Assessment of the quality and quantity of organic matter in the Rufiji mangrove surface sediments using biochemical composition

Abstract

This study was carried out to investigate spatial changes in the quality and quantity of sedimentary organic matter in the Rufiji mangrove system, Tanzania. Sediment samples were collected from three sampling sites. Total organic matter in mangrove sediments ranged from 7.28 ± 2.02% to 10.58 ± 1.34%. Protein concentrations varied from 1,145.33 ± 20.33 μg/g to 2,747.50 ± 25.14 μg/g in the mangrove sediments. Total carbohydrates, lipids and biopolymeric carbon in mangrove sediments ranged between 1,110.50 ± 16.31 μg/g and 1,914.17 ± 27.79 μg/g, 1,436.50 ± 24.13 μg/g and 6,373.50 ± 25.79 μg/g, and 4,496 μg C/g and 10,231.50 μg C/g, respectively. Tannins and lignins in mangrove sediments varied from 817.67 ± 12.97 μg/g to 1786.50 ± 30.74 μg/g, while stable carbon isotope (δ13C) in Rufiji mangrove sediments ranged between –26.64 ± 0.10 ‰ and –25.48 ± 0.13 ‰. Higher protein:carbohydrate (PRT:CHO) at station 3 indicated the presence of freshly deposited organic matter. The high lipid:carbohydrate (LPD:CHO) ratios observed in the Rufiji mangrove systems pointed towards the high quality of labile organic matter which supports benthic fauna. PCA revealed the association of variables and their distribution on trends across sites of the Rufiji mangrove system.
 Keywords: Organic matter, biochemical composition, Rufiji, mangroves, sediments

Spatial variability of organic matter in two mangrove ecosystems in Langkawi, Kedah, Malaysia

“…Organic matter in the sediment positively affects all functions, from fertility to the sediment structure (Lal et al 2021). Sediment with higher organic matter content has a better structure, which helps absorb water and retain nutrients (Shilla 2021). Furthermore, it promotes the growth of the mangrove trees by supplying energy from carbon compounds, nitrogen for protein production, and other nutrients (Keesstra et al 2016).…”

Composition of sedimentary organic matter in Thrissur Kole wetland, southwest India

“…The summative measure of total OM content in sediments provide only limited knowledge on its availability to consumers (Incera et al 2003). The nutritional value of sedimentary OM is assessed by its biochemical composition (Fabiano and Danovaro 1994 Shilla 2021). Nutritional quality and quantity of sedimentary OM rely on its origin (viz.…”

“…Total lipids are the third most dominant fraction of labile OM in the study region. Lipids are produced by living organisms(Burdige et al 2000;Salas et al 2015) and derived not only from aquatic biota, but also from higher plant wax(Shilla 2021). Sedimentary LPD are more dominant in eutrophic systems than in oligo-trophic systems.…”

Composition of sedimentary organic matter in Thrissur Kole wetland, Southwest India

“…The summative measure of total OM content in sediments provide only limited knowledge on its availability to consumers (Incera et al 2003). The nutritional value of sedimentary OM is assessed by its biochemical composition (Fabiano and Danovaro 1994 Shilla 2021). Nutritional quality and quantity of sedimentary OM rely on its origin (viz.…”