Aquaculture; Sustainable or not sustainable?

As the human population continues to increase exponentially, we are constantly faced with the question; how in the world do we feed everyone? Luckily advancing technologies have helped ease this burden, with the birth of things like pesticides, new farming methods and GMOs.

Overfishing and the depletion of the oceans’ natural stock has been a constant battle for wildlife managers and economies all over the world. According to the World Wildlife Foundation, “[m]ore than 85 percent of the world’s fisheries have been pushed to or beyond their biological limits and are in need of strict management plans to restore them.” Fortunately over the past years the aquaculture industry has been able to help cushion the fall. Not only does it produce a variety of fish for market all over the world, but it is a big contributor to the country’s economy as well.

One of the best examples of this is right here in Louisiana. Shrimp, oysters, crab, crawfish and alligator are the biggest fisheries exports we have. According to Louisiana Seafood, shrimp alone accounts for 15,000 jobs and an annual impact of $1.3 billion. We also produce 70% of the world’s oysters right here in the Gulf coast, and this accounts for almost 4,000 jobs with an economic impact of $317 million annually. According to Louisiana State University’s Agriculture Center, freshwater fisheries contributed $23.4 million and marine fisheries added an estimated $320.4 million in 2013 alone. However, one of the biggest questions that has come up since is whether its practice is sustainable or not.

Now what does it mean to be sustainable? According to Webster’s Dictionary sustainable means “able to be used without being completely used up or destroyed” and “able to last or continue for a long time.” But in ecological terms sustainable practices are “techniques that protect the environment, public health, human communities, and animal welfare.”

One of the arguments against aquaculture is that the industry has gotten so big in first world countries that it is displacing and destroying traditional fishing communities. Not only are they putting them out of jobs, but they are also taking their main source of food. The same fish that the aquaculture industries refer to as “trash fish” and use for their feeding production is the usual meal for some local communities. Another problem with the industry is that recently modern methods of aquaculture have been emphasizing unsustainable practices, specifically in order to produce higher value product like shrimp and salmon. These unsustainable practices have led to the destruction of coastal ecosystems, depletion of freshwater sources, and the release of inorganic waste that has the potential to be toxic.

However in many third-world countries like Haiti, aquaculture has been a blessing. In these areas most families live in poverty and lack daily nutrients such as protein needed for basic health and learning development. Non-profits like Operation Blessing International have been spreading the practice of aquaculture in order to give these families not only a reliable source of food, but a source of income as well. According to their website “Haiti has been crippled by disasters, creating a food security crisis. They need jobs to strengthen the economy and sustainable solutions to increase food security for the population. Operation Blessing is responding to that need through aquaculture — specifically, the farming of tilapia — which is providing jobs and food to hurting families across the nation”.

In cases like these it is evident that aquaculture has a lot of potential for success in what it was originally made to do; feed the world, as well as its many economic benefits. However the lack of regulation and sustainable practices have given the name a bad reputation.

To get an inside opinion on the subject I talked briefly with Dr. Greg Lutz at the LSU Aquaculture Research Station. Dr. Lutz has been working in the industry for years, and has been traveling from Baton Rouge to South America as a professional consultant. “I personally never saw Aquaculture as the solution to fish stock depletion, but I do believe that if practiced right Aquaculture holds a tremendous amount of benefits” says Dr. Lutz.

So is Aquaculture sustainable? It seems to me that the answer isn’t a “yes” or a “no”, but rather an “it depends.” It depends on whether or not sustainable methods are being used or not! It’s as simple as that. No one management plan is perfect and there are always going to be flaws. Rather than trying to label the industry as one that works or doesn’t work, we should simply try to step back, identify the main problems and find a solution for reformation.

By: Greer Darden


How to Prevent Shark Attacks: An Infographic

In the United States, one person dies of a shark attack every two years. While sharks are generally not threatening towards humans, public perception is that they are oceanic killing machines. This infographic was created as an easy way for people to see where shark attacks occur and provide some basic, common sense suggestions for how to avoid an attack while at the beach.

