Browsing by Author "Posselt, Malte"

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    Is the hyporheic zone relevant beyond the scientific community?
    (MDPI, 2019-10-25) Lewandowski, Jörg; Arnon, Shai; Banks, Eddie; Batelaan, Okke; Betterle, Andrea; Broecker, Tabea; Coll, Claudia; Drummond, Jennifer D.; Garcia, Jaime Gaona; Galloway, Jason; Gomez-Velez, Jesus; Grabowski, Robert C.; Herzog, Skuyler P.; Hinkelmann, Reinhard; Höhne, Anja; Hollender, Juliane; Horn, Marcus A.; Jaeger, Anna; Krause, Stefan; Löchner Prats, Adrian; Magliozzi, Chiara; Meinikmann, Karin; Babak Mojarrad, Brian; Mueller, Birgit Maria; Peralta-Maraver, Ignacio; Popp, Andrea L.; Posselt, Malte; Putschew, Anke; Radke, Michael; Raza, Muhammad; Riml, Joakim; Robertson, Anne; Rutere, Cyrus; Schaper, Jonas L.; Schirmer, Mario; Schulz, Hanna; Shanafield, Margaret; Singh, Tanu; Ward, Adam S.; Wolke, Philipp; Wörman, Anders; Wu, Liwen
    Rivers are important ecosystems under continuous anthropogenic stresses. The hyporheic zone is a ubiquitous, reactive interface between the main channel and its surrounding sediments along the river network. We elaborate on the main physical, biological, and biogeochemical drivers and processes within the hyporheic zone that have been studied by multiple scientific disciplines for almost half a century. These previous efforts have shown that the hyporheic zone is a modulator for most metabolic stream processes and serves as a refuge and habitat for a diverse range of aquatic organisms. It also exerts a major control on river water quality by increasing the contact time with reactive environments, which in turn results in retention and transformation of nutrients, trace organic compounds, fine suspended particles, and microplastics, among others. The paper showcases the critical importance of hyporheic zones, both from a scientific and an applied perspective, and their role in ecosystem services to answer the question of the manuscript title. It identifies major research gaps in our understanding of hyporheic processes. In conclusion, we highlight the potential of hyporheic restoration to efficiently manage and reactivate ecosystem functions and services in river corridors.
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    The riverine bioreactor: an integrative perspective on biological decomposition of organic matter across riverine habitats
    (Elsevier, 2021-02-01) Peralta-Maraver, Ignacio; Stubbington, Rachel; Arnon, Shai; Kratina, Pavel; Krause, Stefan; Mello Cionek, Vivian de; Leite, Nei Kavaguichi; Lemes da Silva, Aurea Luiza; Thomazi, Sidinei Magela; Posselt, Malte; Milner, Victoria Susan; Momblanch, Andrea; Moretti, Marcelo S.; Nóbrega, Rodolfo L. B.; Perkins, Daniel M.; Petrucio, Mauricio M.; Reche, Isabel; Saito, Victor; Sarmento, Hugo; Strange, Emily; Taniwaki, Ricardo Hideo; White, James C.; Alves, Gustavo Henrique Zaia; Robertson, Anne L.
    Riverine ecosystems can be conceptualized as ‘bioreactors’ (the riverine bioreactor) which retain and decompose a wide range of organic substrates. The metabolic performance of the riverine bioreactor is linked to their community structure, the efficiency of energy transfer along food chains, and complex interactions among biotic and abiotic environmental factors. However, our understanding of the mechanistic functioning and capacity of the riverine bioreactor remains limited. We review the state of knowledge and outline major gaps in the understanding of biotic drivers of organic matter decomposition processes that occur in riverine ecosystems, across habitats, temporal dimensions, and latitudes influenced by climate change. We propose a novel, integrative analytical perspective to assess and predict decomposition processes in riverine ecosystems. We then use this model to analyse data to demonstrate that the size-spectra of a community can be used to predict decomposition rates by analysing an illustrative dataset. This modelling methodology allows comparison of the riverine bioreactor’s performance across habitats and at a global scale. Our integrative analytical approach can be applied to advance understanding of the functioning and efficiency of the riverine bioreactor as hotspots of metabolic activity. Application of insights gained from such analyses could inform the development of strategies that promote the functioning of the riverine bioreactor across global ecosystems