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Browsing by Issue Date, starting with "2023-08-28"

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  • Less is more: seagrass restoration success using less vegetation per area
    Publication . Mourato, Carolina; Padrão, Nuno; Serrao, Ester A.; Paulo, Diogo
    Seagrass restoration in open coast environments presents unique challenges. Traditional sod transplant designs, though relatively successful in these environments, are impractical for large-scale restoration due to high biomass requirements. Here, we develop the checkers design, which aims to optimise the usage of biomass by transplanting fewer sods in a checkerboard pattern. We established six plots (9 m2 each) for each species (Zostera marina and Zostera noltei), with 25 sods in each plot. The area, percent cover, density, and leaf length were measured at 1, 6, and 12 months. The plots located on the seaward end of the transplant design vanished over the winter, suggesting location-dependent survival influenced by winter storms. Nevertheless, both species exhibited increased percentages of cover, density, and vegetated area after one year, with variations between species. Z. noltei showed a slower expansion but greater resilience to winter, while Z. marina displayed a higher density and cover over the first 6 months but experienced area loss during the winter. Despite these differences, both species survived and increased vegetated areas after one year, indicating the viability and promise of the checkers method for large-scale restoration. However, careful consideration of location or storm-mitigating measures is essential for the successful implementation of this method.
    2023-08-28Journal article Open access Show more
  • Global reorganization of atmospheric circulation during Dansgaard–Oeschger cycles
    Publication . Jens Fohlmeister; Natasha Sekhon; Andrea Columbu; Guido Vettoretti; Nils Weitzel; Kira Rehfeld; Maya Ben-Yami; Norbert Marwan; Niklas Boers; Veiga-Pires, Cristina
    Ice core records from Greenland provide evidence for multiple abrupt cold-warm-cold events recurring at millennial time scales during the last glacial interval. Although climate variations resembling Dansgaard- Oeschger (DO) oscillations have been identified in climate archives across the globe, our understanding of the climate and ecosystem impacts of the Greenland warming events in lower latitudes remains incomplete. Here, we investigate the influence of DO-cold-to-warm transitions on the global atmospheric circulation pattern. We comprehensively analyze delta O-18 changes during DO transitions in a globally distributed dataset of speleothems and set those in context with simulations of a comprehensive high-resolution climate model featuring internal millennial-scale variations of similar magnitude. Across the globe, speleothem delta O-18 signals and model results indicate consistent large-scale changes in precipitation amount, moisture source, or seasonality of precipitation associated with the DO transitions, in agreement with northward shifts of the Hadley circulation. Furthermore, we identify a decreasing trend in the amplitude of DO transitions with increasing distances from the North Atlantic region. This provides quantitative observational evidence for previous suggestions of the North Atlantic region being the focal point for these archetypes of past abrupt climate changes.
    2023-08-28Conference object Open access Show more