 3) straightforward computation of the posterior distributions of both active stream length and a [...]
Subsurface geologic, geophysical and chronological data for paleo-hydrologic reconstructions in Danube’s lower floodplain - delta system
Published: 2022-12-16
Subjects: Life Sciences
Abstract: Records of paleofloods can be reconstructed from special fluvial sedimentary environments such as oxbows; however, deposits in in such lakes, if they exist at all, are still short, on the order of hundreds of years. Longer sedimentary records need to be developed for evaluating paleo-hydrologic regimes of large rivers transiting from a natural Holocene to Anthropocene. Here we report [...]
Thermal stratification and meromixis in four dilute temperate zone lakes
Published: 2022-12-14
Subjects: Life Sciences, Physical Sciences and Mathematics
Four adjacent lakes (Arco, Budd, Deming, and Josephine) within Itasca State Park in Minnesota, USA are reported to be meromictic in the scientific literature. However, seasonally persistent chemoclines have never been documented. We collected seasonal profiles of temperature and specific conductance and placed temperature sensor chains in two lakes for ~ 1 year to explore whether these lakes [...]
Climate change impacts on surface heat fluxes in a deep monomictic lake
Published: 2022-12-08
Subjects: Life Sciences
Turbulent and radiative energy exchanges between lakes and the atmosphere play an important role in determining the process of lake-mixing and stratification, including how lakes respond to climate and to climate change. Here we use a one-dimensional hydrodynamic lake model to assess seasonal impacts of climate change on individual surface heat flux components in Lough Feeagh, Ireland, a deep, [...]
A Sentinel-2 based multi-temporal monitoring framework for wind and bark beetle detection and damage mapping
Published: 2022-11-18
Subjects: Life Sciences
The occurrence of extreme windstorms and increasing heat and drought events induced by climate change leads to coniferous forests showing severe damage and stress and making trees more vulnerable to spruce bark beetle infestations. The combination of abiotic and biotic disturbances in forests can cause drastic environmental and economic losses. The first step for containing such damage is the [...]
The unknown fate of macroplastic in mountain rivers
Published: 2022-11-09
Subjects: Earth Sciences, Environmental Indicators and Impact Assessment, Environmental Monitoring, Geology, Geomorphology, Hydrology, Life Sciences, Natural Resources and Conservation, Sedimentology, Stratigraphy, Sustainability, Terrestrial and Aquatic Ecology, Water Resource Management
Mountain rivers are typically seen as relatively pristine ecosystems, supporting numerous goods (e.g., water resources) for human populations living not only in the mountain regions but also downstream from them. Recent evidence suggests, however, that mountain river valleys in populated areas can be substantially polluted by macroplastic (plastic item > 5 mm). It is, however, unknown how [...]
Gaia: Complex Systems Prediction for Time to Adapt to Climate Shocks
Published: 2022-11-08
Subjects: Engineering, Life Sciences, Physical Sciences and Mathematics
A proposal, called “Gaia”, that life regulates Earth’s climate to its advantage, is partially supported by Earth’s climate history, wherein temperature fluctuations over the past ca. half billion years have mostly been small enough to protect life from extremes of climatic fluctuations, while global temperatures overall cooled during the 3.8 Ga when life was present, in spite of increased solar [...]
Regional drivers of fire regimes in the Brazilian Amazon between 2009 and 2021
Published: 2022-10-18
Subjects: Environmental Studies, Forest Sciences, Life Sciences, Social and Behavioral Sciences
Fires are a major source of carbon emissions in the Brazilian Amazon. Climatic and ecological processes affect the flammability of the landscape, while socio-economic processes influence the use of fire. An analysis of the regional drivers of fires used for land clearing, subsequent land management and forest fires is still missing, despite its importance in informing targeted policy [...]
Taxon cycles in Neotropical mangroves
Published: 2022-09-27
Subjects: Life Sciences
The concept of taxon cycle involves successive range expansions and contractions over time through which a species can maintain indefinitely its core distribution. Otherwise, it becomes extinct. A typical taxon cycle can be subdivided into four stages: (I) expansion, (II) population differentiation, (III) local extinction and incipient speciation (eventually initiating a new cycle), and (IV) [...]
Eocene/Oligocene global disruption and the revolution of Caribbean mangroves
Published: 2022-09-27
Subjects: Life Sciences
In a recent paper, the author demonstrated that, in contrast with the prevailing view of eventual gradual regional differentiation from a hypothetical Cretaceous pantropical mangrove belt around the Tethys Sea, the Caribbean mangroves originated de novo in the Eocene after the evolutionary appearance of the first mangrove-forming tree species known for the region, the ancestor of the extant [...]
Calling time on alien plantscapes
Published: 2022-09-22
Subjects: Life Sciences
Both urban and rural environments around the globe have become dominated by alien plant species to the extent that plantscapes from one region or country have become difficult to distinguish from many others. This process of plant community homogenisation comes at a cost to cultural identity and undermines people’s sense of place. Although invasive alien plant species have received considerable [...]