CoralReproduction: Difference between revisions
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===Zooxanthellae=== | ===Zooxanthellae=== | ||
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===Fish=== | ===Fish=== | ||
Revision as of 23:59, 14 April 2015
Coral Reproduction
Sexual Reproduction
Mass Spawning Events
Synchronization
Cross Fertilization
Controlling Factors
Asexual Reproduction
Asexual reproduction propagates successful genotypic polyps within a coral head through budding and fragmentation. In asexual reproduction, new clonal polyps bud or fragment off from their parent polyp in order to expand current colonies or begin new ones. The extent of asexual reproduction is related to habitat conditions, day length, and the rate of temperature change.[3] Asexual reproduction methods are often used when conditions are relatively stable in order to rapidly expand, and switch to sexual reproduction in order to produce genetically diverse offspring. [2]
Budding
Budding involves the formation of a daughter polyp from a parent polyp, through intra- or extra-tentacular budding. Different species may bud through either process, or both. [5]
Intratentacular Budding
Intratentacular budding occurs when the parent polyp divide itself into two or more daughter polyps. [6]
Extratentacular Budding
Extratentacular budding occurs when daughter corallites form adjacent to the parent colony, external to the wall. [7] The resulting daughter corallite is generally smaller than its surrounding neighbors, and will grow over time. Only coral species that possess separate walls will reproduce through extratentacular budding. [4]
Fragmentation
Fragmentation can be both intentional or unintentional. Intentional fragmentation occurs when localized skeletal dissolution occurs along the corallum for easy breakage, and pieces of the coral fall away. [8] Unintentional fragmentation occurs when corals are subject to physical disturbances, such as storms.[9] The success of fragmentation depends largely on the substrate upon which the coral fragments settles. Success is much greater for fragments that settle on top of living colonies, as opposed to sand.[9] If conditions are favorable, fragmentation allows a portion of one colony to establish a new coral colony that is genetically identical to its parent colony. [9]
Abiotic Factors
Temperature Change
Coral have a very specific temperature that they thrive in, between 20ºC and 32ºC. As the ocean temperatures are rising, corals are less able to survive. As temperature increases, the symbiotic zooxanthellae leave the coral, causing coral bleaching. Without this algae, the corals do not have a source of photosynthetic material. [10] The temperature has a direct affect on the density of zooxanthellae. [11]
Water Contamination
Human pollution, especially runoff and untreated sewage, causes stressors on the reefs. [12] Researchers are currently studying the effects of salinity, nutrients, and sediments, among other factors, that interdependently affect coral reproduction. [13]
Ocean Acidifcation
Rising CO2 levels, as a result of human pollution, prevent coral from reproducing as effectively as possible. In particular, excess CO2 damages tissue regeneration of the corals. [14]
Eutrophication
Eutrophication, the excessive enrichment of nutrients, can primarily increases coral reproductive success due to abundance of nutrients. However, these nutrients eventually limit coral growth, as they harm coral calcification rates, reduce exposure to sunlight, and overall decrease the quality of the water. As a result, eutrophication stunts coral growth. However, many studies show conflicting [12].
UV radiation
While coral have functions that allow them to respond to high levels of UV radiations, it is shown that abnormal rays lead to coral vulnerability, which in turn affects reproduction rates. In particular, UV rays degenerate the skeletal of corals. [15] However, another experiment concludes that light has little effect on coral reproduction. [11]
Tropical Storms
Storms are crucial in coral reproduction, since they act a distributing agent for the coral polyps. Tropical storms also provide for genetic diversity, as seen in the Pocillopora verrucosa population in the Gulf of California. [16]
Biotic Factors
Heterotrophy
Zooxanthellae
Fish
Porites Case Study
The reproduction of the Porites evermanni, a coral species found in the eastern Pacific was found to have a survival rate much higher than that of a closely related species, Porites lobata, which is more susceptible to the effects of coral bleaching. Researchers concluded that the housing of mussels by Porites evermanni boosts reproduction rates. Triggerfish bit on the coral in order to feed on these mussels. They then spit out the coral, spreading them onto the ocean floor and allowing the polyps to grow into colonies. [10]
The two Porites species are shown; the Porites Lobata (left) is bleached while the Porites evermanni (right) remains unbleached.
