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Key points All wetland ecosystems provide valuable services to local people and influence global carbon budgets; climate delimits four major ecosystems: arctic and subpolar marshes, temperate marshes, subtropical tidal wetlands and tropical mangrove swamps; wetlands worldwide have specialized plant forms adapted to physical extremes of soil salinity, instability and low oxygen; global biogeographic studies are the tools of wetlands biodiversity studies; primary regional differences in species composition reflect ancient paleogeographic changes; plate tectonics and icesheets isolated tropical ‘Old World’ from ‘New World’ biological provinces; coastal wetlands are azonal vegetation types highly influenced by soil conditions; differences in temperature and precipitation regimes shift the ecosystem boundaries north or south on different coasts of continents; seasonal variations in temperature–precipitation conditions drive subregional soil water salinity differences. In this chapter, general distinctions (both physical and biological features) of major latitudinal and climatic zones are outlined, so the reader can appreciate the broad similarities and dramatic differences in coastal wetlands across the globe (Chapters 7 to 11). We also look at the phytogeographical variations found on different coasts of the same continent and explain why the tropical floras of Atlantic and Pacific regions often are different, even within the same latitudinal range. Climate zones and coastal wetland ecosystems On a worldwide basis, there are four broad latitudinal zones of tidal wetlands (Figure 1.1). These world coastal wetland zones are: arctic and subpolar marshes; temperate zone marshes; subtropical marshes and mangroves; and tropical mangrove swamps. Each of these major ecosystems comprises a set of biological components interacting with their physical environment and providing characteristic wetland services (Figure 6.1) These services are defined by the Ramsar Convention as ‘the benefits people obtain from ecosystems, including provisions (food and water), regulating functions (buffering from floods and storms), nutrient cycling, and cultural needs (recreation, spiritual, and esthetic qualities)’. The vital services for human wellbeing include water purification and nitrate detoxification, climate regulation through sequestering and releasing of carbon in the biosphere, and mitigation of climate-driven sea level rise and storminess, which can result in erosion and devastating coastal floods (Millennium Ecosystem Assessment, 2005). Barbier et al . (2011) provide further details of the quality of estuarine and coastal ecosystem services and they estimate the financial losses to be expected from elimination of these services.

Salt marshes and mangrove forests, the intertidal wetlands of the world's coastlines, provide key ecological services to all areas of the globe. This cutting-edge, richly illustrated book introduces the essential elements of coastal wetlands and their applications. The book opens by introducing coastal oceanography, the physical features of wetlands, their ecology, and human impacts upon them, giving all students the necessary background for wetlands studies. It then presents detailed case studies from around the world with extensive illustrations, supplying a wider, global-scale picture of wetlands geomorphology and biodiversity. The final chapters discuss some unique applications of coastal wetlands, including geological monitoring, uses in biotechnology and agriculture, and various experimental mesocosms. This is ideal as supplementary reading to support students on a wide range of earth and life science courses, from environmental science, ecology and palaeoecology to geomorphology and geography. It will also be a valuable interdisciplinary reference for researchers.

Key points Africa’s pantropical location bridges Atlantic and Indian Ocean mangrove forests; microtides support extensive estuarine and lagoonal wetlands on low coastal plains; population growth drives wetlands degradation and escalates mangrove loss from global warming and sea level rise; now many African countries are conserving and restoring mangroves; the case history for the Gambia River, Africa’s longest estuary, illustrates problems of protecting mangroves for services to local peoples; the Nile Delta on the world’s longest river records near-disappearance of the wetlands over the past ~2000 years; in South Africa, a 220 km-long UNESCO World Heritage Site spanning St. Lucia Bay (iSisangaliso) marks growing awareness of estuarine values and conservation needs; smaller East African sites have escaped major changes and new studies show caution is needed when interpreting wetland changes from grey mangrove pollen archives. Location and biodiversity: introduction to Africa as a pantropical bridge The continent of Africa effectively is a link between the New World continents of North and South America (Chapters 7–8) and the Old World regions of Europe and Asia (Chapter 10), with its southern satellites, Australia and New Zealand (Chapter 11). The African continent spans the Equator roughly equally north and south (36° N to ~35° S), covering warm- temperate and tropical regions, but not extending into any cool climate or polar region (Figure 9.1). Most of Africa lies in the Afrotropical biodiversity region of the Ramsar Convention (1977). However, the West Coast wetlands border the Atlantic–East Pacific biogeographical region, while the East Coast wetlands border the Indian Ocean and belong to the Indo-West Pacific region. Hence, Africa, the least industrially developed continent in the world, is a transition zone between the long-settled Old World and the rapidly settled and exploited New World.

