Ocean Acidification: Another consequence of climate change

Our increasing fossil fuel consumption is hurting the ocean and the life it contains in more ways than increasing temperature. Reports confirming negative impacts that climate change are inevitably going to cause in our lifetime have been spreading through the media in recent weeks. Higher temperatures, rising seas, melting ice, drought, and many other consequences are the focus. However, you may not have heard about how marine life and our agriculture will be affected by our lifestyle. For many years marine scientists have been warning us that the oceans are becoming more acidic as a result of our increasing carbon dioxide (CO₂) emissions. Last month scientists found that acidic oceans are beginning to dissolve the shells of sea snails, and at least half of this damage is due to human activity. This is a threat to marine life and the economies that rely on it.

How do carbon dioxide emissions make the ocean more acidic?

Gases like CO_­2 and oxygen dissolve in water the same way that salt does. Oceans absorb about 1/3 of the CO_­2 emitted by humans, rather than it being released into the atmosphere. While this does slow global warming, it has a negative effect on the ocean and the life it contains. When carbon dioxide is dissolved into oceans, rivers, and lakes, it reacts with water and forms carbonic acid.

Acid separates into hydrogen and the acid component (carbonate in this case) when mixed with water. Acidity is quantified by pH, which is a measurement of the concentration of hydrogen atoms. The higher the concentration of hydrogen, the lower the pH, and the more acidic the water is.  The process of CO_­2 conversion to hydrogen ions is shown in the diagram below. It is estimated that since the industrial revolution the acidity of the ocean has risen 30%, to a pH of 8.1 (pure water has a pH of 7). 

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How do we know that humans are responsible?

As the acidity of the ocean increases, this triggers other chemical reactions which negatively affect marine life. Coral and plankton can’t form strong shells and they become vulnerable to dissolution. Acidic oceans are corrosive and can also harm eggs, larvae, and dissolve shells. A new study was done on pteropods, a type a marine snail more commonly referred to as sea butterflies, to explore the severity of ocean acidification. These snails are found along the pacific coast from Baja, California, to British Columbia. The study collected data from 100 meters of ocean at 17 different sites.

The scientists found that 38% of the snail shells showed signs of damage, resembling cauliflower. By studying the trends, the scientists were able to develop a model that could estimate past and future shell damage due to ocean acidification. Oceanographers were surprised by the extent of the damage to the snail shells. They had hypothesized that the snails would show some resistance to the corrosive waters, but that was not the case.  The study also concluded that human CO_­2 output has doubled the impact of ocean acidification since the industrial revolution and it will continue to get worse. “The picture is likely to worsen as emissions continue, and it bodes ill for the marine food webs that depend on pteropods,” the authors of the studies said.

The progressive damage to a pteropod shell is shown. In the bottom right picture, acidic oceans have caused this shell extensive damage. Source.

What does this mean for us?

More acidic oceans make it harder for animals to fight infection, maintain metabolic activity, defend themselves, and control their buoyancy. The effects span a large chunk of the food chain including corals, crustaceans, and other shell fish.

Commercial fisheries are impacted by ocean acidification because it harms the organisms that are the base of the food webs in the arctic ocean, which includes pteropods. These food chains contain few steps from small to large organisms, so a small disruption greatly impacts the species we depends on like fish and whales. The estimated value of fish that were caught from U.S. fisheries in 2007 alone was $3.8 billion, and 73% was derived from shellfish and their predators. Ocean acidification will harm economies that rely on recreational fishing, the seafood industry, and tourism. This is happening all over the world, not just in the United States.

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The only way to mitigate the destruction of marine life due to carbon dioxide emissions is to reduce them. Policymakers around the world are trying to find solutions to reduce or contain emissions through climate engineering, regulations, and investing in newer technology.

However, changing our lifestyle is the only way to slow the problem. We need to reduce our fossil fuel consumption, invest in new technology, and regulate emissions. It will have to be a joint effort across the entire world. We all need to work together to save each other from the devastating effects of climate change. Here's to working together for the greater good!

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Thanks for reading, and cheers to your brain!

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References: 

'Sea Butterflies' Are a Canary for Ocean Acidification

• Eli Kintisch

Science 9 May 2014: 344 (6184), 569. [DOI:10.1126/science.344.6184.569]

Alzheimer’s Disease: Researchers have found a new piece of the puzzle

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Dementia causes painful memory loss problems to those who are affected by it along with their friends and families. Chances are that someone you know in their 60s or older has memory problems that will or have already progressed into more serious cognitive problems. This devastating form of dementia is called Alzheimer’s disease, and is rapidly increasing as our life expectancy increases and currently has no cure. A new study might hold the key to better understanding why people get this heartbreaking disease, and provide insights into how to prevent it.

