The Mesoamerican Barrier Reef
Embed Size (px)
Transcript of The Mesoamerican Barrier Reef
The Mesoamerican Barrier ReefWe need to start looking at having a way of managing the whole ecosystem, because you cant pick away at it piece by piece, you have to truly start being coordinated and managing our resources as a system. We havent gotten to that point yet.The Mesoamerican reef helps to stabilize and protect the coasts, and serve as feeding and nursery habitats for marine mammals, reptiles, fishes and invertebrates; many of which have great commercial importance. The Mesoamerican reef, however, has been significantly damaged recently due to a combination of human and natural perturbations, with threats ranging from fishing, tourism and coastal development, land use and agriculture to global climate change. A number of natural disturbances have threatened the reefs, especially coral bleaching, hurricanes and disease outbreaks; all of which may be accentuated by global climate change and thus not entirely natural. Such events are not readily controllable at the local management level, while other human threats are potentially under local, national, or regional control. Reef managers in the region, however, are often limited by the resources available to carry out necessary interventions such as fisheries regulation, protection of coastal habitats, agricultural run-off and sewage pollution reduction, as well as possible restorative activities. The following presentation concludes the threatening effects of global warming and invasive species on the biological diversity of the Mesoamerican Reef, concluding with a proposal to allocate specific funds toward the prevention of these threatening causes.
MESOAMERICAN REEF AbstractMap of the world, Mesoamerican Reef highlighted in green (WWF, 2010).MESOAMERICAN REFF Global WarmingGlobal Warming is the gradual increase in the temperature of the earth's atmosphere, believed to be due to the greenhouse effect, caused by increased levels of carbon dioxide, chlorofluorocarbons, and other pollutants.The ecosystem is held in a delicate balance, and these rising temperatures have insinuated two major effects on the biodiversity of the Mesoamerican Reef (WWF,2009):
Global Warming ImpactRamificationsEffects A symbiotic RelationshipHow it happensToluene: What we do with our productionGlobal Warming ImpactRamificationsEffectsA Symbiotic RelationshipHow it HappensToluene: What we do with our production
A Symbiotic Relationship.. Corals share a symbiotic relationship with a group of organisms given the genus name zooxanthellaes (Aquarists, 1998)
These microbial protists live in hard or stony coral in the coral polyp tissues (Bouche, 2008)
The symbiotic relation is based on the corals inability to generate sufficient amounts of food and the algaes ability to undergo photosynthesis and conversion of chemical elements into energy (Bouche, 2008)
These activities provide the coral with fixed carbon compounds for energy, enhance calcification ,and mediate elemental nutrient flux (Aquarists, 1998)
The host coral polyp in return provides its zooxanthellae with a protected environment to live within, and a steady supply of carbon dioxide for its photosynthetic processes (Aquarists, 1998)
The symbiotic relationship allows the slow growing corals to compete with the faster growing multicellular algae because the tight coupling of resources and the fact that the corals can feed by day through photosynthesis and by night through predation (Bouche, 2008)MESOAMERICAN REFF Coral Bleaching
How it HappensMESOAMERICAN REFF Coral BleachingCoral bleaching results from either a decrease in the density of the zooxanthellae or a loss in the concentration of photosynthetic pigment in the symbiotic algae (Corals, 1996)It causes a loss of colour, subsequently leaving the coral white, or bleached, as an indicator of poor health (WWF, 2010)Studies of bleached coral in stressed waters show a decrease of 60-90% of the symbiotic algae, and a loss of 50-80% of photosynthetic pigment in the zooxanthellae (Corals, 1996)Results in disease, failed reproduction, partial/complete mortality of coral colony (Bouche, 2008)
EffectMESOAMERICAN REFF Coral BleachingWithout the symbiotic relationship in tact, the coral cannot receive a sufficient amount of food to keep it aliveIn 1998, a mass coral bleaching caused significant coral death on the Mesoamerican Reef. A study conducted in Belize and Honduras showed that in areas with clean waters and healthy reefs, coral was able to recover and grow normally within two to three years after the bleaching (WWF, 2009) In comparison, corals living with excessive human pressures, such as pollution, coastal development, and runoff, had not recovered even eight years after the eventThe fast-recovering corals were located far offshoreThe corals that took longer to recover were located in areas with significant land-based runoff and heavily populated and developed coastlinesAs a result, coral that cannot recover will not survive and die off