All data obtained from the International Shark Attack File provided by the Ichthyology Department at the Florida Museum of Natural History.

Public Health and the Volkswagen Emissions Scandal

By David Fertitta

From 2009-2015, Volkswagen has been installing devices in certain vehicles designed to recognize when the vehicle was being tested to make sure it complied with U.S. Environmental Protection Agency (EPA) emission standards. Once the device software detected that the vehicle was being tested, the engine switched to a calibration that met the EPA emissions standards. However, when not in testing, the engine switched to a different calibration that would be used in normal driving. The EPA notice of violation of the Clean Air Act mentions that this reduced the effectiveness of the emission control system and that “emissions of [nitrogen oxides] increased by a factor of 10 to 40 times above the EPA compliant levels” for certain models of Volkswagen’s 2.0-liter diesel engine vehicles that were equipped with these “defeat devices.”

But what do the excess levels of nitrogen oxides mean for your health?

To understand how an increase in nitrogen oxides could affect people’s health, I spoke with Dr. Vince Wilson, a toxicology professor in the LSU Department of Environmental Sciences.

“When they say nitrogen oxides, it’s really nitric oxide (NO) and nitrogen dioxide (NO2),” Wilson said. He explained that these two molecules get involved with chemical reactions in the atmosphere that can lead to problems associated with ozone and smog. An accumulation of nitrogen oxides in the atmosphere can also react with water and lead to a buildup of nitric acid, which contributes to acid rain.


Nitrogen dioxide and nitric oxide

Nitrogen dioxide is a pulmonary irritant and as its concentration in the atmosphere increases, people may start to get watery eyes, scratchy throats, and other irritations in their upper respiratory tract.

However, nitrogen dioxide can undergo several reactions in the atmosphere, so the more nitrogen oxides that are being put into the air, the worse the air quality is. In the presence of UV light from the sun, nitrogen dioxide can react with oxygen to create ozone in the air we breathe which can cause a host of other health problems.

Wilson also discussed the reactive nature of nitrogen oxides with volatile organic compounds (VOCs), carbon-containing compounds that are often emitted to the atmosphere from the burning of fossil fuels and vegetation. “These VOCs will react with UV light and various compounds including nitrogen dioxide,” he said, “and you end up with aldehydes which are toxic.”

“For nitric oxide, the concentration is usually low enough that it’s not a problem,” Wilson said, “but it can be toxic at high levels.” He also said the nitric oxide is very reactive in the atmosphere. “This leads to more ozone produced at ambient breathing level instead of the upper atmosphere where we want it,” he said. Ozone at this level contributes to poor air quality and can affect our lungs.

Levels of nitrogen oxides are so critical for air quality measures that nitrogen dioxide is one of the compounds constantly being monitored in our air under the Louisiana Department of Environmental Quality (DEQ) Ambient Air Monitoring program. “There are 6 stations around East Baton Rouge Parish that monitor for these compounds,” Wilson said. “[For] one of my master’s students, part of her project was collecting all that information and correlating it with health.”

EPA standards exist to regulate emissions of nitrogen oxides, a byproduct of combustion, in order to ensure clean air and a healthy population. While the increase in levels of nitrogen oxide emissions can create enough health problems on their own, the reactive nature of nitrogen dioxide and nitric oxide can also lead to a host of other environmental problems associated with air quality that can directly affect people’s health and well-being. When Volkswagen installed these defeat devices, they directly bypassed EPA emission standards, which could lead to detrimental issues associated with people’s health.

Researchers find new way to remove mercury from water using post-industrial waste

Pregnant women rejoice; Australian scientists Max Worthington and Justin Chalker, along with a team of researchers, have found a method to remove mercury from water using industrial waste and orange peels. High concentrations of mercury in food and water can have toxic effects on the nervous, digestive and immune systems, and on lungs, kidneys, skin and eyes, and the answer, at least a large part of the answer, grows on trees.

