Biotechnological Utilization of Mangrove Resources

Mangroves are typically tropical coastal ecosystems found in the inter-tidal zones of river deltas and back water areas. They represent highly dynamic and fragile ecosystems, yet they are the most productive and biologically diversified habitats of various life forms including plants, animals and microorganisms. Mangroves are a resource of many different products, including; microorganisms that harbor a diverse group of industrially important enzymes, antibiotics, therapeutic proteins and vaccines; timber resistant to rot and insects; and medicinal plants.

Divided into three main parts, Biotechnological Utilization of Mangrove Resources first provides a broad introduction into mangrove ecology. Subsequent chapters discuss the biodiversity of mangroves, including the diverse nature of the organisms within the mangroves themselves. The final part pays special attention to biotechnological utilization of mangroves. Topics such as antimicrobial activity of mangrove-derived products, anti-oxidant activity of mangrove derived products and pharmaceutical applications, are covered in detail.

Biotechnological Utilization of Mangrove Resources brings the latest research and technologies in mangrove biology into one platform, providing readers with an up-to-date view on the area. This would serve as an excellent reference book for researchers and students in the field of marine biology especially interested in mangrove ecosystems.

• Highlights the diversity of different life forms in the mangrove ecosystem, including the importance of mangroves and mangrove-derived products.
• Focuses on biotechnological utilization of mangrove resources such as antimicrobial and antioxidant properties of microorganisms, and industrial and pharmaceutical applications
• Discusses the different modern tools and techniques used for the study of mangrove resources

• Language: English
• Publisher: Academic Press
• Release date: Apr 17, 2020
• ISBN: 9780128223826

Book preview

India

Preface

Mangroves are typically tropical coastal ecosystems found in the intertidal zones of river deltas and backwater areas. They represent highly dynamic and fragile ecosystems, yet they are the most productive and biologically diversified habitats of various life forms including plants, animals, and microorganisms. Mangrove ecosystems provide a unique and valuable range of resources and services. Mangrove wetlands are multiple-use ecosystems that provide protective, productive, and economic benefits to coastal communities. Mangroves are capable of growing in hostile environmental conditions and are biochemically unique, producing a wide array of natural products with unique bioactivities. These natural products possess active metabolites with novel phytochemicals belonging to diverse chemical classes such as alkaloids, phenols, steroids, terpenoids, tannins, and the like.

Biotechnological Utilization of Mangrove Resource is an edited book of 22 chapters that provides a unique, single source of valuable information on the diversity of life forms in the mangrove ecosystem, including the importance of the mangroves and mangrove-derived products. Special emphasis has been placed on the biotechnological potential of mangrove resources, such as the plants, animals, and microbes and their possible exploitation for the benefit of humankind. In addition, the book also discusses the modern tools and techniques used in the study of mangrove resources.

In a nutshell, the book intends to bring the latest research, advancements, and technologies in the area of mangrove biology onto one platform, providing readers with an up-to-date view on the subject. The book serves as an excellent reference resource for teachers, scientists, researchers, and students in the fields of life sciences, biotechnology, and marine biology, especially those who undertake studies or research on mangrove ecosystems.

We are highly grateful to all the authors who have made their valuable contributions to this book. We wish to thank Andrea Dulberger, Editorial Project Manager, and her whole team at Elsevier for their help and support in finalizing the edited volume. Special thanks go to our valued fellow colleagues and university authorities, for their kind support and constant encouragement throughout the task. Finally, we express our gratitude to our family members and friends for their support and cooperation.

