Shemanski
Naomi Shemanski
V. Fong
English 1T
1 June, 2015
Changes in Earth’s Ocean and Effects on the Environment
Oceans cover approximately 70% of the earth, and play a vital part in the earth’s climate.
The earth’s climate impacts events on land as well as the temperature of the ocean. The United
States Environmental Protection Agency (EPA) has indicated that “the world’s oceans have a
two-way relationship with weather and climate. The oceans influence the weather on local to
global scales, while changes in climate can fundamentally alter many properties of the oceans”
(EPA, 1). This information is relevant because it affects the whole world and its species. This
paper discusses many of these effects, including declining fish stocks, melting ice caps playing a
part in worldwide climate and changes in the ocean’s currents that can affect weather in specific
regions. According to an article by the San Francisco Chronicle’s Washington correspondent,
Carolyn Lochhead, President Obama’s science advisor, John Holdren, has said that “Climate
change is moving faster than anticipated” (Lochhead, A1), which makes this issue worthy of our
immediate attention. Not only are these climate changes moving quickly, but according to recent
scientific studies, “rapidly rising greenhouse gas concentrations are driving ocean systems
towards conditions not seen for millions of years” (Hoegh-Guldberg and Bruno, 1523). These
concentrations are affecting both the acidity and temperature of the ocean.
Ocean Warming
Studies indicate that the ocean’s temperature is rising due to the burning of fossil fuels by
humans. Ocean heat content is defined as the total amount of heat stored by the oceans, and it’s
measured in joules. Measurements of ocean heat content are made at specific locations.
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According to the EPA, “Three separate analyses show that the amount of heat stored in the ocean
has increased substantially since the 1950’s” (EPA, 2). Many scientists agree with Doctor Rod
Fujita, the Environmental Defense Fund’s chief marine biologist, that “For decades, the ocean
has been absorbing carbon dioxide dumped into the atmosphere by burning fossil fuels. It has
also absorbed a lot of the extra heat produced by elevated… carbon dioxide levels” (Fujita, 2).
These analyses are done by taking scientific measurements using core samples. As indicated by
the Congressional Digest, “Cores from corals, ocean sediments, ice records, and other indirect
temperature measurements indicate the recent rapid increase of ocean temperature is the greatest
that has occurred in at least the past millennium” (U.S. Global Change Research Program
(USGCRP), 1).
These analyses go on to say, “[this ocean increase] can only be reproduced by climate
models with the inclusion of human-caused sources of heat-trapping gas emissions” (USGCRP,
1). The emission of these gases is caused by the burning of fossil fuels, like gasoline in cars and
coal-fired energy plants. However, it is important to note that if we were to stop the causes of
ocean warming, it would not solve the problem immediately. As the EPA has indicated,
“Changes in ocean systems generally occur over much longer periods than changes in the
atmosphere… trends can persist for decades, centuries, or longer” (EPA, 1). This means that if
humanity switched to cleaner energy and put far less CO2 in the atmosphere, it would still take a
long time for the ocean to go back to normal. Also, this quote explains why the changes have
taken so long to happen. After all, the Industrial Revolution was well over one hundred years
ago, and many of the changes to the oceans were noticed only relatively recently.
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Ocean Acidification
Not only has the rise in CO2 caused the ocean to heat up, it has also caused the ocean to
be more acidic. According to Fujita, “The ocean has absorbed about 30% of all carbon dioxide
that we humans have sent into the atmosphere since the start of the Industrial Revolution --some 150 billion tons… the trend in ocean acidification is about 30 times greater than natural
variation, and the average surface ocean pH (the standard measure of acidity) has dropped by 0.1
unit (a highly significant increase in acidity)” (Fujita, 1).
