Not Many Other Fish in the Sea: Our Current Overfishing Crises

Catalyst Volume 9

Prevailing notions of the ocean make it seem as if it is "too big to fail” since it takes up 70% of the surface of Earth and contains 321,003,271 cubic miles of water.¹ Additionally, most of the oceans’ immense biodiversity has yet to be documented. The Census of Marine Life estimates that there could be between 178,000 to 10,000,000 different species living in ocean shoreline habitats due to the vast abundance of photosynthesizing microbes.² However, like any ecosystem, the oceans are not immune to anthropogenic and environmental stressors such as overfishing, climate change, and pollution. There are many interconnected problems surrounding the way in which people currently treat the oceans. Extracting large amounts of fish for human consumption threatens the dynamic balance that currently exists and threatens scientists’ potential for making groundbreaking discoveries about what lies below.

In 2010, the United Nations predicted that over 80% of the world’s fish are reported as fully exploited or overexploited, and thus “require effective and precautionary management.”³ Overexploitation refers to the extraction of marine populations to unsustainable levels.4 Fishing techniques have become exponentially more efficient since the Industrial Revolution, focusing on getting the largest catches in the fewest trips. Today’s fishing fleets are so large that it would require two to three times Earth’s supply of fish to fill them.⁴ These harmful practices lead to three main types of overfishing:

1. Growth overfishing: The removal of larger fish leaves behind only individuals that are too small to maximize the yield, or full amount of fish that could theoretically be obtained.⁵
2. Recruitment overfishing: When adult fish are excessively taken out of the ecosystem, recruitment and stock productivity decreases.⁵
3. Ecosystem overfishing: The targeting of a particular species leads to serious trophic cascades and ecological consequences.⁵

Unfortunately, the most popularly consumed fish species are subject to all three practices. Bluefin tuna, sturgeon, sea bass, and Atlantic salmon are examples of large, long-lived predatory species that only provide a few offspring each breeding cycle.⁵ For example, Bluefin tuna release ten million eggs each year, but only a small number survive to adulthood. Even then, these tuna do not reach reproductive maturity until eight to twelve years of age.⁶ When the largest fish are specifically targeted, many ecological consequences arise. Removing the largest fish of the largest species in an ecosystem significantly decreases the mean size for that species. As a result, only smaller fish are left to reproduce.⁷ This shift causes trophic level decline: as species at higher trophic levels are overfished, fishermen decide to catch the comparatively larger fish at lower trophic levels.⁷ This vicious cycle continues so that the average size of fish consumed decreases significantly. This phenomenon, known as “eating down the food chain,” puts many fish at risk, including herbivorous fish in coral reef ecosystems.⁷ To maintain a coral-dominated state, herbivorous fish consume macro-algae that otherwise would overgrow and suffocate corals. When coral-dominated reefs become overtaken by macro-algae, habitats for many other fish and organisms are severely reduced. Over 25% of the world’s fish species live exclusively within these three-dimensional coral communities, which themselves only take up 0.1% of the ocean floor.⁵ Not only are species being depleted at the very top of the food chain, smaller species that are endemic to specific ocean environments are also indirectly experiencing survival pressure.

These problems are further magnified by the fact that current fishing practices produce a large amount of by-catch, or the incidental capture of non-target species.⁵ The rustic image of a humble fisherman using a single hook at the end of a line no longer reflects reality for most commercial fishermen. Now, longlines are weighted at the bottom and can have as many as 3,000 hooks attached, probing deeper into the water column.⁸ A similar weighted system exists for large fishing nets, known as trawl nets, so that shellfish and other small or bottom-dwelling organisms can be collected in larger quantities. Bottom trawling, the practice of dragging a trawl net across the ocean floor, has contributed to 95% of the damage inflicted on deep water systems by destroying and smothering benthic communities.⁹ These practices are non-specific in nature, and thus collect anything and everything that attaches or gets caught. Fishing gear alone has threatened around 20% of shark species with extinction and leads to over 200,000 loggerhead sea turtles deaths annually.¹⁰ Sylvia Earle, a renowned ocean-conservationist, describes these unsustainable fishing practices as “using bulldozers to kill songbirds.”¹¹

