dataesr/scientific-paragraphs-categorization huggingface dataset:
, 2001)  and the El Niño-Southern Oscillation (ENSO; e. g. Randel et al. , 2009 ), in temperature, in ODS emissions, and in volcanic eruptions (e. g. Mt Pinatubo in 1991 and Calbuco in 2015)  with their feedbacks on stratospheric temperature and dynamics (e. g. Jonsson et al. , 2004). Furthermore, the differences in vertical and spatial resolution and in retrieval methodologies (inducing biases), possible instrumental degradations (inducing drifts), and use of merged datasets into composites likely explain part of the trend divergence between various studies. If merging performed on deseasonalized anomalies offers the advantage of removing instrumental biases between the individual data records  (Sofieva et al. , 2017) , large differences remain in anomaly values between the independent datasets, as well as large instrumental drifts and drift uncertainty estimates that prevent statistically accurate trends from being derived  (Harris et al.
, 2015; Hubert et al. , 2016). In this context, there is a pressing need for a long-duration, high-density and homogenized O 3 profile dataset to assess significant O 3 changes in different parts of the stratosphere and their contributions to the total O 3. In this paper, we exploit the high frequency (daily) and spatial coverage of the IASI satellite dataset over the first decade of the mission (January 2008-December 2017) to determine global patterns of reliable trends in the stratospheric O 3 records, separately in the middle-upper stratosphere (MUSt) and the lower stratosphere (LSt). This study is built on previous analysis of stratospheric O 3 trends from IASI, estimated on latitudinal averages over a shorter period  (2008) (2009) (2010) (2011) (2012) (2013)   (Wespes et al. , 2016). A multivariate linear regression (MLR) model (annual and seasonal formulations) that is similar to that previously used for tropospheric O 3 studies from IASI  (Wespes et al.
IASI O 3 data The Infrared Atmospheric Sounding Interferometer (IASI) is a nadir-viewing Fourier transform spectrometer designed to measure the thermal infrared emission of the Earthatmosphere system between 645 and 2760 cm -1. Measurements are taken from the polar sun-synchronous orbiting meteorological Metop series of satellites, every 50 km along the track of the satellite at nadir and over a swath of 2200 km across the track. With more than 14 orbits a day and a field of view of four simultaneous footprints of 12 km at nadir, IASI provides global coverage of the Earth twice a day at about 09:30 and 21:30 mean local solar time. The Metop program consists of a series of three identical satellites successively launched to ensure homogenous measurements of atmospheric parameters covering more than 15 years.
0 DU in the 55-90 • latitude band of each hemisphere. The estimated amplitude of the jump is found to be relatively small in comparison to that of the decadal trends derived in Sect. 4; hence, it cannot explain the trend observed in the IASI dataset. Therefore, the jump is not taken into account in the MLR. The jump values will be, however, considered in the discussion of the O 3 trends (Sect. 4). Finally, the present study only uses the daytime measurements (defined with a solar zenith angle to the sun < 83 • ) from the IASI-A (aboard Metop-A) instrument, which fully covers the first decade of the IASI mission. The daytime measurements are characterized by a higher vertical sensitivity (e. g. Clerbaux et al. , 2009). Quality flags developed in previous IASI studies (e. g. Boynard et al. , 2018)  were applied a posteriori to exclude data with a poor spectral fit, with less reliability or with cloud contamination.
That proxy consists of latitudinally averaged (22. 5-90 • N: AERO-N; 22. 5-90 • S: AERO-S; and 22. 5 • S-22. 5 • N: AERO-Eq) extinction coefficients at 12 µm calculated from merged aerosol datasets (SAGE, SAM, CALIPSO, OSIRIS, 2-D model simulation and Photometer;  Thomason et al. , 2018)  and vertically integrated over the two IASI stratospheric O 3 columns (AERO-MUSt and AERO-LSt). Figure  2  shows the AERO proxies (AERO-N, AERO-S and AERO-Eq) corresponding to the AOD over the whole stratosphere (150-2 hPa), while Fig. 3  represents the latitudinal distribution of the volcanic sulfuric acid extinction coefficients integrated over the whole stratosphere (a) and, separately, over the MUSt (b) and the LSt (c) from 2005 to 2017. The AOD distributions indicate the need for considering one specific AERO proxy for each latitudinal band (AERO-N, AERO-S and AERO-Eq) and for each vertical layer (AERO-MUSt and AERO-LSt).