The Effect of the Ocean’s Warming and Acidification on the Ocean
Now that the changes in the ocean by the greenhouse gases put into the atmosphere have been
discussed, the next question to consider is, “why does this all matter?” Well, these changes have
a great effect on not only ocean life and marine ecosystems, but wetlands and the polar ice cap as
well. The Congressional Digest explains how the warming ocean affects marine biology, stating,
“Climate change impacts such as increasing ocean temperatures can profoundly affect
production of natural stocks of fish by changing growth, reproduction, survival, and other critical
characteristics of stocks and ecosystems” (USGCRP, 4). Because of the ocean warming, diseases
are affecting the ocean’s ecosystem. One such example is the spread of the oyster parasite,
Perkinsus Marinus in the Northeastern United States in 1990 and 1991. Another example is the
deadly rickettsial infection among California’s red abalone. These are just a few of the diseases
that scientists have found to be spreading due to the ocean warming. The Congressional Digest
explains, “Climate-driven warming reduces vertical mixing of ocean water that brings nutrients
up from deeper water, leading to potential impacts on biological productivity. Warming and
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altered ocean circulation are also expected to reduce the supply of oxygen to deeper waters…”
(USGCRP, 2). When there are fewer nutrients in certain parts of the water, the food web will be
greatly affected, as these nutrients are central to the structure and life of marine organisms.
Hoegh-Guldberg and Bruno observed this problem as well, stating that, “The warming of
the upper layers of the ocean also drives greater stratification of the water column, reducing
mixing in some parts of the ocean, and consequently affecting nutrient availability and primary
production” (Hoegh-Guldberg and Bruno, 1524). This has resulted in an increased size of
nutrient-poor ocean deserts. If there are not enough nutrients available, ocean species will not
have enough food and will not be able to sustain themselves or reproduce.
What has happened to the ocean so far? The changes have started even now, as HoeghGuldberg and Bruno explain in their article. According to them, “Marine ecosystems are already
responding to the rapid pace of change in the physical and chemical conditions that surround
them. One of the most important impacts has been on the organisms and physical processes that
create habitat for millions of other species” (Hoegh-Guldberg and Bruno, 1527). This habitat
destruction now threatens the ocean’s biodiversity, which is also in danger from other
environmental factors such as pollution and overfishing. Three of these habitats are the coral
reefs, the wetlands, and the kelp forests. Scientists refer to the threat to the coral reefs from
carbon dioxide in the atmosphere as the “bleaching” of coral reefs. According to Fujita, “…Mass
coral-bleaching events that scientists observed during the 1980s were probably due to
anomalously warm temperatures related to climate change” (Fujita, 1). Calcium carbonate is
used not only by ocean species to form their skeletons and shells, but also by the coral reefs to
build their formations, where reef organisms live. The increased frequency of the coral
bleaching and mortality of the reefs can be seen on Heron Island, part of the southern Great
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Barrier Reef, where coral reef ecosystems which inhabit these reefs are declining. The wetlands,
another habitat, are not able to grow fast enough to keep up with the rise of the sea level due to
the ocean absorbing heat. The wetlands cannot keep their blades above water so the marine life
is not able to sustain itself on the wetlands. Likewise, the kelp forests are also shrinking due to
the warmer ocean waters. One example is the Daintree River in northeastern Australia. In
addition, the changes in the ocean affect the biology of the ocean as well. Hoegh-Guldberg and
Bruno state, “Variation in temperature can also have impacts on key biological processes. For
example, the distribution and abundance of phytoplankton communities throughout the world…
are changing in response to warming, acidifying, and stratifying oceans” (Hoegh-Guldberg and
Bruno, 1525). The warming trends and the uneven distribution of heat influences the ocean
currents, which are crucial in the biology of the ocean.
The authors continue, “the steady increases in heat content of the ocean and atmosphere
are likely to have profound influences on the strength, direction, and behavior of the world’s
major current systems. Changes in the behavior of ocean currents have the potential to strongly
influence the distribution and abundance of marine ecosystems” (Hoegh-Guldberh and Bruno,
1525). So not only does ocean warming make disease more prevalent, it also changes the way the
ocean streams flow. As the currents are altered due to the change in heat, one can imagine how
this will affect ocean life as life forms suddenly find themselves in an environment that they have
not adapted to, and thus cannot survive in. Think of it similar to a tropical plant, which can only
live in areas with heavy rainfall, suddenly in the desert. Also imagine a reptile in a very cold
location, where it would surely freeze to death. This sounds an awful lot like the proverbial “fish
out of water,” doesn’t it?
