Ecosystem Sustainability for Coastal Wetlands

Impact of land cover and land use changes on nutrient stoichiometry in coastal estuarine wetland soils

The quantity and relative supply of nutrients in soils have important implications for global biogeochemical cycles [1]. Vital nutrients in soils, viz. Carbon (C), Nitrogen (N), Phosphorus (P), and Potassium (K) and their biogeochemical cycles are closely intertwined with the ecological structure, processes, and functions in soils [2]. Study finds that anthropogenic interventions can alter strongly the soil elemental pools by changing nutrient inputs-outputs [3]. Still less information is available till date for elemental stoichiometric patterns, their ratio and shifts due to the impact of land cover and land use changes on coastal wetland soils. Coastal estuarine wetlands are located in the transition zones between land and marine systems [4]. Both the terrestrial and marine ecosystems influence greatly estuarine wetlands in terms of their nutrient biogeochemical cycling, element transport, exchange, circulation, patterns, and dynamics [5].

Coastal wetlands often have high productivity, high nutrient loading rates, and dynamic oxidation-reduction shifts that facilitate nutrient processing, resulting into nutrients dynamics and associated biogeochemical functioning, leading to highly variable elemental ratios [6,7]. Anthropogenic inputs of N, P and K increased in last few decades and caused an anomaly in C, N, P, K relative stoichiometry that might increase in near future [8-10]. Therefore, in-depth study of the C, N, P and K concentrations and stoichiometry in coastal wetland soils is useful for determining the cycles and balances of the elements and the overall functioning of the soil system.

Impacts of land cover changes and land use practices on soil organic C (SOC) pools in the tropical and subtropical coastal wetland ecosystems

Coastal wetlands in the tropical and subtropical regions have been regarded as one of the most important C reservoirs among global ecosystems [11,12]. The SOC pools and its dynamics are complex and heterogeneous, consisting of active/labile, slow, and passive pools that vary in turnover time, as well as their effects on the rate of organic matter decomposition, energy transfer, and nutrient cycling [13,14]. The amount and composition of SOC can vary with land use practices and land cover changes in coastal wetland ecosystems [15,16]. Wetlands have considerable C stocks because of the low decomposition rates under the predominantly anaerobic environments [17,18]. However, the drainage of wetlands and/or conversion of land cover for human development could accelerate the decomposition of SOC significantly, resulting in the release of gaseous C into the atmosphere, significantly affecting the global C budget [11,19]. Coastal tidal inundation in conjunction with nutrient influx can affect the soil C pools [20,21]. Till date relatively little is known regarding such influence on the composition of SOC pools and overall dynamics in coastal wetland soils [22,23]. Studies examining the dominant controls of the relative magnitudes of different SOC pools would help improve future wetland management in enhancing the capability of coastal wetland soils in long-term C storage.

Studies investigating afore-mentioned topical aspects and outcomes thus generated will help to manage the coastal estuarine wetlands under tidal exposure through devising proper scientific intervention strategies and adoption of pertinent conservation processes and rehabilitation programme in a holistic way minimizing adverse environmental effects under changing climatic conditions.

1. Wang W, Sardans J, Zeng C, Zhong C, Li Y, et al. (2014) Responses of soil nutrient concentrations and stoichiometry to different human land uses in a subtropical tidal wetland. Geoderma 232-234: 459‐
2. (2014) Advances in nutrient dynamics in soil-plant atmosphere system for improving nutrient use efficiency. Indian Council of Agricultural Research, New Delhi, India.
3. FAO and ITPS (2015) Status of the World’s soil resources: Main report. Food and Agriculture Organization of the United Nations and Intergovernmental Technical Panel on Soils, Rome, Italy.
4. Levin LA, Donald FB, Alan C, Cliff D, Christer E, et al. (2001) The function of marine critical transition zones and the importance of sediment biodiversity. Ecosystems 4(5): 430-451.
5. Regnier P, Arndt S, Goossens N, Volta C, Laruelle GG, et al. (2013) Modelling estuarine biogeochemical dynamics: From the local to the global scale. Aquat Geochem 19(5-6): 591-626.
6. US EPA (2008) Methods for evaluating wetland condition: Biogeochemical indicators. US Environmental Protection Agency, Washington, USA, EPA-822-R-08-022.
7. Ruth R, Ilka CF, Catherine EL (2010) Nutrition of mangroves. Tree Physiology 30(9): 1148-1160.
8. Qaswar M, Ahmed W, Jing H, Hongzhu F, Xiaojun S, et al. (2019) Soil carbon(C), Nitrogen(N) and Phosphorus(P) stoichiometry drives phosphorus lability in paddy soil under long-term fertilization: A fractionation and path analysis study. PLoS One 14(6): e0218195.
9. Glibert PM (2020) Harmful algae at the complex nexus of eutrophication and climate change. Harmful Algae 91: 101583.
10. IPCC (2019) Technical summary. In: Pörtner HO, Roberts DC, (Eds.). IPCC special report on the ocean and cryosphere in a changing climate.
11. Moomaw WR, Chmura GL, Davies GT (2018) Wetlands in a changing climate: Science, policy and management. Wetlands 38 183-205.
12. Mitra, Sudip, Wassmann, Reiner, Vlek, Paul, et al. (2003) Global inventory of wetlands and their role in the carbon cycle. University of Bonn, Center for Development Research (ZEF), Discussion Papers.
13. Sahoo UK, Singh SL, Gogoi A, Kenye A, Sahoo SS, et al. (2019) Active and passive soil organic carbon pools as affected by different land use types in Mizoram, Northeast India. PLoS One 14(7): e0219969.
14. Sanchez P (2019) Organic carbon. In properties and management of soils in the tropics, Cambridge University Press, USA, pp. 259-306.
15. Zhang X, Liu L, Henebry GM (2019) Impacts of land cover and land use change on long-term trend of land surface phenology: A case study in agricultural ecosystems. Environmental Research Letters (ERL).
16. Jinquan Ai, Zhang C, Chen L, Dajun Li (2020) Mapping annual land use and land cover changes in the yangtze estuary region using an object-based classification framework and landsat time series data. Sustainability 12: 659.
17. Were D, Kansiime F, Fetahi T (2019) Carbon sequestration by wetlands: A critical review of enhancement measures for climate change mitigation. Earth Syst Environ 3: 327-340.
18. Middleton BA (2020) Trends of litter decomposition and soil organic matter stocks across forested swamp environments of the southeastern US. PLoS One 15(1): e0226998.
19. Rajib K, Indranil D, Debashis D, Rakshit A (2016) Potential effects of climate change on soil properties: A review. Science International 4: 51-73.
20. Chambers LG, Steinmuller HE, Breithaupt JL (2019) Toward a mechanistic understanding of "peat collapse" and its potential contribution to coastal wetland loss. Ecology 100(7): e02720.
21. Daniel MA (2018) Impact of global change on nutrient dynamics in mangrove forests. Forests 9(10): 596.
22. Jackson RB, Lajtha K, Susan EC, Hugelius G, Kramer M, et al. (2017) The ecology of soil carbon: Pools, vulnerabilities, and biotic and abiotic controls. Annual Review of Ecology, Evolution, and Systematics 48: 419-445.
23. Yang RM ( 2019) Interacting effects of plant invasion, climate, and soils on soil organic carbon storage in coastal wetlands. Journal of Geophysical Research: Biogeosciences 124(8): 2554-2564.

© 2020 Suvadip Neogi. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and build upon your work non-commercially.