Preface

There are increasing environmental concerns about the current status of the world’s oceans. The rapid development of industrial zones and growth of human population in coastal areas have led to exploitation of marine resources resulting in chemical pollution from industry, domestic wastewater intrusion, invasion of non-native species, toxic algal bloom, and microbial pathogens. On the other hand, earth’s oceans offer abundant food resources, easy shipping, and coastal living. In this book, the experts from different countries in Asia, Europe, and America give their overviews and opinions about the current status of marine pollution, environmental impacts, and possible remedies.

Introductory Chapter 1 highlights the overall theme of this book: the importance of oceans in the 21^st century. This chapter orderly presents an overview of pollution dynamics including inorganic pollutants (heavy metals, metalloids), organic pollutants (POPs-persistent organic pollutants, PAHs-polycyclic aromatic hydrocarbons, and PCBs-polychlorinated biphenyls), microplastics, and algal blooms in the marine environment. The second section specifically introduces the negative impacts of marine pollution and assessment methods to highlight the toxicity of marine pollutants. The last section of Chapter 1 is an overview of various remedial techniques, such as bioremediation, phytoremediation, and the challenges related to marine pollution. Chapter 2 describes common sampling procedures for the most diverse and abundant marine organisms that comprise ecosystem components under the Essential Ocean Variables (EOVs), such as phytoplankton, zooplankton, and fish. In this framework, biodiversity is assessed based on the status of ecosystem components, including phytoplankton biomass and diversity, zooplankton biomass and diversity, fish abundance and distribution, as well as marine turtle, bird and mammal abundance and distribution.

Chapters 3 & 4 highlight the important reactions of metals and non-metals with inorganic and organic constituents in marine water and sediments. In addition to these reactions, Chapter 3 also covers biokinetic aspects of two major marine environmental problems: eutrophication and the release of organotin compounds and copper from antifouling paints used on ships’ hulls, as an example of the effects of uncontrolled introductions of metals and non-metals on marine ecosystems. Chapter 4 highlights natural and anthropogenic sources of metals and non-metals, as well as their toxicity and accumulation in different marine organisms. Chapter 5 discusses pollution dynamics of organic contaminants and associated impacts in marine ecosystems. These contaminants include persistent organic pollutants (POPs), such as pesticides, brominated flame retardants, perfluoroalkyl compounds, fluorotelomer alcohols, perfluoroalkyl sulfonic acids (PFSAs), perfluorocarboxylic acids (PFCAs), fluorotelomer carboxylic acids, fluorotelomer sulfonic acids, and fluorinated polymers. Apart from POPs, microplastics and accidental oil spills are also highlighted in terms of their growing concern in oceanic gyres. Chapter 6 explores monitoring of organic pollutants in the marine ecosystem, including fate, distribution, and behavior of PCBs, as well as uptake of organic contaminants/PCBs by marine organisms.

Chapter 7 describes pollution dynamics along the Pakistan coast with special reference of nutrient pollution. In this Chapter, the magnitude of pollution (organic and inorganic) in coastal environments of Pakistan is discussed including plastic pollution, and enrichment of macro-nutrients in coastal waters leading to the explosion in frequency of harmful algal blooms. Chapter 8 explores ecotoxicology of heavy metals in marine fish. The authors review the occurrence and chemistry of heavy metals in the marine environment, as well as the bioaccumulation and toxicity of heavy metals in marine fish. Chapter 8 also summarizes the public health risks due to the consumption of heavy metals’ contaminated fish. Chapter 9 highlights the effects of microplastic on the marine ecosystem. Further, several aspects related to research gaps for the management of microplastic waste are proposed. Chapter 10 explores methods to measure toxicity in flora and fauna exposed to different categories of marine pollutants, their sources, various exposure routes, and associated toxicological impacts on marine organisms. Chapter 11 covers the topic of chemical toxicity screening by using marine medaka (O. melastigma) as a model system. This chapter provides the recent research progress in the toxicological impacts and responsive biomarker of O. melastigma caused by various marine pollutants, such as heavy metals, endocrine disruptors, and organic pollutants.

Chapter 12 reviews the problems of invasive species in Andaman and Nicobar Islands, Andaman Sea, India. Chapter 13 highlights the problems of dispersal of invasive species through marine ecosystems with a special focus on the case study of five invasive species and associated problems. Chapter 14 describes the effects of the disturbing unique island biodiversity of marine protected areas linked with the environmental changes influenced by anthropogenic activities, overexploitation of resources, and the habitat loss due to developmental activities and natural change in climate. Chapter 15 presents information on monitoring environmental indicators and bacterial pathogens in aquaculture practices impacted the Muthupettai Mangrove Ecosystem, Tamil Nadu, India. This chapter, a research article instead of a review, reports on the vulnerability of the mangrove ecosystems after continuous discharges of untreated aquaculture effluents have caused water quality to deteriorate so far that physiochemical parameters and bacterial pathogens highly exceed WHO, EU, and CPCB standard permissible limits.

Chapter 16 highlights the vast potential of marine microbes (bacteria and fungi) for their application in bioremediation of heavy metals. This chapter also discusses the specific factors influencing heavy metal bioremediation including biotic and abiotic factors. Chapter 17 focuses on bioremediation of low and high-molecular-weight polycyclic aromatic hydrocarbons (PAHs) in the marine environment through bacterial and fungal strains (lignolytic fungi and non-lignolytic fungi). Further, recent advancements in applications of genomics, proteomics and metabolomics technologies for in-depth investigation of microbial communities involved in PAHs remediation are summarized. Chapter 18 provides final thoughts and concluding remarks.

This book contains the latest progress in the theoretical background of marine pollutants, occurrence, distribution, risk assessment, and the bioremediation in the marine environment, which will be of specific interests for academic scientists, students, and government officials to develop background knowledge of marine pollution based multidisciplinary research.