Soil Organic Carbon in Mangrove Ecosystems with Different Vegetation and Sedimentological Conditions

Abstract

A large number of studies have been conducted on organic carbon (OC) variation in mangrove ecosystems. However, few have examined its relationship with soil quality and stratigraphic condition. Mangrove OC characteristics would be explicitly understood if those two parameters were taken into account. The aim of this study was to examine mangrove OC characteristics qualitatively and quantitatively after distinguishing mangrove OC from other OC. Geological survey revealed that the underground of a mangrove ecosystem was composed of three layers: a top layer of mangrove origin and two underlying sublayers of geologic origin. The underlying sublayers were formed from different materials, as shown by X-ray fluorescence analysis. Despite a large thickness exceeding 700 cm in contrast to the 100 cm thickness of the mangrove mud layer, the sublayers had much lower OC stock. Mangrove mud layer formation started from the time of mangrove colonization, which dated back to between 1330 and 1820 14 C years BP, and OC stock in the mangrove mud layer was more than half of the total OC stock in the underground layers, which had been accumulating since 7200 14 C years BP. pH and redox potential (Eh) of the surface soils varied depending on vegetation type. In the surface soils, pH correlated to C% (r = −0.66, p < 0.01). C/N ratios varied widely from 3.9 to 34.3, indicating that mangrove OC had various sources. The pH OPEN ACCESS J. Mar. Sci. Eng. 2015, 3 1405 and Eh gradients were important factors affecting the OC stock and the mobility/uptake of chemical elements in the mangrove mud layer. Humic acids extracted from the mangrove mud layer had relatively high aliphatic contents, in contrast with the carboxylic acid rich sublayers, indicating that humification has not yet progressed in mangrove soil.

C Stock of Top Soil and It Spatial Distribution in Mangrove Community of Trimulyo, Semarang City

“…The amount of OC in the sediment is affected by the depth of the soil layer, the type and age of the standing on it [25,26]. The study also showed that OC has a significant association with BD, salinity and pH, similar to the study [27,28]. The distribution of OC in the study site generally shows a decrease in concentration towards the sea [29].…”

The effect of seasonal and human pressure on macrobenthic fauna in the Caroni Swamp Ramsar Site, Trinidad and Tobago

“…As the TOC % decreased, there was an increase in AMBI values. The high organic matter content may be due to the continuous supply of fresh matter into the system from inland sources as well as the fact that mangrove ecosystems normally act as carbon sinks resulting in higher organic content than would be expected of terrestrial ecosystems (Matsui, Meepol, & Chukwamdee, 2015).…”

Risk of acidification of the organic shrimp model at Tam Giang commune, Nam Can district, Ca Mau province

“…Kết quả này phù hợp với nghiên cứu trước đó trong đất RNM [20]. Sơ đồ phân bố các yếu tố gây chua từ đất rừng trong mô hình tôm sinh thái được thể hiện trong Hình 4.…”

“…Tương tự như trong đất rừng, sự phân hủy chất hữu cơ giải phóng các acid yếu làm tăng độ chua trong bùn đáy. Kết quả tương tự đã được ghi nhận [20]. Eh biến thiên từ -299 --1 mV (-177,8±14,75 mV).…”