The United Nations now predicts that by 2050, the world will run out of commercially viable catches and oceans could turn fishless.³ Driving this problem is the fact that seafood consumption has increased over the past 30 years.¹² Many coastal communities and developing countries rely on fishing as their main source of income and protein, with approximately 2.9 million people relying on fish for over 20% of their animal protein intake. One of the largest importers, the United States, imports 91% (by value) from other countries with lower production costs.¹³ The cheap labor comes from subsistence fishermen, who meet this increased demand by opting for unsustainable practices. Consequently, a “poverty cycle” emerges, where short-term survival takes precedence over sustainability and conservation efforts, further exacerbating ecological and economic damages.¹⁴

Recognizing that environmental considerations alone could put many developing countries at risk, policymakers have adopted a community-based approach in the planning, construction, implementation, and management of preservation policies.¹⁵ This ecosystem approach to fisheries, strives to ensure that the capability of aquatic ecosystems to provide the necessary resources for human life is maintained for present and future generations.¹⁶

The establishment of Marine Protected Areas, or MPAs, is another effective technique similar to the National Park Service’s preservation programs. Although MPAs have a wide range of management plans and enforcement, all strive to limit or restrict human activity so that natural populations can be restored.⁵ Allowing an environment to restore its fish populations without any human mitigation can take a long time, and the most effective MPAs extend across large tracts of area that can more fully encompass fish populations and migratory species.⁵ Because these areas often overlap with highly profitable fishing zones, MPAs are regularly met with backlash from coastal communities and later can be hard to enforce.¹⁷

These international efforts to reduce the amount of seafood extracted from ocean environments are generally invisible in a grocery store, so it is easy for consumers to engage passively with the food they see. However, recognizing the production, labor, and ecosystem that goes into fish and fish products (and all foods) is critical for maintaining the livelihood of the world’s natural environments. The ocean may seem vast, but there is not an infinite supply of resources that can meet current demands.

References

1. National Oceanic and Atmospheric Administration. http://oceanservice.noaa.gov/facts/oceanwater.html (accessed Oct. 31, 2015).
2. Smithsonian Institute. http://ocean.si.edu/census-marine-life (accessed Nov. 1, 2015).
3. Resumed Review Conference on the Agreement Relating to the Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks; United Nations: New York, 2010.
4. Marine Biodiversity and Ecosystem Functioning. http://www.marbef.org/wiki/over_exploitation (accessed Oct. 31, 2015).
5. Sheppard, C.; David,S.; Pilling, G. The Biology of Coral Reefs,1; Oxford University Press: 2009.
6. World Wildlife Foundation http://wwf.panda.org/what_we_do/endangered_species/tuna/atlantic_bluefin_tuna/ (accessed Nov. 1, 2015).
7. Pauly, D., et al. Science. 1998, 279, 860-863.
8. Food and Agriculture Organization. http://www.fao.org/fishery/fishtech/1010/en (accessed Feb. 25, 2016).
9. The Impacts of Fishing on Vulnerable Marine Ecosystems; General Assembly of the United Nations: Oceans and the Law of the Sea Division, 2006.
10. Monterey Bay Aquarium. http://www.seafoodwatch.org/ocean-issues/wild-seafood/bycatch. (accessed Oct. 31, 2015).
11. Saeks, Diane Dorrans. US oceanographer Dr. Sylvia Earle. Financial Times, Aug. 9, 2013.
12. The State of World Fisheries and Aquaculture; Food and Agriculture Organization; United Nations: Rome 2014.
13. Gross, T. ‘The Great Fish Swap’: How America Is Downgrading Its Seafood Supply. National Public Radio, Jul. 1, 2014.
14. Cinner, J. et al. Current Biology. 2009. 19.3, 206-212.
15. Agardy, T. M. ; Information Needs for Marine Protected Areas: Scientific and Societal; 66.3; Bulletin of Marine Science, 2000; 875-878.
16. Food and Agriculture Organization. http://www.fao.org/fishery/topic/13261/en (accessed Nov. 1, 2015).
17. Agardy, T.M.; Advances in Marine Conservation: The Role of Marine Protected Areas; 9.7; Trends in Ecology and Evolution, 1994; 267-270.

Nomming on Nanotechnology: The Presence of Nanoparticles in Food and Food Packaging

Catalyst Volume 9

Nanotechnology is found in a variety of sectors—drug administration, water filtration, and solar technology, to name a few—but what you may not know is that nanotechnology could have been in your last meal.