Editors

Jayanta Kumar Patra,

Rashmi Ranjan Mishra

Hrudayanath Thatoi

Chapter 1

Potential contribution of multifunctional mangrove resources and its conservation

Priyanka Kumari, Jitendra Kumar Singh and Bhawana Pathak,    School of Environment and Sustainable Development, Central University of Gujarat, Gandhinagar, India

Abstract

Mangrove forests serve as interfaces between the land and sea. They serve as most productive and good bioindicators of the environmental quality and health of any coastal ecosystem and as long-term carbon sinks for carbon storing or sequestration. Mangroves are seen in 123 tropical and subtropical countries, and 73 species are recognized as true mangroves. The world mangrove distribution totals 150,000 km², of which Southeast Asia basically covers the highest percentage at 33.5%, followed by South America covering 15.7%, North and Central America at 14.7%, and West and Central Africa 13.2%. In last 25 years a 20% decline has occurred, mainly due to conversion and coastal development, which is three to four times faster than the decline in terrestrial forest. From combating climate change to protecting fisheries and coastlines around the world, mangroves are among the most vital and interconnected of environments. More proportionally than any other type of forest, mangroves sequester up to five times more carbon per hectare than tropical rainforests. Community-based approaches for their restoration and sustainable management are dynamic options for improving the livelihood of mangrove forest ecosystems and reducing their vulnerability.

Keywords

Tropical; community; livelihood; sustainable; mangroves

1.1 Introduction

The term mangrove, as alluded to by Tomlinson (1986), includes the trees and forested bushes that occupy the spaces between tropical tidal wood populaces and the mangrove networks themselves. Mangroves are the most productive natural biomes in the world, are defenders of their own young stock, and structure the most substantial biomass (Wong and Tam, 1995). Mangroves have a distinctive salt-tolerant natural forest framework, in addition to providing a broad array of ecological and business benefits and amalgamating other shoreline and marine conditions.

Mangroves, also called halophytes, are salt-tolerant forest ecosystems and among the most particularly beneficial beachfront living spaces on the planet. Mangroves are frequently called tidal timberlands, beachfront forests, or maritime rainforests. Mangrove trees are characterized by stilt roots, knee roots, pneumatophores, salt-discharging organs (hydathodes), coriaceous leaves (with sonic xerophytic structures), vivipary—all empowering the natural product to stay lightweight and practical for extensive stretches and to mature in delicate mud and under differing states of saltiness.

1.2 Classification of mangroves

Mangroves can be arranged into five classifications depending on their area settings and circulation:

1. onshore mangroves: mangroves developing on the shore;

2. estuarine mangroves: mangroves found on estuaries of streams;

3. deltaic mangroves: mangroves developing on deltas of streams;

4. mangroves of the inlet; and

5. mangroves on seaward islands.

When all is said and done, the mangroves of India can be isolated into two sections: mangroves of the west coast and mangroves of the east coast. Three types of mangroves are present in India:

1. deltaic,

2. backwater estuarine, and

3. insular.

Mandal and Naskar (2008) also recognized three habitat types of Indian mangroves:

1. deltaic mangrove habitat (east coast mangrove and gulfs of Gujarat);

2. coastal mangrove habitat (west coast mangroves); and

3. island mangrove habitat (Lakshadweep, Andaman, and Nicobar Islands).

1.3 Mangroves: distribution and stature

Globally, mangroves occur in subhumid and humid areas in many countries (118–124 countries and territories) throughout world, and the mangroves that are partially protected (137,760–152,000 km²) have been the attention of many studies (Spalding et al., 2010; Giri et al., 2011). Most of the mangrove vegetation lies between 5°S and 5°N, 32°N and 38°S (Richards and Friess, 2016; Frederick et al., 2013). Out of 124 countries, 64% of the global mangrove cover is found in nine countries, whereas the remaining 36% is distributed over 115 countries.

Mangrove is found predominately in nations around and in the Indian Ocean, as shown in Figs. 1.1 and 1.2. Indonesia is home to the world’s biggest mangrove population, logging over 20% of all the mangroves on Earth. Mangrove species generally run along nearly 75% of the world’s coastlines within 25°N and 25°S (Tomlinson, 1986; Wong and Tam, 1995). Around 70 sorts of mangrove plants are found far and wide, parceled into 20 genera (Spalding et al., 2010).

Figure 1.1 Mangrove cover spreading in different nations of the worldwide.

