ALBERT

Description: A correction to this paper has been published: 10.1140/epjc/s10052-021-09344-w

Description: The results of a search for gluino and squark pair production with the pairs decaying via the lightest charginos into a final state consisting of two W bosons, the lightest neutralinos ($$ilde{chi }^0_1$$ χ ~ 1 0 ), and quarks, are presented: the signal is characterised by the presence of a single charged lepton ($$e^{pm }$$ e ± or $$mu ^{pm }$$ μ ± ) from a W boson decay, jets, and missing transverse momentum. The analysis is performed using 139 fb$$^{-1}$$ - 1 of proton–proton collision data taken at a centre-of-mass energy $$sqrt{s}=13$$ s = 13   delivered by the Large Hadron Collider and recorded by the ATLAS experiment. No statistically significant excess of events above the Standard Model expectation is found. Limits are set on the direct production of squarks and gluinos in simplified models. Masses of gluino (squark) up to 2.2  (1.4 ) are excluded at 95% confidence level for a light $$ilde{chi }^0_1$$ χ ~ 1 0 .

Description: Accurate and reliable biodiversity estimates of marine zooplankton are a prerequisite to understand how changes in diversity can affect whole ecosystems. Species identification in the deep sea is significantly impeded by high numbers of new species and decreasing numbers of taxonomic experts, hampering any assessment of biodiversity. We used in parallel morphological, genetic, and proteomic characteristics of specimens of calanoid copepods from the abyssal South Atlantic to test if proteomic fingerprinting can accelerate estimating biodiversity. We cross-validated the respective molecular discrimination methods with morphological identifications to establish COI and proteomic reference libraries, as they are a pre-requisite to assign taxonomic information to the identified molecular species clusters. Due to the high number of new species only 37% of the individuals could be assigned to species or genus level morphologically. COI sequencing was successful for 70% of the specimens analysed, while proteomic fingerprinting was successful for all specimens examined. Predicted species richness based on morphological and molecular methods was 42 morphospecies, 56 molecular operational taxonomic units (MOTUs) and 79 proteomic operational taxonomic units (POTUs), respectively. Species diversity was predicted based on proteomic profiles using hierarchical cluster analysis followed by application of the variance ratio criterion for identification of species clusters. It was comparable to species diversity calculated based on COI sequence distances. Less than 7% of specimens were misidentified by proteomic profiles when compared with COI derived MOTUs, indicating that unsupervised machine learning using solely proteomic data could be used for quickly assessing species diversity.

Description: Rationale To detect the small changes in past pH, the boron isotope ratio of coral carbonates, expressed as the δ11B value, needs to be both precise and accurate (2sd〈〈1‰). Boron measurements by Multi‐collector Inductively Coupled Plasma Mass Spectrometry (MC‐ICPMS) requires the boron to be carefully purified before analysis, which is time consuming, and requires specialist training. Here, we use the prepFAST‐MC that enables the automatic extraction of B (up to 25 ng load) from a CaCO3 matrix. Methods Samples were purified using the prepFAST‐MC automated system with a ~25‐μL column of Amberlite IRA743 resin. Boron isotope measurements were performed byMC‐ICPMS. The effect of matrix load, speed of sample load onto the column, and blank contamination were tested to evaluate the effect on the purification process. The optimised protocol was tested on various standards and samples of aragonite corals. Results The blank contribution for the approach is ~60 pg and is negligible given our sample size (〈0.2% sample size). Efficiency of matrix removal is demonstrated with the addition of up to 1.6 mg of dissolved low‐B calcium carbonate to NIST SRM 951 with no impact on the accuracy of δ11B values. The Japanese Geological Survey Porites reference material JCp‐1, boric acid standard NIST SRM 951, and seawater, all processed on the prepFAST‐MC, give δ11B values within error of literature values (δ11BJCp‐1 = 24.31 ±0.20‰ (2sd, n=20); δ11BNIST 951 = ‐0.02 ±0.15‰ (2sd, n=13) and δ11BSeawater = 39.50 ±0.06 ‰ (2sd, n=2)). Results obtained from the coral Siderastrea siderea purified with the prepFAST‐MC show an average offset from the manual ion exchange protocols of Δδ11B=0.01 ±0.28‰ (2sd, n=12). Conclusions Our study demonstrates the capacity of the prepFAST‐MC to generate accurate and reproducible δ11B values for a range of material, without fractionation, with efficient matrix removal and with negligible blank contribution.