The synthetic material in question is sulfur-limonene polysulfide, which combines sulphur, a petroleum byproduct, and limonene, the main component of orange oil. Both of these substances are produced in the order of tens of thousands of tons each year and then discarded. When reacted together and combined, these compounds create a soft red rubber that essentially pulls mercury out of water.

Ocean mercury levels have tripled since the beginning of the industrial revolution. Mercury has permeated sea-life, posing a threat to fish-consuming humans. This is why pregnant women are advised to avoid seafood; fetuses are especially susceptible to the negative health outcomes of mercury exposure. Children exposed to high levels exhibit clear signs like mental retardation, seizures, and cerebral palsy. Mercury, however, can negatively affect children in more subtle ways at lower doses – causing behavior problems, memory deficits, and shorter attention spans.  This new compound discovered by Worthington and Chalker, therefore, has huge implications. The sulfur-limonene polysulfide is cheap to produce and can be diffused through large bodies of water with relative ease.

As with all things, however, there may be a catch. Limonene is considered highly toxic to aquatic life. This new substance will require extensive toxicity research to ensure that it is safe for our oceans. Preliminary tests have shown promising results; liver cells exposed to water containing the substance showed no change in viability. If the new substance can be effective while the concentration of limonene remains below the threshold for adverse effects, there are huge implications to this discovery.

The team set out to create a polymer or plastic out of something in large supply. When they assert that the material is easy to make, they are not over-exaggerating. To get the materials to react, sulfur was melted and then heated to 170 degrees Celsius (338 degrees Fahrenheit). An equal amount of limonene was added to the molten sulfur, and a red wax-like substance resulted once cooled to room temperature. The first shape the polysulfide was molded into was a lego brick, as researcher Michael Crockett explains, “just because we found a high temperature food mold that we were able to pour the material into.”  This original manifestation may have been unintentionally yet perfectly appropriate; the pliability of the material implies that it has the potential to be used in coating pipes or molded into any number of shapes, providing a truly ubiquitous material.

In their testing of the substance, the team explored its abilities to sequester metals from water. They began with palladium, which is another metal byproduct which pollutes water. When tested, the new material removed 42% of palladium from water within the first hour, then reached an equilibrium in which no more could be sequestered.  But, this finding showed that sulfure-limonene polysulfide had promising abilities to remove soft metals from water.

This led the researchers to test its affinity for mercury. “When an aqueous solution of HgCl2 (10 mM) was added to the surface of the polysulfide, the result was a surprise: a bright yellow deposit formed that remained immobilized on the polysulfide. The deposit typically appeared within 30 min and remained on the polysulfide, even after washing with water.” Sulfur is already used in the disposal of mercury, but because of its structure is difficult to form into anything else useful in regards to mercury. Sulfur-limonene polysulfide, however, traps the mercury and keeps it there.

Worthington and Chalker then went on to challenge the substance’s mercury-removal power in a manner more applicable to the natural environment. They spiked river water and soil deposits with mercury and then added the polysulfide. Again, insoluble mercury deposits formed on its surface. The telltale yellow deposits remained adhered in the soil suspension as well, indicated its ability to remove mercury even in these more complex conditions.

Crockett, an American researcher who did the initial synthesis, says the team intentionally made the material, based on “theories about the kinds of properties that it would have just based on the nature of sulfur.” What they didn’t expect, however, that it would “react specifically with mercury to give a color change.” Most of the research on materials to sequester mercury concerned granular or powdered substances, but this gel-like substance can be put to a much wider variety of uses. The study was just published Tuesday October 20, so it hasn’t been widely read, but according to Crockett, they have already seen some interest in the material from governmental and/or private entities. Furthermore, the team has seen “some luck with lead binding to the material as well, but those results are qualitative. We have reason to believe it could remove most heavy metals.”

The uncovered sulfide is highly advantageous for three distinct reasons: it is cheap to produce, it is easy to produce on a mass scale, and the yellow deposits formed by the mercury serve as an easily identifiable indication of its efficacy. The coolest part, as Chalker puts it, is that “it literally grows on trees.”