Figure 1.2 Mangrove-dominated nations in the Indian Ocean area.

1.4 Mangrove diversity in the world

Evaluations of the quantity of mangrove species thought to exist on the planet extend from 48 to 90. Worldwide, 90 species representing mangroves were reported by Bernays and Chapman (1970); Walsh et al. (1974) reported 55 species, Wolf et al. (1977) 60 species, Saenger et al. (1983) 83 species, Chan and UNDP/UNESCO Regional Mangroves Project (1986) 65 species, Kathiresan and Bingham (2001) 65 species, and Tomlinson (1986) just 48 mangrove species [40 in the humid area of the Eastern gathering (Australia, Southeast Asia, India, Western Pacific, and East Africa) and eight genuine mangroves from the New World Tropics, or Western gathering (Atlantic South America, Florida, West Africa, Pacific North and South America and Caribbean)]. Wang et al. (2003) detailed 84 species, incorporating 12 assortments in 24 genera and 16 families, and 70 types of 16 genera were accounted for as evident mangrove. Approx 80–90 types of genuine mangrove trees/bushes and 50–60 species types of species exist in mangrove woodlands.

1.5 Distribution of Indian mangroves

In India, mangroves are found along the coastline of nine states and four union territories: Andhra Pradesh, Gujarat, West Bengal, Orissa, Andaman and Nicobar Islands, Daman and Diu, Tamil Nadu, Kerala, Karnataka, Goa, Pondicherry, Lakshadweep, and Maharashtra. Significant mangrove areas on the Indian coastline are the Sundarbans mangrove forests in West Bengal, Devi mouth, Mahanadi, and Subarnarekha; the Bhitarkanika mangrove forest in Orissa; the Pichavaram mangrove estuary; Muthupet in Tamil Nadu; Godavari and Krishna delta in Andhra Pradesh, Karwar, Coondapur; the Malpe area in Karnataka; the Bombay mangrove creeks in Maharashtra; the Cochin estuary in Kerala; the Gulf of Kutch and Gulf of Khambhat estuary in Gujarat; the Zuary estuary in Goa; the Andaman and Nicobar islands and Lakshadweep. The coastal wetlands of India cover an estimated 6750 km² and are abundantly controlled by mangrove vegetation. The evaluated region of India’s mangrove-containing wetlands is 474,000 ha, of which about 29% are lengthwise along the west coast (Arabian Sea); 13% are along the Andaman and Nicobar Islands, and the remaining 58% are along the east coast (Bay of Bengal). Thus the Indian mangroves appear in two parts along the west coast and east coast. The mangroves on the west coast are more abundant and less sensitive to prevalent conditions than are those of the east coast because of their unique geomorphology.

Mangrove environments in the Indian territories are found in three regions: the west coast (850 km²), east coast (4700 km²), and Andaman and Nicobar Islands (1190 km²). The most significant mangrove swamplands are situated along the east coast of the Indian subcontinent. Additionally, the east coast has delicate inclines with broad pads that serve as foundations for mangroves and huge, delta-shaped estuaries for the spillover and deposit of silt. In total, Indian mangroves spread over 3.1% of the full scale overall spread as well as dispersed along all the seaside states, besides affiliation locale of Lakshadweep, covering a zone of nearby 4461 km² of the 7500-km-long Indian coastline. India has the fourth largest mangrove zone on the planet, covering the long seashore coastlines of about 7516.6 km and the island areas (Wang et al., 2003), involving a mangrove front of around 6749 km². These mangrove conditions, or biomes (7°N–23°N latitude and 69°E–89.5°E longitude), contain three specific zones: on the Bay of Bengal, the east coast has a shoreline of around 2700 km; the west coast offers living spaces along a shoreline of about 3000 km; and these extend up to islands of the Arabian Sea, consisting of various districts with around 1816.6 km of coastline. In India, Maharashtra, Orissa, West Bengal, Andhra Pradesh, Kerala, Tamil Nadu, Andaman and Nicobar Islands, Goa, and Gujarat all contain mangrove forests.

