scholarly journals The late blooming amphipods: global change promoted post-Jurassic ecological radiation despite Palaeozoic origin

2019 ◽  
Author(s):  
Denis Copilaş-Ciocianu ◽  
Špela Borko ◽  
Cene Fišer

AbstractThe ecological radiation of amphipods is striking among crustaceans. Despite high diversity, global distribution and key roles in all aquatic environments, little is known about their ecological transitions, evolutionary timescale and phylogenetic relationships. It has been proposed that the amphipod ecological diversification began in the Late Palaeozoic. By contrast, due to their affinity for cold/oxygenated water and absence of pre-Cenozoic fossils, we hypothesized that the ecological divergence of amphipods arose throughout the cool Late Mesozoic/Cenozoic. We tested our hypothesis by inferring a large-scale, time-calibrated, multilocus phylogeny, and reconstructed evolutionary patterns for major ecological traits. Although our results reveal a Late Palaeozoic amphipod origin, diversification and ecological divergence ensued only in the Late Mesozoic, overcoming a protracted stasis in marine littoral habitats. Multiple independent post-Jurassic radiations took place in deep-sea, freshwater, terrestrial, pelagic and symbiotic environments, usually postdating deep-sea faunal extinctions, and corresponding with significant climatic cooling, tectonic reconfiguration, continental flooding, and increased oceanic oxygenation. We conclude that the profound Late Mesozoic global changes triggered a tipping point in amphipod evolution by unlocking ecological opportunities that promoted radiation into many new niches. Our study also provides a solid, time-calibrated, evolutionary framework to accelerate research on this overlooked, yet globally important taxon.


Author(s):  
Lars Stemmerik ◽  
Finn Dalhoff ◽  
Birgitte D. Larsen ◽  
Jens Lyck ◽  
Anders Mathiesen ◽  
...  

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Stemmerik, L., Dalhoff, F., Larsen, B. D., Lyck, J., Mathiesen, A., & Nilsson, I. (1998). Wandel Sea Basin, eastern North Greenland. Geology of Greenland Survey Bulletin, 180, 55-62. https://doi.org/10.34194/ggub.v180.5086 _______________ The Wandel Sea Basin in eastern North Greenland is the northernmost of a series of fault-bounded Late Palaeozoic – Early Tertiary basins exposed along the eastern and northern margin of Greenland (Fig. 1). The basin and the surrounding shelf areas are located in a geologically complex region at the junction between the N–S trending Caledonian fold belt in East Greenland and the E–W trending Ellesmerian fold belt in North Greenland, and along the zone of later, Tertiary, continental break-up. The Wandel Sea Basin started to develop during the Carboniferous as a result of extension and rifting between Greenland and Norway, and Greenland and Spitsbergen (Håkansson & Stemmerik 1989), and was an area of accumulation during the Early Carboniferous – Early Tertiary period. Two main epochs of basin evolution have been recognised during previous studies of the basin fill: an early (late Palaeozoic – early Triassic) epoch characterised by a fairly simple system of grabens and half-grabens, and a late (Mesozoic) epoch dominated by strike-slip movements (Håkansson & Stemmerik 1989). The Mesozoic epoch only influenced the northern part of the basin, north of the Trolle Land fault zone (Fig. 1). Thus the northern and southern parts of the basin have very different structural and depositional histories, and accordingly different thermal histories and hydrocarbon potential. This paper summarises the results of a project supported by Energy Research Program (EFP-94), the purpose of which was to model the Wandel Sea Basin with special emphasis on hydrocarbon potential and late uplift history, and to provide biostratigraphic and sedimentological data that could improve correlation with Svalbard and the Barents Sea. It is mainly based on material collected during field work in Holm Land and Amdrup Land in the south-eastern part of the Wandel Sea Basin during 1993–1995 with additional data from eastern Peary Land (Stemmerik et al. 1996). Petroleum related field studies have concentrated on detailed sedimentological and biostratigraphic studies of the Carboniferous–Permian Sortebakker, Kap Jungersen, Foldedal and Kim Fjelde Formations in Holm Land and Amdrup Land (Fig. 2; Døssing 1995; Stemmerik 1996; Stemmerik et al. 1997). They were supplemented by a structural study of northern Amdrup Land in order to improve the understanding of the eastward extension of the Trolle Land fault system and possibly predict its influence in the shelf areas (Stemmerik et al. 1995a; Larsen 1996). Furthermore, samples for thermal maturity analysis and biostratigraphy were collected from the Mesozoic of Kap Rigsdagen and the Tertiary of Prinsesse Thyra Ø (Fig. 1).



