Plastics can be found in all ecosystems across the globe. This type of environmental pollution is important, even if its impact is not fully understood. The presence of small plastic particles at the ...micro- and nanoscales is of growing concern, but nanoplastic has not yet been observed in natural samples. In this study, we examined four size fractions (meso-, large micro-, small micro-, and nanoplastics) of debris collected in the North Atlantic subtropical gyre. To obtain the nanoplastic portion, we isolated the colloidal fraction of seawater. After ultrafiltration, the occurrence of nanoscale particles was demonstrated using dynamic light scattering experiments. The chemical fingerprint of the colloids was obtained by pyrolysis coupled with gas chromatography–mass spectrometry. We demonstrated that the signal was anthropogenic and attributed to a combination of plastics. The polymer composition varied among the size classes. At the micro- and nanoscales, polyvinyl chloride, polyethylene terephthalate, polystyrene and polyethylene were observed. We also observed changes in the pyrolytic signals of polyethylene with decreasing debris size, which could be related to the structural modification of this plastic as a consequence of weathering.
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IJS, KILJ, NUK, PNG, UL, UM
Identifying the presence of animals based on faecal deposits in modern and ancient environments is of primary importance to archaeologists, ecologists, forensic scientists, and watershed managers, ...but it has proven difficult to distinguish faecal material to the species level. Until now, four 5β-stanols have been deployed as faecal biomarkers to distinguish between omnivores and herbivores, but they cannot distinguish between species. Here we present a database of faecal signatures from ten omnivore and herbivore species based on eleven 5β-stanol compounds, which enables us to distinguish for the first time the faecal signatures of a wide range of animals. We validated this fingerprinting method by testing it on modern and ancient soil samples containing known faecal inputs and successfully distinguished the signatures of different omnivores and herbivores.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The molecular composition of 10 Cretaceous and one Eocene ambers from France was analyzed by infrared spectroscopy, solid-state 13C nuclear magnetic resonance spectroscopy, and thermochemolysis gas ...chromatography–mass spectrometry. The terpenoids identified in the samples were used as biomarkers for the botanical origin of the resins. The Cretaceous samples, comprising the so-called Alpine, Anjou, Charentese, Provence, Pyrenean, and Vendean ambers, ranged from the Albian–Cenomanian transition to the early Santonian (100 to 85 Ma) and correspond to class Ib resins typical of conifers. The extinct conifer family Cheirolepidiaceae was proposed as the plant source of Pyrenean and brown Charentese ambers. Araucariaceae or Cheirolepidiaceae were the plant sources of the Cenomanian Alpine, Anjou, and yellow Charentese ambers. The Santonian ambers of Provence and Vendée were found to derive from the Cupressaceae. The Eocene Oise amber (ca. 53 Ma) is a class Ic resin typical of angiosperms and was produced by a Fabaceae. The evolution of resin sources from the early Cretaceous to the Eocene periods is discussed. Finally, a possible fingerprint hitherto unveiled is proposed for cheirolepidiaceous resins, defined by the simultaneous presence of phenolic diterpenoids, labdanoic acids, callitrisate structures, and their respective derivatives.
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IJS, KILJ, NUK, PNG, UL, UM
Abstract
The carbon footprint of academia has become a prominent concern and a burgeoning research area, with a notable focus on greenhouse gas emissions (GHG) from research-related travels. ...Mitigation strategies often promote alternatives, such as developing virtual communication or adopting sustainable transportation modes for short distances. While more ambitious strategies involving the transformation of research practices are increasingly discussed, these mitigation solutions are rarely subjected to rigorous quantitative assessments or meaningful comparisons. This study analyzes a unique database of about 130 000 travel segments by car, train and plane in 159 research entities across a wide array of disciplines in France. We investigate the patterns and associated carbon footprint of these research travels and explore a diversity of mitigation options. Our analysis shows that air travel overwhelmingly outweighs the carbon footprint of research travel, representing more than 96% of GHG emissions. Intercontinental flights are infrequent (less than 10% of all plane trips) but dominate GHG travel emissions, accounting for over 64% of total emissions. In contrast, domestic and continental flights are the most common but their mitigation potential by modal shift to train is limited (e.g. less than 15% for trips under 1000 km). Similar reductions can be achieved by targeting a small subset of travels, for example by modulating the frequency of conference attendance. The greatest and possibly most robust mitigation potential lies in combining modal shift with moderating air mileage (e.g. reducing travelled distance or number of flights). Strategies focusing on electrification or modal shifts for cars, proposed in official guidelines, are found to have negligible impact. In the absence of low-carbon alternatives for long-haul flights, we contend that only comprehensive strategies and policies which include moderating air travel distance or frequency can achieve a robust significant reduction in the GHG emissions from academic travel.
