Where are Coral Reefs Found?
The spatial scale of coral reefs is global. Coral reefs are found in the Caribbean, along with all three of the Earth's oceans in the tropics: the Atlantic, Indian, and Pacific. The global distribution of these reefs is not random, and is determined by the ecological requirements of the reef-building corals. The tropical reefs are constructed by coral animals, and this requires sunlight - therefore the reefs are found in clear, shallow water, where the most sunlight is found. These coral animals only function in warm water, and thrive in annual temperature regimes which are found in tropical seas. Because of this, coral reefs are predominately located toward western margins.
Major Regions of Coral Reef Development:
(1) The Indo-Pacific - most of the Indian Ocean, along with the western Pacific.
(2) The Wider Caribbean (aka the tropical western Atlantic) - Includes Florida, The Bahamas, Caribbean Sea, and coastal waters off northeastern South America.
(3) The Red Sea
Map of Hawaii's Reefs:
History
Reefs are affected by the island on which they are located, and are derived from the plants and animals that make up that island. In order to understand the history of coral reefs and how they came to be, one must analyze their location. The Hawaiian islands have a wide span, stretching over 2300 km, from Hawaii in the south-east to Kure atoll in the north-west. These islands were created by a volcanic hot spot (Macdonald and Abbott, 1970). Because of continental drift, the islands formed a chain as the ocean floor transitioned to the north-west. As a result of continental drift, the islands vary in age. As each individual island in the chain formed, animals and plants colonized the shallow waters and began to develop reefs. Coral reefs take over hundreds of years to form a solid framework and are made up of skeletons, along with sediments from snails, urchins, algae, and other organisms which accreted together. Most of the reefs on the main Hawaiian islands, including Hawaii and Kauai, are fringing reefs, which are near the shore. Over time, as islands drift and sink, the reefs are left above the surface, forming a ring of accumulated sediment, which is also known as an atoll. They begin to grow outward and away from the shore, forming a barrier reef. The only barrier reefs located on the Hawaiian islands are located in the Bay of Oaho and on the north coast of Kauai. The variation in these types of reefs, and variation in reef composition, is due to the geologic history of Hawaii. Because of changes in sea level, current reefs are geologically young. Most reefs are between 7,000 and 9,000 years old, which is the period of time when the rate of sea level change slowed to less than 2m per century, which is the maximum rate of reef growth (Jackson, 1992). However, older reefs which drowned were re-colonized by coral, and therefore this preserved long-term patterns of fringing reef, barrier reef, and atoll development. Corals grow at an extremely slow pace over a long period of time, and therefore it is not easy to track or directly observe their development. On the Hawaiian Islands, it is possible to make inferences about the development of reefs by comparing reefs that that were affected by lava flow at various ages. Scientists discovered that reefs usually take twenty to fifty years to develop, and this is based on the reefs’ exposure to waves. On the wave-exposed Puna coast, reefs developed within twenty years, yet on the wave-protected Kona coast, reefs developed in over fifty years (Grigg and Maragos, 1974). The extensive coral reefs found in the North-western Hawaiian Islands, also known as the rainforest of the sea, are home to over 7,000 marine species. 25% of these are only found in Hawaii. Most of the Hawaiian Islands’ shallow water environments are habitats for rare species such as the threatened green sea turtle and the endangered Hawaiian monk seal.
Historic vs. Present
coral bleaching and its rapid increase over time:
What is Coral Bleaching?
When corals are unhealthy and stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white ("What Is Coral Bleaching?").
Healthy Coral
http://www.piercepioneer.com/wp-content/uploads/2014/10/Coral.jpg
VS.
Diseased Coral Reefs
“Scientists have no idea what’s causing the outbreak, which they say has reached epidemic proportions, though they wonder if the coral may first been weakened by pollution, which made it more susceptible to infection.” ("A Mysterious Disease Is Killing Hawaii.").
