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Sources and major biogeochemical pathways of organic matter in the mangrove system of Rufiji estuary
- Shilla, Daniel Abel
- Chemistry in ecology 2019 v.35 no.6 pp. 524-536
- biomarkers, estuaries, fatty acid composition, molecular weight, organic matter, polyunsaturated fatty acids, sediments
- Fatty acids were extracted from the surface sediments (10 cm) of three sampling sites of Rufiji estuary to infer their sources and biogeochemical pathways. The fatty acids ranging from C₈ to C₂₄ were distinguished from this study, and were broadly classified into saturated (SFAs), monounsaturated (MUFAs) and polyunsaturated fatty acids (PUFAs). SFAs were found to be the major fraction at station 1 and 3 where as at station 2, MUFAs dominated. A total of 19 fatty acids with a total concentration of 64.91 μg/g dry weight were characterised at station 1. C₁₆:₀ was the most abundant fatty acid contributing 21.94% of total fatty acids (TFAs). C₂₂:₂ was the second most abundant, which accounted for 9.46% of TFAs. Fatty acids ranging from C₁₂ to C₂₄ were identified at station 2. C₂₀ fatty acid was the most abundant fatty acid contributing 21.94%, followed by C₁₆:₀. At station 3, fatty acids ranging from C₈ to C₂₄ were obtained. The PUFA C₂₀:₅ₙ₋₃ was the most abundant fatty acid contributing 21.65%, followed by C₂₄:₀ (15.00% of TFAs). The ratio of lower molecular weight (LMW) to higher molecular weight (HMW) biomarkers was used as an indicators to distinguish higher plants organic matter from algae-derived fatty acids.