Tim René de Groot, Anne Margriet Mol, Katherine Mesdag, Pierre Ramond, Rachel Ndhlovu, Julia Catherine Engelmann, Thomas Röckmann, Helge Niemann
{"title":"Diel and seasonal methane dynamics in the shallow and turbulent Wadden Sea","authors":"Tim René de Groot, Anne Margriet Mol, Katherine Mesdag, Pierre Ramond, Rachel Ndhlovu, Julia Catherine Engelmann, Thomas Röckmann, Helge Niemann","doi":"10.5194/bg-20-3857-2023","DOIUrl":null,"url":null,"abstract":"Abstract. The Wadden Sea is a coastal system along the fringe of the land–sea borders of Denmark, Germany and the Netherlands. The Wadden Sea is extremely productive and influenced by strong variations in physical and biological forcing factors that act on timescales of hours to seasons. Productive coastal seas are known to dominate the ocean's methane emission to the atmosphere, but knowledge of controls and temporal variations in methane dynamics in these vastly dynamic systems is scarce. Here we address this knowledge gap by measuring methane inventories and methanotrophic activity at a temporal resolution of 1 h over a period of 2 d, repeatedly during four successive seasons in the central Dutch Wadden Sea. We found that methane dynamics varied between colder and warmer seasons, with generally higher water column methane concentrations and methanotrophic activity in the warmer seasons. The efflux of methane to the atmosphere was, on the other hand, lower in the warmer seasons because of lower wind speeds. On a diel scale, tides controlled methanotrophic activity, which increased ∼40 % at low tide compared to high tide. We estimate that methane oxidizing bacteria reduce the methane budget of the Dutch Wadden Sea by only 2 %, while ∼1/3 escapes to the atmosphere and ∼2/3 are flushed out into the open North Sea at ebb tide. Our findings indicate that tides play a key role in controlling methane dynamics and methanotrophic activity and highlight the importance of high-resolution and repeated sampling strategies to resolve methane dynamics in fast-changing coastal systems.","PeriodicalId":8899,"journal":{"name":"Biogeosciences","volume":"17 1","pages":"0"},"PeriodicalIF":3.9000,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biogeosciences","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.5194/bg-20-3857-2023","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ECOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Abstract. The Wadden Sea is a coastal system along the fringe of the land–sea borders of Denmark, Germany and the Netherlands. The Wadden Sea is extremely productive and influenced by strong variations in physical and biological forcing factors that act on timescales of hours to seasons. Productive coastal seas are known to dominate the ocean's methane emission to the atmosphere, but knowledge of controls and temporal variations in methane dynamics in these vastly dynamic systems is scarce. Here we address this knowledge gap by measuring methane inventories and methanotrophic activity at a temporal resolution of 1 h over a period of 2 d, repeatedly during four successive seasons in the central Dutch Wadden Sea. We found that methane dynamics varied between colder and warmer seasons, with generally higher water column methane concentrations and methanotrophic activity in the warmer seasons. The efflux of methane to the atmosphere was, on the other hand, lower in the warmer seasons because of lower wind speeds. On a diel scale, tides controlled methanotrophic activity, which increased ∼40 % at low tide compared to high tide. We estimate that methane oxidizing bacteria reduce the methane budget of the Dutch Wadden Sea by only 2 %, while ∼1/3 escapes to the atmosphere and ∼2/3 are flushed out into the open North Sea at ebb tide. Our findings indicate that tides play a key role in controlling methane dynamics and methanotrophic activity and highlight the importance of high-resolution and repeated sampling strategies to resolve methane dynamics in fast-changing coastal systems.
期刊介绍:
Biogeosciences (BG) is an international scientific journal dedicated to the publication and discussion of research articles, short communications and review papers on all aspects of the interactions between the biological, chemical and physical processes in terrestrial or extraterrestrial life with the geosphere, hydrosphere and atmosphere. The objective of the journal is to cut across the boundaries of established sciences and achieve an interdisciplinary view of these interactions. Experimental, conceptual and modelling approaches are welcome.