Coasts and their Varied Nature

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Coasts and their Varied Nature

• Daniel Suman

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What is the Coast?

• The coastal zone is that physical space composed
  of both land and sea that each impact the other.
• Shorelines are dynamic features constantly
  affected by erosion and accretion.
• We can classify shorelines by their different
  geomorphologies, wave energies, grain sizes, and
  vegetation.

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Rocky Coasts and Bluffs

• High energy shorelines
• High scenic value
• Important sediment sources

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Muddy Coasts

• Fine sediments found in inter-tidal areas
• Important sites for shellfish and seabirds
  feeding areas
• Nutrient traps

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Beaches and Sandy Shorelines

• Dynamic habitats susceptible to erosion and
  deposition
• Unconsolidated sand extends from the upper berm
  to the low tide line.

• Complex inter-tidal ecological communities
• Important sites for nesting and reproduction of
  sea turtles and sea birds

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Dunes

• Dynamic deposits of sand landward of the active
  beach created by wind and waves
• Their sand reserves help protect against waves
  and storms.

• Dune vegetation traps grains of sand.
• Preservation of this ecosystem is of great
  importance.

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Barrier Islands

• Dynamic and mobile
• Barrier islands respond to changes in sea level,
  wave energy, currents, and sediment sources.
• These landforms are the product of erosion and
  deposition.
• Wetlands on the interior portion and beaches on
  the ocean front.
• Important for coastal protection
• High scenic value

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Coastal Lagoons

• Semi-enclosed ,shallow shoreline water bodies
• Little freshwater input
• Coastal lagoons comprise about 15 of the
  worlds shoreline.
• Important in the life cycles of many species of
  fish and mollusks
• High biological productivity
• They export nutrients to coastal waters.
• important habitat for avifauna

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Mangroves

• A dozen species of trees that are capable of
  growing in saline and inter-tidal conditions.
• 24 million hectares in tropical and subtropical
  countries
• High ecological value
• Mangrove leaf litter is important as a source
  of organic matter for coastal waters.
• Mangroves create a physical habitat for many
  species.
• important for shoreline stabilization
• Millions of people depend of the resources that
  mangroves offer.

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Coastal Wetlands

• Assimilate nutrients
• Protect the shoreline and stabilize sediments
• Provide habitat for many species of fauna
• Serve as nursery habitat for many species of
  fish and shellfish

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Estuaries

• Semi-enclosed water bodies with permanent
  connection to the sea
• Mixing zone of freshwater from rivers and
  seawater
• Variable salinities
• High levels of biological productivity
• Export nutrients to coastal waters

• Important habitat values for many species of
  avifauna and fish
• Preferred sites for many human settlements

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Seagrass Beds

• Considered one of the most productive ecosystems
• Provide food and protection for many species of
  fish and mollusks
• Tolerate a wide range of salinities
• Seagrass beds may be an ecological connection
  between mangroves and coral reefs.
• Seagrass roots stabilize fine sediments.

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Coral Reefs

• Tropical ecosystems based on the calcium
  carbonate skeletons built by colonies of marine
  polyps that maintain a symbiotic relationship
  with zooxanthellae algae.
• Centers of high biological diversity and
  exceptional scenic value in tropical environments
• Their faunal biodiversity is equivalent to that
  of tropical rainforests.
• They require transparent waters and good water
  quality.
• High biological productivity based on rapid and
  highly efficient nutrient recycling

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Coastal Islands

• High scenic values
• Variety of habitats
• Oceanic islands may display high indices of
  endemic species.

• Their fragility demands a special management
  regime.
• They are particularly susceptible to human
  impacts.

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Conclusions

• Ocean shorelines present a variety of habitats
  that are of great importance for biological
  communities.
• Moreover, they offer many services for the
  ecosystem and human societies.
• Given their sensitivity and the important
  services they offer, shorelines deserve
  protection and special management regimes.