Carbon accumulation within anthropogenically impacted Peruvian Coastal saltmarshes

Abstract

Coastal wetlands are critical ecosystems due to the wide range of ecosystem services they provide. This study investigates the accumulation of total organic carbon (TOC) and total nitrogen (TN) in sediment cores from anthropogenically impacted saltmarsh wetlands of Puerto Viejo (PV) and Ventanilla ( () from Peru. Sediment cores, each 30 cm in length, were collected by duplicate from both sites and analyzed for TOC, TN, and stable isotopes (δ¹³C and δ¹⁵N). Sediment accumulation rates (SAR) were determined using the Constant Flux Constant Supply (CFCS) model, and carbon and nitrogen accumulation rates were subsequently calculated based on SAR and elemental concentrations. The SAR were ~ 3.4 mm yr⁻¹ in PV and ~ 3.3 mm yr⁻¹ in VEN, values lower than the global average for coastal marshes (6.0 mm yr⁻¹), yet closer to those reported for non-impacted systems (4.0 mm yr⁻¹). Beginning in the early 1990´s, anthropogenic impacts such as urban expansion and increased sewage discharge coincided with elevated TOC and TN accumulation rates within both study areas. Maximum accumulation rates for TOC and TN in PV reached 235 ± 49 g m⁻² yr⁻¹ and 28 ± 3 g m⁻² yr⁻¹, while in VEN reached 459 ± 99 g m⁻² yr⁻¹ and 23 ± 9 g m⁻² yr⁻¹, respectively. Post-1990´s, markedly lighter δ¹³C values in PV and VEN ranged in − 25.2 ± 1.6 ‰ and − 19.3 ± 3.5 ‰, respectively, indicating increased inputs of non-terrestrial material in sediments. Concurrently, elevated δ¹⁵N values in PV and VEN ranged + 11.4 ± 0.65‰ and + 7.37 ± 8.16‰, respectively, suggesting that the carbon sources were derived from a mixture of terrestrial vegetation and algae, stimulated by nutrient enrichment linked to anthropogenic activity. These findings highlight the pivotal role of coastal wetlands in accumulating carbon from both natural and anthropogenic sources, reinforcing the imperative for their conservation amid escalating global human-induced pressures.

Keywords

Coastal wetlands / Carbon accumulation / Organic matter source / Urban expansion / Anthropogenic impacts

References

[1] Abril-Hernández JM (2023) 210Pb-dating of sediments with models assuming a constant flux: CFCS, CRS, PLUM, and the novel χ-mapping. Review, performance tests, and guidelines. J Environ Radioact 268-269. https://doi.org/10.1016/j.jenvrad.2023.107248

[2] Alongi DM (2014) Carbon Cycling and Storage in Mangrove Forests. Annu Rev Mar Sci 6(Volume 6, 2014):Article Volume 6. https://doi.org/10.1146/annurev-marine-010213-135020

[3] Andrews JE, Samways G, Shimmield GB. Historical storage budgets of organic carbon, nutrient and contaminant elements in saltmarsh sediments: biogeochemical context for managed realignment, Humber Estuary, UK. Sci Total Environ, 2008, 405(1): 1

[4] Aponte H, Cano A. Estudio florístico comparativo de seis humedales de la costa central del Perú: Actualización y nuevos retos para su conservación. Revista Latinoamericana De Conservación, 2013, 3(215-27

[5] Aponte H, Gonzales S, Gomez A (2020) Impulsores de cambio en los humedales de América Latina: El caso de los humedales costeros de Lima. South Sustain 1(2):Article 2. https://doi.org/10.21142/SS-0102-2020-023

[6] Breithaupt JL, Smoak JM, Byrne RH, Waters MN, Moyer RP, Sanders CJ (2018) Avoiding timescale bias in assessments of coastal wetland vertical change. Limnol Oceanogr 63(Suppl 1):Article Suppl 1. https://doi.org/10.1002/lno.10783

[7] Callaway JC, Borgnis EL, Turner RE, Milan CS. Carbon sequestration and sediment accretion in San Francisco Bay tidal wetlands. Estuaries Coasts, 2012, 35(5): 5

