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The Effect of Rising pH Levels on Marine Organisms in Tide Pools
Jessica Garcia and Jackie Olvera (1.)
Department of Biological Science
Saddleback College
Mission Viejo, CA 92692
Abstract (1)
Marine organisms are being affected by the acidity of the ocean. The
hypothesis tested was that there would be a less abundance of animals in an environment
with a higher acidity. Two locations in Southern California were observed: Doheny State
Beach in Dana Point and Treasure Island in Laguna Beach. The average pH at Doheny
was 8.2 and the average pH at Treasure Island was 8.8. The variation in pH was too
slight to see a difference in abundance of organisms. The area of the tide pools however
did have an affect of abundance of marine organisms. At Treasure Island the tide pools
were much deeper therefore they had significantly more organisms than that at Doheny.
We concluded that to see if the acidity of the ocean does in fact have an effect on the
abundance of organisms then a wider range of locations would be needed to be observed
(2). More organisms were found in the larger tide pools which was expected (3.) so in
order to have more accurate results we would need to visit tide pools that were much
closer in size at all locations.
(4)
Introduction
Recent studies have shown that the rise in carbon dioxide levels in Earth’s (1)
atmosphere has had an effect on Ocean acidity. When carbon dioxide in the air hits the
ocean water a chemical reaction occurs and turns that carbon dioxide into carbonic acid.
An abundance of Carbon Dioxide (2) changes the chemistry of the sea causing the life for
most marine organisms to be in danger (Caldeira 2003).
The distribution of animals is correlated with the environmental factors such
as dissolved oxygen (Jayalakshmy 2008), water temperature, depth, tidal amplitude, and
turbidity (Cha 2004). Water temperature and acidity are directly related. As the water
temperature increases the pH of the water becomes more acidic. The carbonic acid
present in intertidal environments has a negative effect on its inhabitants. Most marine
organism shells and skeletons are composed of the mineral calcium carbonate which is
slowly dissolved by the carbonic acid (Caldeira 2003). Therefore the higher the water
temperature and the more carbon dioxide polluted into the air leads to a more acidic
ocean that can dissolve the shells and skeletons of marine organisms that play an
important role in the food chain. For example smaller shelled organisms called pteropods
are becoming rarer (3) which can disrupt the food chain. Pteropods are a major food
source for larger organisms such as fish and lobsters which are a major food source for
humans (Caldeira 2003). Temperature cannot be controlled as easily as carbon dioxide
abundance. The solution to this problem is to simply lower carbon dioxide emissions. If
we continue to emit carbon dioxide into our atmosphere, then the continuation of
dissolving shells and skeletons of marine organisms that are vital to the food chain will
quickly be eliminated.
Marine organisms already have other dangers to worry about such as
predators. For example in areas where starfish are more abundant sea urchins tend to
emigrate from that environment (Schroeter 1983). Most marine organisms are capable of
adapting to other environmental changes such as turbidity. Not only do shelled organisms
suffer from the rise in pH of the ocean but coral reefs are also struggling to survive
(Smith 1992). Scientists are considering ocean acidification as the other carbon problem
with the first carbon problem being global warming. The first step to solving this
problem is lowering the carbon dioxide emissions given off from automobiles. Doing
this can also help the ozone layer and ultimately halt the ocean acidity problem.
Methods & Materials
Observations were determined during low tide in November of 2009 (1) for the
following two locations: Doheny State Beach in Dana Point, California and Treasure
Island Beach in Laguna Beach, California. The locations were selected by their
variations in pH levels. At each location three tide pools of various sizes (small, medium,
and large) was (2) observed by calculating the area for each using a tape
measure. Having once determined the area calculations of the tide pools, all organisms
visible were counted within each pool.
Determining the quantity of each organism found in the tide pools, allowed us
to foresee any possible differences that could potentially be affected due to its levels of
pH. Among the organisms discovered were the Amthopleura xanthogrammica (sea
anemone), Pisaster ochraceus (sea star), Mytilus californianus (California mussel),
Pagurus samuelis (hermit crab), Tegula funebralis (snail), Octopus vulgaris (common
octopus), and Aplysia californica (sea hare) (3). The pH at both locations was
determined by using a pH probe (4) provided by Professor Steve Teh, Professor of
Biological sciences at Saddleback College. (5)
Results
In Table 1 (1), the frequency of organisms was graphed according to their
location and size of tide pool they were located in. This indicates that organisms were
more abundant at the tide pools located at Treasure Island, specifically in the large tide
pool.
In Table 2 (1), the amount of each individual species observed was graphed
along with the pH of the tide pool it was located in. The results indicated that there was a
difference in the abundance of organisms located in tide pools with different acidity
levels. The average pH of the tide pools located at Doheny State Beach was 8.2 and the
average pH of the tide pools located at Treasure Island was 8.9. There was a difference
in the abundance of organisms at both locations due to there varying pH levels. More
organisms were found in the tide pools at Treasure Island than at Doheny State Beach. (2)
Table 1 (1)
60
Mean Frequency
50
40
Doho
30
T.Isle
20
10
0
Small
Medium
Large
Table 1 (1) caption: Bar graph displaying the mean frequency of marine organisms in tide
pools at the locations of Doheny State Beach (Doho) and Treasure Island (T. Isle).(2)
Table 2 (1)
250
Sea Anemone
200
Frequency
Mussels
Snails
150
Hermit Crabs
100
Starfish
Sea Slug
50
Octopus
0
8.2
8.9
pH
Table 2 (1) caption: Bar graph displaying the amount of total organisms of a specific
species found in different levels of pH.