This study investigates the combined effects of land management and hydrology on the temporal dynamics of dissolved organic matter (DOM) quantity and composition in stream water and groundwaters in ...an agricultural watershed. We assessed dissolved organic carbon (DOC) concentrations, DOM UV–Vis absorbance, and DOM fluorescence in groundwater under cultivated upland, riparian grassland, and riparian woodland land covers, as well as in the stream water at the watershed outlet and livestock-impacted runoff. During one year, stream water and groundwater were monitored weekly to biweekly, complemented by sub-hourly stream sampling during seven storm events. Results showed that: (1) groundwater DOC concentration was lower in cultivated upland (6.4 ± 5.6 mg l⁻¹) than in riparian grassland and woodland (22.4 ± 13.7 mg l⁻¹ and 17.2 ± 9.9 mg l⁻¹, respectively). (2) The proportion of microbially processed compounds decreased in the order upland cropland > riparian grassland > riparian woodland. (3) Principal component analysis (PCA) of groundwater DOM revealed a change in composition indicating that low-aromaticity microbially processed compounds were preferentially exported to the stream. (4) PCA of stream DOM indicated that seasonal increases in groundwater elevation expanded the contributing source areas, thereby increasing the connectivity between upland croplands and the stream, which amplified the effects of cultivation on fluvial DOM during the winter. (5) Storm events occurring after manure application in spring produced hot moments of manure-derived protein-like DOM transport to streams. Together, these results suggest that cultivated uplands in agricultural lands using animal manure as fertilizer may leach more DOM than vegetative buffers.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Despite increasing recognition of storm-induced organic carbon (C) export as a significant loss from the terrestrial C balance, little is known about the biodegradation and chemical transformation of ...particulate organic carbon (POC) in mountainous river systems. We combined analyses of C isotopes, solution-state¹H NMR, and lipid biomarkers with biodegradable dissolved organic C (BDOC) measurements to investigate downstream changes of POC composition and biodegradability at a mountainous, mixed land-use watershed in South Korea. Water and suspended sediment (SS) samples were collected in a forested headwater stream, a downstream agricultural stream, and two downstream rivers during peak flow periods of four storm events, using either sequential grab sampling from the headwater stream to the most downstream river within a few hours around the peak flow or sediment samplers deployed during the whole storm event. DOC concentrations exhibited relatively small changes across sites, whereas POC concentrations were highest in the agricultural stream, and tapered along downstream reaches. The δ¹³C and δ¹⁵N of SS in the agricultural stream were distinct from up- and downstream signatures and similar to those for erosion source soils and lake bottom sediment, although increases in radiocarbon age indicated continuous compositional changes toward the lake.¹H NMR spectra of SS and deposited sediment exhibited downstream decreases in carbohydrates and lignin but enrichment of organic structures related to microbial proteins and plant wax. The downstream sediments had more microbial n-alkanes and lipid markers indicating anthropogenic origin such as coprostanol compared to the forest soil n-alkanes dominated by plant wax. While the BDOC concentrations of filtered waters differed little between sites, the BDOC concentrations and protein- to humic-like fluorescence ratios of DOC leached from SS during a 13-day incubation were higher in downstream rivers, pointing to contribution of labile POC components to the enhanced biodegradation. Overall, inputs of microbial and anthropogenic origin, in interplay with deposition and mineralization, appear to substantially alter POC composition and biodegradability during downstream transport, raising a question on the conventional view of mountainous river systems as a passive conduit of storm pulses of POC.