In 2000, President Clinton and his administration recognized the severe loss of coral reefs in the northwestern Hawaiian Islands. Through an executive order the remaining coral reefs gained status as an ecosystem reserve in order to establish sustainable use of the ecosystem. The new law required additional fishing & scuba permits, limited pollutants, and banned dumping. (1)
Harsh human practices and urbanization are seen as the main source of destruction to the coral reefs along the Hawaiian Islands. The continuous growing of Hawaiian coastal populations has caused more and more demand on its coral reefs for food, touring, and recreational use (2). Commitment to these demands has created unsustainable overuse of its resources. For example, coral tourism produces 360 million dollars per year (3), attracting over a million tourists because of its activities such as snorkeling and scuba diving. Unfortunately, the reefs corals are soft and extremely fragile - easily destroyed by eager vacationers. Tourists, along with over a million Hawaiian inhabitants, eat the aquatic life and destroy its coral habitats in the process of capturing them. “Juicing” is one problematic fishing method. Fishers place concentrated chlorine in the water to stun fish simultaneously killing the coral reef habitat in which the fish are located (4). The long gill nets that fishers use are also seen as a problem when they become detached bringing anything trapped inside them to the sea floor where they cover and kill coral reefs (4). Similar pollution from the island factories and boats like dumping of plastics and chemicals also contribute to the contamination and death of coral reefs.In addition to direct human pollution, climate change has caused damage to coral reefs. The heating of oceanic temperatures over 91 degrees fahrenheit has introduced bleaching or an effect inciting the reefs to dispose of the algae they rely on for food. The corals lose their nutrients and color hence “bleaching”. Ruth Gates, the director of the Hawaiian Institute of Marine Biology, said, ”30% to 40% of the world’s reefs have died from bleaching events” (5). This year, temperatures are expected to rise 3-6 degrees, potentially creating the worst bleaching in Hawaiian history (5).
2015 Oceanic Temperatures causing Bleaching (90-99 F) (6)
The Hawaiian coral reefs can be categorized into two regions: the populated main Hawaiian Islands (MHI) and the mostly uninhabited atolls, islands, and banks of the Northwestern Hawaiian Islands (NHI).
Protected Areas in the MHIs and the NHIs:
The United States Coral Reef Task Force (USCRTF) has made it their mission to protect at least 20% of US coral reefs. Additionally, the NOAA’s Coral Reef Conservation Program is in full support of efforts to assess the existing protection levels of coral reefs within Marine Protected Areas (MPA) along with calculating the area of US coral reef ecosystems protected in no-take reserves. The official federal definition of an MPA is “any area of the marine environment that has been reserved by federal, state, tribal, territorial, or local laws or regulations to provide lasting protection for part or all of the natural and cultural resources therein.” When an area is designated as a “no-take MPA,” human access is permitted but the extraction or destruction of natural and cultural resources is prohibited. Below are maps of the Main Hawaiian Islands Marine Protected Areas and Northwestern Hawaiian Islands Marine Protected Areas. Hawaii is recognized as being one of the most isolated archipelagos on Earth because over 25% of majority of the coral species in Hawaii cannot be found anywhere else around the world. Therefore, protecting both the MHIs and the NHIs has become a main priority of these organizations. Between these two areas, there are 43 established MPAs, 12 of which are designated as no-take areas.
Main Hawaiian Islands
Northwestern Hawaiian Islands
The uninhabited NHI coral reefs are very healthy, productive, and, because they are so remote, nearly pristine. In fact, these coral reefs are recognized as one of the largest remaining large-scale predator-dominated coral reef ecosystems. In 2006, the US government deemed the Northwestern Hawaiian Islands Marine National Monument, later known as the Papahānaumokuākea Marine National Monument (PMNM), the world’s largest conservation areas and it managed by the State of Hawaii; US Department of the Interior, Fish and Wildlife Service; and the Department of Commerce. The monument was established to protect coral reefs that are rich in natural and cultural resources. Being as the NHI coral reefs are protect and there is essentially no impact on the area from human pressures, monitoring and researching of the area is made easy.
The Future of the Northwestern Hawaiian Islands
The future for this area looks promising because the PMNM has made it its mission “to carry out seamless integrated management to ensure ecological integrity and achieve strong, long-term protection and perpetuation of NWHI ecosystems, Native Hawaiian culture, and heritage resources for current and future generations.” That being said, the co-trustees of this monument formulated an agreement in which roles and responsibilities were delegated; coordination bodies and mechanisms for management were established; and a research plan guide the future of the NHI in the right direction. Because there is minimal evidence of human impact on this area, the most pressing matter is introduction of alien and invasive species. In response to this issue, the Aquatic Invasive Species Response Team inspects the exteriors of all vessels travelling to the NHI from the MHI with the hopes of preventing the introduction of alien species. In years to come, there will hopefully be no alien species in the area that threaten native species.
