6 Key excerpts on "Coastlines"

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  eBook - ePub

  Marine Conservation Ecology

  • John Roff, John Roff(Authors)
  • 2013(Publication Date)
  • Routledge

    (Publisher)

  Figure 11.1 . However, there is still little agreement as to where the coastal zone even begins or ends. Some definitions of the coast: ‘The general area between land and sea’, or coastal zone: ‘The interface between land and water’, are too vague. Other definitions are too inclusive: ‘The regions of the continental shelves up to and including the watersheds whose drainage influences the region.’ The last definition would encompass most of the neritic zone and indeed much of the terrestrial environment.

  There is an obvious need for clear operational definitions, because the coastal zone is where humans most strongly interact with the oceans. The Encyclopedia of Earth gives the following definition:

  The coastal ocean is the portion of the global ocean where physical, biological and biogeochemical processes are directly affected by land. It is either defined as the part of the global ocean covering the continental shelf or the continental margin. The coastal zone usually includes the coastal ocean as well as the portion of the land adjacent to the coast that influences coastal waters. It can readily be appreciated that none of these concepts has a clear operational definition.

  Source: Adapted from Ray and McCormick-Ray (2004) and University of Liverpool Encyclopedia of Earth

  Figure 11.1 Showing various definitions and extents of the coastal realm and coastal zone

  Again, by following this definition, the coastal zone would seem to include the entire continental shelf and any land (all of any island, and most of any continental land mass) that drains into the oceans.

  More realistically from an ecological perspective, and more restrictively, the coastal zone might be defined by: seaward – the extent of the fringing communities (i.e. the depth limit of the benthic euphotic zone, some 30–50m in temperate waters); and landward – by the extent of beaches, cliffs and headlands (i.e. a terrestrial morphological limit), and by wetlands associated with bays and estuaries to the null zone or ‘zero’ salinity point (i.e. a marine influence limit). It is perhaps easier to define the limits of the sea on the land than vice versa, but these suggested limits would define the major types of influences (especially trophic and energetic) within the zone. Seaward of this zone lies the neritic province and then the open ocean. Landward of this zone lies the terrestrial environment and freshwater ecosystems. In this chapter, we shall adopt this approximate definition of the coastal zone.

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  Coastal Landscapes of the Mesolithic

  Human Engagement with the Coast from the Atlantic to the Baltic Sea

  • Almut Schülke, Almut Schülke(Authors)
  • 2020(Publication Date)
  • Routledge

    (Publisher)

  Figure 1.1 ).

  Figure 1.1  

  The coastal areas between the Atlantic Ocean and the Baltic Sea. The areas dealt with in this book are marked with their chapter number: 2: Jutland (Denmark); 3, 8, 11, 13, 15: southeastern Norway and the Oslo fjord region (Norway); 4: Ireland; 5: Latvia; 6: central Norway; 7: western Scotland; 9: western France; 10: western Norway; 12: the Baltic Sea area (Denmark, northeastern Germany, Poland, Lithuania, Estonia, eastern Sweden); 14: southern Norway; 16: Lolland (Denmark). Illustration: A. Schülke.

  Though connected, these seas are different in character, across space and time, with differing environments and temporalities, due to their different geological, geographical, oceanographic and climatic conditions and developments. Different types of land meet different kinds of seas with varying resources. These shorelines, as a junction between fast and fluid, wet and dry, warm and cold, salty and brackish and so forth, have many different facets and were prioritized and utilized differently at different times. The varying character of coastal zones across geographic regions, their formation and human use through time have had an impact on research traditions and methods, which responded differently to the prehistoric remains preserved in the different areas. As we will see, they create interesting tensions between research landscapes in the different regions.

  The notion ‘landscape’ is complex, and can have many meanings and connotations (Bender 1993; Thomas 2001; David et al. 2014). It can denote a specific geographic area with specific topographic, climatic, environmental and cultural characteristics in the sense of a surface. Or it can be understood more in the sense of a ‘container’, in which cultural and natural characteristics merge with, for example, human actions, reactions and memories. But it can also be applied to denote a relationship between a contemplator and a subject – in the sense of a (world-)view or a concept of understanding surroundings, comprising humans and non-humans (Thomas 2001; Schülke 2016). Either way, the term ‘landscape’ denotes a ‘section’, either as a spatial section and thus a delimited area, or as a culturally/individually defined understanding of a certain surrounding. In the latter sense, ‘landscape’ applies both to past and present situations and understandings. It encompasses the relationship of people to the coast in the Mesolithic period as well as in our, archaeological, contemporary approaches to it. Thus, the main title of this volume Coastal Landscapes of the Mesolithic

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  Introduction to Coastal Processes and Geomorphology

  • Gerd Masselink, Michael Hughes, Jasper Knight(Authors)
  • 2014(Publication Date)
  • Routledge

    (Publisher)

  CHAPTER 1

  COASTAL SYSTEMS

   

  AIMS This chapter outlines how the coastal zone can be defined and discusses the properties and characteristics of systems, highlighting the importance of sedimentary processes and concepts such as self-organisation. Consideration of systems is useful because it provides a framework by which the dynamic behaviour of geomorphological processes and landforms can be understood.