Full-scale Indian mangrove forests, besides the 53% found in the Sundarbans, spread across about 78% of India’s shorelines. Other shoreline mangroves are created close to the intertidal shorelines, negligible stream openings, checked straights, and backwater districts of the west shoreline, constituting 12% of the mangrove zone of India. Finally, island mangroves are established end to end in the shallow at-risk intertidal zones of the Channel Islands, for example, in the Andaman and Nicobar Islands and Lakshadweep, which are about 16% of the overall mangrove region.

Mangrove conditions are rich in biodiversity and in the extent of faunal and floral species. They also serve as nurseries for shellfish, finfish, molluscs, and scavengers. Alongside mangrove waters are a particular type of faunal people who rely on this marine life in one way or the other. The planktonic and benthic faunal masses invite an exceptionally huge ingress of close-by creatures. The vegetation of Indian mangroves is novel and hypnotizing. In addition to the surprising estuarine crocodile (Crocodilus porosus) and the Royal Bengal Tiger, there are changing assortments of otters, monkeys, deer, wild pigs, snakes, and competing felines. The mangrove swamplands of India are reinforced by other not all that awful groups of flying creatures, both transient and tenant.

1.6 Mangrove diversity in India

In India, there are around 46 veritable mangroves (42 species and 4 regular crossbreeds), at home with 14 families and 22 genera along the coastline. Out of them, about 40 sorts of certifiable mangroves contain 14 families and 22 genera from the east coast and around 27 species, 11 families, and 16 genera from the west coast (Wang et al., 2003). In general, an excess of around 18 million hectares of mangroves are found in 112 nations and regions in tropical and subtropical locales. There are 20 minor and 34 newly discovered mangrove species sharing space with 20 genera and 11 families (Tomlinson, 1986). The diversity of South Asian and Southeast Asian mangroves include 41.4% of flora fauna diversity. Which makes these healthy and distinctive from other mangroves.

1.7 Mangrove species’ variety and exposure

In tropical regions, fauna and flora species in mangroves are especially sensitized to climate change because increased temperatures necessitate changes in the functional proportions of humidity in order to maintain their ideal temperature. The effects of latitudinal constraints for different mangroves, as well as for saline shoreline surroundings, are usually engaged by salt swampland vegetation and the more herbaceous plants in those populations; mangrove species will play a role in the moderate to extensive period, probably with the slow replacement of salt marshland plants by spare mangroves, initially of Avicennia and after that of Rhizophora (Pernetta, 1993). It is projected that if normal global rainfall occurs, then regional variations will increase (IPCC, 2001). Many species are more responsive to profligate variations due to anthropogenic activities and sea level rise, particularly Suaeda sp., Acanthus ilicifolius, Avicennia marina, and Avicennia alba, in the semiarid region in Gujarat. Which mixture of species variety may feel stress in a given zone is more predictable, mainly in the Andaman and Nicobar Islands.

