Ocean Acidification

Humans today are relying very heavily on carbon dioxide to fuel our way of life. We expel tons of carbon into the atmosphere every year from industry, agriculture, and from our own daily activities. Carbon emissions stay trapped in the atmosphere and cause a greater level of insulation of the sun’s heat, causing the earth’s temperature to increase. This phenomenon commonly referred to as global warming.

The greenhouse effect explains how increased levels of carbon dioxide contribute to the increased temperatures of earth.

While many people are familiar with the concept of global warming, significantly fewer people know about an equally problematic result of carbon emissions: ocean acidification. About 30-40% of carbon emissions get sucked into the oceans and have drastic effects on ecosystems. Some of this carbon combines with water and forms carbonic acid. An increased amount of carbonic acid causes there to be more hydrogen ions and thus a lower pH because there is a higher acidity. From 1751 to 1994, the oceanic pH dropped from 8.25 to 8.14 with an almost 30% increase in hydrogen ion concentration.

Increased acidity could have many negative effects on the ocean and on sea life. It could cause organisms to have lower metabolic rates and less responsive immune systems, both of which could lead to death.

Acidification also adds to coral bleaching. Corals have a symbiotic relationship with an algae called zooxanthellae. The algae provides the corals with increased nutrients from photosynthesis while the coral provides it with a home. Due to increased acidity levels, the coral cannot sustain the algae so it expels it and the coral turns white because the algae give it color. Because it lacks the algae, the coral therefore cannot get as many nutrients and is therefore more likely to perish. The carbonic acid resulting from ocean acidification also causes calcium carbonate to disintegrate, which is the substance that corals use to create their skeletons. It is therefore harder for corals to grow and even if they do have algae with them, they are more likely to die.

Corals are the most diverse ecosystems in the ocean (25% oceanic animal species live in them even though corals make up less than 1% of the ocean floor) and if they perish, so will all of the species that call reefs home. Coral death would cause many organisms to be without homes and many food chains would be disrupted. The diversity in the ecosystem would greatly decrease, and many organisms which we might even use for food would also die. Many animals would die and humans would also be unable to get many kinds of food. 

Sources:
http://www.pmel.noaa.gov/co2/story/Ocean+Acidification
http://www3.epa.gov/climatechange/kids/basics/today/greenhouse-effect.html

Shark Finning and the Dangers it Poses

One major issue currently afflicting the oceans is the vast scale of shark finning. Humans perceive these animals as threats to us despite the horrendous destruction we are causing to their populations. Sharks are only responsible for around 76 attacks and 5 human fatalities in the world each year. Meanwhile, we kill 100 million sharks annually for their fins. This, however, is a conservative estimate and the number could really be as high as 273 million.
           In order to keep shark populations stable, humans can only kill up to 4.9% of sharks annually. However, we are killing far more than the ecosystem can support. An estimated 93-99% of large sharks off the east coast of North America and 90% in the world have already been wiped out. 50 species of sharks are at a “high risk of extinction” according to the IUCN’s Red List of endangered species. Additionally, 63 are soon to be “threatened” and 199  have unknown status, but easily could be endangered.

Why are we killing all these sharks?

Sharks are primarily killed in Asia and Europe so their fins can be used to make shark fin soup. Only the fins are required to make this delicacy so up to 98% of the shark is wasted. Fishermen catch the sharks, cut off the fins, and throw the animals back alive. The shark then sinks to the bottom because it is unable to swim and is left to drown or be eaten by other animals. 
         Many of the shark finning practices are still legal and there are very few areas where it is banned. In places where it is not legal, there is a large black market for the fins which still allows many sharks to be killed.

Shark fins laying out on a rooftop in Asia. 

Thousands and thousands of shark fins. This helps to show the enormous scale of the fishing.

What are the repercussions of shark finning?

Sharks play a vital part in the ecosystem because they are at the top of the aquatic food chain. If shark populations are decreased or are eliminated completely, organisms that are usually killed by sharks will increase in number. If there are more of these fish, they will eat more and their prey organisms will be diminished as well. Overall, ecosystems will become unbalanced because a primary predator is eliminated. 

