Regional Studies in Marine Science 36 (2020) 101299 Contents lists available at ScienceDirect Regional Studies in Marine Science journal homepage: www.elsevier.com/locate/rsma Nutrient properties of tidal-borne alluvial sediments from a tropical mangrove ecosystem Abu Hena Mustafa Kamal a,∗ , Mohammed Muzammel Hoque b , Mohd Hanafi Idris a , Md. Masum Billah c , Nurul Ulfah Karim a , Md Khurshid Alam Bhuiyan d,∗ a Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Terengganu Darul Iman, Malaysia b Integrating Community Based Adaptation into Afforestation and Reforestation (ICBA-AR) Programmes in Bangladesh, UNDP, Bangladesh c The United Graduate School of Agriculture Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0056, Japan d Department of Physical Chemistry, Faculty of Marine and Environmental Sciences, University of Cádiz, Puerto Real 11510, Cádiz, Spain article info Article history: Received 11 June 2019 Received in revised form 14 April 2020 Accepted 15 April 2020 Available online 18 April 2020 Keywords: Tidal-borne alluvial sediments Productivity Nutrients Tropical mangrove Rhizophora apiculata Xylocarpus granatum abstract Mangroves are inundated through tidal action, which mobilizes a large quantity of suspended and dissolved particles, including both decomposed mangrove and terrigenous materials. Sediments brought in by tidal water and trapped by mangrove roots contribute to the productivity of coastal, tropical mangrove ecosystems. They play an important role in the nutrient cycling of these ecosystems. However, there is limited information on sediment properties, inclusive of nutrients levels in tidal- borne sediments affecting mangrove ecosystems. Selected properties of sediment, including cation exchange capacity (CEC), texture, organic matter (OM) content, organic carbon (OC) content, and nutrient content (C, N, S, P, K, Ca and Mg) were studied, in a seasonal pattern, in tidal-borne sediment from Sibuti estuary mangrove. Sediment showed a high proportion of sand (range: 60%–65%) with high mean values of CEC 17 cmol/kg, a sediment OM content of 15%, and OC content of 13%. The mean average content of C was 15%, and mean concentrations of N, S, P, K, Ca, Mg and Na were 12, 10, 2, 3, 34, 18 and 16 (mg/kg), respectively. Significant positive relationships were found among nutrient concentrations in sediment and nutrient concentrations in leaf, stipule, flower, propagule, stem, bark, and root of both Rhizophora apiculata (Blume) and Xylocarpus granatum (Koenig) trees and their saplings. Seedlings are indicative of the growth, health, and productivity of the mangrove ecosystem, and are largely dependent on the phenomenon of nutritive aspects of tidal-borne sediments. The results of this study provide baseline information on the roles of nutrient productivity of a less disturbed tropical mangrove forest, adjacent to the South China Sea. © 2020 Elsevier B.V. All rights reserved. 1. Introduction Mangroves are a highly productive ecosystem that typically lies between land and sea in the tropical and sub-tropical regions (Almahasheer et al., 2017; Pastor-Guzman et al., 2018). They are frequently inundated by tidal action, and they exhibit the exchange of a large amount of nutrients in the land-sea inter- faces (Cummings and Shah, 2018). They grow in intertidal areas and are recognized globally as a dynamic ecosystem in terms of economic, ecological, and environmental aspects. Out of their many characteristics, the most remarkable is to trap, retain and accumulate suspended sediments (Hoque et al., 2015a; Kamal et al., 2017; Almahasheer et al., 2017). The unique and complex structure within the mangrove ecosystem includes prop roots, ∗ Corresponding authors. E-mail addresses: a.hena@umt.edu.my (A.H. Mustafa Kamal), mohammed.bhuiyan@alum.uca.es (M.K.A. Bhuiyan). knee roots, and pneumatophores that reduce the velocity of tidal flow, thus trapping sediments, which eventually play a key role in the land-building process (Krauss et al., 2014; Zhang et al., 2015). Suspended sediment is the carrier of nutrients and trace elements (Feng et al., 2017; Castro-Rodríguez et al., 2018) that may have a significant impact on the productivity of mangroves. Sediment flow also plays an essential ecological role in coastal and in estuarine ecosystems by storing or releasing a variety of compounds either from mangroves to the aquatic ecosystem, or vice versa (Castro-Rodríguez et al., 2018). Mangroves also produce bulk litter matrices composed of ma- terials such as leaves, stipule, flower, propagule, twigs, bark, stem and root, which are decomposed gradually in the surround- ing environment. Indeed, the decomposition of litter matrices in mangrove systems naturally releases nutrients and organic matter in the coastal areas (Abu Hena et al., 2020). Mangrove sediments are generally anoxic and acidic. As a surficial layer in nature, the condition of sediment changes with its depth. A vast https://doi.org/10.1016/j.rsma.2020.101299 2352-4855/© 2020 Elsevier B.V. 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