Sedimentation and sediment geochemistry in a tropical mangrove channel meander, Sungai Kerteh, Peninsular Malaysia
|Author(s)||Shaari Hasrizal1, 2, Mohd Nasir Qatrunnada1, Pan Hui-Juan3, 4, Mohamed Che Abd Rahim5, Yusoff Abdul Hafidz6, Wan Mohd Khalik Wan Mohd Afiq1, Naim Erick2, Setiawan Riza Yuliratno7, Anthony Edward J.8, 9|
|Affiliation(s)||1 : Univ Malaysia Terengganu, Fac Sci & Marine Environm, Terengganu 21030, Malaysia.
2 : Univ Malaysia Terengganu, Inst Oceanog & Environm, Terengganu 21030, Malaysia.
3 : Natl Taiwan Ocean Univ, Inst Earth Sci, Coll Ocean Sci & Resource, Keelung, Taiwan.
4 : Natl Taiwan Ocean Univ, Coll Engn, Ctr Excellence Ocean Engn, Keelung, Taiwan.
5 : Univ Kebangsaan Malaysia, Fac Sci & Technol, Bangi 43600, Selangor, Malaysia.
6 : Univ Malaysia Kelantan, Fac Bioengn & Technol, Jeli 17600, Kelantan, Malaysia.
7 : Univ Gadjah Mada, Fac Agr, Dept Fisheries, Jl Flora Gd A4, Bulaksumur 55281, Yogyakarta, Indonesia.
8 : Aix Marseille Univ, Coll France, INRA, IRD,CEREGE,CNRS,UM 34, Aix En Provence, France.
9 : CNRS, USR LEEISA, Cayenne, French Guiana, French Guiana.
|Source||Progress In Earth And Planetary Science (2197-4284) (Springer), 2020-09 , Vol. 7 , N. 1 , P. 46 (11p.)|
|Keyword(s)||Mangrove, Tidal channel meander, Mangrove geochemistry, Mangrove sedimentation|
Tropical mangrove swamps are commonly characterized by dense networks of tidal channels that may show pronounced meandering and dendritic patterns. Channel meanders are sometimes accompanied by cut-offs, and, like classical fluvial meanders, record changes in hydrology and sedimentation over time. Channel meandering can, thus, be an important process that contributes to spatial and temporal variability in the preserved record of the sedimentology and geochemistry of mangrove sediments. The aim of this study is to highlight changes in channel meander sedimentation in response to a meander cut-off in a tropical mangrove swamp. Two short sediment cores were sampled, respectively from a point bar (core KR1, 122 cm) at the junction with the neck cut-off and inside the cut-off (core KR2, 98 cm) in the Sungai Kerteh mangroves of Peninsular Malaysia. The profile comparison was based on sediment characteristics, total organic carbon (TOC), and selected elements (Fe, Na, Mg, Mn, Ba, and Sr). A smaller standard deviation of mean grain size (MGS) was found at the point bar (4.37 +/- 0.51 phi) than in the cut-off (4.43 +/- 1.76 phi), indicating a difference in flow velocity between the two settings. In turn, these changes in grain size influence channel meander evolution via associated changes in TOC and heavy metals. In order to clarify these relationships, we used principal components analysis and factor analysis. An increased accumulation of selected elements and TOC at the cut-off site from a depth of similar to 60 cm to the core-top segment was probably associated with a slowing down of sediment settling. A higher TOC recorded in the cut-off (2.74 +/- 1.42%) compared to the point bar (1.14 +/- 0.46%) suggests a propensity for prolonged in situ accumulation of organic matter in the abandoned meander bend. This study provides grain size and sediment geochemical information that is consistent with patterns of active and inactive sedimentation in the meander bends of mangrove channels.