Test Design Lighthouse


Life on the coasts

The world's coastlines measure around one million kilometres in total, making them the most widely distributed type of landscape on earth. Though depicted as thin lines on a world map, in nature they are transitional zones between land and sea which vary considerably in breadth. The ebb and flood currents, the incline of the coastal shelf, rocky or sandy substrates, ice scour, wave erosion and, not least, plants and animals all exert a visible influence on the shape of the coastline.

 

The influence of surf and wind-borne sea-spray extends over a broad coastal zone, both on and off shore.

Coastal biotic communities have adapted in a huge variety of ways to the special natural conditions, like the constantly changing water levels and atmospheric conditions governed by the tides. But the force of the waves, and sudden and extreme fluctuations in temperature, salinity and light all pose special challenges to life on the seashore. Moreover, the water is often very cloudy, with particles stirred up from the sea bed or washed from dry land into the sea.

 

As protection against drying up at low tide, or pounding by the forceful waves, nature has developed effective survival strategies. But for all their fascination, coastal zones are more than just a habitat for special flora and fauna – they are also an attraction for a growing number of people worldwide. So conflicts are the order of the day. Coasts are used intensively for fishing and collecting, for holidaymaking, and for discharging wastewater. Now and then, a tanker breaks up on the cliffs. The coasts are the marine ecosystems most severely disturbed by humans.

 

 

Tidal flats: Amphibious habitat on soft ground

Wherever tidal variations in sea level are greater than a metre, a broad margin develops on flat coasts, which is alternately submerged under seawater for hours at a time and then left to dry for a similar period ... more

Rock on the shore

Nobody would suspect the special species diversity and population density to be found on coasts with soft, sandy or muddy soils, like the tidal flats. Not so on hard rocks, because anyone strolling along a rocky coast as the tide recedes will be ... more

Kelp beds and sea grass meadows

As on land, primary production by photosynthesis is the driving force that sustains life in the sea. But unlike on land, where vegetation dominates and trees grow to enormous heights, the primary producers in the marine environment are usually minute ... more

Mangroves – masters of survival on salty ground

Nowhere else do sea and land organisms share the same habitat to such a great extent as in the mangrove swamps of the tropical and subtropical coasts. The biotic communities of the mangroves are unique. ... more

280,000 square kilometers beneath the ocean

Coral reefs are among the most spectacular eco-systems on the planet. They span the globe in the tropical waters of every sea in the world covering a surface area of around 280,000 square kilometers. ... more

Shelf seas

Shelf seas are the coastal waters surrounding every continent, and are typically shallow: in cartography, their boundaries are marked where the water depth around the continental margin exceeds 200 metres. ... more