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BFBNIB, DOBA, EMUNI, GEOZS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NMLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Core Ideas
AgrHyS is a long‐term observatory of the agroecosystem.
AgrHyS supports strongly interdisciplinary environmental research.
AgrHyS offers an original experimental setup to explore the ...soil–groundwater–water–plants–atmosphere continuum.
AgrHyS supports original and innovative techniques for environmental monitoring.
The AgrHyS is a long‐term agro‐hydrological observatory dedicated to studying the processes controlling hydro‐chemical fluxes in headwater catchments in response to the effects of agricultural. AgrHyS is composed of instrumented catchments located in western France in a temperate oceanic climate that are characterized by shallow groundwater (<8 m deep) over crystalline bedrocks (granite or schist) and is dominated by intensive agriculture with farming. AgrHyS provides long‐term observations starting in 1990 and supports highly interdisciplinary studies that provide novel contributions to environmental sciences, including hydrology, geochemistry, agricultural and soil sciences, hydrogeology, bioclimatology, and ecology. Here we describe the observatory sites, observation strategy, data management policy, and data access. The objective is to show how AgrHyS has contributed to research in hydrological and environmental sciences through a review of major insights of the research. This analysis highlights the role of AgrHyS in linking, validating, and enriching successive and complementary projects conducted over the last 25 yr. The second objective is to invite new collaborations with a large scientific community for future research.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A new Cenomanian amber- and plant-bearing deposit has been discovered at Neau, in the Mayenne department (France). The Cenomanian fossiliferous lignites are located in karst filling in a substratum ...of Cambrian limestones. The amber corresponds mainly to tiny millimetric grains, devoid of arthropod inclusions, but rich in microorganisms, especially the sheated bacteria
Leptotrichites resinatus
, and containing pollen grains (
Classopollis
) and wood fibers (Araucariacae or Cheirolepidiaceae). The lignites provide abundant conifer and ginkgoale cuticle fragments (
Frenelopsis
,
Eretmophyllum
) and a lot of palynomorphs (
e.g. Gleicheniidites senonicu
s,
Cyathidites
,
Deltoidospora
,
Appendicisporites
and
Cicatricosisporites
). The chemical signature of the amber suggests it was produced by conifers of the extinct family Cheirolepidiaceae. According to the palynological assemblage, the age of the lignites is upper lower Cenomanian or lower mid Cenomanian. The deposit environment corresponded to the upstream portion of a mangrove or the most inner part of a lagoon.
Un nouveau site à ambre et plantes du Cénomanien a été découvert à Neau, en Mayenne (France). Les lignites fossilifères cénomaniens sont localisés dans des remplissages de karsts développés dans des calcaires du Cambrien. L’ambre se présente essentiellement sous forme de grains millimétriques, dépouvus d’inclusions d’arthropode, mais riches en microorganismes, notamment en bactéries gainées de type
Leptotrichites resinatus
, et contenant des grains de pollen (
Classopollis
) et des fibres de bois (Araucariacae ou Cheirolepidiaceae). Les lignites fournissent d’abondants fragments de cuticules de conifères et de ginkgoales (
Frenelopsis
,
Eretmophyllum
) et une grande quantité de palynomorphes (
e.g. Gleicheniidites senonicu
s,
Cyathidites
,
Deltoidospora
,
Appendicisporites
et
Cicatricosisporites
). La signature chimique de l’ambre suggère qu’il a été produit par des conifères de la famille éteinte des Cheirolépidiacées. D’après l’assemblage palynologique, l’âge des lignites est Cénomanien inférieur tardif ou Cénomanien moyen basal. L’environnement de dépôt correspondait à la partie amont d’une mangrove ou la partie la plus interne d’un lagon.
