Download reesearch paper coral reefs June

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The Ecosystem in Danger—Coral Reef Ecosystems, With the Case
Study of the Great Barrier Reef
June Wu 98501063
Instructor: Michael Cheng
Date: 2011/6/21
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Abstract
Since I am always interested in certain kinds of biological issues, especially
marine biology, I have decided long before to have biological topic for my research
paper. The Great Barrier Reef is an issue I have read in the National Geographic
Magazine in May, 2011, so I want to study more about the cases of coral reefs.
Coral reef system is a very unique ecosystem in coastal environment. Rather
than being just “reefs,” it contains in fact a huge biomass of coral polyps, with
symbiotic algae staying with them. Together, these coral polyps using the sun energy
which algae supplies to them to secrete “a ‘house’ of calcium carbonate or
limestone” (Holland2011), cementing as well as expanding their ecosystems. There
are coral reefs systems near the coasts of many tropical countries, inclusive of
Taiwan.
A few cases of coral reefs systems around the world are cited in this research
paper, but the main case will be provided as that in the Great Barrier Reef, located off
the coast of Queensland in Australia, is the oldest and largest “creatures” in the
world which has been listed in the World Heritage. This paper is divided into two
parts: reasons to protect coral reef systems in ecological aspect, and the threats that
coral reefs, mainly the Great Barrier Reef, have been facing so far. To know the
current situation of the Great Barrier Reef and coral reefs in other regions, I cite
information from latest science magazine and other websites as my methodology. As
to the result, one will gradually get to know the huge price we all have to pay once
the whole ecosystem of coral reefs suspend.
Why Should One Protect Coral Reefs—From the Ecological Considerations
When it comes to protecting certain species or ecosystems, advocators of
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environmental protection often emphasize the rarity or scarcity of their targets
without mentioning what kind of good these targets do to human beings or the
whole environment. One will know that these species are endangering, but never do
he or she know the actual consequences after the species extinct. And if one doesn’t
know the benefit a species or ecosystem brings and the cost once it vanishes, the act
of protection will be incomplete and impracticable.
So, why should people protect coral systems? The reasons are not only the
astonishing beauty of coral reefs. In fact, coral reefs serve further than tourist
attractions. The benefits of their existence will be listed in the following passages.
1. Biodiversity
As mentioned above, coral reef ecosystems are one of the oldest and most
complicated ecosystems in the world. With its effort to maintain the biodiversity,
coral reefs systems become the most species-rich habitats not merely in the sea but
also in the world. Over “one third of the world’s marine fish species are found on
coral reefs” (Moberg and Folke1999), not including other non-fish marine species.
Coral ecosystems are even called “rainforests of the sea” due to its biodiversity.
This awesome diversity among species can be attributed to a property of coral
reefs—the three-dimensional space. With its limestone skeleton, coral reefs are able
to pile up its “height,” or “layers” and offer shelter to different species. This is a
rather unique structure in ocean ecosystems. As one can see, river or open sea
ecosystems do not have this property; creatures can go randomly from one spot to
another, but their habitats or shelters are limited to the bottom of waters. Thus, the
complex three-dimensional structures “creates the extremely high habitat
heterogeneity of reef systems” (Moberg and Folke1999) from benthos (species which
move around at the bottom of the seas) like sea stars, fouling organisms to fishes
that dwell in caves. Also, this environmental advantage can provide possible
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evolution of new species.
In the case of the Great Barrier Reef, there are huge statistics as to the
species nurtured in its area. According to Klappenbach’s essay,
It has “more than 1500 species of marine fishes including manta rays, tiger sharks,
whale sharks and countless tropical fishes; 360 species of hard corals which are basic
builders of coral reefs, 1500 species of sponges like tubular sponges, 600 species of
echinoderms such as sea urchins and sea cucumbers, 5000 species of mollusks
including giant clams and octopuses, 23 marine reptiles from sea turtles to sea
snakes, and finally 30 marine mammals, dolphins, whales and dugongs included”
(Klappenbach), not to mention the numerous organisms which “earn their living” by
either parasitism or symbiosis. These species, fish and non-fish species alike, all
belong to their communities that together form an intact, complicated and
irreplaceable marine ecosystems. Once it is lost, even it is only an ordinary species,
will cause disorders in the whole ecosystem and make it in chaos. Also, these
abundant lives help maintain the resilience of coral reefs (in this case, the Great
Barrier Reef) ecosystems.
2. Renewable Sources
On account of the symbiotic condition between corals and the microalgae
which act as producer in the food chain, coral reefs provide plenty of sun energy with
the photosynthesis of algae to the whole ecosystem. In addition to it, coral reefs
“generate a variety of seafood products like fish, mussels, crustaceans, and
seaweeds” (Moberg and Folke1999). Based on the same study, “more than 100
countries have coastlines with coral reefs, and people depend on coral reefs for part
of their livelihood or part of their protein intake.” This is related to not only the living
of people near coral reefs but also the economic benefits. For instance, local
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Australians fish those sea products produced by the Great Barrier Reef, depending on
them deeply. However, unfortunately, this is also the source of overfishing for certain
high-valued sea products like mother-of-pearl shells and red corals.