Additionally, once shark numbers decrease, fisherman will resort to killing other animals as a source of revenue. Already in some places where shark numbers have dwindled, people are selling parts of manta rays and other large fish, severely decreasing their populations.

My Connection


Several weeks ago I travelled to the Bahamas to study sharks. I stayed for 5 nights at the Shark Lab in Bimini. During that time, I learned about sharks and interacted with wild Caribbean reef sharks, bull sharks, lemon sharks, nurse sharks, hammerhead sharks and even got to tag a tiger shark. This experience was very eye opening for me, because, like many people, I was unaware of the troubles afflicting these marvelous creatures. During the trip, I learned about how the mangroves young sharks use as sanctuaries are being destroyed by hotels and other companies. These habitats are vital to their survival and without them, sharks will not be able to survive to adulthood. 

Sharks are important to keep the food web in order.

In addition to the harmful effects on marine life, humans will also be negatively affected in the long run. If there is less marine life and less diversity, humans will no longer be able to profit off marine life. If, however, we learn to fish sustainably, we can both benefit and will be able to live in harmony with the marine world.

Sources:

http://www.seaweb.org/resources/briefings/marinebio.php

http://natgeotv.com/ca/human-shark-bait/facts

http://www.iflscience.com/plants-and-animals/how-many-sharks-do-humans-kill-hour
http://sharkangels.org/issues-facing-sharks/looming-extinction

http://voices.nationalgeographic.com/2013/03/01/100-million-sharks-killed-every-year-study-shows-on-eve-of-international-conference-on-shark-protection/

Intro to Marine Biodiversity

Throughout my life, I have been immensely passionate about animals and the entirety of the natural environment. I've spent countless hours hiking and exploring, catching lizards and reading animal books to broaden my understanding of the world around me. I have consistently been inspired to protect the natural world so as soon as I discovered the tremendous problems afflicting the planet, I have been compelled to solve them. Here is a brief outline of some of these issues and the effects they may have on ecosystems. I hope they will help you to protect the oceans too! (Note: Marine biodiversity is “the variety of life in the sea” encompassing all life, from the very small to the very large)

Causes of the Loss of Marine Biodiversity:

• “Hunting mammals, birds, turtles; toxic chemicals and nutrient pollution; habitat destruction; the human-assisted transport and release of species to environments where they did not previously exist; and possibly, the increased ultra-violet radiation due to ozone layer depletion” in addition to global climate change can cause changes to occur in the ocean and cause organisms to die.
• Chemicals released by humans can cause many organisms to perish upon consuming the toxins. Additionally, organisms that can adapt and survive take over the ecosystem and change it, potentially contributing to the death of more species.
• Commercial fishing depletes wild populations and some species, such as white abalone in California, are almost extinct because of it. Dragging nets along the sea floor destroys ecosystems and if they are used continuously, they prevent them from being quickly restored.
• “Residential development, tourism, aquaculture, industrial development, and dams” have massive impacts on coastal habitats like wetlands and estuaries which tend to be breeding waters for many species.

Effects of the Loss of Marine Biodiversity:

• If migrations or routes animals must travel to find a mate are disrupted, they will not be able to breed and genetic diversity will decrease.
• When the number of organisms in a population is diminished, there is less genetic diversity and it is harder for species to adapt to environmental changes. Thus, the likelihood of their extinction is increased.
• Many marine species are isolated to a single area so if something happens, they can easily be wiped out.
• Once one species perishes, others will follow because species are interdependent and depend on one another for survival. Thus, ecosystems can crumble and can affect species that humans depend on for food.

http://www.seaweb.org/resources/briefings/marinebio.php

Through the rest of these blogs, I will focus on specific issues and their solutions and discuss why they are not being addressed like they should be.  Some of the problems I will primarily focus on are:

•       Overfishing and harmful nets
•       Shark finning
•       Coral bleaching and ocean acidification 
•       Climate change

All of these issues will have tremendous effects on not only oceanic species, but human life as well. However, they can be lessened with a diligent effort to do so!