1977 ◽  
Vol 25 (1-3) ◽  
pp. 131-147 ◽  
Author(s):  
Stanley V. Margolis ◽  
Peter M. Kroopnick ◽  
David E. Goodney


2021 ◽  
Author(s):  
Chloé Duffaut ◽  
Nathalie Frascaria-Lacoste ◽  
Pierre-Antoine Versini

<p>Hydro-meteorological risks are increasing and this could be due to global changes. These risks are particularly important in the urban context where most human beings live. Indeed, the impervious surfaces present in cities increase the risk of flooding, for example. Nature-Based Solutions can help to reduce these risks by creating permeable soils or storing water while promoting biodiversity. In this context, it is essential to understand what hinders the development and sustainability of these Nature-based Solutions in the city and what could help to deploy them on a large scale. For this purpose, various professionals working on Nature-Based Solutions in the city in France, were interviewed between 2020 and 2021, both in the academic and operational sectors, or even at the interface between the two: researchers in ecology or hydrology, IUCN (International Union for Conservation of Nature) project manager, project managers at the Regional Biodiversity Agency, director and natural environment manager of a watershed union, agro-economists engineer among others. They were asked what are the barriers and potential opportunities for Nature-Based Solutions implementation and sustainability in city. By analysing their answers, it emerges that the obstacles are more often cultural, political or financial than technical. The potential levers often mentioned are education and awareness-raising at all levels, especially for elected officials and the general public. Regulations such as the PLU (Local Urban Plan) and new funding for more natural spaces in the city also seem to be means of promoting Nature-based Solutions in urban areas. These interviews with diverse professionals directly involved in Nature-Based Solutions in cities allow to give real courses of action to be taken to democratize these Solutions throughout the French territory, or even internationally, and therefore ultimately reduce the risks of hydro-meteorology. This is one of the objectives of the French ANR project EVNATURB (Assessment of ecosystem performance of a renaturation of the urban environment), in which this study has been carried out.</p>





2019 ◽  
Vol 11 (12) ◽  
pp. 1505 ◽  
Author(s):  
Heng Zhang ◽  
Anwar Eziz ◽  
Jian Xiao ◽  
Shengli Tao ◽  
Shaopeng Wang ◽  
...  

Accurate mapping of vegetation is a premise for conserving, managing, and sustainably using vegetation resources, especially in conditions of intensive human activities and accelerating global changes. However, it is still challenging to produce high-resolution multiclass vegetation map in high accuracy, due to the incapacity of traditional mapping techniques in distinguishing mosaic vegetation classes with subtle differences and the paucity of fieldwork data. This study created a workflow by adopting a promising classifier, extreme gradient boosting (XGBoost), to produce accurate vegetation maps of two strikingly different cases (the Dzungarian Basin in China and New Zealand) based on extensive features and abundant vegetation data. For the Dzungarian Basin, a vegetation map with seven vegetation types, 17 subtypes, and 43 associations was produced with an overall accuracy of 0.907, 0.801, and 0.748, respectively. For New Zealand, a map of 10 habitats and a map of 41 vegetation classes were produced with 0.946, and 0.703 overall accuracy, respectively. The workflow incorporating simplified field survey procedures outperformed conventional field survey and remote sensing based methods in terms of accuracy and efficiency. In addition, it opens a possibility of building large-scale, high-resolution, and timely vegetation monitoring platforms for most terrestrial ecosystems worldwide with the aid of Google Earth Engine and citizen science programs.



2020 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Hernández-León ◽  
R. Koppelmann ◽  
E. Fraile-Nuez ◽  
A. Bode ◽  
C. Mompeán ◽  
...  

AbstractThe biological pump transports organic carbon produced by photosynthesis to the meso- and bathypelagic zones, the latter removing carbon from exchanging with the atmosphere over centennial time scales. Organisms living in both zones are supported by a passive flux of particles, and carbon transported to the deep-sea through vertical zooplankton migrations. Here we report globally-coherent positive relationships between zooplankton biomass in the epi-, meso-, and bathypelagic layers and average net primary production (NPP). We do so based on a global assessment of available deep-sea zooplankton biomass data and large-scale estimates of average NPP. The relationships obtained imply that increased NPP leads to enhanced transference of organic carbon to the deep ocean. Estimated remineralization from respiration rates by deep-sea zooplankton requires a minimum supply of 0.44 Pg C y−1 transported into the bathypelagic ocean, comparable to the passive carbon sequestration. We suggest that the global coupling between NPP and bathypelagic zooplankton biomass must be also supported by an active transport mechanism associated to vertical zooplankton migration.



2020 ◽  
Vol 49 (3) ◽  
pp. 340-356
Author(s):  
Paula C. Rodríguez‐Flores ◽  
David Buckley ◽  
Enrique Macpherson ◽  
Laure Corbari ◽  
Annie Machordom


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