Marine Pollution Bulletin 201 (2024) 116184 0025-326X/© 2024 Published by Elsevier Ltd. Baseline Ecological ramifcations of marine debris in mangrove ecosystems: Estimation of substrate coverage and physical effects of marine debris on mangrove ecosystem in Negombo Lagoon, Sri Lanka H.P.S. Jayapala a , H.B. Jayasiri a , R.R.M.K. Ranatunga b , I.J.J.U.N. Perera c , B.K. A. Bellanthudawa c, * a Ocean University of Sri Lanka, Colombo 15, Sri Lanka b Department of Zoology, Faculty of Applied Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka c Department of Agricultural Engineering and Environmental Technology, Faculty of Agriculture, University of Ruhuna, Matara 81100, Sri Lanka A R T I C L E INFO Keywords: Mangroves Debris cover Negombo Lagoon Physical impacts Seedling Root damages ABSTRACT The adverse environmental impacts on mangrove ecosystems due to anthropogenic marine debris contamination have attracted public attention not only in Sri Lanka but worldwide. Therefore, quantifcation of marine debris in sensitive ecosystems like mangroves is critical to assess the impacts on ecosystem vitality and services. We conducted this study to assess the abundance and density of marine debris in Negombo lagoon, Western Prov- ince, Sri Lanka. We selected two sites (n = 2) using the purposive sampling technique. Marine debris cover and concentration were calculated to explore the extent of pollution from marine debris. The fndings revealed that 9.83 ± 1.05 % of the substrate of the mangrove ecosystem is covered by debris. Nine types of marine debris were recorded, and a higher abundance belonged to single-use plastic items. A signifcantly higher debris cover was found in Kadolkele (18.80 ± 1.74 %, n = 120) than in Molekadolwetiya (0.85 ± 0.03 %, n = 120) (One-way ANOVA, p < 0.05). The study indicated that the mangroves in lagoon are highly polluted with marine debris and act as “litter catchers.” Correlation coeffcient analysis was used to fnd the impact of debris cover on physical damage to roots, seedlings, and undergrowth vegetation. Correlation analysis revealed that physical damage to seedlings and branches/barks have a positive correlation with debris cover. To conserve these valuable coastal habitats in Negombo lagoon, it is recommended to take remedial measures to reduce arriving debris loads and to remove the debris present in mangroves. 1. Introduction Marine ecosystems are signifcantly affected by marine debris, defned as any enduring, manufactured, or processed solid substance that is discarded, disposed of, or left abandoned in the marine and coastal environments (Bat et al., 2022). Marine debris category en- compasses materials like plastics, wood, metals, glass, rubber, clothing, and paper, which people have intentionally or unintentionally deposited into water bodies, including oceans, rivers, lakes, or coastal beaches (Bat et al., 2022; Martin et al., 2019). Marine debris can be found all over the world on beaches in the pelagic and benthic environments (Agamuthu et al., 2019). Consequently, the deposition of debris along marine water bodies and subsequent accumulation on seashores has evolved into a signifcant issue affecting both developed and developing countries. This poses threats to marine ecosystems and human health (Agamuthu et al., 2019). Mangroves are recognized as one of the most crucial coastal wetland habitats owing to their elevated productivity and substantial contribu- tion to ecosystem services, including storm protection and carbon stor- age (Friess et al., 2020). Despite their pivotal role, these ecosystems face signifcant threats, such as hydrological alteration, clearance due to land reclamation, conversion into aquaculture ponds, and pollution from anthropogenic debris (Lugendo et al., 2006). Further, the complex aboveground root systems of mangroves play a crucial role by dissi- pating and absorbing wave energy (Kathiresan, 2021; Asari et al., 2021), altering boundary layer dynamics, and simultaneously serving as eff- cient traps for foating debris that enters the system (Kesavan et al., 2021; Luo et al., 2021). Martin et al. (2019) reported that mangrove * Corresponding author. E-mail address: aravindabellanthudawa@gmail.com (B.K.A. Bellanthudawa). Contents lists available at ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul https://doi.org/10.1016/j.marpolbul.2024.116184 Received 6 January 2024; Received in revised form 16 February 2024; Accepted 18 February 2024