Description: Most arcs show systematic temporal and spatial variations in magmatism with clear shifts in igneous rock compositions between those of the magmatic front (MF) and those in the backarc (BA). It is unclear if similar magmatic polarity is seen for extensional continental arcs. Herein, we use geochemical and isotopic characteristics coupled with zircon U‐Pb geochronology to identify the different magmatic style of the Iran convergent margin, an extensional system that evolved over 100 Myr. Our new and compiled U‐Pb ages indicate that major magmatic episodes for the NE Iran BA occurred at 110–80, 75–50, 50–35, 35–20, and 15–10 Ma. In contrast to NE Iran BA magmatic episodes, compiled data from MF display two main magmatic episodes at 95–75 and 55–5 Ma, indicating more continuous magmatism for the MF than for the BA. We show that Paleogene Iran serves as a useful example of a continental arc under extension. Our data also suggest that there is not a clear relationship between the subduction velocity of Neotethyan Ocean beneath Iran and magmatic activity in Iran. Our results imply that the isotopic compositions of Iran BA igneous rocks do not directly correspond to the changes in tectonic processes or geodynamics, but other parameters such as the composition of lithosphere and melt source(s) should be considered. In addition, changes in subduction zone dynamics and contractional versus extensional tectonic regimes influenced the composition of MF and BA magmatic rocks. These controls diminished the geochemical and isotopic variations between the magmatic front and backarc.

Description: There is a strong economic interest in commercial deep‐sea mining of polymetallic nodules and therefore a need to define suitable preservation zones in the abyssal plain of the Clarion Clipperton Fracture Zone (CCZ). However, besides ship‐based multibeam data, only sparse continuous environmental information is available over large geographic scales. We test the potential of modelling meiofauna abundance and diversity on high taxonomic level on large geographic scale using a random forest approach. Ship‐based multibeam bathymetry and backscatter signal are the only sources for 11 predictor variables, as well as the modelled abundance of polymetallic nodules on the seafloor. Continuous meiofauna predictions have been combined with all available environmental variables and classified into classes representing abyssal habitats using k‐means clustering. Results show that ship‐based, multibeam‐derived predictors can be used to calculate predictive models for meiofauna distribution on a large geographic scale. Predicted distribution varies between the different meiofauna response variables. To evaluate predictions, random forest regressions were additionally computed with 1,000 replicates, integrating varying numbers of sampling positions and parallel samples per site. Higher numbers of parallel samples are especially useful to smoothen the influence of the remarkable variability of meiofauna distribution on a small scale. However, a high number of sampling positions is even more important, integrating a greater amount of natural variability of environmental conditions into the model. Synthesis and applications. Polymetallic nodule exploration contractors are required to define potential mining and preservation zones within their licence area. The biodiversity and the environment of preservation zones should be representative of the sites that will be impacted by mining. Our predicted distributions of meiofauna and the derived habitat maps are an essential first step to enable the identification of areas with similar ecological conditions. In this way, it is possible to define preservation zones not only based on expert opinion and environmental proxies but also integrating evidence from the distribution of benthic communities.

Description: The Clarion Clipperton Fracture Zone (CCZ) is a vast deep-sea region harboring a highly diverse benthic fauna, which will be affected by potential future deep-sea mining of metal-rich polymetallic nodules. Despite the need for conservation plans and monitoring strategies in this context, the majority of taxonomic groups remain scientifically undescribed. However, molecular rapid assessment methods such as DNA barcoding and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) provide the potential to accelerate specimen identification and biodiversity assessment significantly in the deep-sea areas. In this study, we successfully applied both methods to investigate the diversity of meiobenthic copepods in the eastern CCZ, including the first application of MALDI-TOF MS for the identification of these deep-sea organisms. Comparing several different species delimitation tools for both datasets, we found that biodiversity values were very similar, with Pielou’s evenness varying between 0.97 and 0.99 in all datasets. Still, direct comparisons of species clusters revealed differences between all techniques and methods, which are likely caused by the high number of rare species being represented by only one specimen, despite our extensive dataset of more than 2000 specimens. Hence, we regard our study as a first approach toward setting up a reference library for mass spectrometry data of the CCZ in combination with DNA barcodes. We conclude that proteome fingerprinting, as well as the more established DNA barcoding, can be seen as a valuable tool for rapid biodiversity assessments in the future, even when no reference information is available.