Over the last ten years, the food industry has been utilizing nanotechnology in a multitude of ways.¹ Nanoparticles can increase opaqueness of food coloring, make white foods appear whiter, and even prevent ingredients from clumping together.¹ Packaging companies now utilize nano-sized clay pieces to make bottles that are less likely to break and better able to retain carbonation.² Though nanotechnology has proven to be useful to the food industry, some items that contain nanoparticles have not undergone any safety testing or labeling. As more consumers learn about nanotechnology’s presence in food, many are asking whether it is safe.

Since the use of nanotechnology is still relatively new to the food industry, many countries are still developing regulations and testing requirements. The FDA, for example, currently requires food companies that utilize nanotechnology to provide proof that their products won’t harm consumers, but does not require specific tests proving that the actual nanotechnology used in the products is safe.² This oversight is problematic because while previous studies have shown that direct contact with certain nanoparticles can be harmful for the lungs and brain, much is still unknown about the effects of most nanoparticles. Currently, it is also unclear if nanoparticles in packaging can be transferred to the food products themselves. With so many uncertainties, an activist group centered in Washington, D.C. called Friends of the Earth is advocating for a ban on all use of nanotechnology in the food industry.²

However, the situation may not require such drastic measures. The results of a study last year published in the Journal of Agricultural Economics show that the majority of consumers would not mind the presence of nanotechnology in food if it makes the food more nutritious or safe.³ For example, one of the applications of nanotechnology within the food sector focuses on nanosensors, which reveal the presence of trace contaminants or other unwanted microbes.⁵ Additionally, nanomaterials could be used to make more impermeable packaging that could protect food from UV radiation.⁵

Nanotechnology could also be applied to water purification, nutrient delivery, and fortification of vitamins and minerals.⁵ Water filters that utilize nanotechnology incorporate carbon nanotubes and alumina fibers into their structure, which allows microscopic pieces of sediment and contaminants to be removed from the water.⁶ Additionally, nanosensors made using titanium oxide nanowires, which can be functionalized to change color when they come into contact with certain contaminants, can help detect what kind of sediment is being removed.6 Encapsulating nutrients on the nanoscale-level, especially in lipid or polymer-based nanoparticles, increases their absorption and circulation within the body.⁷ Encapsulating vitamins and minerals within nanoparticles slows their release from food, causing absorption to occur at the most optimal part of digestion.⁴ Coatings containing nano-sized nutrients are also being applied to foods to increase their nutritional value.⁷ Therefore, there are many useful applications of nanoparticles that consumers have already shown to support.

While testing and research is an ongoing process, nanotechnology is already making food safer and healthier for consumers. The FDA is currently studying the efficacy of nanotechnology in food under the 2013 Nanotechnology Regulatory Science Research Plan. Though the study has not yet been completed, the FDA has stated that in the interim, it “supports innovation and the safe use of nanotechnology in FDA-regulated products under appropriate and balanced regulatory oversight.”^8,9 As nanotechnology becomes commonplace, consumers can also expect to see an increase in the application of nanotechnology in food and food packaging in the near future.

References

1. Ortiz, C. Wait, There's Nanotech in My Food? http://www.popularmechanics.com/science/health/a12790/wait-theres-nanotechnology-in-my-food-16510737/ (accessed November 9, 2015).
2. Biello, D. Do Nanoparticles in Food Pose a Health Risk? http://www.scientificamerican.com/article/do-nanoparticles-in-food-pose-health-risk/ (accessed October 1, 2015).
3. Yue, C., Zhao, S. and Kuzma, J. Journal of Agricultural Economics. 2014. 66: 308–328. doi: 10.1111/1477-9552.12090
4. Sozer, N., & Kokini, J. Trend Biotechnol. 2009. 27(2), 82-89.
5. Duncan, T. J. Colloid Interface Sci. 2011. 363(1), 1-24.
6. Inderscience Publishers. (2010, July 28). Nanotechnology for water purification. ScienceDaily. (accessed March 3, 2016)
7. Srinivas, P. R., Philbert, M., Vu, T. Q., Huang, Q., Kokini, J. L., Saos, E., … Ross, S. A. (2010). Nanotechnology Research: Applications in Nutritional Sciences. The Journal of Nutrition, 140(1), 119–124.
8. U.S. Food and Drug Administration. http://www.fda.gov/ScienceResearch/SpecialTopics/Nanotechnology/ucm273325.htm (accessed November 9, 2015).
9. U.S. Food and Drug Administration. (2015). http://www.fda.gov/ScienceResearch/SpecialTopics/Nanotechnology/ucm301114.htm (accessed November 9, 2015).