1.8 Importance of mangrove ecological unit

Mangroves play different roles in the environment and afford various ecosystem utilities, such as inhibiting soil destruction, the materialization of soil, the creation of animal habitats, the auxiliary cycling of nutrients, carbon requisitioning or sequestration, and the enhancement of water quality (Moberg and Rönnbäck, 2003). Mangrove forest and wetland environments provide upward of 21 biological administrations and 45 common items (Rönnbäck, 1999). Mangroves are linked to multiple ecosystem services. These services include timber and fuel (Black et al., 2011), carbon sequestration (Komiyama et al., 2008), nutrients for marine systems (Duarte and Cebrián, 1996), and a rare habitat for terrestrial fauna (Kossin and Velden, 2004), ecologically and economically important fisheries (Laegdsgaard and Johnson, 2001; Mumby et al., 2004; Nagelkerken et al., 2008). Practically 80% of fish worldwide are somewhat reliant on mangroves (Kujoth et al., 2005; Gilman et al., 2008). Mangroves absorb 70%–90% of the strength of waves (Andrefouet et al., 2006) and filter contaminants (Harbison, 1986a,b). Mangroves offer physical security from tempest floods, twisters, and other traumatic climatic occurrences (Andrefouet et al., 2006) and the potential reduction in the end products of sea tempests, tidal waves, and tempest floods (Granek and Ruttenberg, 2007; Danielsen et al., 2005; Alongi, 2002). Mangrove habitats have a diversity-promoting function (Bennett et al., 2007), providing protection from predators and increased food availability for marine fauna (Laegdsgaard and Johnson, 2001) and acting as native species (Duke et al., 2007; Dorenbosch et al., 2004). Overall, the worldwide total estimated worth of the ecosystem services provided by mangrove forests is at least US$1.6 billion per year (Field et al., 1998; Costanza et al., 2014). The yearly market for fish from mangroves is assessed at US$7500–167,500 per km² (Carpenter et al., 2009). Mangroves assume a key job in maintaining the legitimate harmony among the abiotic and biotic parts of a marine biological system, and they have been viewed as the main essential makers of beachfront ecosystems.

1.9 Mangroves: ecologically sensitive areas

Mangroves are indigenous and most important contributors to their shoreline surroundings. They are a very interesting cluster of humid plants (shrubs and trees) that are suited to a rainy season, are compatible with the saline habitat of intertidal zones, and are exposed to highly variable physicochemical conditions of salinity, light, temperature, and flooding, all of which contribute to the vast mixture of components that describes mangrove ecosystems (Reef et al., 2010). Mangroves are commonly found in intertidal zones and are the mainstay bond between the land and aquatic biomes. Mangroves, as palm or ground fern, shrub, tree normally grow above mean sea level in the intertidal zone of estuarine margins, and the salt tolerance ecosystems: area along shorelines (Duke et al., 2007; Hamilton and Snedaker, 1984) make them uniquely endangered.

Mangroves are collections of woody halophytes (i.e., salt-tolerant plants) that are the foundational species of dense intertidal forest ecosystems occurring along subtropical coastlines and tropical creeks, lagoons, estuaries, rivers, and bays (Tomlinson, 1986; Werner and Smith, 1992) and that have enormous ecological and environmental importance. They are remarkably diverse, with unique characteristics and the most productive systems on Earth. In India, mangroves have been declared ecologically sensitive areas (ESAs) by the Indian Ministry of Environment, Forest & Climate Change (MoEFCC) since 1989 and have been clearly identified and documented in the costal regulation zone notification released in 2011 under the Environment (Protection) Act 1986. ESAs are areas that require special attention for their protection and conservation. The National Environment Policy (2006) of India also recognizes that mangroves are imperative shoreline ecological resources that offer protection from extreme weather events, that are a resource base for sustainable tourism, and that afford surroundings for marine species. Moreover, this strategy also underlines the need to mainstream the supportable control of mangroves through a comprehensive approach to consolidated shoreline region supervision.

1.10 Potential aspects of mangroves

1.10.1 Carbon sequestration in mangroves

Mangrove woods are the most carbon-rich living spaces on the globe. Besides protecting nature’s precious carbon appropriation process and providing their various advantages, mangroves supply twice the usual living biomass of tropical backwoods. As for carbon production, mangroves are normally profoundly more productive than backwoods, and their noteworthy role in dirt carbon storing in plants may be significant in the evaluation of the net essential efficiency of flora and fauna in mangroves and in related trees and plants, particularly benthic or lower microalgae. The estimation of essential carbon creation in mangrove woodlands is restricted by practical deficiencies, yet the best measures recommend that mangrove production of carbon is quicker than that of marine and other estuarine essential makers. The steady-state development stage can be drawn out in some mangrove stands and has progressively unsettling influences. The connection between the mangrove and timberland photosynthetic creation must be perpetuated, or the woodlands will be traumatized. Dangerous carbon proportions and biologically systemized stockpiling, as well as dispensed carbon as fixed by trees, must be precisely appraised in terms of the role of mangroves in the seaside and the worldwide cycle of carbon. Just as mangroves build fresh vegetation, other woody plants, regenerative organs, root tissues, stem, and branches maintain remaining tissue, stockpiling saves and gives substance to resistance. The proportion of all CO2 absorbed by mangroves comes back to the atmosphere via above- and underground means. This is just a rough gauge in the absence of observational information and the difficulty of estimating root processes and role of timbered parts. The corresponding allotment of stable carbon inside trees fluctuates with several mechanisms, such as light power, species piece, supplement and water accessibility, saltiness, tides, waves, temperature, and atmosphere. The best way to know the distribution of carbon has to do with root creation but particularly in wet soil it is hard to compute distribution of carbon.

