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Paleolimnology and the restoration of aquatic systems

- Gell, Peter, Bennion, Helen, Battarbee, Richard

Succession of microbial community in a small water body within the alluvial aquifer of a large river

- Kulaš, Antonija, Marković, Tamara, Žutinić, Petar, Kajan, Katarina, Karlović, Igor, Orlić, Sandi, Keskin, Emre, Filipović, Vilim, Gligora Udovič, Marija

  • Authors: Kulaš, Antonija , Marković, Tamara , Žutinić, Petar , Kajan, Katarina , Karlović, Igor , Orlić, Sandi , Keskin, Emre , Filipović, Vilim , Gligora Udovič, Marija
  • Date: 2021
  • Type: Text , Journal article
  • Relation: Water Vol. 13, no. 2 (2021), p. 115
  • Full Text: false
  • Reviewed:
  • Description: Nitrogen is one of the essential elements limiting growth in aquatic environments. Being primarily of anthropogenic origin, it exerts negative impacts on freshwater ecosystems. The present study was carried out at the nitrate-vulnerable zone within the alluvial aquifer of the large lowland Drava River. The main aim was to investigate the ecosystem’s functionality by characterizing the bacterial and phytoplankton diversity of a small inactive gravel pit by using interdisciplinary approaches. The phytoplankton community was investigated via traditional microscopy analyses and environmental DNA (eDNA) metabarcoding, while the bacterial community was investigated by a molecular approach (eDNA). Variations in the algal and bacterial community structure indicated a strong correlation with nitrogen compounds. Summer samples were characterized by a high abundance of bloom-forming Cyanobacteria. Following the cyanobacterial breakdown in the colder winter period, Bacillariophyceae and Actinobacteriota became dominant groups. Changes in microbial composition indicated a strong correlation between N forms and algal and bacterial communities. According to the nitrogen dynamics in the alluvial aquifer, we emphasize the importance of small water bodies as potential buffer zones to anthropogenic nitrogen pressures and sentinels of the disturbances displayed as algal blooms within larger freshwater systems. Special Issue Microbial Communities in Water Environments: Dynamics and Interaction)

Regime shifts, thresholds and multiple stable states in freshwater ecosystems; a critical appraisal of the evidence

- Capon, Samantha, Lynch, Jasmyn, Bond, Nick, Chessman, Bruce, Davis, Jenny, Davidson, Nick, Finlayson, C. Max, Gell, Peter, Hohnberg, David, Humphrey, Chris, Kingsford, Richard, Nielsen, Daryl, Thomson, James, Ward, Keith, Mac Nally, Ralph

  • Authors: Capon, Samantha , Lynch, Jasmyn , Bond, Nick , Chessman, Bruce , Davis, Jenny , Davidson, Nick , Finlayson, C. Max , Gell, Peter , Hohnberg, David , Humphrey, Chris , Kingsford, Richard , Nielsen, Daryl , Thomson, James , Ward, Keith , Mac Nally, Ralph
  • Date: 2015
  • Type: Text , Journal article
  • Relation: Science of the Total Environment Vol. , no. (2015), p.
  • Full Text: false
  • Reviewed:
  • Description: The concepts of ecosystem regime shifts, thresholds and alternative or multiple stable states are used extensively in the ecological and environmental management literature. When applied to aquatic ecosystems, these terms are used inconsistently reflecting differing levels of supporting evidence among ecosystem types. Although many aquatic ecosystems around the world have become degraded, the magnitude and causes of changes, relative to the range of historical variability, are poorly known. A working group supported by the Australian Centre for Ecological Analysis and Synthesis (ACEAS) reviewed 135 papers on freshwater ecosystems to assess the evidence for pressure-induced non-linear changes in freshwater ecosystems; these papers used terms indicating sudden and non-linear change in their titles and key words, and so was a positively biased sample. We scrutinized papers for study context and methods, ecosystem characteristics and focus, types of pressures and ecological responses considered, and the type of change reported (i.e., gradual, non-linear, hysteretic or irreversible change). There was little empirical evidence for regime shifts and changes between multiple or alternative stable states in these studies although some shifts between turbid phytoplankton-dominated states and clear-water, macrophyte-dominated states were reported in shallow lakes in temperate climates. We found limited understanding of the subtleties of the relevant theoretical concepts and encountered few mechanistic studies that investigated or identified cause-and-effect relationships between ecological responses and nominal pressures. Our results mirror those of reviews for estuarine, nearshore and marine aquatic ecosystems, demonstrating that although the concepts of regime shifts and alternative stable states have become prominent in the scientific and management literature, their empirical underpinning is weak outside of a specific environmental setting. The application of these concepts in future research and management applications should include evidence on the mechanistic links between pressures and consequent ecological change. Explicit consideration should also be given to whether observed temporal dynamics represent variation along a continuum rather than categorically different states.

First human impacts and responses of aquatic systems : A review of palaeolimnological records from around the world

- Dubois, Nathalie, Saulnier-Talbot, Emilie, Mills, Keely, Gell, Peter, Battarbee, Richard, Bennion, Helen, Chawchai, Sakonvan, Dong, Xuhui, Francus, Pierre, Flower, Roger, Gomes, Doriedson, Gregory-Eaves, Irene, Humane, Sumedh, Kattel, Giri, Jenny, JeanPhilippe, Langdon, Peter, Massaferro, Julieta, McGowan, Suzanne, Mikomagi, Annika, Ngoc, Nguyen, Ratnayake, Amila, Reid, Michael, Rose, Neil, Saros, Jasmine, Schillereff, Daniel, Tolotti, Monica, Valero-Garces, Blas

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