5 and -1. 7 DU yr -1. Negative trends in lower stratospheric O 3 have already been reported in extrapolar regions from other space-based measurements  (Kyrölä et al. , 2013; Gebhardt et al. , 2014; Sioris et al. , 2014; Harris et al. , 2015; Nair et al. , 2015; Vigouroux et al. , 2015; Wespes et al. , 2016; Steinbrecht et al. , 2017; Ball et al. , 2018)  and may be due to changes in stratospheric dynamics at the decadal timescale  (Galytska et al. , 2019). These previous studies, which were characterized by large uncertainties or resulted from composite-data merging techniques, are confirmed here using a single dataset. The negative trends which are observed at lower stratospheric middle latitudes are difficult to explain with chemistry-climate models  (Ball et al. , 2018). It is also worth noting that the significant MUSt and LSt O 3 trends are of the same order as those previously estimated from IASI over a shorter period (from 2008 to 2013) and latitudinal averages (see  Wespes et al.
These results verify the efficacy of the ban on O 3 -depleting substances imposed by the Montreal Protocol and its amendments, throughout the stratosphere and in the total column, from only one single satellite dataset for the first time. The decline observed in LSt O 3 at northern mid-latitudes is unequivocal over the available IASI measurements in winterspring of the NH. The exact reasons for that decline are still unknown but O 3 changes in the LSt are estimated to be mainly attributable to dynamics, which likely perturbs the healing of LSt and total O 3 in the NH. A significant speeding up (within 95 %) in that decline is measured in LSt and total O 3 over the last 10 years (from ∼ -0. 7 ± 0. 2 DU yr -1 over 2008-2017 to ∼ -2. 8 ± 1. 2 DU yr -1 over 2015-2017 in LSt O 3 on zonal averages).
Acknowledgements. IASI has been developed and built under the responsibility of the  Centre National d'Etudes Spatiales (CNES, France). It is flown on board the Metop satellites as part of the  EU-METSAT Polar System. The IASI L1 data are received through the EUMETCast near real time data distribution service. We acknowledge the financial support from the  ESA O 3 -CCI  and Copernicus O 3 -C3S projects. FORLI-O 3 is being implemented at Eumetsat with the support of the  AC SAF  project. The research in Belgium is also funded by the  Belgian State Federal Office for Scientific, Technical and Cultural Affairs  and the  European Space Agency (ESA Prodex IASI Flow and B-AC SAF ). We acknowledge  Ingo Wohltmann  ( Alfred Wagner Institute, Postdam, Germany ) as well as  Beiping Luo  ( Institute for Atmosphere and Climate, ETH Zurich, Switzerland ) and  Larry Thomason  ( NASA Langley Research Center, Hampton, USA ), for processing and providing datasets of volume of polar stratospheric clouds and of sulfuric acid extinction coefficients, respectively.
Data availability. The IASI O 3 data processed with FORLI-O 3 v0151001 can be downloaded from the Aeris portal at http://iasi. aeris-data. fr/O3/ (last access: 13 September 2019). Supplement. The supplement related to this article is available online at: https://doi. org/10. 5194/acp-19-14031-2019-supplement. Author contributions. CW performed the analysis, wrote the paper and prepared the figures. DH was responsible for the retrieval algorithm development and the processing of the IASI O 3 dataset. All co-authors contributed to the analysis and reviewed the paper.
sent the first detection of a significant recovery in the stratospheric and the total O 3 columns over the Antarctic from one single satellite dataset. 4. 4 Speeding up in O 3 changes Positive trends in total O 3 over Antarctica were already determined earlier by Solomon et al. (2016) and by We- ber et al. (2018) during September over earlier periods (∼ 2. 5±1. 5 DU yr -1 over 2000-2014 and 8. 2±6. 2 % per decade over 2000-2016, respectively). The larger trends derived from the IASI records (see Fig. 10b; ∼ 3. 7 ± 1. 7 DU yr -1 or ∼ 14. 4 ± 5. 8 % per decade on average in TOC during SON) suggest that the O 3 response could be speeding up due to the accelerating decline of O 3 -depleting substances (ODSs) resulting from the Montreal Protocol. This has been investi- gated here by estimating the change in trend in MUSt, LSt and total O 3 over the IASI mission.
