Projekt

Zurück zur Übersicht

Interactive effects of global warming and nutrient enrichment on litter decomposition in freshwater marshes

Titel Englisch Interactive effects of global warming and nutrient enrichment on litter decomposition in freshwater marshes
Gesuchsteller/in Gessner Mark
Nummer 122424
Förderungsinstrument Projektförderung (Abt. I-III)
Forschungseinrichtung
Hochschule Eidg. Anstalt für Wasserversorgung, Abwasserreinigung und Gewässerschutz - EAWAG
Hauptdisziplin Oekologie
Beginn/Ende 01.04.2009 - 31.12.2011
Bewilligter Betrag 333'165.00
Alle Daten anzeigen

Alle Disziplinen (2)

Disziplin
Oekologie
Hydrologie, Limnologie, Glaziologie

Keywords (12)

ecosystem process; wetland; global change; nutrient enrichment; plant litter; decomposition; microbes; stable isotopes; detritivores; carbon cycling; mesocosm experiment; Phragmites

Lay Summary (Englisch)

Lead
Lay summary
Many human activities have repercussions that are profoundly altering natural ecosystems at large-scales. The physical interference by humans with the climate systems has been intensively studied and has become increasingly clear. Significant progress has also been made in assessing range shifts of species and various other ecological responses such as altered species interactions. However, the consequences for ecosystem functioning and possible feedbacks on climate are still poorly understood. This is particularly true for aquatic ecosystems. In addition, information is exceedingly scant on the interactive effects of multiple environmental factors that are changing simultaneously. The proposed project builds on our previous experiments in a freshwater marsh to assess the combined effects of elevated temperature and nutrient loading on litter decomposition, a critical component of carbon cycling at the local and global scale in a variety of ecosystems. The general hypothesis is that impacts of elevated temperature, nutrient loading and the interaction of both are not readily predictable from current theory or through simple laboratory experiments, and that the magnitude of effects is such that important ramifications for elemental flows both within wetlands and across their boundaries are likely to result. I propose testing at this stage a series of specific hypotheses derived from our previous findings and relating to the effects of temperature and nutrients on decomposition. The focus will be on three priorities: (1) testing whether the lack of stimulation of litter decomposition by nitrogen enrichment that we observed is due to the limiting role of phosphorus in the marsh; (2) testing whether a shift in life-history patterns of specific detritivore taxa is responsible for the observed dramatic acceleration of litter decomposition in spring under simulated global warming; and (3) assessing whether the observed lack of effects by elevated temperature and nutrient loading on stem litter decomposition may be related to changes in O2 regimes during long-term operation of enclosures. The backbone of the proposed experiments to address these questions is a unique manipulative field experiment in enclosures installed in a littoral marsh dominated by Phragmites australis. Enclosures are heated to 4 °C above ambient water temperature or enriched with Ca(NO3)2 or both. The experiment is set up as a randomized block design (N = 4) with two factors (temperature and nitrate enrichment), each with two levels. An open-marsh control is also included. The first two questions will be addressed in combined field enclosure and laboratory microcosm experiments, while the third question will be addressed in a field enclosure experiment only. The processes considered in different experiments include litter decomposition, nutrient immobilization, microbial respiration and productivity, enzymatic activity, and various measures of detritivore performance. Results are expected to deepen understanding of the mechanisms controlling litter decomposition and carbon cycling in general in wetlands and thus to facilitate predictions about ecosystem responses in the face of global change.
Direktlink auf Lay Summary Letzte Aktualisierung: 21.02.2013

Verantw. Gesuchsteller/in und weitere Gesuchstellende

Mitarbeitende

Publikationen

Publikation
Experimentally Simulated Global Warming and Nitrogen Enrichment Effects on Microbial Litter Decomposers in a Marsh
(2011), Experimentally Simulated Global Warming and Nitrogen Enrichment Effects on Microbial Litter Decomposers in a Marsh, in APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 77(3), 803-809.
Interaction of Climate Change and Eutrophication
(2010), Interaction of Climate Change and Eutrophication, 119-151.
Methane emissions from a freshwater marsh in response to experimentally simulated global warming and nitrogen enrichment
(2010), Methane emissions from a freshwater marsh in response to experimentally simulated global warming and nitrogen enrichment, in JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES, 115, ---.

