Ocean acidification is caused by higher levels of carbon dioxide in the atmosphere being absorbed by the ocean, which increases the acidity of ocean water over time. The pH of ocean water has dropped from around 8.2 to 8.1 and is projected to decrease by 0.3 to 0.4 units over the next century. As the pH of the ocean decreases, it absorbs more CO2 from the atmosphere. This interacts with water molecules to form carbonic acid, lowering pH further. Additionally, ocean acidification may amplify ocean noise levels by around 10% and extend the range of underwater sounds by about 500 kilometers. This can negatively impact marine species by disrupting communication, increasing stress levels, and potentially causing hearing

1. AJ SHOCKLEY
Ocean Acidification and
Ocean Noise

2. The pH of the Ocean
 Ocean acidification is the lowering of oceanic pH
 The ocean is naturally slightly basic
 Historic pH= ~8.2
 Current pH= ~8.1
 pH is projected to decrease .3-.4 within the next
century.

3. Setting the
Stage
GHG like CO₂, CH₃, and
water vapor trap the
solar energy in the
Earth’s atmosphere,
heating the Earth.
Higher anthropogenic
CO₂ emissions causes
Global Warming.
But what does this have
to do with the ocean’s
pH?
The Greenhouse Effect

4. CO₂ CO₂ CO₂!!! CO₂ vs Oceanic pH
 While land sinks more
atmospheric CO₂ the
ocean has a better
capacity to store it (30-
40%).
 As atmospheric CO₂
increases the pH of the
ocean decreases.
The Evil Twin of Global Warming

5. How It Works
 CO₂ interacts with
H₂O to form carbonic
acid which lowers pH.
 Carbonate generated
by carbonic acid
saturates the ocean.
 For every CO₃ two
HCO₃ are produced
while only one CaCO₃
is produced resulting
in an over
accumulation of HCO₃.
Bicarbonate
CO₂ + CO₃ + H₂O ⇔ 2HCO₃
Calcium Carbonate
Ca + CO₃ → CaCO₃

6. Sound in
the Ocean
Water v Air
Water is ~800 times denser
than air so sound travel 5 times
faster.
Marine communication
Chemical
Visual
Audio
THE OCEAN IS LOUD
Hunt Mate
Stake
Territory
Navigation
Uses of sound
by marine
species
Anthropogenic Sources
Oil exploration and Mining
Cargo Ships
Submarines
Military Sonar
Fishery noisemakers
Natural Sources
Storms and Earthquakes
Other animals
Vents

7. Two-Fold Effect Effects to Marine Species
 Low pH decreases levels
of B(OH)₄⁻ a known
sound absorbing ion
causing it to dionized.
 CO₂ is known to
propagate low
frequency (10-500Hz)
sound about ~10%
 Increased tissue
trauma, cortisol and
heart rate
 Hearing loss
 Displacement and
strandings
 Disruption of feeding,
breeding and nursing
Ocean Noise in the Context of Ocean
Acidification

8. Misconception Reality
 Due to acidification
sound absorption will
decrease by half so
sound will double
increasing distance
exponentially.
 Exposure to sound
pollution will end in the
extinction of several
species.
 Sound is predicted to
increase by two dB (x2) on
average by 2100.
 Acidification adds 10%
amplification and ~500km
to the average 4000km
reach of sound.
 Current sound pollution
contributes to species
mortality but not nearly to
the extent of ocean
warming.
Effects of Ocean Sound

9. There Are Some Issues…
Incomplete knowledge of mechanisms
• Namely borate and sound absorption
Models are difficult construct because many patterns cannot be
predicted
Dissonance in scientific communities
• Obsolete models?
• Conflicting information
Distance vs Intensity and regional effects?
• Areas with high noise pollution will have higher CO₂ levels
• Research focuses on sources with borate as the only sink

10. AsForFutureResearch…
Updated models
and formulas
More inclusive
studies
Filling knowledge
gaps
Addressing
climate change

11. Questions?

12. Bibliography
1. Hester, K. C., Peltzer, E. T., Kirkwood, W. J., and Brewer, P. G. "Unanticipated Consequences of Ocean
Acidification: A Noisier Ocean at Lower PH." Geophysical Research Letters 35.19 (2008): 1-5.
Web. http://www.mbari.org/highCO2/peerart/noisy-ocean.pdf
2. Brewer, P., and Hester, K. "Ocean Acidification and the Increasing Transparency of the Ocean to
Low-Frequency Sound." Oceanography22.4 (2009): 86-93. Web.
http://www.tos.org/oceanography/archive/22-4_brewer.pdf
3. Slabbekoorn, H. "Measuring Behavioural Changes to Assess Anthropogenic Noise Impact in Adult
Zebrafish (Danio Rerio)." Noise Impact on Fish(n.d.): 244+. Web.
<http://www.measuringbehavior.org/files/2012/ProceedingsPDF(website)/Special%2
0Sessions/Progress%20in%20Assessing%20Animal%20Welfare%20in%20Relation%
20to%20New%20Legislation%20Opportunities%20for%20Behavioural%20Research
ers/Slabbekoorn_MB2012b.pdf>
4. Joseph, J. E., and Chiu, C-S. "A Computational Assessment of the Sensitivity of Ambient Noise Level
to Ocean Acidification." N.p., n.d. Web.
http://scitation.aip.org/content/asa/journal/jasa/128/3/10.1121/1.3425738
5. Hildebrand, J. A. "Anthropogenic and Natural Sources of Ambient Noise in the Ocean." Contribution to
the Theme Section ‘Acoustics in Marine Ecology’ Anthropogenic and Natural Sources of Ambient
Noise in the Ocean 395 (2009): 5+. Web.
http://faculty.wwu.edu/~shulld/ESCI%20432/Hildebrand2009.pdf
6. Winner, C. "Will More Acidic Oceans Be Noisier?" Oceanus Magazine. N.p., 8 Oct. 2010. Web. 31 Jan.
2015. http://www.whoi.edu/oceanus/feature/will-more-acidic-oceans- be-noisier

13. Bibliography Cont.
 Images
 http://envis.tropmet.res.in/kidscorner/greenhouse.htm
 http://davidappell.blogspot.com/2013/10/epa-sued-to-stop-
pacnw-ocean.html
 http://tygae.weebly.com/ocean-acidification.html
 http://sciexplorer.blogspot.com/2012/02/earths-atmosphere-
part-8-how-to-care.html
 http://ngm.nationalgeographic.com/2011/01/big-idea/noisy-
ocean
 http://en.wikipedia.org/wiki/National_Oceanic_and_Atmospheri
c_Administration
 http://www.whoi.edu/oceanus/feature/will-more-acidic-oceans-
be-noisier