1.11 Salt tolerance of mangrove

Salt flexibility is the limit of trees or plants to complete their whole life cycle on different substrates comprised of high centralizations of dissolvable salt. Plants or trees that are able to deal with high centralizations of rhizosphere salt are called halophytes. Dependent upon the tolerance of their salt confinement, halophytes are depicted taxonomically and morphologically as having better-than-average relative improvement rates, growing in up to half seawater and taking root in less saline domains along the periphery of nonsaline and saline upland and then adjusting to nonsaline and saline conditions. Mangroves work as facultative halophytes tolerant of both high and fluctuating saltiness, and mangrove woods overrun the coastlines of the tropical and subtropical regions of the world. In shorefront areas, mangroves offer security against tempests and separation to create wellsprings of benefits for human inhabitants.

Research on mangroves got little attention before the 20th century, aside from how soil properties influence the vegetation, species mix, and structure of mangrove timberlands. A couple of mangrove tree classifications showed that the perfect level of saltiness was 5%–25% of normal seawater (Ball, 1988a; Burchett et al., 1989; Ball and Pidsley, 1995; Downton, 1982; Clough, 1984). However, the level of saltiness that the mangrove plant can endure differs according to species (Downton, 1982). In a few animal groups, development might be influenced by either the nonappearance or the overabundance of NaCl in the substrate (Downton, 1982; Clough, 1984; Burchett et al., 1989; Ball and Pidsley, 1995). Since mangroves flora and fauna effectively live in high salt conditions, it is profitable to utilize that fact and to consider how the plant systems react and then adjust to those conditions. Mangroves develop in dirt that is pretty much wet and in water whose saltiness varies and might be as highly concentrated as unadulterated ocean water (Naidoo et al., 1997). Mangrove trees directly adjust to endure such saline ambiences with a few salt-discharging leaves and viviparous water-scattered propagules. Because of the saltiness everywhere, leaves are thicker and water economy more rigorous in mangroves (Ball, 1988a,b), and there are interspecific contrasts in saltiness resilience among mangroves trees (Ball and Pidsley, 1995), in addition to the convergence of saltiness in Avicennia and Aegiceras (Ball, 1988b; Saintilan, 1997).

1.12 Supplement take-up in mangrove

Since the dirt is unendingly waterlogged, minimal O2 is accessible. Anaerobic microbes free N2 gas, dissolvable iron, inorganic PO4²−, sulfides, and CH4, making the dirt significantly less healthful. Pneumatophores enable mangroves tree to retain gases straightforwardly from the environment, along with supplements, such as Fe, from the unhealthful topsoil. Mangroves mainly store different types of air, vapors, and gases inside their roots, preparing them for inundation during high tide.