Nano-Materials with Giga Impact

Catalyst Volume 9

What material is so diverse that it has applications in everything from improving human lives to protecting the earth? Few materials are capable of both treating prolific diseases like diabetes and creating batteries that last orders of magnitude longer than industry standards. None are as thin, lightweight, and inexpensive as carbon nanotubes.

Carbon nanotubes are molecular cylinders made entirely of carbon atoms, which form a hollow tube just a few nanometers thick, as illustrated in Figure 1. For perspective, a nanometer is one ten-thousandth the width of a human hair.¹ The first multi-walled nanotubes (MWNTs) were discovered by L. V. Radushkevich and V. M. Lukyanovich of Russia in 1951.² Morinobu Endo first discovered single-walled nanotubes (SWNTs) in 1976, although the discovery is commonly attributed to Sumio Iijima at NEC of Japan in 1991.^3,4

Since their discovery, nanotubes have been the subject of extensive research by universities and national labs for the variety of applications in which they can be used. Carbon nanotubes have proven to be an amazing material, with properties that surpass those of existing alternatives such as platinum, stainless steel, and lithium-ion cathodes. Because of their unique structure, carbon nanotubes are revolutionizing the fields of energy, healthcare, and the environment.

Energy

One of the foremost applications of carbon nanotubes is in energy. Researchers at the Los Alamos National Laboratory have demonstrated that carbon nanotubes doped with nitrogen can be used to create a chemical catalyst. The process of doping involves substitution of one type of atom for another; in this case, carbon atoms were substituted with nitrogen. The synthesized catalyst can be used in lithium-air batteries which can hold a charge 10 times greater than that of a lithium-ion battery. A key parameter in the battery’s operation is the Oxygen Reduction Reaction (ORR) activity, which is a measure of a chemical species’ ability to gain electrons. The ORR activity of the nitrogen-doped material complex is not only the highest of any non-precious metal catalyst in alkaline media, but also higher than that of precious metals such as platinum.⁵

In another major development, Dr. James Tour of Rice University has created a graphene-carbon nanotube complex upon which a “forest” of vertical nanotubes can be grown. This base of graphene is a single, flat sheet of carbon atoms ‒ essentially a carbon nanotube “unrolled.” The ratio of height-to-base in this complex is equivalent to that of a house on a standard-sized plot of land extending into space.⁶ The graphene and nanotubes are joined at their interface by heptagonal carbon rings, allowing the structure to have an enormous surface area of 2000 m² per gram and serve as a high potential storage mechanism in fast supercapacitors.⁷

Healthcare

Carbon nanotubes also show immense promise in the field of healthcare. Take Michael Strano of MIT, who has developed a sensor composed of nanotubes embedded in an injectable gel that can detect several molecules. Notably, it can detect nitrous oxide, an indicator of inflammation, and blood glucose levels, which diabetics must continuously monitor. The sensors take advantage of carbon nanotubes’ natural fluorescent properties; when these tubes are complexed with a molecule that then binds to a specific target, their fluorescence will increase or decrease.⁸

Perhaps the most important potential application for carbon nanotubes in healthcare lies in their cancer-fighting applications. In the human cell, there is a family of genes called HER2 that is responsible for the regulation of growth and proliferation of cells. Normal cells have two copies of this family, but 20-25% of breast cancer cells have three or more copies, resulting in quickly-growing tumor cells. Approximately 40,000 U.S. women are diagnosed every year with this type of breast cancer. Fortunately, Huixin He of Rutgers University and Yan Xiao of the National Institute of Standards and Technology have found that they can attach an anti-HER2 antibody to carbon nanotubes to kill these cells, as shown in Figure 2. Once inserted into the body, a near-infrared light at a wavelength of 785 nm can be reflected off the antibody-nanotube complex, indicating where tumor cells are present. The wavelength then increases to 808 nm, at which point the nanotubes absorb the light and vibrate to release enough heat to kill any attached HER2 tumor cells. This process has shown a near 100% success rate and leaves normal cells unharmed.⁹