3. Protection and Buildup of Lands
One of the most important functions of coral reefs is the protection as well as
the buildup of coastal lands. “Without coral reefs protecting the shoreline from
currents, waves, and storms, there will be loss of land due to erosion” (Moberg ad
Folke1999). Furthermore, coral reefs actually build up lands. A well-known example
is Maldives, a tropical nation which are located on islands built by coral reefs. The
buffer of coral reefs also creates a rather comfortable environment for sedimentary
ecosystems like lagoons and mangroves.
4. Interaction with other Ecosystems
Although every ecosystem has its own independency, it is linked to other
adjacent ecosystems indirectly but essentially, and coral reef system is no exception.
It has an intimate relationship with mangrove, sea bed grass and pelagic ecosystems.
Mangroves and sea grass beds ecosystems, which are more near-coast than
that of coral reef ecosystem, play the role to precipitate the sediments from lands
such as sands and dusts, thus providing a clearer environment for coral reefs to grow
offshore; to return this favor, coral reefs “export fish and invertebrate larvae”
(Moberg and Folke1999) to the sea grass area, affecting the growth of sea grass and
algae through the process of food-consuming. As to the pelagic area, coral reefs
systems also export organisms to it as a kind of nutrients for the pelagic species.
Interestingly, some coral reef residents actually “move their homes” often between
coral reefs and the neighboring ecosystems, and this activity is called “grazing”. There
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are evidences of grazing as well as predation of these species. “Herbivorous fishes
and sea urchins from the reefs move to sea grasses for grazing and influence plant
community structure there, and may serve as a food source for predators in other
systems” (Moberg and Folke1999). To conclude, this interaction between ecosystems
is like trade agreement, and coral reefs ecosystem is similar to a mediating factor
between coastal waters and pelagic area, providing places to “rest” for certain
species and “babies.”
5. Supervisor of the Environment
The last benefit of having coral reefs is a rather practical one—coral reefs can
substantially help experts supervise as well as rebuild marine environment. The main
reason why coral reefs have this special function lies in the symbiotic phenomenon
between corals and algae. Due to the symbiosis that needs sufficient light and good
water circulation, coral systems are highly sensitive to its surroundings, and therefore
can act as the supervisor of their environment.
First of all, the “skeletons of reef building corals act as long-term chemical
recorders” (Moberg and Folke1999)on the grounds of its ingredient of calcium; coral
reefs play the role of climate recorders as well. These skeletons “can be used to
reconstruct the sea surface temperature of the topics” (Moberg and Folke1999), and
can detect the current sea temperature by showing bleaching—by sacrificing
themselves to tell people there are problems happening underwater. What’s more,
the discoveries of ancient reefs structures can be even more exciting to experts
because by examining the breadth, color, and other properties of the structure,
experts are able to rebuild the paleoclimatology, paleogeography and the ancient
environment that reefs had once lived in. This is similar to observing the annual rings
of a tree. There is an example that researchers from Australia and New Zealand had
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found a 9000-year-old reef off the coast of an island which is 600 kilometers east of
Australia in the Tasman Sea. According to them, the discovery of this old reef “may
help scientists determine how coral should be damaged if the sea temperature rises”
(Shannon2010).
From the above five reasons, one can see the very importance of coral reefs
conservation. Without even mentioning the economic benefits, coral reefs already
have so much functions and roles to play. They maintain the biodiversity, producing
renewable sources, protect and build up lands, interact with other ecosystems, and
are responsible for the supervision of the marine environment. In the next part,
threats to coral reefs will be offered.
Facts about Threats and Outcomes that Coral Reefs are Facing
There are many potential threats to not only the Great Barrier Reef but also all
the coral reef habitats in the world. Among them, three dominant factors are listed
below.
1. Changing of the World Climate
Everybody knows the deterioration of green house effect leads to numerous
problems, but seldom do people notice that the green house effect also affects the
growth of coral reef secretly. Green house gases such as carbon dioxide and methane
rise global temperature, land and ocean alike, and the changing of world climate is
perhaps the toughest problem to all coral reefs. According to the National
Geographic magazine published in May, 2011, “major bleaching in the Great Barrier
Reef and elsewhere in 1997-98 was linked to severe El Nino year and record-high
sea-surface temperature (Holland2011).” In fact, one phenomenon that brings this
issue to the public is the coral bleaching of the Great Barrier Reef, which will be
discussed later in this research paper. Even though the reef has experienced
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expansion and erosion since the ice ages, the world climate changing this time is
somehow more serious because of human industry activities.
2. Ocean Acidification
Ocean acidification, an aspect which people neglect even more than that of
changing of world climate, actually originates from the same element of green house
effect. Due to the increasing emission of carbon dioxide from industries, the level of
PH lower, meaning that the seawater becomes “sour.” According to chemistry,
carbonate can erode calcium, a major constituent which composes limestone and
shells on animals. In other words, ocean acidification “thwarts the ability of marine
creatures to build their limestone shells and skeletons” (Holland). It is clearly for one
to see the harm it does to the coral reefs.