Molecular tools have been extensively used in recent decades to examine biological invasion processes, and are increasingly being adopted as efficient tools to support non-indigenous species surveys, notably through barcoding approaches, i. e. , the use of a reference sequence specific to a given species to validate its identification. The technique is easy to use but requires reliable reference sequences to be available in public databases. In addition, the increasing discovery of cryptic species in marine taxa may complicate taxonomic assignment. We illustrate these two issues in the ascidian genus Botrylloides, in which at least three global marine invaders have been recognized, including B. violaceus and B. diegensis. We obtained COI sequences from >750 colonies of Botrylloides spp. sampled in W Europe or provided by expert colleagues from other regions.
Phylogenetic trees clearly distinguished our targeted taxa [i. e. , B. violaceus, B. diegensis and B. leachii (native)]. They also revealed another discrete lineage apparently related to a recently described eastern Mediterranean species. By examining public databases, we found sequences of B. diegensis erroneously assigned to B. leachii. This observation has major implications as the introduced B. diegensis can be misidentified as a putatively native species. We also checked published sequences of the genus Botrylloides in the Mediterranean Sea, complemented with new samples. Based on our custom reference database, all published sequences of B. leachii corresponded to B. diegensis, although this NIS has hardly been reported at all in the Mediterranean region. Such database errors are unfortunate, as the barcoding approach is a powerful tool to identify the recognized Botrylloides species currently present in European seas.
Thus, the prompt updating of databases is essential following taxonomic revision and discovery of unrecognized cryptic species. The sequences delivered in public databases such as GenBank  (Benson et al. , 2013)  or BOLD [Barcode of Life Data System;  (Ratnasingham and Hebert, 2007) ] should thus be error-free and validated by taxonomic experts. BOLD is expected to provide such a framework. However, the public portal also retrieves non-curated sequences from Genbank that can propagate errors. There is so far a limited number of initiatives specifically aimed at delivering reference data for marine NIS. Although rare, such initiatives should be strongly encouraged, notably to support international regulations and policies such as the MSFD in Europe  (Darling et al. , 2017). Such an initiative has recently been undertaken in Western Australia, where a reference collection (vouchers, DNA and sequences for one marker (COI)) was assembled for 75 species (out of 79) of the "Western Australian Prevention List for Introduced Marine Pests"  (Dias et al.
violaceus in its N American introduced range  (Bock et al. , 2011; Lejeusne et al. , 2011) , besides being a marker commonly used in barcoding studies of marine invertebrates  (Comtet et al. , 2015)  and a standard for BOLD  (Hebert et al. , 2016). This dataset was completed with data from specimens kindly provided by taxonomic experts (see acknowledgment section); this allowed us to get reliable reference sequences for the three.
violaceus colonies, also displaying the distinctive large larvae of this species, were obtained in two French localities. Finally, to be used as an outgroup, 18 specimens of Botryllus schlosseri were collected in United Kingdom and France. All these samples were preserved in 96% ethanol after their collection. In order to update Mediterranean records, a third dataset was constructed, using samples obtained from the NE of the Iberian Peninsula (oyster cultures in the Ebro Delta, 40 • 46 27. 43 N, 00 • 44 27. 11 E), the S of France (marina of Sète, 43 • 23 44. 2 N, 3 • 41 51. 0 E), the SW of Italy (Miseno Lagoon, Naples, 40 • 47 34. 19 N, 14 • 04 39. 37 E) and the Adriatic (Venetian Lagoon, 45 • 25 50. 54 N, 12 • 22 07. 77 E), as well as a compilation of all Mediterranean Botrylloides COI sequences available in GenBank (Supplementary Table  S2 ).
Accession numbers for the COI haplotypes are provided in Supplementary Table  S3  as Supplementary Material. 1 The Bloscon marina was under construction at the collection date (i. e. , no floating pontoons; colonies were sampled on pilings). elongation step at 72 • C for 5 min. Sequencing reactions were performed at the LGC Genomics platform (Berlin, Germany) on purified (ExoSAP R -it) PCR products using the reverse primer (HCO2198). Mediterranean amplicons were obtained with the same primers and protocols, and sequenced at Macrogen Company (Korea).