— Patricia Kane


Promiscuous Plants Make Problems

An acacia. Photo from Flickr

An acacia. Photo from Flickr

Beautiful isn’t it?  This is an acacia tree, a member of the pea family from Australia. Its good looks have led to its introduction around the world.  California is one of those places, and 16 acacia species have been introduced for the horticultural trade.

These new plants on the block are non-native species, meaning they aren’t from around these parts.  Regardless, at least three species of non-native California acacias have begun to exploit the landscape. These pushy plants are called invasive species.  Invasive species crowd out native plants and wildlife, negatively affect the environment, and cause over $120 billion in damages each year.  But what makes these acacia plants so successful as invaders?

Microbes.  That’s right, tiny organisms that live just about anywhere, including the soil and roots of plants.

These microbes are a special type of soil bacteria called rhizobia. Rhizobia colonize pockets in the roots of certain plants, like those in the pea family. The pockets of rhizobia, or nodules as scientist call them, convert unusable Nitrogen into a form of Nitrogen that plants can use.  Nitrogen is one of the important chemicals that determine plant growth and success.

Dr. Metha Klock, doctoral student at Louisiana State University, has found that the relationship between rhizobia soil microbes and certain acacias help them spread to new areas.  If an acacia species can associate with more types or strains of rhizobia, it is more likely to spread and become invasive. Dr. Klock calls these invasive acacia plants “promiscuous hosts.” Getting friendly with more rhizobial strains increases the chances of getting lucky and spreading to new habitats.  

Of course everything is fine until someone (or something) gets hurt, and California’s ecosystems take the blow. Prior to her days of research, Klock was a restoration professional in California.  She was on the ground every day ripping out invasive plants like acacias and replacing them with natives.  But she could see the battle couldn’t be won by force alone, we needed to know why these plants were spreading and how to prevent future introductions.

In a recently published study, Klock grew over 1600 acacia plants of multiple species and harvested the root nodules for analysis.

An example of a bacterial culture. Photo from Flicker.

An example of a bacterial culture. Photo from Flicker.

 She also sampled acacias invading California.  She cultured the bacteria and through molecular analysis was able to determine the different rhizobial strains associated with different acacia species.  Her results show that invasive acacias associate with more rhizobial strains then non-invasive acacias. The implications of which span a variety of topics:

  1. We’ve identified that rhizobia-plant interactions can contribute to invasion.  We can use this knowledge to identify future invasive species before they become a problem.
  2. Acacias are native to Australia, and in areas where restoration is being conducted, these promiscuous plants can be a benefit.  They may spread and restore areas more efficiently than other native plants.  
  3. We can select agricultural crops that are more promiscuous host, and therefore grow better. Or;
  4. There is a potential to develop soil inoculants for improve growth of pea family agricultural plants (a.k.a. probiotics for plants).   

There is more research to be done, but we’ve taken a step in the right direction. Observing how below ground activities affect plant growth and establishment is not an easy task, but we have now identified one mechanism of how acacias spread in new ranges. Klock hopes future studies will include a comparison of more genetically diverse rhizobia strains, and she has more publications to come.  Check out this recent story from one of her presentations, and keep an eye out for her work!

Note to the reader: Invasive species are not just a problem in California.  All over the world, invasive species are altering ecosystems, impacting landscapes, and threatening ecosystem services that both wildlife and people depend on.  The first step to preventing invasion is people.  Before planting a plant, or releasing an animal, do some homework.  If it’s not found there naturally, don’t introduce it.  Check with you local governments for policies on invasive species management, and share what you learn with others.  Invasive species reportings can be sent to local agencies or uploaded here.

Why We Are Spending Money on Restoartion of Coastal Habitats & Wetlands

By Kathryn Cannon

On August 29, 2005, Hurricane Katina ripped through the coastal wetlands and into the city of New Orleans. Most people remember only how New Orleans and the surrounding areas were affected but not how the coastal wetlands, barrier islands or marshes were also impacted.