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“Sea ice, like coral reefs and kelp forests, plays a critical role in structuring the
biodiversity of polar oceans. The spring melt has a major role in determining the timing in
phytoplankton blooms, and consequently influences polar marine food web dynamics” (HoeghGuldberg and Bruno, 1526). Sea ice contains sea-ice algae which is a source of food for many
species such as krill whose population has been decreasing and is thought to be a result of the
melting sea ice. In addition, sea ice also plays an important role for many mammals and birds as
it provides a permanent site for reproductive, migratory, and predatory activities. The U.S.
Global Change Research Program, which is made up of thirteen federal government agencies,
states:
In conjunction with a warming climate, the extent and thickness of Arctic Sea ice has
decreased rapidly over the past four decades. Models that best match historical trends
project seasonally ice-free northern waters by the 2030s. (USGCRP, 2)
Indeed, a grim outlook for the many dependent mammals and birds. The populations of penguins
and seals in the Antarctic are already declining and could risk extinction if warming continues.
The changes caused by ocean warming are a threat to life all around the world, of course
including humans.
Some Effects of the Ocean’s Warming on the Earth’s Climate
Recent ocean temperature changes have probably had a role in the current California
drought. As a result of the ocean’s two-way relationship with the climate, ocean warming also
plays a part in unusual and extreme climate changes around the world. The ocean’s temperature,
particularly the temperature of its surface, has a significant influence on the earth’s climate. The
surface of the ocean provides energy for storm creation, which influences weather around the
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world. Robson adds, “It is also well-established that multidecadal variability in Pacific [Ocean]
SSTs [sea-surface temperatures]… can affect the climate in many regions, especially droughts
and flooding in North America” (Robson, 6329).
Conclusion
There are people who don’t believe that the changes in the ocean are affecting the
climate. They could say that the ocean’s temperature hasn’t gone up dramatically and the change
in the ocean’s pH is small. They would point out that there are other factors that would cause
changes in the climate such as volcanic eruptions or the sun’s heat becoming more intense. They
would also question the method of measuring the ocean’s temperature, saying that it has been
inconsistent. In response to this, it is important to say that scientists have done studies of the
ocean’s temperature in many countries that show that the ocean is warming and that the warming
has similar effects around the world.
Hoegh-Guldberg and Bruno note, “The rapid ecological shifts that are occurring in the
world’s oceans present major challenges for managers and policy-makers… reducing greenhouse
gas emissions remains the priority… because it will reduce the growing risk of pushing our
planet into an unknown and highly dangerous state” (Hoegh-Guldberg and Bruno, 1527). Policy
makers need to act quickly. Unfortunately, pollution laws are generally managed on a countryto-country basis, and lowering pollution would take global agreement and action. World-wide
education is a possible solution to include how to change pollution laws in the major countries
contributing to climate change.
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Annotated Bibliography
Hoegh-Guldberg, Ove and Bruno John F. “The Impact of Climate Change on Marine
Ecosystems.” sciencemag.org. Science Magazine, 18 June 2010. Web. 19 May 2015.
Lochhead, Carolyn. “Climate Change Worsens Drought” San Francisco Chronicle, 25 May 2015
page A1. Print.
Fujita, Rod. “The Argo Project.” elsevier.com. Live Science Journal, mid 2012. Web. 20 May,
2015.
Environmental Protection Agency. “Climate Change Indicators in the United States.”
EPA.gov, May 2014. Web. 25 May 2015.
“Oceans and the Environment.” Congressional Digest 93.7 (2014): 2. MAS Ultra – School
Edition. Web. 25 May 2015.
Robson, Jon and Sutton, Rowan. “Predictable Climate Impacts of the Decadal in the Ocean in the
1990’s.” American Meteorological Society, 1 September 2013. Web. 20 May 2015.
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