  1.1

  Introduction

  This book is about coastal processes and geomorphology. The spatial boundaries of the coastal zone as considered in this book are defined in Figure 1.1 and follow the definitions set out by Inman and Brush (1973). The upper and lower boundaries correspond to the elevational range over which coastal processes have operated during the Quaternary period, and include the coastal plain, the shoreface and the continental shelf. During the Quaternary (from 2.6 million years ago until present), sea level fluctuated over up to 135 m vertically due to expansion and contraction of ice sheets and warming and cooling of the oceans. The landward limit of the coastal system therefore includes the coastal depositional and marine erosion surfaces formed when sea level was high (at or just above its present-day position) during global warm periods. The lowest sea levels, during global cold periods, placed coastal processes close to the edge of the continental shelf. The seaward limit of the coastal system is therefore defined by the continental shelf break, which typically occurs in water depths of 100–200 m. Changes in global climate during the Quaternary markedly shifted the position of the coastal zone, changing coastal geography particularly in areas with extensive shelves (Case Study 1.1 ). Many of today’s coastal landscapes reflect their Quaternary (and older) geological inheritance, and are responding dynamically to human activity in the coastal zone and ongoing global warming. Having defined the spatial boundaries of the topic of this book, we now need to indicate the time scale we are interested in. Cowell and Thom (1994) group the time scales over which coastal processes operate into four overlapping classes (Figure 1.3

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  Influences of Geographic Environment

  On the Basis of Ratzel's System of Anthropo-Geography

  • Ellen Churchill Semple(Author)
  • 2005(Publication Date)
  • Perlego

    (Publisher)

  Chapter VII—Geographical Boundaries

  The boundary zone in nature.

  Nature abhors fixed boundary lines and sudden transitions; all her forces combine against them. Everywhere she keeps her borders melting, wavering, advancing, retreating. If by some cataclysm sharp lines of demarcation are drawn, she straightway begins to blur them by creating intermediate forms, and thus establishes the boundary zone which characterizes the inanimate and animate world. A stratum of limestone or sandstone, when brought into contact with a glowing mass of igneous rock, undergoes various changes due to the penetrating heat of the volcanic outflow, so that its surface is metamorphosed as far as that heat reaches. The granite cliff slowly deposits at its base a rock-waste slope to soften the sudden transition from its perpendicular surface to the level plain at its feet. The line where a land-born river meets the sea tends to become a sandbar or a delta, created by the river-borne silt and the wash of the waves, a form intermediate between land and sea, bearing the stamp of each, fluid in its outlines, ever growing by the persistent accumulation of mud, though ever subject to inundation and destruction by the waters which made it. The alluvial coastal hems that edge all shallow seas are such border zones, reflecting in their flat, low surfaces the dead level of the ocean, in their composition the solid substance of the land; but in the miniature waves imprinted on the sands and the billows of heaped-up boulders, the master workman of the deep leaves his mark. [See map page 243.]

  Under examination, even our familiar term coastline proves to be only an abstraction with no corresponding reality in nature. Everywhere, whether on margin of lake or gulf, the actual phenomenon is a coast zone, alternately covered and abandoned by the waters, varying in width from a few inches to a few miles, according to the slope of the land, the range of the tide and the direction of the wind. It has one breadth at the minimum or neap tide, but increases often two or three fold at spring tide, when the distance between ebb and flood is at its maximum. At the mouth of Cook's Inlet on the southern Alaskan coast, where the range of tides is only eight feet, the zone is comparatively narrow, but widens rapidly towards the head of the inlet, where the tide rises twenty-three feet above the ebb line, and even to sixty-five feet under the influence of a heavy southwest storm. On flat coasts we are familiar with the wide frontier of salt marshes, that witness the border warfare of land and sea, alternate invasion and retreat. In low-shored estuaries like those of northern Brittany and northwestern Alaska, this amphibian girdle of the land expands to a width of four miles, while on precipitous coasts of tideless sea basins it contracts to a few inches. Hence this boundary zone changes with every impulse of the mobile sea and with every varying configuration of the shore. Movement and external conditions are the factors in its creation. They make something that is only partially akin to the two contiguous forms. Here on their outer margins land and ocean compromise their physical differences, and this by a law which runs through animate and inanimate nature. Wherever one body moves in constant contact with another, it is subjected to modifying influences which differentiate its periphery from its interior, lend it a transitional character, make of it a penumbra between light and shadow. The modifying process goes on persistently with varying force, and creates a shifting, changing border zone which, from its nature, cannot be delimited. For convenience' sake, we adopt the abstraction of a boundary line; but the reality behind this abstraction is the important thing in anthropo-geography.