“After hurricane Katrina we lost several thousand acres of marsh on several of our refuges,” said James Harris, Senior Wildlife Biologist for the Southeast Louisiana Refuges Complex. “It was converted from emergent marsh with vegetation and various forms of wildlife to open water.” Our coastal wetlands are important to our wildlife and even our way of living. Through coastal restoration programs funded by the state and other federal entities, the USF&WS tries to preserve and rebuild our coastal wetlands through various means.

James Harris Photo Credit: Katie Cannon

James Harris Photo Credit: Katie Cannon

The Southeast Louisiana Refuges Complex is a branch with the United States Fisheries & Wildlife Services. Harris specializes in restoration of coastal habitats including marsh and barrier islands. He has constructed numerous small-scale sediment diversions at Delta NWR, which is one of the 8 National Wildlife Refuges covered by the Southeast Louisiana Refuges Complex. They have also restored marsh using dedicated dredge disposal within the complex.

Off the coast of Louisiana, there are barrier islands, marshes and coastal wetlands. Barrier islands are a coastal landform of offshore deposits of sand or sediment. They are a long and relatively narrow islands running parallel to the mainland. They serve to protect the coast from erosion by surf and tidal surges, and act as a barrier to storm surges from hurricanes. However, every 38 minutes, another football field of wetlands disappears into the sea, taking with it nature’s best storm protection and water filter, as well as a cradle for sea life.

The Gulf of Mexico’s coastal wetlands have an abundance and variety of wildlife. They are home to 132 federally listed species, 95 of which are endangered. The Gulf region provides habitats for millions of waterfowl, shore birds, song birds, herons and egrets. The coastal wetlands are home to hardwood forests, cypress swamps, coastal marshes, estuaries and barrier islands.

If Louisiana continues to lose her barrier islands and coastal wetlands, it will have an enormous effect on our way of life. “There are a huge number of species negatively impacted by the loss of coastal habitats,” Harris commented. We use these habitats for cultural recreation such as fishing, photography, hunting, education and wildlife observation. “Then we get into what’s really important to a lot of Louisianans – the seafood. The seafood industry is the main source of income for many south Louisianians,” Harris said. “The coastal habitats are extremely important as they serve as nursery areas for shrimp, fish, blue crabs etc., and it would not only impact us, but the nation as a whole.”

Demonstrating Google Earth Photo Credit: Katie Cannon

Demonstrating Google Earth Photo Credit: Katie Cannon

The million dollar question is how we stop the excessive land loss of our coastal wetlands, marshes and barrier islands without ultimately causing further damage to our already fragile ecosystem. The USF&WS is creating ways to lessen the damage done by hurricanes, erosion and rising sea levels by using a process called sediment diversions. River diversions are one of the fundamental tools available for coastal restoration in Louisiana. Under certain scenarios, they offer an efficient and effective means of building new land, provide a substrate for wetland growth and vegetation regrowth, and provide an opportunity for enhancement of ecological diversity. “We are getting better, if you will, at designing projects and designing restoration to take advantage of the natural processes that either sustains what we’ve built or makes it more resilient to storms,” Harris said. “So that a storm may damage it, but hopefully it won’t completely wipe it away again.”

Harris demonstrated on Google Earth how they use the program to look backward and forward over a period of years to see how the land was and how it develops via satellite photos. When they create a sediment diversion they use Google Earth to map out where the diversion will go and view the progress that is made over a period of time.

Google earth without sediment diversion Photo Credit: Katie Cannon

Google earth without sediment diversion Photo Credit: Katie Cannon

Google Earth with sediment diversion Photo Credit: Katie Cannon

Google Earth with sediment diversion Photo Credit: Katie Cannon

The coastal marshes of Louisiana are extremely important both from the natural resource side and from the human side. “These areas are culturally important and that can’t be discounted when you’re talking about people. People are most comfortable when they have a sense of place – a sense of protection if you will – and these marshes and barrier islands and all these habitats provide that,” Harris said. “It’s what protects us. It is what not only protects our livelihood, but it protects our houses and infrastructure; so it’s tremendously important.” If we have the ability to make the environment better, we should do it by any means necessary.