Alzheimer’s disease (AD) is a costly and emotionally taxing disease for those who have it and for their friends and family. With no current cure, most research today is focused on understanding this complex brain disease.  It is the most common cause of dementia, which starts with memory loss and can eventually lead to the loss of the ability to do every day tasks. 13% of people over 65 and 33% of people over 85 have developed Alzheimer’s and it is the sixth leading cause of death in the United States.

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As the population continues to age and live longer than the generation before it, Alzheimer’s becomes more common continues to consume more money in health care. Current research is trying to understand what happens in the brain that causes loss of memory and basic cognitive function so a cure or treatment can be found. Currently, there are treatments that delay or slow down the progression of the disease, but none that completely get rid of it or prevent it. Finding a cure or preventative measure for Alzheimer’s will dramatically decrease the cost of care for older people and reduce such devastating losses.

What we know about Alzheimer’s disease

The cause of AD and its progression are not well understood. The cells in the brain are damaged or killed, preventing the brain from telling the rest of the body what to do. As the disease spreads through the brain, the symptoms become worse, eventually making it impossible to do simple everyday tasks or hold conversations.

Plaques called beta amyloids are an indicator of AD. Beta amyloids plaques sometimes build up inside the nerve cells in the brain preventing them from connecting to send messages through the body. Another common indicator of AD is when proteins, called tau proteins, in the brain cells become tangled and build up inside the cell. Tau tangles and plaques usually initially develop in the memory region of the brain, which is why memory loss is the first symptom of AD.

Source. Beta-amyloids build up between nerve cells. As shown they can get in the way of the connections between cells so they can’t communicate to the rest of the body.

Scientists think that tangles and plaques play a role in blocking the communication between nerve cells, and the death of these cells are what causes memory loss. However, some people with tau tangles and plaques never develop symptoms of the disease, like memory loss. This has been a big challenge in the field, as scientists can conclude that plaques and tangles are not the cause of the disease, and something else must be occurring. The following video does a great job of visually explaining what happens inside the brain when Alzheimer’s disease develops.

A recent study may have found which protein causes Alzheimer’s disease

A new study from Harvard has shown that a stress response in the brain may be the key to the development of AD. A protein called REST (repressor element 1 silencing transcription factor) is a protein that regulates the expression of genes and is most commonly found in the brains of fetuses.

Genes are contained within DNA and tell proteins in the body what to do. Repressor proteins, like REST, interfere with the DNA structure and block the genes from telling other proteins in the body what to do. A recent Harvard study found that REST is the most active gene regulating protein in healthy older brains. The group now has reason to believe that REST is expressed in fetal brains and older brains to protect them because they encounter the most stress during those periods of time. REST appears to switch off genes that promote cell death.  They protect your brain from this:

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In the study, the researchers (Yankner et al.) found that brains of young adults (20-35 years old) had very low levels of REST, and brains of older people (73-106) without AD had very high levels of it. They also found that as age increases, levels of REST also increase unless the patient develops dementia.

Brains of the patients with no symptoms that had plaques and tangles had 3 times more REST than those who did have symptoms. In addition, people that had mild cognitive problems had significantly more REST than those with AD. Most of the REST was found to be in the region of the brain that is responsible for learning, memory, and planning (the prefrontal cortex hippocampus). One third of people whose brains have plaques and tau tangles do not develop symptoms of AD, and the presence of REST could explain why.

These results demonstrate an obvious connection between REST and AD, however, it is too early to tell if REST cause or consequence. High levels of REST in older brains indicates that they are healthy, whereas low levels of REST in older brains indicates dementia, but it is unknown if dementia results from the lack of REST or causes lower levels of REST. More research is needed to determine what the relationship is between the two.

Understanding this relationship could lead to the development of treatments for AD. Treatment for AD would result in better quality of life for the population as we age, and would translate into huge savings in medical costs – both for families enduring it and for the economy. I hope to hear more about positively life-changing discoveries in science!

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Thanks for reading, and cheers to your literal brain!

Like my Facebook page to stay up to date on weekly blog posts and other science findings!

References:

REST and stress resistance in ageing and Alzheimer/'s disease. T Lu, L Aron, J Zullo, Y Pan, H Kim, Y Chen, TH Yang, et al.  Nature, 2014