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  The Geography of Tourism and Recreation

  Environment, Place and Space

  • C. Michael Hall, Stephen J. Page(Authors)
  • 2014(Publication Date)
  • Routledge

    (Publisher)

  The environment for coastal leisure pursuits has seen the geographer make a number of influential contributions from a range of perspectives. In the early analysis of the coastline for tourism and recreation, Cosgrove and Jackson (1972) identified the vital characteristic which makes the coast a major focal point for geographical analysis: it is a zonal resource, with activities concentrated at specific places, making management a key issue in time and space (Jennings 2006).Although the coast may have a number of different resource designations (e.g. Heritage Coastline and Area of Outstanding Natural Beauty in England and Wales), the impacts of tourism and recreation are multifaceted. In the wide-ranging study by the German Federal Agency for Nature Conservation (1997), the dominant coastline regions globally were the Mediterranean, the Caribbean, the Gulf of Mexico, the Indian Ocean islands, Australasia and the Pacific islands. In this context, the coastal resource is a global environmental issue which is complex, diverse and not simply reduced to beach resorts, as the discussion has alluded to so far. (See Visser and Njunga’s (1992) examination of the Kenyan coastline, where the ecological diversity in the coastal environment comprises coral reefs, sea grass and seaweed beds, mangrove forests, sand dunes and inland tropical forests.) According to the German Federal Agency for Nature Conservation (1997), coastal tourism environments may be categorised as follows:

  • oceanic islands;
  • coral reefs;
  • offshore waters;
  • mangroves;
  • near-coastal wetlands;
  • sandy beaches;
  • coastal dunes.

  The environments under the greatest recreational and tourism pressure are sandy beaches, followed by coastal dunes (see Nordstom et al. 2000 for a review of management practices to restore dunes). Within a European context, the principal erosion and sedimentation processes affecting coastal environments are related to natural processes, including:

  • wave and tidal action;
  • geomorphological factors (e.g. rivers which impact upon the river mouth and deltas);
  • meteorological factors (e.g. wind and storms);
  • changes in sea level;
  • geological processes (e.g. seismic and volcanic activity).

  In addition, the European coastline is also subjected to a great number of environmental stresses, to the point where some researchers consider it to be under the greatest pressure of any coastal environment globally (German Federal Agency for Nature Conservation 1997; Hall 2006c). For example, Jiménez et al. (2011) found that 72 per cent of Catalan beaches in Spain were experiencing an average rate of erosion of 1 m a year, a feature also observed in other studies of beach erosion (e.g. Phillips and House 2009). Indeed, El Mrini et

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  Encyclopedia of Soil Science

  • Rattan Lal(Author)
  • 2017(Publication Date)
  • CRC Press

    (Publisher)

  Fig. 1 ). It is utterly dependent upon where you happen to be standing. There is a huge difference between “what the eye can comprehend” (see) from a mountain top vs. the view from a coastal plain marsh. This perspective depends exclusively upon your field of view. It encompasses everything, and yet only, what you happen to see (doesn’t address things out-of-view).

  2.  Explicit Geomorphic context—e.g., mountains (any mountains) vs. plains (any plains): “Landscape—a broad or unique land area comprised of an assemblage or collection of natural landforms that define a general geomorphic form or setting (e.g., mountain range, lake plain, river valley, etc.). Landforms within a landscape share spatially associated formational processes but can vary in details and age.”[ 2 ] This context recognizes landform groups that are spatially associated in a unique, recognizable pattern (clustered, oriented, and arranged) indicating a common link (Fig. 2 ). The link(s) may be similar topography (elevation and relief), composition (bedrock or sediment types), structure (tectonic, crustal deformations), surficial modification (erosional or depositional alterations), etc. and are tangibly different from adjoining landform groups. If landscape subtypes (e.g., different types of mountains) are recognized, the emphasis is on specific geologic or geomorphic attributes (e.g., fault-block mountains vs. volcanic mountains) rather than differences in climate, vegetation, or geography (e.g., the Organ Mountains vs. the Cascade Mountains). A list of common landscapes is shown in Table 1 .

  3.  Physiographic context: Landscape—a collection or group of individual landforms that are spatially associated in a unique, recognizable pattern (clustered, oriented, and arranged) indicating common links. The links are not restricted to geomorphic and geologic parameters but may also include geography (where on a continent), native plant communities (desert vs. savannah), dominant cropping or management practices, or some combination of these. If subtypes of a physiographically based landscape are recognized (e.g., different types of mountains), the emphasis is on differences in geography, climate, vegetation or geography, dominant land use practices,[ 4 ] or plant communities, not just geologic or geomorphic attributes. For example, interest has grown in ecosystem or “ecoregions” basis[ 5 , 6 ]

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