Mitochondrial DNA Analyses The sequences were edited using CodonCode Aligner v. 3. 7. 1 (CodonCode Corporation, Dedham, MA). They were aligned using BioEdit v. 7. 1. 981 33  (Hall, 1999). After alignment, a 455 base-pair fragment was retained, further reduced to 435 base pairs for the EC dataset and to 395 base pairs for the Mediterranean dataset, for comparison with sequences obtained for our reference samples or available in public databases. DnaSP version 5  (Rozas et al. , 2003)  was used to compute the number and frequency of haplotypes (i. e. , unique sequences) per taxon or locality and estimate polymorphism. The number of base substitutions per site across sequences was computed with MEGA7  (Tamura et al. , 2011) , using the Maximum Composite Likelihood model  (Tamura et al. , 2004)  with positions with less than 95% site coverage eliminated.
Phylogenetic trees were built with MEGA7  (Tamura et al. , 2011)  using 32 unique sequences for the analyses of the EC dataset and 54 sequences with the Mediterranean dataset (details in Results). Goodness of fit with various evolution models was first tested: based on both BIC criteria and AICc value, the best model explaining the data was the Hasegawa-Kishino-Yano model with 54-61% of the sites evolutionarily invariable, according to the trees. Rooted phylogenetic trees were constructed using a maximum likelihood method with heuristic search (Subtree-Pruning-Regrafting method). To assess the reliability of the inferred trees, bootstrap tests were carried out (1000 bootstraps). Note that similar topologies were obtained using other tree construction methods, in particular a simple distance-based method (i.
e. , Neighbor-joining). To start investigating the status of a new reported lineage (see results), GMYC  (Pons et al. , 2006)  and mPTP  (Kapli et al. , 2017)  species delimitation analyses were carried out on the EC and Mediterranean unique sequences of Botrylloides spp. These two approaches differ in their properties (e. g. , GYMC requires ultrametric trees), and one may be more confident in the inferred species delimitation when similar results are obtained with both. GMYC analysis was carried out with the R library splits, using an ultrametric tree built using the Beast2 software  (Bouckaert et al. , 2019) , with a Yule tree prior and site model as obtained with MEGA analysis (see above). The mPTP analysis was carried out with the web-service available at http://mptp. h-its. org, with the tree produced with MEGA (note that the same results were obtained with the tree produced by the Beast2 Bayesian phylogenetic inference).
Comparison With Sequences in Public Databases We completed our analysis with a species identification search on the BOLD portal, using as a query each of the distinct haplotypes obtained in this study. The five B. violaceus haplotypes were found to match with reference sequences in the BOLD system (Supplementary Table  S3 ): they were assigned with high similarity (97. 59-97. 62%) to 'Botrylloides violaceum' (note that this neuter form of the specific name is no longer accepted according to WoRMS, being replaced by the masculine form used here; see  Ryland, 2015). These haplotypes (Bv-H1 to Bv-H5) matched with four haplotypes (named as Bv2, Bv8, Bv9, and Bv11) obtained as part of two population genetics studies of B. violaceus in N. America  (Bock et al. , 2011; Lejeusne et al. , 2011). The haplotype BvX-H6 did not match any sequences in BOLD, and the best match obtained using a BLAST search on the NCBI portal was with Botrylloides israeliense  (Reem et al.
Comparison With Mediterranean Sequences A total of 22 sequences were retrieved from GenBank of Mediterranean Botrylloides (six of them from whole mitochondrial mtDNA data), and 17 new sequences were obtained from the samples collected in Spain, France and Italy (Supplementary Table  S2 ). These samples were mapped onto a phylogenetic tree with the 25 haplotypes obtained with the EC dataset (EC sampling and reference sequences; Supplementary Tables  S3, S4 ). The results (Figure  3 ) showed that all sequences in GenBank previously assigned to B. leachii clustered unambiguously with B. diegensis. The only previous B. violaceus sequence (i. e. , complete mitochondrial genome HF548552;  Griggio et al. , 2014)   As for the newly generated sequences, two colonies from Venice (with a clear two-color pattern), all colonies from Sète (with a clear two-color pattern), and one from the Ebro Delta (with a uniform reddish color) grouped with B.
