Coral Bleaching in the Mesoamerican Reef

Mexico

Belize

Guatemala

Honduras

By Gabriela López
corals, bleaching, diving, nature,

One of the largest coral reefs in the world is in danger of being damaged beyond repair because of urban development and other human activities.

Coral reefs are the most diverse of all marine ecosystems and also the largest structures ever made by life on earth. One quarter of all ocean species depend on reefs for food and shelter although they cover just a tiny fraction (less than one percent) of the Earth’s surface and less than two percent of the ocean bottom.

The global distribution of coral reefs is largely determined by the ecological requirements of the corals themselves. They require sunlight found in clear, shallow ocean waters in order to build the reefs; this is why they are located in tropical areas. This need for light is tied to the corals’ dependence upon their photosynthetic partners dwelling within the animal tissues. Even in the clearest of tropical seas, most photosynthesis only occurs in the relatively thin uppermost 100-200 ft. of the sea.

When corals are stressed by a variation in conditions such as temperature, light, or nutrients, they expel the algae living in their tissues, causing them to bleach. Bleached corals continue to live, but as the algae provide the coral with up to 90% of its energy, after expelling the algae the coral begins to starve. In the last 30 years we have damaged 50% of the worlds corals and between 2014 and 2016, the longest global bleaching events ever were recorded. According to the United Nations Environment Program, these bleaching events killed coral on an unprecedented scale and it is expected that this tendency will continue to grow in the coming years.

One of the reefs in greatest danger is The Mesoamerican Reef, which is located within the Caribbean Sea and touches the coasts of Mexico, Belize, Guatemala and Honduras. It contains the largest barrier reef in the Western Hemisphere stretching almost 700 miles from the northern tip of the Yucatan Peninsula down through the Honduran Bay Islands. All types of coral form this underwater wilderness, and provide homes and food to hundreds of fish species, marine turtles, and sharks. Along the shores, mangroves provide habitat for fish and shorebirds as well as protect coastal areas from the damage associated with hurricanes and strong storms.

The beauty of the region’s coastal areas makes it a prime tourist destination, which puts a lot of pressure on this fragile environment. From massive land development to agriculture industry and waste disposal, humans are damaging the Mesoamerican Coral Reef and it is currently in danger of being completely bleached. Although global climate change and its effects on reefs because of warming and acidification of coastal waters are usually pointed at, local human activities may destroy this reef before climate change does. The harmful effects of mining, agriculture, urbanization and fishing have already damaged more than two-thirds of reefs across the Caribbean in addition to worsening the negative effects of climate change.

Local threats addressed in this project are:

  • Coastal Development: Based on cities, ports, airports, hotels and coastal population.
  • Watershed‐based pollution: Takes into account to land‐based pollutants discharged to coastal waters.
  • Marine‐based pollution and damage: Commercial shipping ports, cruise ship ports, shipping traffic, and oil infrastructure.
  • Overfishing and destructive fishing destructive fishing, which includes dynamite (blast) fishing and poison fishing: Destructive fishing designates threat of blast or poison.

Data sources: http://www.conabio.gob.mx/gap/index.php/Procesos_oceanogr%C3%A1ficos http://apps1.semarnat.gob.mx/dgeia/informe_resumen/04_biodiversidad/cap4.html https://datos.gob.mx/busca/dataset/inventario-de-corales-petreos-anelidos-crustaceos-decapodos-moluscos-equinodermos-y-peces-oseos http://www.reefbase.org/global_database/default.aspx?section=t4