The Impact of Climate Change on the Oceans Coral Bleaching Rates Research Paper

The Impact of Climate Change on the Oceans Coral Bleaching Rates - Research Paper Example The presence of zooxanthellae within coral polyps is able to provide protection from ultraviolet rays from the sun, as well as a stable carbohydrate supply to the corals during the day (Brown, 1997). At the same time, the corals provide CO2 for the photosynthetic activities, as well as providing a shelter from other predators (Graham, et al., 2006). Most corals can be found in sunny seas in tropical waters, which foster photosynthetic activity of the symbiotic algae during the day. Coral reefs are found throughout tropical areas across the globe, and are mostly thriving near coastal areas (Figure 1). Often called â€Å"flowers of the sea†, these creatures are not only aesthetically pleasing for many tourists such as divers and underwater photographers, these are also ecologically-important members of ocean ecosystems by being a habitat for fish and other aquatic animals, as well as protecting the shoreline’s structure by serving as breakwater for the ocean’s waves (Cesar, 2000). Such a feat is possible due to the hard exoskeletons of corals, which are durable to the kinetic effects of ocean waves. The process in which coral skeletons grow and develop takes a very long time due to the gradual calcification process in building up the coral skeleton by very small animals. However, recent climate changes causes a degeneration of this coral exoskeleton, which not only poses a threat to the corals themselves but also to the creatures that dwell w ithin them, which in turn could affect livelihoods such as tourism and fishing industries of people living alongside coral reefs. Figure 1. The distribution of coral reef systems are limited to the tropics, seen here as dark brown markings around coastlines and islands (ReefBase, n.d.). Figure 2. Various species of common coral after undergoing bleaching lose their color. Scale bars=5cm (Anthony, et al., 2008). The steady rise in global temperatures have been causing various abnormalities in nature such as drastic weather changes, the growth and proliferation of invasive pests, and the destruction of marine ecological systems such as coral reefs. Several disasters within coral reefs have been recorded in the past decades, and most are attributed to the effects of rising atmospheric and ocean temperatures (Brown, 1997; Cao & Caldeira, 2008; Doney, et al., 2009; Glynn, 1993; Hoegh-Guldberg, et al., 2007; McNeil, et al., 2004). However, these are not the only factors that could contribute to the declining populations of corals and reefs, since other man-made factors also come into play. The acidification of sea w ater due to increasing dissolved CO2, saturation of nutrients due to leaching of fertilizer runoffs, and the increase of disease-causing pathogens and other agents due to the warmer waters causes the disruption of the symbiotic relationship of the zooxanthellae and the coral polyps (Bruno, et al., 2003; De’ath et al., 2009; Grandcourt & Cesar, 2003; Obura, 2004; Silverman, et al., 2009). Corals become bleached when the number of symbionts decreases in the polyps’ bodies, leaving them colorless and much more exposed to the ultraviolet rays of the sun (Figure 2). The lack of zooxanthellae decreases carbohydrate production which translates to a lesser food supply for the corals. This causes the death of the coral polyps,