Notes
- ↑ 1.0 1.1 1.2 1.3 Veron, J.E.N. “Sexual Reproduction.” The Australian Institute of Marine Sciences. The Australian Institute of Marine Sciences, 2013. Web. 23 Feb 2015.
- ↑ 2.0 2.1 Miller, K. J., and D. J. Ayre. "The Role of Sexual and Asexual Reproduction in Structuring High Latitude Populations of the Reef Coral Pocillopora Damicornis." Nature.com. Nature Publishing Group, 21 Apr. 2004.
- ↑ "Coral Reproduction." NOAA's Coral Reef Conservation Program:. N.p., n.d.
- ↑ 4.0 4.1 AIMS. "Extra-tentacular budding." Coral Hub Resources Training for Coral Identification RSS. Web.
- ↑ "Colony Formation." Corals of the World. Australian Institute of Marine Science, n.d. Web. 13 Apr. 2015. <http://coral.aims.gov.au/info/structure-colony.jsp>.
- ↑ ="Colony Formation"> "Colony Formation." Corals of the World. Australian Institute of Marine Science, n.d. Web. 13 Apr. 2015. <http://coral.aims.gov.au/info/structure-colony.jsp>.
- ↑ ="Colony Formation"> "Colony Formation." Corals of the World. Australian Institute of Marine Science, n.d. Web. 13 Apr. 2015. <http://coral.aims.gov.au/info/structure-colony.jsp>.
- ↑ Yamashiro, H., and M. Nishihira. "Radial Skeletal Dissolution to Promote Vegetative Reproduction in a Solitary CoralDiaseris Distorta." Experientia 50.5 (1994): 497-98. Web.
- ↑ 9.0 9.1 9.2 Lirman, Diego. "Fragmentation in the Branching Coral Acropora Palmata (Lamarck): Growth, Survivorship, and Reproduction of Colonies and Fragments." Journal of Experimental Marine Biology and Ecology 251.1 (2000): 41-57. Web.
- ↑ 10.0 10.1 "Research Areas." Nsf.gov. National Science Foundation, 12 Dec. 2013. Web. 24 Feb. 2015 <http://www.nsf.gov/news/news_summ.jsp?cntn_id=129838&WT.mc_id=USNSF_51&WT.mc_ev=click>.
- ↑ 11.0 11.1 11.2 Rodolfo-Metalpa, R., et al. "Effects of Temperature, Light and Heterotrophy on the Growth Rate and Budding of the Temperate Coral Cladocora Caespitosa." Coral Reefs 27.1 (2008): 17-25. ProQuest. Web. 24 Feb. 2015.
- ↑ 12.0 12.1 Loya, Y., et al. "Nutrient Enrichment Caused by in Situ Fish Farms at Eilat, Red Sea is Detrimental to Coral Reproduction." Marine pollution bulletin 49.4 (2004): 344-53. ProQuest. Web. 24 Feb. 2015.
- ↑ Humphrey, C., et al. "Effects of Suspended Sediments, Dissolved Inorganic Nutrients and Salinity on Fertilisation and Embryo Development in the Coral Acropora Millepora (Ehrenberg, 1834)." Coral Reefs 27.4 (2008): 837-50. ProQuest. Web. 24 Feb. 2015.
- ↑ Horwitz, Rael, and Maoz Fine. "High CO2 Detrimentally Affects Tissue Regeneration of Red Sea Corals." Coral Reefs 33.3 (2014): 819-29. ProQuest. Web. 24 Feb. 2015.
- ↑ Torres-Perez, J., and R. A. Armstrong. "Effects of UV Radiation on the Growth, Photosynthetic and Photoprotective Components, and Reproduction of the Caribbean Shallow-Water Coral Porites Furcata." Coral Reefs 31.4 (2012): 1077-91. ProQuest. Web. 24 Feb. 2015.
- ↑ Aranceta-Garza, F., et al. "Effect of Tropical Storms on Sexual and Asexual Reproduction in Coral Pocillopora Verrucosa Subpopulations in the Gulf of California." Coral Reefs 31.4 (2012): 1157-67. ProQuest. Web. 24 Feb. 2015.