Is peat accumulation in mangrove swamps influenced by the “enzymic latch” mechanism?

Decomposition as a regulator of carbon accretion in mangroves: a review

“…Although the phenolic compounds (e.g. tannins) found in mangrove leaf litter may inhibit microbial activity, due to the effect of the 'enzymic latch', (Freeman et al, 2001;Freeman et al, 2004;Saraswati et al, 2016), it is unlikely to inhibit all activity prior to leaching as labile carbon is still available in the fresh litter. This is utilized by microorganisms to produce exoenzymes (Keuskamp et al, 2015).…”

“…Rates of OM accumulation in mangrove ecosystems are not entirely determined by phenolic compound concentration. Saraswati et al (2016) conducted a study to assess whether the 'enzymic latch', that is responsible for the accumulation of carbon stores in peatlands (Freeman et al 2001;Freeman et al, 2004) is present in mangrove ecosystems. The 'enzymic latch' is the inhibition of phenol oxidase activity, the enzyme responsible for the decomposition of phenolic compounds, through the build-up of phenolics as a result of anaerobic conditions in the soil (Freeman et al, 2001).…”

“…The 'enzymic latch' is the inhibition of phenol oxidase activity, the enzyme responsible for the decomposition of phenolic compounds, through the build-up of phenolics as a result of anaerobic conditions in the soil (Freeman et al, 2001). Saraswati et al (2016) identified that the 'enzymic latch' likely causes the accumulation of peat in red mangroves (Rhizophora mangle) as identified by the lower hydrolase enzyme activity in anaerobic conditions (phosphatase: -44%; βglucosidase: -14%; and glucosaminidase: -11%) when compared to aerobic conditions; which could possibly explain the accumulation of peat in all mangroves. However, because red mangroves have been identified as having higher tannin concentrations in their litter (Ashton et al, 1999), it is possible that the 'enzymic latch' may not occur in mangroves with litter containing lower phenolic concentrations.…”

“…However, because red mangroves have been identified as having higher tannin concentrations in their litter (Ashton et al, 1999), it is possible that the 'enzymic latch' may not occur in mangroves with litter containing lower phenolic concentrations. Saraswati et al (2016) refer to the potential for an ecoengineering approach involving supplementing mangrove systems with phenolic-rich substances to inhibit degradation, following the technique suggested by Freeman et al (2012) for peatland environments.…”

Examining the Process of Decomposition and Carbon Cycling in 'Fadama' Coastal Wetlands: A Case Study of Heaping Wetlands Ecosystem

“…High water and organic matter contents in wetland soils indicates a low microbial activity which encourages huge storage of SOM as well as high storage of GHGs over the years. This occurs usually as a result of the anoxic condition in such ecosystems due to low oxygen availability, thereby reducing decomposition and encouraging massive carbon deposit as well enhancing burial of GHGs (Foster et al, 2012, Saraswati et al, 2016. Soils from site A (Gada biyu) had the lowest Phenol oxidase enzyme activity (1536.56 nmoldicq g-1 h-1 ) this was followed by site B (Pwomol) which had slightly more than two-fold activity (3397.31nmoldicq g-1 h-1 ) while site B had a statistically significantly higher phenol oxidase activity (5340.44nmoldicq g-1 h-1 ) (p<0.05) in comparison with the other two sites (Figure 2).…”