Review of the physical and chemical properties of seagrass soils

• Published in: Geoderma
• Main Authors: Piñeiro-Juncal, Nerea, Serrano, Oscar, Mateo, Miguel Ángel, Diaz-Almela, Elena, Leiva-Dueñas, Carmen, Martinez-Cortizas, Antonio
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2022
• Subjects: Blue carbon; Grain size; Marine phanerogams; Seagrass sediments; Subaqueous soils; Antarc*; Antarctica
• Online Access: https://pure.au.dk/portal/da/publications/review-of-the-physical-and-chemical-properties-of-seagrass-soils(0bef7837-af96-4201-b271-63abcb1e9625).html; https://doi.org/10.1016/j.geoderma.2022.116219; https://pure.au.dk/ws/files/333397631/1_s2.0_S0016706122005262_main.pdf; http://www.scopus.com/inward/record.url?scp=85140587553&partnerID=8YFLogxK

Seagrasses are a polyphyletic group of angiosperms that colonized marine environments more than 30 million years ago and currently inhabit coastal soft and rocky substrates in all continents except Antarctica. Due to their evolution from terrestrial plants, seagrasses have belowground organs that interact with the substrate, transforming it through chemo-physical processes analogous to terrestrial soil formation. Although seagrass substrates provide valuable ecosystem services including carbon and coastal stabilization, they have been largely regarded as sediments by marine scientists and neglected in soil science research. However, over the last decades, the increasing interest in carbon accumulation by seagrasses has generated multiple data on seagrass soil physical and chemical characteristics. Here, we review clay and silt content (<0.063 mm particle size), redox potential, pH, carbonate content, organic carbon or organic matter contents, dry bulk density, porosity and color of seagrass soils worldwide, summarizing data typically used for soil description, and looking for generalities in soil characteristics across seagrass habitats. The data gathered was biased towards temperate species and high-income countries, while data about color, porosity, redox potential and pH was scarce. Soil characteristics did not show significant differences among seagrass bioregions. Most seagrass substrates showed sandy textures, whereas one of the most sampled genera, Posidonia, was not present in muddy substrates. The soil C org content was significantly higher in meadows formed by persistent species (mean ± SD; 1.76 ± 2.17 %) than in meadows formed by species with opportunistic and colonizing life-strategies (1.52 ± 2.24 and 0.76 ± 0.95 %, respectively), while mud content was significantly higher in meadows formed by opportunistic and colonizing species (27.87 ± 29.58 and 21.23 ± 21.77 %, respectively) than in those formed by persistent species (11.83 ± 14.45 %). Redox potential was significantly lower in intertidal ...