Colloids (1–1,000 nm) are important phosphorus (P) carriers in agricultural soils. However, most studies are based on colloids from soil waters extracted in the laboratory, thus limiting the ...understanding of the natural transfer of colloidal P along the soil‐to‐stream continuum. Here, we conducted a field study on the colloidal P in both natural soil waters and their adjacent stream waters in an agricultural catchment (Kervidy‐Naizin, western France). Soil waters (10–15 cm, Albeluvisol) of two riparian wetlands and the adjacent stream waters were sampled monthly during wet seasons of the 2015–2016 hydrological year (seven dates in total). Ultrafiltration at three pore sizes (5 kDa, 30 kDa, and 0.45 µm) was combined with inductively coupled plasma mass spectrometry (ICP–MS) to investigate variability in colloidal P concentration and its concomitant elemental composition. Results showed that colloidal P represented, on average, 45 and 30% of the total P (<0.45 µm) in the soil waters and stream waters, respectively. We found that colloidal P was preferentially associated with (a) organic carbon in the fine nanoparticle fraction (5–30 kDa) and (b) iron‐oxyhydroxides and organic carbon in the coarse colloidal fraction (30 kDa–0.45 µm). The results confirmed that colloidal P is an important component of total P in both soil waters and stream waters under field conditions, suggesting that riparian wetlands are hotspot zones for the production of colloidal P at the catchment scale, which has the potential to be transported to adjacent streams.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Pools are common features of peatlands and can represent from 5 % to 50 % of
the peatland ecosystem's surface area. Pools play an important role in the
peatland carbon cycle by releasing carbon ...dioxide and methane to the
atmosphere. However, the origin of this carbon is not well constrained. A
hypothesis is that the majority of the carbon emitted from pools
predominantly originates from mineralized allochthonous (i.e.,
plant-derived) dissolved organic matter (DOM) from peat rather than in situ
primary production. To test this hypothesis, this study examined the origin,
composition, and degradability of DOM in peat porewater and pools of an
ombrotrophic boreal peatland in northeastern Quebec (Canada) for 2 years
over the growing season. The temporal evolution of dissolved organic carbon
(DOC) concentration, the optical properties, molecular composition
(THM-GC-MS), stable isotopic signature (δ13C-DOC), and
degradability of DOM were determined. This study demonstrates that DOM, in
both peat porewater and pools, presents a diverse composition and
constitutes highly dynamic components of peatland ecosystems. The molecular
and isotopic analyses showed that DOM in pools was derived from plants.
However, DOM compositions in the two environments were markedly different.
Peat porewater DOM was more aromatic, with a higher molecular weight and
DOC : DON (dissolved organic nitrogen) ratio compared to pools. The temporal dynamics of DOC concentration
and DOM composition also differed. In peat porewater, the DOC concentration
followed a strong seasonal increase, starting from 9 mg L−1 and reaching a plateau above 20 mg L−1 in summer and autumn. This was
explained by seasonal peatland vegetation productivity, which is greater
than microbial DOM degradation. In pools, DOC concentration also increased
but remained 2 times lower than in the peat porewaters at the end of the
growing season (∼ 10 mg L−1). Those differences might be
explained by a combination of physical, chemical, and biological factors.
The limited hydraulic conductivity in deeper peat horizons and associated
DOM residence time might have favored both DOM microbial transformation
within the peat and the interaction of DOM aromatic compounds with the peat
matrix, explaining part of the shift of DOM compositions between peat
porewater and pools. This study did not report any photolability of DOM and
only limited microbial degradability. Thus, it is likely that the DOM might
have been microbially transformed at the interface between peat and pools.
The combination of DOM quantitative and qualitative analyses presented in
this study demonstrates that most of the carbon present within and released
from the pools originates from peat vegetation. These results demonstrate
that pools represent a key component of the peatland ecosystem ecological
and biogeochemical functioning.
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