Organic carbon accumulation and metabolic pathways in sediments of mangrove forests in southern Thailand

Abstract Mangrove forests are among the world’s most productive ecosystems and provide essential ecosystem services such as global climate regulation through the sequestration of carbon. A detailed understanding of the influence of drivers of ecosystem connectivity (in terms of exchange of suspended particulate organic matter), such as geomorphic setting and carbon stocks, among coastal ecosystems is important for being able to depict carbon dynamics. Here, we compared carbon stocks, CO2 fluxes at the sediment-air interface, concentrations of dissolved organic carbon and suspended particulate organic carbon across a mangrove-seagrass-tidal flat seascape. Using stable isotope signatures of carbon and nitrogen in combination with MixSIAR models, we evaluated the contribution of organic matter from different sources among the different seascape components. Generally, carbon concentration was higher as dissolved organic carbon than as suspended particulate matter. Geomorphic settings of the different locations reflected the contributions to particulate organic matter of the primary producers. For example, the biggest contributors in the riverine location were mangrove trees and terrestrial plants, while in fringing locations oceanic and macroalgal sources dominated. Anthropogenic induced changes at the coastal level (i.e. reduction of mangrove forests area) may affect carbon accumulation dynamics in adjacent coastal ecosystems.

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Assessing the Effect of Age and Geomorphic Setting on Organic Carbon Accumulation in High-Latitude Human-Planted Mangroves

Forests ◽

10.3390/f13010105 ◽

2022 ◽

Vol 13 (1) ◽

pp. 105

Author(s):

Jianxiong Hu ◽

Pei Sun Loh ◽

Siriporn Pradit ◽

Thi Phuong Quynh Le ◽

Chantha Oeurng ◽

...

Keyword(s):

Organic Carbon ◽

Sediment Cores ◽

Stable Carbon Isotope ◽

Carbon Accumulation ◽

Mangrove Forests ◽

Fine Grained ◽

Positive Effects ◽

Organic Carbon Pool ◽

Organic Carbon Stock ◽

Interior Part

Mangroves are highly productive blue carbon ecosystems that preserve high organic carbon concentrations in soils. In this study, particle size, bulk elemental composition and stable carbon isotope were determined for the sediment cores collected from the landward and seaward sides of two mangrove forests of different ages (M1, ca. 60; M2, ca. 4 years old) to determine the effects of geomorphic setting and age (L1 = old mangrove and S1 = salt marsh stand in M1; L2 = young mangrove and S2 = bare mudflat in M2) on sediments and organic carbon accumulation. The objective of this study was to determine the feasibility of the northernmost human-planted mangroves in China to accumulate sediment and carbon. Our results showed that fine-grained materials were preserved well in the interior part of the mangroves, and the capacity to capture fine-grained materials increased as the forest aged. The biogeochemical properties (C/N: 5.9 to 10.8; δ13C: −21.60‰ to −26.07‰) indicated that the local organic carbon pool was composed of a mixture of autochthonous and allochthonous sources. Moreover, the accumulation of organic carbon increased with the forest age. The interior part of the old mangrove had the highest organic carbon stock (81.93 Mg Corg ha−1). These findings revealed that mangrove reforestation had positive effects on sediments and organic carbon accretion.

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Changes in sediment and organic carbon accumulation in a highly-disturbed ecosystem: The Sacramento-San Joaquin River Delta (California, USA)

Marine Pollution Bulletin ◽

10.1016/j.marpolbul.2009.03.025 ◽

2009 ◽

Vol 59 (4-7) ◽

pp. 154-163 ◽

Cited By ~ 26

Author(s):

Elizabeth A. Canuel ◽

Elizabeth J. Lerberg ◽

Rebecca M. Dickhut ◽

Steven A. Kuehl ◽

Thomas S. Bianchi ◽

...

Keyword(s):

Organic Carbon ◽

River Delta ◽

Carbon Accumulation ◽

San Joaquin River

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Organic mulching promotes soil organic carbon accumulation to deep soil layer in an urban plantation forest

Forest Ecosystems ◽

10.1186/s40663-020-00278-5 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Xiaodan Sun ◽

Gang Wang ◽

Qingxu Ma ◽

Jiahui Liao ◽

Dong Wang ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Carbon Content ◽

Fine Roots ◽

Soil Layer ◽

Carbon Accumulation ◽

Bulk Soil ◽

Organic Mulch ◽

The Impact ◽

Soc Fractions

Abstract Background Soil organic carbon (SOC) is important for soil quality and fertility in forest ecosystems. Labile SOC fractions are sensitive to environmental changes, which reflect the impact of short-term internal and external management measures on the soil carbon pool. Organic mulching (OM) alters the soil environment and promotes plant growth. However, little is known about the responses of SOC fractions in rhizosphere or bulk soil to OM in urban forests and its correlation with carbon composition in plants. Methods A one-year field experiment with four treatments (OM at 0, 5, 10, and 20 cm thicknesses) was conducted in a 15-year-old Ligustrum lucidum plantation. Changes in the SOC fractions in the rhizosphere and bulk soil; the carbon content in the plant fine roots, leaves, and organic mulch; and several soil physicochemical properties were measured. The relationships between SOC fractions and the measured variables were analysed. Results The OM treatments had no significant effect on the SOC fractions, except for the dissolved organic carbon (DOC). OM promoted the movement of SOC to deeper soil because of the increased carbon content in fine roots of subsoil. There were significant correlations between DOC and microbial biomass carbon and SOC and easily oxidised organic carbon. The OM had a greater effect on organic carbon fractions in the bulk soil than in the rhizosphere. The thinnest (5 cm) mulching layers showed the most rapid carbon decomposition over time. The time after OM had the greatest effect on the SOC fractions, followed by soil layer. Conclusions The frequent addition of small amounts of organic mulch increased SOC accumulation in the present study. OM is a potential management model to enhance soil organic matter storage for maintaining urban forest productivity.

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