Remotely Sensing the Source and Transport of Marine Plastic Debris in Bay Islands of Honduras (Caribbean Sea)

Aikaterini Kikaki,Dionysios E Raitsos,Konstantinos Karantzalos,Caroline A Power

doi:10.3390/rs12111727

Aikaterini Kikaki, Dionysios E Raitsos + Show 2 more

Open Access

https://doi.org/10.3390/rs12111727

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Abstract

Plastic debris in the global ocean is considered an important issue with severe implications for human health and marine ecosystems. Here, we exploited high-resolution multispectral satellite observations over the Bay Islands and Gulf of Honduras, for the period 2014-2019, to investigate the capability of satellite sensors in detecting marine plastic debris. We verified findings with in situ data, recorded the spectral characteristics of floating plastic litter, and identified plastic debris trajectories and sources. The results showed that plastic debris originating from Guatemala’s and Honduras’ rivers (such as Motagua, Ulua, Cangrejal, Tinto and Aguan) ends up in the Caribbean Sea, mainly during the period of August to March, which includes the main rainfall season. The detected spatial trajectories indicated that floating plastic debris travels with an average speed of 6 km d−1, following primarily a southwest (SW) to northeast (NE) direction, driven by the prevailing sea surface currents. Based on several satellite observations, there is no indication of a specific accumulation point, since plastic debris is dispersed by the dynamic circulation in the broader region. Our findings provide evidence that satellite remote sensing is a valuable, cost-effective tool for monitoring the sources and pathways of plastic debris in marine ecosystems, and thus could eventually support management strategies in the global ocean.

Highlights

With evidence of a significant cumulative increase over the last 60 years, plastic debris in marine environments is currently considered one of the most topical issues in marine pollution due to its potential impact on human and ecosystem health [1,2]
Microplastics from various sources have been found on seafloor sediments [7], in sea surface microlayer in estuarine systems [8] and in arctic waters [9], indicating that marine debris is abundant across all marine systems
Plastic debris was occasionally detected in fronts, which were identified in satellite data through blue color differentiation due to discrete water masses (e.g., Figure 2c,d)

Summary

Introduction

With evidence of a significant cumulative increase over the last 60 years, plastic debris in marine environments is currently considered one of the most topical issues in marine pollution due to its potential impact on human and ecosystem health [1,2]. Plastic debris events have been reported even in deep-sea organisms (such as Cnidaria, Echinodermata and Arthropoda) in the equatorial mid-Atlantic and the SW Indian ocean, mainly due to their exposure to human waste and ingestion of plastic microfibres [6]. Microplastics from various sources have been found on seafloor sediments [7], in sea surface microlayer in estuarine systems [8] and in arctic waters [9], indicating that marine debris is abundant across all marine systems

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