Decomposition rate and invertebrate colonization of seagrass detritus along a hydrodynamic gradient in a Mediterranean coastal basin: The Stagnone di Marsala (Italy) case study

Abstract

Seagrass leaf litter decomposition is a key component of marine carbon flow driven by both biotic and abiotic factors, including water movement. In this study, we analyse Posidonia oceanica litter decomposition and invertebrate colonization in three sites with different hydrodynamics in a coastal basin. Litterbags were put on the seabed along a gradient of distance from the open-sea, implying a different level of water exchange. Leaf litter mass loss and carbon and nitrogen concentration were analysed and density and biomass of benthic invertebrates colonising litterbags were recorded after 3, 7, 14, 47, 101, 152 and 221 days. Results showed that in the most sheltered site, the leaf litter decomposition rate, the invertebrate density and biomass and the detrital carbon release were the lowest. The reduction of the decomposition rates of seagrass leaves in the site characterised by low hydrodynamic forces may promote organic matter burial and carbon stocks, emphasising the role of coastal basins such as ponds and lagoons as sinks of carbon and their viability for blue carbon areas.

Resilient consumers accelerate the plant decomposition in a naturally acidified seagrass ecosystem

“…This could be related to North Castello being located at a shallower depth (~3 m) closer to the shoreline, where wave‐induced water motion is stronger. Hydrodynamic forcing can facilitate the biological decay processes by promoting mechanical fragmentation and consumer colonization of seagrass detritus (Costa et al, 2019; Mateo & Romero, 1997; Romero et al, 2006). It should also be noted that the total detritivore and G. fucicola abundances were comparable between the two sites from day 55, when detritivores began actively consuming the detritus.…”

Decomposition of Organic Matter in Caves

“…Their influence has been investigated using exclusion experiments and detritivore effects on decomposition rate seem most important on a regional scale (Wall et al, 2008) and to depend on climate and habitat (Garcia-Palacios et al, 2013). In the marine environment lower rates of decomposition were observed at more sheltered sites (Costa et al, 2019) where invertebrate biomass was low compared to open sea. This effect though was also a result of less mechanical impact.…”

Tropicalization of seagrass macrophytodetritus accumulations and associated food webs

“…from hours to months), depending on meadow depth, microbial and mechanical degradation rates, fauna processing and local hydrodynamics (i.e. swell, current, wind gust or storm) or local seascape morphology (Hyndes et al, 2014;Ricart et al, 2015;Ricart et al, 2017;Costa et al, 2019). In many cases, a significant part of this detritus can be exported outside the meadow as large fragments (i.e.…”