When talking about the area where the land meets the sea, people often use the word “coastline.” But, it is much more accurate to think of the coast as a “zone” than as a “line.” The coast includes the land and the sea surrounding the area where the two meet.
Coastal development is any human-induced change of the landscape in this coastal zone. This could include farming, mining, urbanization, industrial development, port and marina development, aquaculture, sand mining, and more. Additionally, development in or near the water such as seawall construction, beach renourishment, nearshore dredging, and oil platform construction are all types of coastal development.
The high level of biodiversity in coastal zones has always attracted human activity – as a source for food and other resources, transportation, defense, recreation, and more recently, tourism. For these reasons, development is focused along coastal zones. Worldwide, 2.5 billion people (40% of the world’s population) live within 100km (62 miles) of the coast.
In some parts of the world, tourism relies heavily on the coastal zone which contributes significantly to local economies. Tourism can be a major portion of foreign currency earnings with increasing growth potential. The infrastructure to support growing populations and increasing numbers of tourists can have severe impacts for the surrounding marine ecosystems.
The ocean habitats that comprise the coastal zone make up less than 10% of the marine environment but 90% of all marine life live in these areas due to the shallow water and access to sunlight. These waters also provide a breeding and nursery habitat for other animals that spend much of their lives further from the coast.
In addition to the incredible biodiversity in coastal waters, coastal ecosystems are instrumental in carbon absorption and storage. Salt marshes, kelp forests, seagrass beds, and mangrove forests store at least ten times more carbon than terrestrial ecosystems. These habitats are tremendously helpful in mitigating the effects of global warming.
Finally, healthy coastal ecosystems protect the coast from waves, storms, and erosion. They cause waves to break before they hit the shore, reducing both the force and height of the wave. A 5m (15ft) section of marshland can absorb half of all incoming waving energy while mangroves can absorb between 70-90%. These ecosystems also hold sediment in place reducing coastal erosion and flood risk.
Coastal development can have a number of unintended impacts (directly or indirectly) on marine environments as well as the land itself. In some cases, entire ecosystems are destroyed. The loss of primary producers and habitat-forming species, such as corals, has ripple effects well beyond the coastal environment.
Coastal development can directly destroy marine habitats:
Deforestation and clearing of terrestrial vegetation remove plant roots which hold sediment in place. This increases runoff and sediment deposits into the surrounding marine environment. Similarly, clearing mangroves from coastal waters leads to a release of organic materials and sediment into the ocean. Sediment can wash onto and smother corals and potentially change the water chemistry.
The development of industrial agriculture, which uses nutrient-rich fertilizers, in coastal areas coupled with the removal of natural plant filters from the coast substantially increases nutrient runoff into coastal marine environments. Increased nutrients cause an increase in algae, at the water’s surface. These algal blooms block sunlight from the sea floor suffocating coral reefs and seagrass.
Chemical and Sewage Pollution
Just as more nutrients enter the ocean, chemicals and sewage follow. Toxic chemicals from mining, industry, aquaculture, agriculture and urban environments all wash into the ocean without the natural filtration of trees and plants. In many developing countries, sewage is one of the most widespread pollutants in the ocean. The combination of chemicals and sewage drastically alter the water conditions and impact the plants and animals who live there.
The removal of coastal vegetation and its roots, causes sediments to wash away. This increases the rate of coastal erosion. The construction of seawalls to combat this coastal erosion causes further issues by adding toxic concrete to the marine environment, blocking turtles from nesting beaches and blocking vital nutrient flow.
Sea turtle hatchlings use the natural light of the horizon to find the ocean at night. With increased coastal development, and the road and building lights that accompany it, hatchlings become disoriented often walking toward land instead of the sea. Many of them die of exposure before reaching the ocean, are eaten by predators, or even run over on busy roadways.
As individuals we can take steps to improve the health of coastal areas.
If you live in a coastal area, talk to your local government officials to make sure that development is minimizing impact through planning and land use regulations. For example,
Regionally, there are a number of organizations fighting for ecologically friendly coastal development. Educate yourself on what is happening in your area and add your voice and your time to the cause.
These multi-national organizations also fight for coastal conservation.
Successes in coastal development often involve individuals or organizations fighting for the coast and the protection of those who inhabit it. Here are some examples.
Protection of Undeveloped Watershed from Highway Development, Southern California
The last remaining undeveloped watershed in southern california was the proposed site of a six-lane toll road. Lawsuits, revisions, and appeals continued for fifteen years and finally came to an end in 2020 when the Governor signed a prohibition of any type of roadway into law. Local and national activists and organizations worked together to protect this valuable coastline and the animals, including several endangered species, who live there.
Salt Mining San Ignacio Lagoon, Mexico
In March 2000, Mitsubishi planned to build the world’s largest industrial salt mining factory in a breeding and calving lagoon for Pacific grey whales. Due to massive campaigns by environmental groups in Mexico and around the world, the Mexican government abandoned the plan; reminding us that we have a voice and should use it!
Patricio Merino – Community-Based Coastal Protection, Chile
After years working in the local fishing industry, Patricio Merino, organized his community to establish the first community-managed marine protected area in Chile. The impetus came from the community. They developed the regulations and then asked public institutions to formalize them; this ensured community buy-in. Patricio hopes to replicate this structure in other parts of Chile, protecting more valuable coastal environments.
Seawall Project Defeated, Ireland
A golf club on Doughmore Beach in Ireland, submitted a proposal to build seawalls along the sand dunes on the beach. After four years of campaigning by a number of conservation groups, the appeals board rejected the plan concerns about adverse impacts on the coastal dunes ecosystem. A strong grassroots coalition armed with science, passion and persistence, can win.