TY - JOUR

T1 - Is peat accumulation in mangrove swamps influenced by the “enzymic latch” mechanism?

AU - Dunn, Christian

AU - Mitsch, William

AU - Freeman, Christopher

AU - Saraswati, Saraswati

PY - 2016/12/15

Y1 - 2016/12/15

N2 - Mangrove swamps accumulate a significant amount (45–98 %) of organic carbon in sediments; however, there is a knowledge gap in explaining the mechanism behind this. Through the analysis of substrate samples from a red mangrove (Rhizophora mangle) swamp in southwest Florida, USA, this study investigated whether the “enzymic latch”, which suppresses decomposition in northern peatlands, is prevalent in mangrove soils. Laboratory analyses were performed to investigate the four hypotheses of the “enzymic latch”. Results showed that under aerobic conditions mangroves soil samples have significantly higher phenol oxidase activity (two-fold, p < 0.05), but lower phosphatase activity (−33 %, p < 0.05), β-glucosidase activity (−14 %) and glucosaminidase activity (−11 %) compared to anaerobic conditions. Soil samples supplemented with phenol oxidase showed significantly lower phenolic concentration (−8.3 %, p < 0.01), but increased β-glucosidase (+79 %, p < 0.05), xylosidase (+99 %, p < 0.01) and glucosaminidase (+102 %, p < 0.01) activities. Supplementation of lignin-based solution significantly lowered β-glucosidase (−55 %, p < 0.001), sulphatase (−82 %, p < 0.001) and glucosaminidase (−45 %, p < 0.01) activities. Based on these findings, it is concluded that the “enzymic latch” is highly likely to play a key role in suppressing decomposition rates in red mangrove covered areas of mangrove swamps.

AB - Mangrove swamps accumulate a significant amount (45–98 %) of organic carbon in sediments; however, there is a knowledge gap in explaining the mechanism behind this. Through the analysis of substrate samples from a red mangrove (Rhizophora mangle) swamp in southwest Florida, USA, this study investigated whether the “enzymic latch”, which suppresses decomposition in northern peatlands, is prevalent in mangrove soils. Laboratory analyses were performed to investigate the four hypotheses of the “enzymic latch”. Results showed that under aerobic conditions mangroves soil samples have significantly higher phenol oxidase activity (two-fold, p < 0.05), but lower phosphatase activity (−33 %, p < 0.05), β-glucosidase activity (−14 %) and glucosaminidase activity (−11 %) compared to anaerobic conditions. Soil samples supplemented with phenol oxidase showed significantly lower phenolic concentration (−8.3 %, p < 0.01), but increased β-glucosidase (+79 %, p < 0.05), xylosidase (+99 %, p < 0.01) and glucosaminidase (+102 %, p < 0.01) activities. Supplementation of lignin-based solution significantly lowered β-glucosidase (−55 %, p < 0.001), sulphatase (−82 %, p < 0.001) and glucosaminidase (−45 %, p < 0.01) activities. Based on these findings, it is concluded that the “enzymic latch” is highly likely to play a key role in suppressing decomposition rates in red mangrove covered areas of mangrove swamps.

U2 - 10.1007/s11273-016-9493-z

DO - 10.1007/s11273-016-9493-z

M3 - Article

VL - 24

SP - 641

EP - 650

JO - Wetlands Ecology and Management

JF - Wetlands Ecology and Management

SN - 0923-4861

IS - 6

ER -