Recommendations for the Northwestern Hawaiian Islands
As stated before, pressures from humans do not affect the NHI; the NHI is its own worst enemy. Such void means that the NHI will face problems such as the introduction of alien species and marine debris build up. So as to avoid the first issue, the Aquatic Invasive Species Response Team must continue what its already doing; the only other thing they can do is to enforce stricter regulations. It is also in the best interest of the NHI to increase the removal of marine debris.
The Future of the Main Hawaiian Islands
The Main Hawaiian Islands are major benefactors of the marine tourism industry in the US with contributions of over $800 million a year. The high biodiversity and conservation value due to the endemic species located in the MHIs reaps a value of $10 billion. The coral reefs located in the MHIs provide commercial, recreational, and subsistence fishing opportunities; world famous surfing and diving locations; unique food; rich culture; and beautiful aesthetics. In addition to the 1.3 million residents that live on these islands, 7 million tourists visit annually, putting harsh pressures on the coral reefs.
As coastal areas are inevitably developed to accommodate he agriculture and urban growth of the islands, the sediment build-up is only going to increase. If sewage treatment plants continue to dispose of secondary treated wastewater into 15-60 meters deep injection wells, then the plume from said wells will enter the near shore waters that are located next to them. This will cause an overgrowth of marine algae near popular beach areas.
Although there has only been 3 documented major bleaching events within the MHIs’ coral reefs, global warming will continue to heat up the ocean water, putting the coral reefs at risk of another bleaching event.
Fish biomass in inversely related to the human population density by islands. For example, Ni’ihau has the highest fish biomass but lowest human population, while Oahu is home to 72% of the Hawaiian population and has the lowest fish biomass. To add to this, there are virtually no apex predators present in Oahu because of intense fishing pressure. That being said, the more the population of the MHIs increases and the more popular fishing becomes, the less fish biomass will exist.
The coral reef waters face contact with storm water runoffs during high rain events, which will close the beaches down for human health and safety reasons. On March 24th, 2006, 18 million liters if untreated wastewater spilled into the Ala Wai canal and Waikiki, polluting 93 streams and 219 coastal areas.
It has been observed that the coral cover across the MHIs has decreased with increasing geological age. The coral cover at 70% of the 1682 sites that have been monitored has decreased by 8% and has decreased by 12% at 10 sites that have been monitored for over 30 years.
The MHIs also face the issue of alien species, or, more specifically, algae; these alien species will continue to damage the coral reefs. For instance, Carijoa has taken over the deep reef areas and has overpowered stands of black coral.
Recommendations for the Main Hawaiian Islands
In regards to coastal development, implementation, maintenance, and enforcement of efficient management practices that will reduce sediment runoff and prevent future occurrences from happening are essential.
The reduction of fish biomass can be alleviated if the harsh fishing pressures are lessened and stocks and ecosystems are rebuilt so that they include coordinated measures such as increasing restrictions on very efficient fishing gear, bag limits, and larger closed areas. Because there are no recreational fishing licenses available in Hawaii and non-commercial fishing is very popular, stricter regulations should be put on these fisheries. The penalties for fishing without a license should become more severe and there should be tighter management to ensure that those who shouldn’t be fishing aren’t.
The Hawaii Marine Algae Group has already developed ways to manage alien and invasive species. Clean-up events have been organized and an underwater vacuum has been invented to remove large amounts of foreign algae from the coral reefs. As long as groups like the HIMAG continue with these efforts, alien species invasion should cease to be an issue. However, these efforts are effective only at a small scale; a method that removes invasive species at a large scale must be formulated.
Increasing the amount of MPAs in the MHIs will conserve biodiversity and fish resources. Additionally, community awareness and involvement will better the coral reefs for the future. When making decisions for the community, the people should have an ecosystem-based mindset. The more people are aware and can participate in the management of the ecosystem, the more likely it is that their concerns will grow and perception of their current lifestyles will change.
