Blue Carbon in Coastal Phragmites Wetlands Along the Southern Baltic Sea

Abstract

Coastal wetlands are important for carbon (C) storage and sequestration. Still, there are large knowledge gaps concerning the amount of “blue carbon” in coastal wetlands dominated by common reed (Phragmites australis). We quantified carbon stocks at the southern Baltic Sea coast at six representative Phragmites wetland sites at the Darss-Zingst-Bodden Chain (DZBC) and the Strelasund, which include different categories of adjacent land use (arable land, woodland, pasture, urban), topography (totally flat to undulating), and geographical restrictions (dyking). Sediment samples were taken to a depth of 1 m, in line with the IPCC guidelines, and total carbon concentrations and bulk densities were measured in 10 cm intervals. The sites stored, on average, 17.4 kg C m−2 with large variability between sites, ranging from 1.76 to 88.6 kg C m−2. The estimated average is generally in good agreement with carbon stocks reported for tidal salt marshes, mangroves, and seagrass meadows. According to our estimation, based on widths of the reed belts and carbon stocks at the sampled sites, approximately 264,600 t of blue carbon could be stored in the coastal reed belts along the DZBC, a typical lagoon system of the southern Baltic Sea. Our study underlines the importance of these unique ecotones between land and sea for storage and sequestration of blue carbon. Since Phragmites is also a common (sometimes invasive) species along other large brackish water basins, such as the Black Sea or Chesapeake Bay, these estimates can be used for improved precision of modeling blue carbon budgets.

Human-Induced Hydrological Connectivity: Impacts of Footpaths on Beach Wrack Transport in a Frequently Visited Baltic Coastal Wetland

“…Beach wrack itself also provides a variety of ecosystem services such as stabilizing soft bottom substrates, providing food and shelter to different organisms or storing blue carbon (Defeo et al, 2009;Malm et al, 2004;Vanhooren et al, 2011;Gilburn, 2012;Weinberger et al, 2021;Pan et al, 2021). However, not only Baltic coastal wetlands are understudied with regard to carbon sequestration and storage (Graversen et al, 2022;Buczko et al, 2022), but also the role of beach wrack remains overlooked (Duarte et al, 2013). Blue carbon storage as well as the potential of greenhouse gas emissions due to decomposition should be considered (Pan et al, 2021).…”

“…Coastal wetlands, as the interface between aquatic and terrestrial ecosystems, are highly productive ecosystems that provide various habitats, sequester carbon, dissipate wave energy, or buffer nutrients (e.g., Reddy and DeLaune, 2008;Karstens et al, 2015;Jurasinski et al, 2018;Heckwolf et al, 2021;Buczko et al, 2022). However, coastal wetlands are at risk of submergence and thus loss of important ecosystem services if vertical growth cannot keep up with the rising sea level (Coleman et al, 2022).…”

Assessment of Ecosystem Services Provided by Macrophytes in Southern Baltic and Southern Mediterranean Coastal Lagoons

“…For instance, we can demonstrate the value of the halophyte Aster tripolium, a red list species, located in the protected area "Smeltes botaninis draustinis" (Klaipeda, Lithuania) that is in the industrial harbor area of the Curonian lagoon (Olšauskas et al 2013). Additionally, macrophyte habitats play a role within climate change mitigation measures, for example by reed belts (Buczko et al 2022) and sea grass beds (Stevenson et al 2022) as carbon storages. Summarizing, our results can support the implementation of management and policy measures by explaining the benefits to humans, for example, of achieving the GES (e.g., restoration of macrophyte habitats by reducing agricultural nutrient loads) and of enhancing the biodiversity of macrophyte habitats (e.g., to protect rare species and prevent monocultures).…”

Influence of reed beds (Phragmites australis) and submerged vegetation on pike (Esox lucius)

“…Emergent vegetation are strong competitor for light in shallow, wave-protected areas with high organic and nutrient concentrations (Li et al, 2021), which may reduce biodiversity of submerged vegetation and more homogeneous vegetation (Munsterhjelm, 1997;Pitkänen et al, 2013;Altartouri et al, 2014;Han and Cui, 2016;Schrank and Lishawa, 2019). On the other hand, reed has important functions in shallow and sheltered habitats (Altartouri et al, 2014) as it protects shorelines from wave erosion, buffers internal nutrient loading and absorbs external nutrient loadings (Kaitaranta et al, 2013), and acts as a carbon sink (Buczko et al, 2022).…”