BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: Ocean Acidification

How are ocean conditions harming its animals?

A recent article written by Rachel Nuwer discusses the dangers of ocean acidification and how the ocean environment could compromise the fishes’ ability to swim and feed. The existence of one of the world’s most threatening predators is being threatened by ocean warming and acidification. Sharks might lose their place at the top of the marine food chain due to the changing ocean environment. As carbon dioxide levels rise in the ocean, it increases the acidity of the water. As this factor starts to rise, the teeth and scales of sharks may begin to damage, which compromises their ability to swim, hunt, and feed. According to research published in Scientific Reports, acid-base adjustments have proved to be the first piece of evidence of “dentical corrosion” caused by ocean acidification conditions. After investigating the impact of hypercapnia on a specific shark species and analyzing the acid-based regulation, the team concluded that the denticle corrosion could increase denticle turnover and compromise the skin and protection of the shark species.

A close up on the denticles and scales of a wild shark

The harsh conditions placed on the sharks could cause several consequences and ultimately could affect the whole ocean community. Biologist Lutz Auerswalk states that sharks could be displaced as apex predators, which could disrupt the whole food chain. In addition, great white sharks are already endangered, and these conditions could wipe them out completely, he states. Ocean research Sarika Singh and Auerswald, while studying over beers, stumbled upon a unique idea. After realizing that the high acidity of beet and many other carbonated beverages causes human teeth to erode, they wondered what effect more acidic ocean water might have on shark teeth.

Most studies on ocean acidification examine species that specifically build shells or other calcium-based structures, including corals and shellfish. Because sharks are large and challenging to work with, only a few studies have been conducted about how acidification might impact these animals. Only one paper has examined the effect of pH on sharks’ skin denticles or scales. The study used small-spotted catsharks and exposed them to different environments and filmed their swimming patterns. After analyzing a pectoral fin skin sample, they did not find a specific impact. However, the results were possible constrained by the low carbon dioxide concentration the researches used, compared with the high levels of acidity already present in many oceans.

To begin exploring this question for themselves, Auerswald and Singh conducted an experiment and focused on puff adder shy sharks, a small species that is easy to handle. They decided to investigate the acidification effects on the bigger scales. They divided the sharks into control and experimental groups and observed the results. After a few months, the electron-microscope analysis revealed that the concentrations of calcium and phosphate in the sharks’ denticles were significantly reduced. They noticed damaged scales on many of the sharks as well. Though the corroded scales might not impact their ability to hunt, for larger species such as the great white shark, scales play an essential role in hydrodynamics. Because denticles are responsible for an increase in swimming speed, damaged denticles could slow sharks down and make it more difficult for them to catch prey. Because many animals have been wiped out, we must strive to protect all the species that are deeply impacted by this condition.

Effect of ocean acidification: Coral growth rate on Great Barrier Reef plummets in 30-year comparison

GreatBarrierReef-EO

A new marine biological study conducted in Australia shows a correlation between rising ocean acidification levels and declining coral growth rates in the Great Barrier Reef. Scientists Ken Caldeira and Jacob Silverman carried out research testing growth rates from samples of current coral on the reef and records from the 1970’s. The findings were astounding. According to the comparison, coral growth rates have declined by almost 40% since the 1970’s and the scientists believe they have an explanation.

Coral produce their exoskeleton by utilizing aragonite, a naturally occurring calcium carbonate (CaCO3). This process is called calcification. However, when acid levels in the water become too high, the environment for producing healthy coral becomes compromised. Since the beginning of the Industrial Revolution about one third of all CO2 released into the atmosphere has made its way into the oceans. This lowers the Ph, causing the water to become more acidic, and creates an environment ill suited for coral growth. The scientists speculate that this acidification of the water is whats leading to decreased growth rates in not only coral, but also many other species of marine life.

Coral plays a vital role in underwater ecosystems, providing food sources and shelter for nearly 25 percent of all marine life. Some reefs admired and studied by scientists today began growing nearly 50 million years ago. There is no question that coral’s role is vital in the fabric of the ocean. However, recent studies similar to the research done by Caldeira and Silverman are prompting scientists to worry deeply about the future of our oceans. When quoted on the status of reefs today, Caldeira stated, “Coral reefs are getting hammered. Ocean acidification, global warming, coastal pollution, and overfishing are all damaging coral reefs. Coral reefs have been around for millions of years, but are likely to become a thing of the past unless we start running our economy as if the sea and sky matters to us very soon.”

Photo credit: Wikipedia Public Domain Images: http://en.wikipedia.org/wiki/Great_Barrier_Reef#mediaviewer/File:GreatBarrierReef-EO.JPG

Article:http://www.sciencedaily.com/releases/2014/09/140917121225.htm

Links for further reading:

http://www.pmel.noaa.gov/co2/story/Ocean+Acidification

http://ocean.nationalgeographic.com/ocean/critical-issues-ocean-acidification/

http://www.greatbarrierreef.org/

 

 

 

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