Key points Arctic wetlands are especially susceptible to damage from climate warming impacts, including permafrost melting, erosion and storm surges; subarctic wetlands are shaped by freeze–thaw cycles and overgrazing by waterfowl; West Coast earthquakes, tsunamis and glacier surges are added stressors in subarctic marshes; temperate marshes of the mountainous West Coast are in isolated valleys, sometimes disconnected from tidal exchange; temperate East Coast marshes are extensive, but altered by farming, frequent hurricanes and ‘nor’easter’ storms; Bay of Fundy megatidal marshes sequester much carbon despite erosion by massive winter ice blocks; subtropical wetlands of Florida and Mexico have shrubby mangroves fringed by brackish water swamp cedars or desert palms and cactus scrub; microtidal Mississippi Delta marshes include floating vegetation islands; tropical mangroves have a high diversity of tall trees and shrubs, particularly in Central America. Arctic Coast: Mackenzie Delta region of the Beaufort Sea The Arctic is warming faster than any other region on Earth, bringing dramatic reductions in sea ice extent, altered weather, and thawing permafrost. Implications of these changes include rapid coastal erosion. . . and unpredictable impacts on subsistence activities and critical social needs. (Clement et al ., 2013, in a report to the President.) Arctic salt marshes are literally few and far between (Figure 1.1), occupying scattered segments of the 25 000 km-long Russian coastline (Lantuit et al ., 2012; Sergienko, 2013), but covering only about 60 km 2 of the Canadian Arctic Islands and small parts of the Arctic shores of Canada and Alaska (Mendelssohn and McKee, 2000; Martini et al ., 2009; Jorgenson, 2011). However, there is a growing interest in their ecology and geological history because of their increased contributions to atmospheric greenhouse gases as the permafrost melts (see Section 5.4), and because they occupy deltas and estuaries where gas and oil exploration and shipping terminals are rapidly changing the landscape. Types of possible impacts are outlined in Chapter 5, but here we present selected examples to demonstrate the magnitude of the unfolding events.

Foraminifera and thecamoebians are highly sensitive to environmental stress (natural or anthropogenic). This feature means that they can be used to biologically characterize a variety of freshwater and coastal marine environments. Due to their small size and hard shells, large quantities are also found fossilised in core samples, making them ideal for reconstructing past environmental conditions. This volume covers the specific environmental applications of these organisms and contains an introduction to the subject, detailed descriptions of methods and techniques and case studies. Written for non-specialists, this book will appeal to resource managers and consultants in the public and private sector who routinely work on coastal environmental problems. The book will also serve as a supplementary text for graduate students in many courses on environmental monitoring, ecological baseline studies and environmental science.

A glossary and some basic taxonomy on all of the species used in this book have been provided, as an appendix, for those readers who want to go a step further. The bibliography is also in the appendix and includes all the text references as well as those only in the taxonomy section of the appendix; this should provide a good literature base for further study. A variety of applications have been shown here, such as: Climatic (including sea-level) Pollution impact, monitoring, mitigation Seismic activity “fingerprints” Sediment transport phenomena (tracers) Storm activity tracers Paleoproductivity indicators Classification and characterisation of estuaries Freshwater–marine transitions There are also remarks on several other subjects. Biostratigraphy, which is the most widely known of all microfossil applications, has been excluded as it was felt that it has been already documented in great detail elsewhere; the type of applications discussed in this book represent the future of micropaleontology and will likely be the most often used in the coming decades. It is clear that there are almost as many applications for microfossils as there are environmental problems. The authors have discussed a few examples derived from their own experience, but new types of problems arise almost daily. The readers of this book should consider these examples as just that – examples – whereas the techniques discussed in the book can be applied to any type of problem that may be encountered in aquatic environments.