Lexi's Reference List:
"A Mysterious Disease Is Killing Hawaii." Smithsonian. N.p., n.d. Web. 24 Nov. 2015. <http://www.smithsonianmag.com/smart-news/a-mysterious-disease-is-killing-hawaiis-coral-146053981/?no-ist>.
"Coral Reefs of Hawai'i." Coral Reefs of Hawai'i. N.p., n.d. Web. 24 Nov. 2015
<http://www.coralreefnetwork.com/reefs/ecology./ecology.htm>
Grigg, R. W. 1983. Community structure, succession and development of corals reefs in Hawaii. Marine Ecology Progress Series 11: 1-14.
<http://www.coralreefnetwork.com/reefs/ecology./ecology.htm>
Grigg, R. W. 1983. Community structure, succession and development of corals reefs in Hawaii. Marine Ecology Progress Series 11: 1-14.
Grigg, R. W. and J. E. Maragos. 1974. Recolonization of hermatypic corals on submerged lava flows in Hawaii. Ecology 55: 387-395.
Jackson, J. B. C.1992. Pleistocene perspectives on coral reef community structure. Amer. Zool. 719-731.
Macdonald G. A. and A. T. Abbott, 1970. Volcanoes in the sea: the geology of Hawaii. University of Hawaii Press, Honolulu, HI. 441 pp.
"What Is Coral Bleaching?" What Is Coral Bleaching? N.p., n.d. Web. 24 Nov. 2015. <http://oceanservice.noaa.gov/facts/coral_bleach.html>.
Isaiah's Reference List:
1. William J. Clinton: "Executive Order 13178 - Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve," December 4, 2000. Online by Gerhard Peters and John T. Woolley, The American Presidency Project. http://www.presidency.ucsb.edu/ws/?pid=61667.
2. "The Hawaiian Coral Reef." To-hawaii. 2015. Web. 21 Nov. 2015.<http://www.to-hawaii.com/troubles/hawaiian-coral-reef.php>.
3. Van Beukering, Peter. "Economic Valuation of the Coral Reefs of Hawai'i." Project Muse. University of Hawai'i Press, 2015. Web. 21 Nov. 2015. <http://muse.jhu.edu/journals/psc/summary/v058/58.2cesar.html>.
4. Gulko, David, and James Maragos. "Status of Coral Reefs in the Hawaiian Archipelago." Coris. National Oceanic and Atmospheric Administration, 2000. Web. 24 Nov. 2015. <http://www.coris.noaa.gov/portals/pdfs/status_coralreef_hawaii.pdf>.
5. "Hawaii to Experience Worst-Ever Coral Bleaching Due to High Ocean Temperatures." The Guardian. Associated Press in Hawaii, 13 Sept. 2015. Web. 24 Nov. 2015. <http://www.theguardian.com/us- news/2015/sep/13/hawaii-coral-bleaching-scientists-predict-worst-ever>.
6. Masters, Jeff. "Record Ocean Temperatures Threaten Hawaii's Coral Reefs."Wunderground. The Weather Channel, LLC, 24 July 2015. Web. 23 Nov. 2015. <http://www.wunderground.com/blog/JeffMasters/record-ocean- temperatures-threaten-hawaiis-coral-reefs>.
Noaa National Ocean Service - Special Projects. Coral Reef Habitiat Assessment for U.S. Marine Protected Areas: Hawaii (n.d.): n. pag. Coral Reef Habitat Assessment for U.S. Marine Protected Areas: State of Hawaii: NW and Main Hawaiian Islands. National Oceanic and Atmospheric Administration, NOAA’s National Ocean Service Management & Budget Office Special Projects, Feb. 2009. Web. <http://www.coris.noaa.gov/activities/habitat_assessment/hawaii.pdf>.
Gulko, David, and James Maragos. "Status of Coral Reefs in the Hawaiian Archipelago." Coris. National Oceanic and Atmospheric Administration, 2000. Web. 24 Nov. 2015. <http://www.coris.noaa.gov/portals/pdfs/status_coralreef_hawaii.pdf>.