[8] Chappuis E, Seriñá V, Martí E, Ballesteros E, Gacia E. Decrypting stable-isotope (δ13C and δ15N) variability in aquatic plants. Freshwater Biol, 2017, 62(1111

[9] Chmura GL, Anisfeld SC, Cahoon DR, Lynch JC (2003) Global carbon sequestration in tidal, saline wetland soils. Global Biogeochemical Cycles 17(4). https://doi.org/10.1029/2002GB001917

[10] Diebel MW, Zanden MJV. Nitrogen stable isotopes in streams: effects of agricultural sources and transformations. Ecol Appl, 2009, 19(55

[11] Duarte CM, Losada IJ, Hendriks IE, Mazarrasa I, Marbà N. The role of coastal plant communities for climate change mitigation and adaptation. Nat Clim Chang, 2013, 3: 961-968

[12] Erwin KL. Wetlands and global climate change: the role of wetland restoration in a changing world. Wetl Ecol Manage, 2009, 17(11

[13] Gomez A, Aponte H, Gonzáles S (2023) ¿Cómo proteger los humedales costeros peruanos? Una respuesta a partir de un modelo conceptual de sus impulsores de cambio. Boletín de Investigaciones Marinas y Costeras 52(2):Article 2. https://doi.org/10.25268/bimc.invemar.2023.52.2.1218

[14] Hao Q, Song Z, Zhang X, He D, Guo L, van Zwieten L, Yu C, Wang Y, Wang W, Fang Y (2024) Organic blue carbon sequestration in vegetated coastal wetlands: Processes and influencing factors. Earth Sci Rev 104853. https://doi.org/10.1016/j.earscirev.2024.104853

[15] Hewitt DE, Smith TM, Raoult V, Taylor MD, Gaston TF. Stable isotopes reveal the importance of saltmarsh-derived nutrition for two exploited penaeid prawn species in a seagrass dominated system. Estuar Coast Shelf Sci, 2020, 236: 106622

[16] Kendall C, Elliott EM, Wankel SD (2007) Tracing Anthropogenic Inputs of Nitrogen to Ecosystems. En Stable Isotopes in Ecology and Environmental Science (pp. 375–449). John Wiley & Sons, Ltd. https://doi.org/10.1002/9780470691854.ch12

[17] Kennedy P, Kennedy H, Papadimitriou S. The effect of acidification on the determination of organic carbon, total nitrogen and their stable isotopic composition in algae and marine sediments. Rapid Commun Mass Spectrom, 2005, 19(81063-1068

[18] Kurniawansyah A, Susiloningtyas D, Manessa MDM. Mangrove ecosystem management in Indonesia: review, limitation, gap, and knowledge. Maritime Technology and Research, 2023, 5(3262310

[19] La Torre MI, Aponte H. Flora vascular y vegetación de los humedales de Puerto Viejo. Rev Peru Biol, 2009, 16(22

[20] Li X, Bellerby R, Craft C, Widney SE. Coastal wetland loss, consequences, and challenges for restoration. Anthropocene Coasts, 2018, 1: 1-15

[21] Mathew V, Agarwala N. Impact of climate change on coastal communities and security. Marit Technol Res, 2025, 7(4277917

[22] Mitsch WJ, Mander Ü (2018) Wetlands and carbon revisited. J Ecol Eng 114:1–6. https://doi.org/10.1016/j.ecoleng.2017.12.027

[23] Moschella P (2012) Variación y protección de humedales costeros frente a procesos de urbanización: Casos Ventanilla y Puerto Viejo [Tesis para optar el título de Magister en Desarrollo Ambiental, Pontificia Universidad Católica del Perú]. https://tesis.pucp.edu.pe/items/dbcd050b-0d67-49db-a746-124fe46e46d7

[24] Nittrouer CA, DeMaster DJ, McKee BA, Cutshall NH, Larsen IL. The effect of sediment mixing on Pb-210 accumulation rates for the Washington continental shelf. Mar Geol, 1984, 54(33

[25] Ouyang X, Lee SY. Updated estimates of carbon accumulation rates in coastal marsh sediments. Biogeosciences, 2014, 11(185057-5071