Description: Deep-sea decapod crustaceans (Crustacea: Decapoda) collected during nine research cruises to the Clarion-Clipperton Zone (CCZ) in the NE Pacific Ocean and the Peru Basin in the SE Pacific Ocean were studied comprehensively using an integrative taxonomic approach. The abyssal seafloors of both areas are rich in economically interesting polymetallic nodules. All specimens were morphologically identified and genetically analysed using a fragment of the mitochondrial cytochrome c oxidase subunit I (COI). Eight species were collected, comprising three anomurans, three carideans, one dendrobranchiate, and one brachyuran, from water depths ranging between 4089 and 4511 m. COI sequences for representatives of the genera Parapagurus Smith, 1879, Ethusina SI Smith, 1884, and Bathystylodactylus Hanamura & Takeda, 1996 are provided for the first time. The molecular barcodes of the species provided herein will be valuable for the full taxonomic assignment of sequences produced in future metabarcoding and eDNA monitoring work. The new records extend the geographical distributional ranges or fill geographical gaps of the species reported, although none of the species is endemic to polymetallic nodule areas. This study is part of a taxonomic series aiming to describe the biodiversity of areas targeted for future deep-sea mining.

Description: Anthropogenic disturbances, including non-indigenous species (NIS) and climate change, have considerably affected ecosystems and socio-economies globally. Despite the widely acknowledged individual roles of NIS and global warming in biodiversity change, predicting the connection between the two still remains a fundamental challenge and requires urgent attention due to a timely importance for proper conservation management. To improve our understanding of the interaction between climate change and NIS on biological communities, we conducted laboratory experiments to test the temperature and pCO2 tolerance of four gammarid species: two native Baltic Sea species (Gammarus locusta and G. salinus), one Ponto‐Caspian NIS (Pontogammarus maeoticus) and one North American NIS (Gammarus tigrinus). Our results demonstrated that an increase in pCO2 level was not a significant driver of mortality, neither by itself nor in combination with increased temperature, for any of the tested species. However, temperature was significant, and differentially affected the tested species. The most sensitive was the native G. locusta which experienced 100% mortality at 24 °C. The second native species, G. salinus, performed better than G. locusta, but was still significantly more sensitive to temperature increase than either of the NIS. In contrast, NIS performed better than native species with warming, whereby particularly the Ponto-Caspian P. maeoticus did not demonstrate any difference in its performance between the temperature treatments. With the predicted environmental changes in the Baltic Sea, we may expect shifts in distributions of native taxa towards colder areas, while their niches might be filled by NIS, particularly those from the Ponto-Caspian region. Although, northern colder areas may be constrained by lower salinity. Additional studies are needed to confirm our findings across other NIS, habitats and regions to make more general inferences.

Description: In this study, we used stable isotopes of oxygen (δ18O), deuterium (δD), and dissolved inorganic carbon (δ13CDIC) in combination with temperature, salinity, oxygen and nutrient concentrations to characterize the coastal (71-78 °W) and an oceanic (82-98 °W) water masses (SAAW-Subantarctic Surface Water; STW-Subtropical Water; ESSW-Equatorial Subsurface water; AAIW-Antarctic Intermediate Water; PDW-Pacific Deep Water) of the Southeast Pacific (SEP). The results show that δ18O and δD can be used to differentiate between SAAW-STW, SAAW-ESSW and ESSW-AAIW. δ13CDIC signatures can be used to differentiate between STW-ESSW (oceanic section), SAAW-ESSW, ESSW-AAIW and AAIW-PDW. Compared with the oceanic section, our new coastal section highlights differences in both the chemistry and geometry of water masses above 1000 m. Previous paleoceanographic studies using marine sediments from the SEP continental margin used the present-day hydrological oceanic transect to compare against, as the coastal section was not sufficiently characterized. We suggest that our new results of the coastal section should be used for past characterizations of the SEP water masses that are usually based on continental margin sediment samples.