DISCUSSION We used COI sequencing to examine >750 colonies of the genus Botrylloides and Botryllus with a special interest in three species, two introduced species, namely B. violaceus and B. diegensis, and one species putatively native to Europe, namely B. leachii. Combining phylogenetic analyses and barcoding, we showed that COI is a robust barcode for distinguishing the three species. We also confirmed the presence of the two NIS in the EC. In addition, this study went well beyond our expectations: it pointed out (1) the risk of mis-identification between the two NIS when rapidly identified in the field based on simple external criteria (colony color patterns), (2) the presence of errors in databases, with reference data available for B. leachii (native) at the time of the analysis (last checked in May 2019) actually being sequences corresponding to B.
diegensis (introduced in the study regions), (3) the presence of B. diegensis, probably previously mistaken as B. leachii, in the Mediterranean Sea, based on our custom reference database, thus pointing to the need to revise all previous reports of B. leachii, as it has likely been confused with B. diegensis and (4) the existence of a cryptic divergent lineage, displaying a single-color pattern similar to B. violaceus. Thus the molecular findings indicate that single-color colonies lacking larvae cannot be identified to species level with confidence from external appearance alone (see brief discussion in  Bishop et al. , 2015a) , at least until additional distinguishing characters are recognized. Preliminary morphological observations based on external features of the species investigated are presented in Supplementary Figure  S3.
This is in line with previous studies showing that COI can be a relevant barcoding marker for metazoans  (Bucklin et al. , 2011) , notably considering its properties as a rapidly evolving marker (as compared to the nuclear genome). This study also highlights a clear benefit of the barcoding approach, i. e. , to enable species identification in groups that lack easy morphological traits to use in taxonomic determination. We carried out extensive sampling of Botrylloides spp. colonies that externally looked like B. violaceus, based on one simple field criterion, namely the single-color patterns of the colonies. The results of COI sequencing and comparison with a newly generated reference dataset clearly indicated that we made a large number of errors in assigning species name in the genus Botrylloides.
Error rates varied 0 to 100% (Figure  1 ) according to the population. We could compare the results of the molecular identifications of the supposedly 'B. violaceus' population samples with results of RAS carried by one of us (JB) while sampling for the intended molecular study in the nine populations from the United Kingdom. During the   S2 ). The tree was built with MEGA 7 by the Maximum Likelihood Method based on the Hasegawa-Kishino-Yano model with 54% of sites evolutionarily invariable. It is made of 52 sequences over 395 base pairs. They include sequences obtained from Mediterranean Botrylloides either newly collected or obtained from GenBank (see Supplementary Table  S2  for codes and details). In addition, we included 6, 5, and 5 haplotypes from our reference sequences for B. diegensis, B.
(2012). These authors also showed they co-occur in three populations (namely Brest, Falmouth and Brixham) from EC. Similarly, we found one haplotype, which we called BvX-H6, from colonies externally somewhat similar to B. violaceus, that showed a very large sequence divergence from the other studied Botrylloides species, with a divergence similar (ca. 20%) to the one measured between reference sequences of B. violaceus and B. diegensis (Table  2  and Supplementary Figure  S1 ). Two populations from United Kingdom, namely Southsea and Gosport, where the first dataset revealed the presence of BvX-H6 were sampled a second time in June 2012. Out of the 13 and 35 specimens examined, 77 and 24% specimens showed this particular haplotype in Southsea and Gosport, respectively. In Gosport, the other specimens were all B.
Another facet of this work has been the documentation of some errors in public databases. Such errors have been pointed out previously (e. g. ,  Harris, 2003; Vilgalys, 2003, and references herein). In our case, this issue was assessed by using simple identification searches in the BOLD system and in the NCBI portal. The outcome is illustrated in the Mediterranean Sea with a phylogenetic tree in Figure  3 , where it is clear that all our B. diegensis references are mixed with sequences named B. leachii in Genbank. Further, new sequences obtained confirmed that B. diegensis in the Mediterranean can also have a two-color pattern (Venice or Sète specimens) or a single reddish coloration (Ebro Delta). We failed to find any sequence, either published or new, of Mediterranean B. leachii. Considering that this is the Botrylloides species most commonly mentioned in this sea, our results suggest that the presence of B.
diegensis might have been strongly underestimated in the Mediterranean region. We also confirm the presence of B. violaceus in the Venice Lagoon, with external aspect identical to single-color colonies of B. diegensis. The case of B. diegensis and B. violaceus is a particularly acute issue as these are two NIS, widespread in the northern hemisphere. The lack of reliability of public databases for notorious NIS is an important shortcoming for their early detection and thus effective management  (Darling et al. , 2017). In this context and for the specific case examined here, it is noteworthy that this mis-identification of B. diegensis occurred during a survey of Mediterranean harbors with the specific aim of examining the distribution of NIS in these well-known introduction hotspots  (López-Legentil et al.