Wissenschaftliche Veranstaltungen

Aktiver Beitrag

Titel Art des Beitrags Titel des Artikels oder Beitrages Datum Ort Beteiligte Personen
Entomological Society of America 13.11.2011 Reno, NV, USA
Ecological Society of America, Annual Meeting 07.08.2011 Austin, TX USA
Ecological Society of America, Annual Meeting 01.08.2010 Pittsburgh, PA, USA
Gordon Conference - The Metabolic Basis of Ecology 18.07.2010 Biddeford, Maine, USA
Symposium, The Role of Littoral Processes in Lake Ecology 29.01.2010 Hegne, Germany
Sixth European Symposium for Freshwater Sciences 17.08.2009 Sinaia, Romania


Selber organisiert

Titel Datum Ort
Special Session at American Society of Limnology and Oceanography/North American Benthological Society, Joint Annual Meeting 06.06.2010 Santa Fe, NM, USA

Auszeichnungen

Titel Jahr
2010 American Society of Limnology and Oceanography Young Investigator Award 2010

Verbundene Projekte

Nummer Titel Start Förderungsinstrument
63701 Large scale anthropogenic effects on ecosystem processes: litter decomposition and associated microbial productivity in littoral wetlands 01.06.2001 Projektförderung (Abt. I-III)
108441 Interactive effects of global warming and nutrient enrichment on carbon cycling in freshwater marshes 01.04.2005 Projektförderung (Abt. I-III)

Abstract

Many human activities have repercussions that are profoundly altering natural ecosystems at large-scales. The physical interference by humans with the climate systems has been intensively studied and has become increasingly clear. Significant progress has also been made in assessing range shifts of species and various other ecological responses such as altered species interactions. However, the consequences for ecosystem functioning and possible feedbacks on climate are still poorly understood. This is particularly true for aquatic ecosystems. In addition, information is exceedingly scant on the interactive effects of multiple environmental factors that are changing simultaneously. The proposed project builds on our previous experiments in a freshwater marsh to assess the combined effects of elevated temperature and nutrient loading on litter decomposition, a critical component of carbon cycling at the local and global scale in a variety of ecosystems. The general hypothesis is that impacts of elevated temperature, nutrient loading and the interaction of both are not readily predictable from current theory or through simple laboratory experiments, and that the magnitude of effects is such that important ramifications for elemental flows both within wetlands and across their boundaries are likely to result. I propose testing at this stage a series of specific hypotheses derived from our previous findings and relating to the effects of temperature and nutrients on decomposition. The focus will be on three priorities: (1) testing whether the lack of stimulation of litter decomposition by nitrogen enrichment that we observed is due to the limiting role of phosphorus in the marsh; (2) testing whether a shift in life-history patterns of specific detritivore taxa is responsible for the observed dramatic acceleration of litter decomposition in spring under simulated global warming; and (3) assessing whether the observed lack of effects by elevated temperature and nutrient loading on stem litter decomposition may be related to changes in O2 regimes during long-term operation of enclosures. The backbone of the proposed experiments to address these questions is a unique manipulative field experiment in enclosures installed in a littoral marsh dominated by Phragmites australis. Enclosures are heated to 4 °C above ambient water temperature or enriched with Ca(NO3)2 or both. The experiment is set up as a randomized block design (N = 4) with two factors (temperature and nitrate enrichment), each with two levels. An open-marsh control is also included. The first two questions will be addressed in combined field enclosure and laboratory microcosm experiments, while the third question will be addressed in a field enclosure experiment only. The processes considered in different experiments include litter decomposition, nutrient immobilization, microbial respiration and productivity, enzymatic activity, and various measures of detritivore performance. Results are expected to deepen understanding of the mechanisms controlling litter decomposition and carbon cycling in general in wetlands and thus to facilitate predictions about ecosystem responses in the face of global change.
-