Environment

Carbon nanotube technology also has environmental applications. Hui Ying Yang from Singapore has developed a water-purification membrane made of plasma-treated carbon nanotubes which can be integrated into portable, rechargeable, and inexpensive purification devices the size of a teapot. These new purifications devices are ideal for developing countries and remote locations, where large industrial purification plants would be too energy- and labor-intensive. Unlike other portable devices, this rechargeable device utilizes a membrane system that does not require a continuous power source, does not rely on thermal processes or reverse osmosis, and can filter for organic contaminants found in brine water - the most common water supply in these developing and rural areas.¹⁰

Oil spills may no longer be such devastating natural disasters either. Bobby Sumpter of the Oak Ridge National Laboratory demonstrated that doping carbon nanotubes with boron atoms alters the curvature of the tubes. Forty-five degree angles form, leading to a sponge-like structure of nanotubes. As these tubes are made of carbon, they attract hydrocarbons and repel water due to their hydrophobic properties, allowing the tubes to absorb up to 100 times their weight in oil. Additionally, these tubes can be reused, as burning or squeezing them was shown to cause no damage. Sumpter and his team used an iron catalyst in the growth process of the carbon nanotubes, enabling a magnet to easily control or remove the tubes from an oil cleanup scenario.¹¹

Carbon nanotubes provide an incredible opportunity to impact areas of great importance to human life - energy, healthcare, and environmental protection. The results of carbon nanotube research in these areas demonstrate the remarkable properties of this versatile and effective material. Further studies may soon lead to their everyday appearance in our lives, whether in purifying water, fighting cancer, or even making the earth a better, cleaner place for everyone. Big impacts can certainly come in small packages.

References

1. Nanocyl. Carbon Nanotubes. http://www.nanocyl.com/CNT-Expertise-Centre/Carbon-Nanotubes (accessed Sep 12, 2015).
2. Monthioux, M.; Kuznetsov, V. Guest Editorial: Who should be given the credit for the discovery of carbon nanotubes? Carbon 44. [Online] 2006. 1621. http://nanotube.msu.edu/HSS/2006/1/2006-1.pdf (accessed Nov 15, 2015)
3. Ecklund, P.; et al. Ugliengo, P. In International Assessment of Carbon Nanotube Manufacturing and Applications, Proceedings of the World Technology Evaluation Center, Inc. Baltimore, MD, June, 2007.
4. Nanogloss. The History of Carbon Nanotubes – Who Invented the Nanotube? http://nanogloss.com/nanotubes/the-history-of-carbon-nanotubes-who-invented-the-nanotube/#axzz3mtharE9D (accessed Sep 14, 2015).
5. Understanding Nano. Economical non-precious-metal catalyst capitalizes on carbon nanotubes. http://www.understandingnano.com/catalyst-nitrogen-carbon-nanotubes.html (accessed Sep 17, 2015).
6. Understanding Nano. James’ bond: A graphene/nanotube hybrid. http://www.understandingnano.com/graphene-nanotube-electrode.html (accessed Sep 19, 2015).
7. Yan, Z. et al. ACS Nano. Toward the Synthesis of Wafer-Scale Single-Crystal Graphene on Copper Foils 2012, 6 (10), 9110–9117.
8. Understanding Nano. New implantable sensor paves way to long-term monitoring. http://www.understandingnano.com/carbon-nanotubes-implant-sensor.html (accessed Sep 20, 2015).
9. Understanding Nano. Combining Nanotubes and Antibodies for Breast Cancer 'Search and Destroy' Missions. http://www.understandingnano.com/nanomedicine-nanotubes-breast-cancer.html (accessed Sep 22, 2015).
10. Understanding Nano. Plasma-treated nano filters help purify world water supply. http://www.understandingnano.com/nanotube-membranes-water-purification.html (accessed Sep 24, 2015).
11. Sumpter, B. et al. Covalently bonded three-dimensional carbon nanotube solids via boron induced nanojunctions. Nature [Online] 2012, doi: 10.1038/srep00363. http://www.nature.com/articles/srep00363 (accessed Mar 06, 2016).
12.  Huixin, H. et al. Anti-HER2 IgY antibody-functionalized single-walled carbon nanotubes for detection and selective destruction of breast cancer cells. BMC Cancer 2009, 9, 351.