[26] Paredes I, Ramírez F, G. Forero M, Green AJ. Stable isotopes in helophytes reflect anthropogenic nitrogen pollution in entry streams at the Doñana World Heritage Site. Ecol Indic, 2019, 97: 130-140

[27] Peng Y, Liu D, Wang Y, Richard P, Keesing JK. Analyzing biases of nitrogen contents and δ15N values arising from acidified marine sediments with different CaCO3 concentrations. Acta Oceanol Sin, 2018, 37(8): 1-5

[28] Pérez A, Escobedo R, Castro R, Jesus R, Cardich J, Romero P, Salas-Gismondi R, Ochoa D, Aponte H, Sanders CJ, Carré M. Carbon and nutrient burial within Peruvian coastal marsh driven by anthropogenic activities. Mar Pollut Bull, 2022, 181: 113948

[29] Pérez A, Gutiérrez D, Saldarriaga M. Hydrological controls on the biogeochemical dynamics in a Peruvian mangrove forest. Hydrobiologia, 2017, 803: 69-86

[30] Pérez A, Libardoni BG, Sanders CJ. Factors influencing organic carbon accumulation in mangrove ecosystems. Biol Lett, 2018, 14(10): 20180237

[31] Pérez A, Machado W, Gutiérrez D, Saldarriaga MS, Sanders CJ. Shrimp farming influence on carbon and nutrient accumulation within Peruvian mangroves sediments. Estuar Coast Shelf Sci, 2020, 243: 106879

[32] Pérez A, Machado W, Sanders CJ (2021) Anthropogenic and environmental influences on nutrient accumulation in mangrove sediments. Mar Pollut Bull 165:112174. https://doi.org/10.1016/j.marpolbul.2021.112174

[33] Peterson BJ, Howarth RW, Garritt RH. Multiple stable isotopes used to trace the flow of organic matter in estuarine food webs. Science, 1985, 227(46924692

[34] Ramirez DW, Aponte H. Por qué los Humedales de Puerto Viejo perdieron su protección legal: Analizando los motivos. Rev Peru Biol, 2018, 25(1049-054

[35] Rivera G, Gonzales S, Aponte H. Wetlands of the South American Pacific coast: a bibliometric analysis. Wetl Ecol Manage, 2022, 30: 869-877

[36] Roulet NT. Peatlands, carbon storage, greenhouse gases, and the Kyoto Protocol: prospects and significance for Canada. Wetlands, 2000, 20(4605-615

[37] Sanchez-Cabeza JA, y Ruiz-Fernández AC (2012) 210Pb sediment radiochronology: An integrated formulation and classification of dating models. Geochimica et Cosmochimica Acta 82(1):183–200. https://doi.org/10.1016/j.gca.2010.12.024

[38] Sanders CJ, Eyre BD, Santos IR, Machado W, Luiz-Silva W, Smoak JM, Breithaupt JL, Ketterer ME, Sanders L, Marotta H, Silva-Filho E. Elevated rates of organic carbon, nitrogen, and phosphorus accumulation in a highly impacted mangrove wetland. Geophys Res Lett, 2014, 41(7): 2475-2480

[39] Sapkota Y, White JR. Carbon offset market methodologies applicable for coastal wetland restoration and conservation in the United States: a review. Sci Total Environ, 2020, 701: 134497

[40] Schlacher TA, Connolly RM, Kurle C. Effects of acid treatment on carbon and nitrogen stable isotope ratios in ecological samples: a review and synthesis. Methods Ecol Evol, 2014, 5(6541-550

[41] Soto-Ceferino R, Aponte H, López-Guiop I, Delgado-Galván C, Apeño A (2025) Geografías en Conflicto: Superposición de actividades extractivas en los humedales peruanos. Tecnología y ciencias del agua 16(4). https://doi.org/10.24850/j-tyca-16-3-9

[42] Theuerkauf EJ, Stephens JD, Ridge JT, Fodrie FJ, Rodriguez AB. Carbon export from fringing saltmarsh shoreline erosion overwhelms carbon storage across a critical width threshold. Estuar Coast Shelf Sci, 2015, 164: 367-378

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