Discussion
The acidity level in intertidal environments has been shown to have a negative
effect on shelled organisms. Shells are beginning to slowly dissolve due to the acidity of
the ocean which is created by the carbon dioxide emissions given off by various creations
made by the Industrial Revolution (1). We tested this by measuring the pH of marine
environments at two different locations in Southern California. Along with the pH
readings we counted the amount of organisms present of different species. The species
included were sea anemones, mussels, snails, hermit crabs, sea stars, sea hares, and
octopus. The area of each tide pool was also conducted by measuring length, width, and
depth.
Our results indicate that our hypothesis was supported however the difference
in the abundance of organisms found in the different pH environments was too slight to
make an assertive decision with confidence. The area of each tide pool indicated that
there was a more abundance of marine organisms living in larger environments. Further
investigation is required in order to justify these results with confidence. (2)
Literature Cited
Cha HR, Buddemeier RW, Fautin DG, Sandhei P. 15 November 2004. Distribution of sea
anemones (Cnidaria, Actiniaria) in Korea analyzed by environmental
clustering. Hydrobiologia. 430(Sp. Issue): 497-502
Jayalakshmy KV, Saraswathy M, Nair M. 20 August 2008. Effect of water quality
parameters on the distribution of Pleuromamma (Copepoda-Calanoida)
species in the Indian Ocean: a statistical approach. Environmental Monitoring
and Assessment. 155(1-4): 373-392
Schroeter SC, Dixon J, Kastendiek J. 1983. Effects of the starfish Patiria miniata
on the distribution of the sea-urchin Lytechinus anamesus in a southern
Californian kelp forest. Oecologia. 56(2-3):141-147
Smith, S. V. and R. W. Buddemeier. 1992. Global change and coral-reef ecosystems.
Annual Review of Ecology and Systematics 23:89-118
Caldeira K, Wickett ME. 2003. Anthropogenic carbon and ocean pH. Nature
425:365-365
Peer Review Comments and Corrections
Title
1. There should be a space between your title and your names
Abstract
1. The title “Abstract” should not be there. The entire paragraph should be bold.
2. Should say “would need to be observed”
3. Reads awkwardly. Remove.
4. There is too much space between the paragraphs. This applies to all of them.
Introduction
1. the Earth’s
2. carbon dioxide should not be capitalized
3. Rarer is not a word. It should be “more rare”
Materials and Methods
1. What dates exactly? (if relevant)
2. Were not was. And add “by” before the word calculating.
3. Common names first, then scientific names in parenthesis.
4. Who makes the pH probe?
5. Should add a sentence saying that you put this into Excel to run the data.
Results
1. Should be figure not table
2. Figure 1 should have a (± SEM, N= ?) values after each of the means. Graph have
Y error bars to represent the SEM. (if relevant)
Disscussion
1. This sentence is awkward, reword it.
2. This discussion section is too short and is just a restating of the other sections of
the paper. It needs to be its own section citing past experiments (if any), and an
explanation as to why you think you got the results that you did. Also think of
suggesting the next experiment you could do based off these results (not what you
did wrong this time, but what you could try differently next time).
Literature Cited
1. Take out the dates in red.
Review Form
Department of Biological Sciences
Saddleback College, Mission Viejo, CA 92692
Author (s): Jessica Garcia and Jackie Olvera
Title: The Effect of Rising pH Levels on Marine Organisms in Tide Pools
Summary
Summarize the paper succinctly and dispassionately. Do not criticize here, just show that you understood the paper.
In this experiment, the researchers were looking at the effects of pH levels on
marine organisms in tide pools. They used two locations to conduct their experiment:
Doheny State Beach in Dana Point and Treasure Island in Laguna Beach. They
hypothesized that there would be fewer organisms in areas with a lower pH (more
acidic). At each location, researchers three different size pools (small, medium and large)
were measured with a tape measure. Area was then calculated, and all visible organisms
were counted in their respective pools. The pH was determined using a pH probe
provided by the college. Data was run in Microsoft Excel and the first table showed that
there was a higher frequency of animals in Treasure Island tide pools than in Doheny tide
pools. The second table showed that both snails and hermit crabs were the most abundant
organisms in each pH. There is not enough information provided in the discussion to
summarize why the researchers got these results.
General Comments
Generally explain the paper’s strengths and weaknesses and whether they are serious, or important to our
current state of knowledge.
Overall I think it was a good idea to look at whether pH has an affect on marine
organisms in the tide pools. It was very relevant to things happening in the news today,
and could be applied to the current body of knowledge on global warming and changing
pH levels in our environment. However, I think it was a little too broad in scope. The
researchers did not specify which marine organisms they were going to look at, just used
the ones they found while measuring the size and pH of the pools. Also, it is not directly
stated how the researchers measured the size of the tide pools (i.e. diameter, radius,
etc…). If any calculations of area were done, the formula the researchers used should be
included in the paper. In the results section there is data missing. Because of these
missing details, this experiment would be hard to duplicate.
The introduction was overall easy to read and informative, but could use more
background information if possible. I believe the biggest weakness in this paper to be the
lack of an appropriate discussion section. The section included in this paper is merely a
restatement of the sections before it. Because of this there is no explanation as to why the
researchers think they got these results.
With some changes, I think this paper could be much stronger.
Technical Criticism
Review technical issues, organization and clarity. Provide a table of typographical errors, grammatical
errors, and minor textual problems. It's not the reviewer's job to copy Edit the paper, mark the
manuscript.
This paper was a final version
X This paper was a rough draft
Most of the major technical and grammatical errors are marked on the actual
paper. There were also several grammatical errors that are not marked. Many sentences
are missing correct punctuation such as commas. Sentence structure is also awkward or
repetitive in some places and should be reworked.Despite these notes, the organization
and clarity of this paper are clear enough that a reader could follow the flow of the
experiment.