Chile intertidal zones
Chile’s intertidal zones are among the most extensive and diverse in the world, greatly influenced by the nutrient-rich Humboldt Current that flows along its coastline. Stretching 2,672 miles, Chile’s geography features various habitats within its intertidal areas, including rocky cliffs, sandy beaches, wetlands, and marshes. The distinct physical divisions—high, middle, and low intertidal zones—host a range of marine life, adapted to fluctuating conditions of temperature, salinity, and moisture due to the rhythm of the tides. The coastal climate varies from dry in the north to temperate rainforests in the south, contributing to a rich biodiversity that includes significant populations of fish, shellfish, and marine mammals.
The intertidal zone is crucial for local ecosystems, supporting species like the Chilean blue mussel, which plays a vital role in the fishing industry. However, human activities such as overfishing and pollution pose significant threats to these delicate ecosystems. Efforts to manage and conserve these areas have been initiated by organizations like Oceana, advocating for sustainable practices and the establishment of marine protected areas. As Chile continues to navigate the balance between economic needs and environmental protection, the intertidal zones remain a focal point for biodiversity and conservation efforts.
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Chile intertidal zones
- Category: Marine and Oceanic Biomes
- Geographic Location: South America
- Summary: Chile has one of the world's longest and most diverse intertidal zones, nourished by the Humboldt Current that flows along its entire coast.
Chile is a long, narrow country in South America and is defined by the Andes mountain range on the east and the Pacific Ocean on the west. Chile is 2,672 miles (4,300 kilometers) long and is an average of 109 miles (175 kilometers) wide. This country is a long strip of coastal land that runs parallel to the Andes and extends from midcontinent to Cape Horn, the southernmost point of South America.
The coastal climate is strongly influenced by the Humboldt Current. This slow, cold Pacific current sustains one of the world's richest fisheries along the western Chilean coast. Many forms of wildlife are also found in abundance along the adjacent land areas. The Humboldt Current begins north of the Antarctic Ocean and runs the full length of the Chilean coast, bringing nutrient-rich waters that nourish the intertidal zones. Intertidal zones along shorelines are the areas between the high tide and the low tide and can include many types of habitats, including steep rocky cliffs, sandy beaches, wetlands, and marshes.
Four physical divisions exist within these zones, each with distinct characteristics and ecological differences. Ocean spray and high waves create spray zones and are only submerged during very high tides and severe storms. High intertidal zones are formed by floods during the peaks of daily high tides, but remain dry for long stretches between high tides. This area hosts hardy sea life that can handle the tumultous conditions. Middle intertidal zones are characterized by the tides that ebb and flow over the area twice per day. This zone hosts a variety of plants and animal life. Finally, the low intertidal zone is almost always underwater, with the exception the lowest spring tides. This area provides the most protection for sea life due to the constant water cover, and hosts a wide variety of abundant sea life.
The organisms that live in the intertidal zone have adapted to survive the significant changes in temperature, salinity, moisture, acidity, dissolved oxygen, and food supply that occur on a daily basis due to the movement of the tides. Plants and animals that have adjusted to various sets of conditions dominate zones at different tidal heights. This distribution pattern of different species along the shore in vertical bands is referred to as intertidal zonation.
Varied climatic conditions along Chile's long coast also contribute to the diversity of intertidal species: An extremely dry climate is typical of the north, but the coast exhibits a rainforest microclimate, as moisture from the sea is trapped by cliffs and valleys; the central region of the country is characterized by the hot, dry summers and mild, wet winters of a Mediterranean climate; and the southern region is cooler and wetter, classified as an oceanic temperate climate.
The complex relationship between the Humboldt Current and the intertidal zones supports a wealth of oceanic and land organisms. Some of the world's greatest populations of shrimp, anchovies, squid, sardines, salmon, and mackerel inhabit Chile's western coast. Marine birds and mammals—such as penguins, pelicans, flamingos, bottle-nosed dolphins, whales, and sea lions—live off of the smaller fish, mollusks, and crustaceans. Intertidal species such as sea urchins, starfish, and coral also contribute to this diverse, yet fragile eco-community, as do seaweeds, kelp, and shoreline grasses.
Many of these organisms are adapted to extremes, as the local water may be fresh, brackish, or salty. They may be subject to varied wave action, and must be able to live exposed to air and sun, or submerged in water. Many types of shellfish thrive here, most notably the Chilean blue mussel, which fishermen regularly harvest for domestic use and export. The blue mussel represents roughly 83 percent of Chile's mollusk production. Wild fisheries and salmon fish farms have been vital in Chile's economy since the 1980s when aquaculture practices rapidly developed around the world, outpacing all other animal protein production. In 2014, Atlantic salmon, rainbow trout, and blue mussels accounted for 90 percent of the volume and value of Chilean exports. By 2023, the value increased to 94 percent.
Human Impact and Conservation
Because there has been an increasing worldwide demand for fish since the 1980s, wild fisheries are being overexploited. Salmon farms consume many of these wild fish, and also have caused problems on some coastal areas due to pollution runoff, low oxygen zones, algal blooms, and the spread of viruses into the marine environment. Inland mining practices have also had a negative impact on shoreline species. Forestry, pulp, and paper industries are present in the south, releasing pollutants that harm the intertidal zones.
The Chilean coast, including the intertidal zone, is administered by the Ministry of National Defense through the Marine Subsecretary. This division addresses issues related to national and state public goods in the intertidal zones, including the harvesting of marine species. Another division under this Marine Subsecretary regulates diverse activities such as aquaculture and harbors. State ownership of the coast tends to occur in the extreme north or south of Chile, as the other coastal lands became private during the long colonial period.
Since the 1990s, scientists have conducted extensive Chilean research on intertidal zones, and two coastal marine research stations have been created: Estación Mehuín in southern Chile of the Universidad Austral de Chile, and Estación Costera de Investigaciones Marinas in Las Cruces in Central Chile of Pontificia Universidad Católica de Chile.
In 2001, Oceana was founded. Oceana is the largest international organization focused solely on ocean conservation. As oceans play a key role in regulating the Earth's temperatures, the organization considers the impacts of global warming. Oceana is moving forward with public education, legislation advocacy, and ecosystem protection. The organization has offices in North America, Central America, South America, and Europe that work together on a limited number of strategic, directed campaigns to achieve measurable outcomes that will help return the oceans to former levels of abundance. In Oceana's first decades of operation, it achieved several policy victories for marine life and habitats around the world. In the 2021, Oceana petitioned the Council of Ministers for Sustainability in Chile to create the Humboldt Archipelago Multi-Use Marine Coastal Protected Area. The area covers more than 5,700 square kilometers and is located between the Atacama and Coquimbo regions, and aims to to protect one Chile's most biodiverse ecosystems in the country and promote sustainable development for local communities.
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