The important role of Turbidity Maximum Zone in sedimentary dynamic of estuarine mangrove swamp

Abstract

Sedimentation is a key process affecting wetland sustainability and carbon burial flux. In context of sea level rise, climate change and human activities, further understanding about the sedimentary dynamic in wetland is critical in predicting the landscape evolution or the change in carbon burial flux. In this study, based on the field hydrological observation in a mangrove system in the Nanliu River estuary, we found the net flux of suspended sediment to mangrove is 39−72 kg/m in tidal cycles with Turbidity Maximum Zone (TMZ) forming in surface layer and only is 9−18 kg/m in tidal cycles without TMZ. The higher net flux of suspended sediment to mangrove in tidal cycles with TMZ forming in surface layer is attributed to high SSC in rising tide and intense flocculation in mangrove. The significant discrepancy in sedimentation rate in the mangrove patches also can be explained by the probability of TMZ forming in the surface layer of estuary. In future, rapid sea level rising may lead to the change of TMZ pattern in estuary, which will result in non-negligible variation in sedimentation rate in wetlands. According to the present data of sedimentation rate in wetlands, the fragility of wetlands in river estuary may be miscalculated.

Graphical abstract

Keywords

mangrove wetland / sedimentation / Turbidity Maximum Zone / Nanliu River

References

[1] Adame F, Neil D, Wright S F, Lovelock C E (2010). Sedimentation within and among mangrove forests along a gradient of geomorphological settings.Estuar Coast Shelf Sci, 86(1): 21–30

[2] Alongi D M (2008). Mangrove forest: resilience, protection from tsunamis, and responses to global climate change.Estuar Coast Shelf Sci, 76(1): 1–13

[3] Alongi D M (2014). Carbon cycling and storage in mangrove forests.Annu Rev Mar Sci, 6(1): 195–219

[4] Alongi D M, Pfitzner J, Trott L A, Tirendi F, Dixon P, Klumpp D W (2005). Rapid sediment accumulation and microbial mineralization in forests of the mangrove Kandelia candel in the Jiulongjiang Estuary, China.Estuar Coast Shelf Sci, 63(4): 605–618

[5] Bouillon S, Borges A V, Castañeda-Moya E, Diele K, Dittmar T, Duke N C, Kristensen E, Lee S Y, Marchand C, Middelburg J J, Rivera-Monroy V H, Smith T J, Twilley R R (2008). Mangrove production and carbon sinks: a revision of global budget estimates.Global Biogeochem Cycles, 22(2): 1–12

[6] Bryce S, Larcombe P, Ridd P V (2003). Hydrodynamic and geomorphological controls on suspended sediment transport in mangrove creek systems, a case study: Cocoa Creek, Townsville, Australia.Estuar Coast Shelf Sci, 56(3–4): 415–431

[7] Clough B (1998). Mangrove forest productivity and biomass accumulation in Hinchlnbrook channel.Mangroves Salt Marshes, 2(4): 191–198

[8] Festa J F, Hansen D V (1978). Turbidity Maximum in partially mixed estuaries: a two dimensional numerical modal.Estuar Coast Mar Sci, 7(4): 347–359

[9] França M C, Francisquini M I, Cohen M C L, Pessenda L C R, Rossetti D F, Guimaraes J T F, Smith C B (2012). The last mangroves of Marajó Island -Eastern Amazon: impact of climate and/or-relative sea-level changes.Rev Palaeobot Palynol, 187: 50–65

[10] Furukawa K, Wolanski E, Mueller H (1997). Currents and sediment transport in mangrove forests.Estuar Coast Shelf Sci, 44(3): 301–310

[11] Geyer W R (1993). The importance of suppression of turbulence by stratification on the estuary turbidity maximum.Estuaries, 16(1): 113–125

[12] Kathiresan K, Rajendran N (2005). Coastal mangrove forests mitigated tsunami.Estuar Coast Shelf Sci, 65(3): 601–606

[13] Kitheka J U, Ongwenyi G S, Mavuti K M (2003). Fluxes and exchange of suspended sediment in tidal inlets draining a degraded mangrove forest in Kenya.Estuar Coast Shelf Sci, 56(3–4): 655–667

[14] Long C, Dai Z, Wang R, Lou Y, Zhou X, Li S, Nie Y (2022). Dynamic changes in mangroves of the largest delta in northern Beibu Gulf, China: reasons and causes.For Ecol Manage, 504: 119855

[15] Lovelock C E, Cahoon D R, Friess D A, Guntenspergen GR, Krauss KW, Reef R, Rogers K, Saunders M L, Sidik F, Swales A, Saintilan N, Thuyen L X, Triet T (2015). The vulnerability of Indo-Pacific mangrove forests to sea-level rise.Nature, 526: 559–563

[16] Mazda Y, Kobashi D, Okada S (2005). Tidal-Scale Hydrodynamics within Mangrove Swamps.Wetlands Ecology Manage, 13: 647–655

[17] Nagelkerken I, Blaber S J M, Bouillon S, Green P, Haywood M, Kirton L G, Meynecke J O, Pawlik J, Penrose H M, Sasekumar A, Somerfield P J (2008). The habitat function of mangroves for terrestrial and marine fauna: a review.Aquat Bot, 89(2): 155–185

[18] Nerem R S, Beckley B D, Fasullo J T, Hamlington B D, Masters D, Mitchum G T (2018). Climate-change-driven accelerated sea-level rise detected in the altimeter era.Proc Natl Acad Sci USA, 115(9): 2022–2025

[19] Van Santen P, Augustinus P G E F, Janssen-Stelder B M, Quartel S, Tri N H (2007). Sedimentation in an estuarine mangrove system.J Asian Earth Sci, 29(4): 566–575

[20] Wolanski E, Gibbs R, Spagnol S, King B, Brunskill G (1998). Inorganic sediment budget in the mangrove-fringed Fly River delta, Papua New Guinea.Mangroves Salt Marshes, 2(2): 85–98

[21] Zhou X, Dai Z, Pang W, Wang J, Long C (2022). Wave attenuation over mangroves in the Nanliu Delta, China.Front Mar Sci, 9: 1–13

Acknowledgments

We are grateful for the help of Mr. Yancheng Tao, Mr. Lianghua Pan and Dr. Xiao Chen in the field investigations. This study was financed by the National Natural Science Foundation of China (Grant No. 41930537) and the Major Project of Guangxi Science and Technology (No. AA23023016) .

Competing interests

The authors declare that they have no competing interests.

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2023 Higher Education Press

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