Effects of ecological restoration on carbon sink and carbon drawdown of degraded salt marshes with carbon‐rich additives application

Abstract

Plant biomass resources have been gradually used to restore and improve saline soils. However, little is known about whether the applications of reed straw (PA) and biochar (BC) in degraded coastal salt marshes are beneficial for blue carbon sink enhancement and carbon drawdown. Here, we evaluated the effects of 3% PA and 3% BC applications on the vegetation, soil and blue carbon sink function of degraded salt marsh ecosystems and assessed their CO2 reduction capacities based on the life cycle. The results showed that the applications of PA and BC improved the soil quality of degraded salt marshes. Suaeda salsa recovered after 3% PA and 3% BC additions, and its carbon sequestration increased by 133% and 12%, respectively. The carbon pool of the degraded salt marshes was elevated by 0.4%–2.8% compared with that before restoration. The structural equation modelling indicated that both PA and BC application decreased soil electrical conductivity, while promoted the recovery of the plant carbon pool and an increase in the soil carbon pool. We calculated a CO2 drawdown of 137 kg·t−1 for the 3% PA addition in comparison with a CO2 emission of 175 kg·t−1 for the 3% BC addition based on a life cycle assessment. These findings indicate that PA and BC can be effectively used to restore degraded salt marshes and enhance blue carbon sinks while PA application is a better choice for degraded coastal wetlands rehabilitation to achieve carbon drawdown from a life cycle perspective.

Maximizing blue carbon stocks through saltmarsh restoration

“…Over half of organic matter production in saltmarsh plants occurs in roots and rhizomes that are buried within the soil (Duarte et al, 2013) and lower dry bulk densities have been associated with high biomass and abundance of roots in saltmarsh plant species (Santini et al, 2019), hence the inverse relationship when carbon stock is higher at lower bulk densities observed across coastal blue carbon habitats (Dahl et al, 2016;Barry et al, 2018;Gao et al, 2019;Lima et al, 2020). In turn, root biomass is known to contribute significantly to carbon stocks (Jones and Donnelly, 2004;Ford et al, 2019;Santini et al, 2019;Chen et al, 2022) and has been shown to be significantly lower in pioneer communities than for plant communities at higher elevations across UK saltmarshes (Harvey et al, 2019).…”

Global sustainable land use and management: Illustrating the linkage between carbon sink and ecological engineering

“…Meanwhile, analysis methods included multiple innovation model combinations as well as meta‐analysis. SD: system dynamics, GIS: geographic information systems, RF Model: random forest model, DNDC Model: denitrification‐decomposition (DNDC) model (Bhardwaj et al, 2022; Chen et al, 2022; Feng et al, 2023, Hashimi et al, 2022; He et al, 2022; Jia et al, 2023; Liu et al, 2022; Ravisankar et al, 2022; Wang et al, 2022, 2023; Xu et al, 2022; Yang et al, 2022, Zhang et al, 2022, 2023). [Colour figure can be viewed at wileyonlinelibrary.com]…”

“…Similarly, the natural vegetation saxaul ( Haloxylon ammodendron ) alleviates desertification better than the artificially planted matrimony vine ( Lycium barbarum L.) in desert ecosystems (Yang et al, 2022). Reed straw ( Phragmites australis ) application effectively improved degraded salt marshes and enriched carbon sinks (Chen et al, 2022). Moreover, salt‐tolerant grasses, in partnership with arbuscular mycorrhizal fungi, can potentially rehabilitate heavy metal‐contaminated saline ecosystems (Jia et al, 2023); this finding suggests that ecological engineering is developing sustainably.…”

“…Currently, grasslands are severely degrading due to climate fluctuations and F I G U R E 1 Research regions of the Special Issue (SI). The research regions of this SI ranged from basin scale to continental scale, and included forest, grassland, saline-alkali land, desert land, and other fragile ecosystem types(Bhardwaj et al, 2022;Chen et al, 2022;Feng et al, 2023;Hashimi et al, 2022;He et al, 2022;Jia et al, 2023;Liu et al, 2022;Ravisankar et al, 2022;Wang et al, 2022. Xu et al, 2022Yang et al, 2022;Zhang et al, 2022Zhang et al, , 2023.…”

Effects of typical artificial reefs on hydrodynamic characteristics and carbon sequestration potential in the offshore of Juehua Island, Bohai Sea

“…In addition to plant photosynthesis, wetland sediment is also a main carbon storage sink in the salt marsh ecosystem. Studies have shown that reed straw and biochar can effectively restore degraded salt marshes and enhance blue carbon sinks (Chen et al, 2022). The carbon sequestration in the seagrass bed ecosystem includes a high productivity of seagrass bed plants, clastic carbon capture ability in seawater, and lower decomposition of sediments (Lee et al, 2021).…”