1.13 Therapeutic estimation of mangrove plants

Mangroves are responsible for a significant part of income around the world. Within a broad time frame, mangrove trees have been essential wellsprings of common items and other items beneficial to human health, and they have an incredible potential for delivering new medications (Nascimento et al., 2000; Morales et al., 2008; Littleton et al., 2005). The humid and subhumid zones of the world are sources of bottomless verdure and herbs with undiscovered antifungal, antimicrobial, and antiviral properties. According to the World Health Organization, plants are a wellspring of aggregates that can battle infection with antimicrobial, antiviral, and antifungal concoctions (Nascimento et al., 2000; Morales et al., 2008). Furthermore, restorative solutions derived from trees have been consumed for a long time to treat human disorders and sicknesses (Littleton et al., 2005). Additionally, such derivatives are less poisonous to people and to the Earth due to the fewer contaminations accumulated during their delivery, thus avoiding significant perils to human well-being (Gazim et al., 2008). Inasmuch as a lot of the income worldwide is needed to pay for human services, the gradient of antimicrobial-resistant microorganisms is an extremely important issue in the global social insurance framework, with irresistible maladies the second most critical type of disease overall (Nascimento et al., 2000; Mojab et al., 2008). To battle such ailments, new medications must be found with fresh antimicrobial intensities (Naidoo et al., 1997). In Sri Lanka, abundant varieties of creation are available within 4000 ha of mangroves trees (Premadasa, 1996), even after considering various trees that account for various restorative offerings (Bandaranayake, 1998). Mangroves and their partner ecosystems contain organic substances with potential antiviral, antibacterial, and antifungal properties (Bandaranayake, 1995, 2002; Chandrasekaran et al., 2009). The basic employment of mangroves in bramble drugs has been evaluated by Bandaranayake (1999). These ecosystems also contain toxic natural substances, which additionally show, for example, antifungal, antibacterial, antifeedant, pesticidal, and molluscicidal properties (Kokpol et al., 1984; Chandrasekaran et al., 2009). Plants or mangrove trees are a rich source as well of triterpenes, steroids, flavonoids, saponins, tannins, and alkaloids (Agoramoorthy et al., 2007; Bandaranayake, 1995, 2002). Concentrates from some mangrove plants exhibit restorative properties, for example, anthelmintic and antibacterial (Bandaranayake, 1998). It has also been discovered that watery and ethanol concentrations of some mangrove species exhibit antimicrobial capability (Abeysinghe et al., 2000). In this manner, it might be possible, utilizing mangrove plant extracts, to control irresistible operators by means of the inhibitory impact on pathogenic microorganisms. A detailed description of mangrove plants and medicinal uses is shown in Table 1.1.

Table 1.1

1.14 Heavy metals absorption by mangroves

The sources of impurities or pollutants in coastal mangrove surroundings, including sediments and the water, may be natural and/or anthropogenic. Heavy metals in mangrove habitats are of serious environmental concern and have significant implications for coastal ecosystem health. Heavy metals are nonbiodegradable and may be bioaccumulated and biomagnified to hazardous levels via the food chain (Zhang et al., 2012). The cycling of pollutants such as heavy metals, because of their toxicity, persistence, and bioaccumulation capacity, is a severe condition that needs to be addressed in environments of mangrove classes (Pekey, 2006; Haiman et al., 2006).

Some mangrove species have developed specific adopting mechanisms to survive in despite concentrations of heavy metals, and they are consequently suitable to understanding pollution (Zaidi et al., 2014; Pinheiro et al., 2018). A number of hypertolerant mangroves take on the capability to gather high concentrations of metals in their tissues (Chinen et al., 2016). Pérez-Brocal et al. (2006) suggested that mangrove trees might be able to act as biochemical reactors due to their active role in decomposing organic matter within the sediments, thus greatly diminishing the effects of heavy metals.