Global Warming ImpactMESOAMERICAN REFF Coral BleachingCoral reef bleaching is a general response to stress. It has been happening more frequently as a result of global warming raising sea temperatures. Coral species live within a relatively narrow temperature margin, and anomalously low and high sea temperatures can induce coral bleaching. A small temperature change of only two degrees can be attributed to an upwelling of coral bleaching. (Bouche, 2008)These higher temperatures act as stressor factors, disrupting zooxanthellae enzyme systems that are responsible for protection against oxygen toxicity. Without this protection, the algae can die off contributing to coral bleaching (National Geographic, 2006).Even further, in more extreme cases, if the water temperature rises above 30 degrees Celsius, photosynthesis pathways in the zooxanthellae are impaired, causing a disassociation of symbiosis because the algae is no longer able to sustain the coral.Sea temperature shocks, a quick raising in the water temperature around the coral, can cause a dysfunction in cell adhesion between the protist and the coral. The coral will release its endodermal cells, carrying the zooxanthellae with it (Nation Geographic, 2006).Studies have proven temperature (indirectly, global arming) to be a causative factor (Corals, 1996).
RamificationsMESOAMERICAN REFF Coral BleachingThe ramifications of dying coral are extremely appalling within the Mesoamerican reef. Coral, in terms of the eco system, provides a habitat and safe sanctuary to over 500 different species of fish, along with the mammoth whale shark, and the endangered salt water crocodile (WWF, 2010). The numerous ecosystems of the Mesoamerican Reef rely on the shelter and nutrients provided by the vast amount of coral. Without this protection and food, the delicate balance of nature will be unevenly weighed. Inversely, other species will begin to decrease because they are no longer able to proficiently hide from predators, or seek the nutrients they need. This catastrophic effect will continue to domino down towards the end of the food chain. Food sources will be depleted to larger fishes who will begin to dye off as a result. These effects do not even take into consideration the exponential increase of other human and environmental stresses. Coral bleaching can lead to a large decrease to the biodiversity of the Mesoamerican Reef, affecting tourism and other commercial operations. Further impact on the poor economies of the Central American countries will leave even fewer resources to conserve the rest of the reef. Bleached corals are effectively starving and susceptible to other stresses including diseases; many will die as a result (Corals, 1996).As a result of increased sea temperature, hurricanes and storms are increasing in frequency and intensity. Studies have proven there to be a strong correlation between an increase in temperature, and an increase in wind speeds during natural disasters over the past few decades. Hurricanes are driven by the transfer of energy from the ocean to the atmosphere. The increased ocean temperature translates to an increase in the kinetic energy of the water molecules, causing the ability of water evaporation to increase. A greater evaporation rate will produce a hurricane with greater intensity because it will allow the storm to easily draw up more air (TIME, 2009).Since 1970, ocean temperatures have risen by 0.5 degrees Celsius, accounting for the powerful storms. According to research conducted by the Nature Organization, it is estimated that for every one degree increase in surface temperature, there is a resulting 31% increase in the global frequency of a category 4 or 5 storm (TIME, 2009).
MESOAMERICAN REFF Natural Disasters
The base coral frame is fairly resistant and immovable to storms and hurricanesStrong storm surge and wave energy can damage and destroy branching corals or smaller coral coloniesReef life that consists of soft corals, sponges, and encrusting organisms living at the base coral frame can break away and be pulverized by churning wave surge (TIME, 2009)Physical ramifications caused by the storm are usually short term and do not have as great an impact on the Mesoamerican ReefOcean life fragmented by the storm can survive, reattach, and continue growing if conditions are not inhospitableReefs are able to repair branching corals as long as damage has been kept to a minimal around the framework (Corals, 1996)MESOAMERICAN REFF Natural DisastersHurricanes cause the biggest damage to the Mesoamerican reef after the actual storm through the initiation of other stressors that can cause long term effectsStorms cause an increase in sedimentationMuddy runoff and sediment get suspended in the water a result of torrential storm down pourSediment laden