3. Overfishing and Tourism
Overfishing and “over tourism” is another threat for the Great Barrier “Reef
which can be regulated by the government or related organizations. Nevertheless,
overfishing a can cause great damage to all kinds of ecosystems when the targets are
keystone species, certain species that play an important part in their ecosystems.
They are the key to “maintain the balance of all other species in the community, and
because of their huge impact on species diversity and community structure, they
have become popular targets for conservation efforts” (Klappenbach). For example,
in the Great Barrier Reef ecosystem, one of the keystone species is giant triton, a kind
of spiral shell which acts as the predator of crown-of-thorns starfish, a species that
feeds on corals. However, overfishing has been aggravated in recent years, keystone
and non-keystone species alike. Based on The latest Bureau of Rural Sciences (BRS)’s
comments on fisheries in Australia, “Among the 83 principal species classified, 17
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were listed as overfished and a further seven were subject to some overfishing.
Another 19 species were classified as not overfished, and 40 were classified as
uncertain.” Mr. Kennedy, director of Humane Society International, said ‘this meant
the number of overfished species had increased from 17 in the previous report to 24
in the 2005 report” (smh 2007).
In addition to overfishing, “overtourism” is another serious problem. The
Great Barrier Reef has always been a paradise for people who love sea activities. But,
too much tourists do harm to the coral reef itself. In national geographic magazines,
it mentions “The reef bears a two-mile-long scar from a collision with a Chinese coral
carrier in April of last year” (Holland2011). Other behaviors like collecting local
marine resources cannot be totally prohibited, either. This is an issue that worth
noticing, because it is a fact that destruction will always be made if there are too
much “visitors” in one place.
Apart from all these factors, the flooding in Australia also damaged the coral
reef system by “sending huge plumes of sediment and toxin-laden waters onto the
reef off Queensland” (Holland2011). These harms have been progressing step by
step, thus it is hard to prevent them from worsening instantly.
4. The Recession of Coral Reef—Coral Bleaching
Most coral species form a symbiotic relationship with algae in their cells to get
energy from them while they are photosynthesizing. However, when the sea
temperature rises and it is warmer in the surroundings, those algae becomes toxic
and will be “driven out” by coral polyps. Without the algae providing nutrients,
corals will starve and ultimately die. Besides, it is algae that make corals colorful.
Once the algae “leaves,” the corals return to their original, skeletal white color. This
process is called “coral bleaching,” a phenomenon fatal to coral systems.
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Based on the information from national geographic magazine, “major
bleaching in the Great Barrier Reef in 1997-98 was linked to severe El Nño year and
record-high sea-surface temperatures—in some spots 3ºF higher than normal”
(Holland2011). It has become the most serious problem for the Great Barrier Reef
ecosystem. Some experts even predict that “mass bleaching will happen more and
more frequently as a vicious cycle responding to the world climate change”
(Australian Government).
Conclusion
From the analysis above, one can agree that it is imperative to help save coral
reefs system. Even though the Great Barrier Reef is far from Taiwan, it is the hugest
coral reef ecosystem in the world. Besides, no countries can exclude themselves from
the action of protecting coral reefs because nearly everything happened in a country
will generally spread out and affect another. If the coral reefs fail to act as the shelter
for marine creatures, certain fishes or invertebrate larvae will lose their habitats and
their food sources, ultimately causing a disorder and imbalance between the
interactions among ecosystems. In fact, every ecosystem is irreplaceable, not only
the coral reefs one. This paper merely shows as an illustration about the causes and
effects of the losing of one ecosystem. Everything is connected to one another from
environmental perspectives, so people cannot afford to ignore even a tiny segment
anymore.
References
Australian Government: Department of Sustainability, Enviornment, Water,
Populations and Communities. n.d. The Great Barrier Reefs. Retrieved from
http://www.environment.gov.au/heritage/places/world/great-barrier-reef/informati
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on.html
Holland, Jennifer. S. (2011). A Fragile Empire. National Geographic, May 2011. 42-53.
Klappenbach, Laura. Great Barrier Reef Animals. Retrieved from
http://animals.about.com/od/naturalhistory/tp/great-barrier-reef-animals.htm
Moberg, Fredrik., Folke, Carl. Ecological Goods and Services of Coral Reef Ecosystems.
Ecological Economics. 29. (1999). 215-233. Retrieved from
http://www.fishdept.sabah.gov.my/pubdocs/coralreef-evaluation.pdf
Shannon, Sarah. (Sep 2010). Ancient Coral Reef Found in Tasman Sea. Digital Journal.
Retrieved from http://www.digitaljournal.com/article/296897
Smh.com. (Feb 2007). Overfished Species ‘up from 17 to 24.’ Retrieved from
http://www.smh.com.au/news/National/Overfished-species-up-from-17-to-24/2007/0
2/01/1169919453858.html
Dear Professor:
Thank you for teaching me for a year in both composition and oral training
classes; thank you for teaching me how to think critically, and thank you for letting
me do such special topics, especially those biological ones. I wouldn’t have chances
to finish them in other classes.
Best Regards
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June