1.15 Heavy metal transport, uptake, and release

The fundamental sources of metal contamination are modern effluents and squanders, urban spillover, drifting movements, horticultural pesticides overflow, residential landfills, and mining tasks (Pérez-Brocal et al., 2006; Tam and Wong, 2000; Lu et al., 2002; McNeil et al., 2005). Mangroves are regularly called tidal woodlands since they are overflowed twice a day with saline water via the approaching tides. Tidal blooming encourages trading waste, supplements, and contaminations with adjoining seawaters (Gonzalez-Mendoza et al., 2007). Substantial pollutants are moved by wind or water to waterfront zones, and they can be stored as residue. Mangroves need to productively trap suspended material from the water section (Joseph and Chandrika, 2000). Mangrove roots frequently serve as a stoppage point, hold an inordinate part of the overwhelming metals, and lessen the translocation of substantial metals to other plant parts. In living mangrove systems, metals are taken up by the roots, discharged by leaves, and sent out by debris. This enormous measure of ordinary issue containing substantial metals recognizably affects the nourishment networks of opposite seashores. Pérez-Brocal et al. (2006) proposed that mangrove trees can be considered biochemical reactors due not just to their physiological and biochemical procedures but also to their dynamic job in natural issue disintegration inside the dregs that extraordinarily impact the portability of overwhelming metals. Mangrove leaf litter can deliver back various heavy metals to the atmosphere in biologically available form, and the concentrations of the metals are much lessened and the degree of metal release from the leaf litter is very low (Furukawa et al., 1997).

1.16 Heavy metals accumulation in mangrove plants

Metal bioaccumulation by mangroves in recent year has widespread the research area. In a plant–soil framework, the solid ingestion and possession of metals by soil with the remaining collection of dirt over the assimilation of substantial metals by developing plants (Furukawa et al., 1997). Numerous mangrove plant species can develop under conditions dirtied by substantial amounts of metal and have amassing capabilities for various overwhelming metals (Table 1.2). These plants must make specific adjustments to make do: They should be metallophytes, pseudometallophytes, or hyperaccumulators. It was found that plants additionally can hypergather overwhelming heavy metals by the activity of metallothioneins and phytochelatins, shaping edifices by translocating them into vacuoles and substantial metals (Esther et al., 2013). The degrees of metal gathered in mangroves change occasionally and spatially shift with saline conditions, which may influence the take-up and conveyance of pollutions in the plant (Suresh and Ravishankar, 2004). Lacerda and Abrao (1984) proposed that the job of mangroves in holding metals depends on the timing of the plants and their biomass generation. Mangrove roots may hinder metal translocation: Higher fixations located in roots discriminated with the ethereal fragments in different plants (Lau et al., 1997). Metal fixation is known to be collected in various species and in various respects according to the seasons and encompassing conditions. MacFarlane and Burchett (2002) researched the groupings of copper (2.1–7.8 μg/g), manganese (3.9–28 μg/g), zinc (5.7–60 μg/g), cadmium (0.014–0.057 μg/g), and lead (0.018–0.038 μg/g) in the propagules of Aegiceras cornicuiatum, Sonneratia caseolaris, Ceriops tagal, Rhizophora stylosa, Bruguiera sexangula, Bruguiera gymnorrhiza, A. marina, Kandelia candel, Sonneratia applaud and A. ilicifolius mangrove species in China. Detailed descriptions of the mangrove plants used for heavy metal accumulator or phytoremediation are shown in Table 1.2.

Table 1.2

1.17 Mangrove as ecoremediation

Ecoremediation has been well thought out as a sustainable natural treatment system for contaminants present in ecosystem, and the process has been widely used for the treatment of pollutants in ecosystems. Ecoremediation is the application of science and engineering principles to improve both terrestrial and aquatic ecosystems, including water, air, and soil resources, to provide healthy air, water, and soil or land for habitation by humans and other organisms, and to remediate polluted sites to their natural states. It is a kind of biological designing, that is, the application of environmental standards to the administration of biological systems. It is the biological structuring of reasonable biological systems that incorporate human culture with its regular habitat to support both (MacFarlane and Burchett, 2002). The reclamation of overwhelmingly metal-dirtied soils by means of plants suitable to fix the toxins, the supportable administration of soil ripeness, water refinement utilizing microorganisms, and biological controls of lakes to keep stave off water eutrophication are instances, among numerous others, of environment building. Biological remediation includes the rebuilding of environments that have been significantly exhausted by human activities, for example, natural contamination and the improvement of new feasible biological systems that have both human and environmental worth. Ecoremediation innovation for waste treatment helps in ecological cleanup and monitors organic