Category: Uncategorized

Potential use of Hydrophobic Aerogels in future oil spill clean-ups

Hinna Hafeez \ Oceans First, Issue 4, 2017, pgs. 23-27.  Download PDF

Abstract

For thirty years, oil spill clean up methods did not change until the Deepwater Horizon Spill, the worst marine oil spill in history, occurred in 2010. This notion has motivated scientific advancement of more efficient methods than those used in the Deepwater Horizon Spill. To date, the most notable oil spill clean up method that was used is the dispersant Corexit 9500. This chemical has been found to negatively affect mammalian cells including inducing oxidative stress and premature cell death. It was also found that the oil dispersed by Corexit 9500 remained in the water and continued to affect marine life one year after the spill. Among the proposals for new clean up methods, hydrophobic, low density solids called aerogels are a serious contender for large scale clean ups in the future. Hydrophobic aerogels act as sponges to absorb oil and not water and can remove several types of oils including dispersed and emulsified oil. The oil can be later removed from the gel to be used commercially. However, aerogels are costly and time-consuming to make and have not yet been tested on a large-scale basis. Next steps should include testing aerogels in the ocean and potentially using them to remove remaining dispersed oils caused by the use of Corexit 9500.

The Role of Iron Fertilization in the Fight Against Climate Change

Bronwen Rowe \ Oceans First, Issue 4, 2017, pgs. 35-42.  Download PDF

Abstract

The input of continental dust plays an important role in biogeochemical cycles in the ocean. This paper brings together information from iron fertilization experiments as well as natural event observations (such as the natural input of continental dust into the ocean, or volcanoes) to highlight how understanding the ramifications of continental dust input into the ocean can be applied to combat climate change. Scientists use the radioactive isotope Thorium-232 as a proxy to determine the input of continental dust into the ocean, and volcanic events are studied to observe the results of a large iron input. The “Iron Fertilization Hypothesis” is proposed as a carbon sink to remove excess CO2 from the atmosphere. It is done by seeding the ocean with iron, a nutrient that limits phytoplankton growth in high nutrient low chlorophyll (HNLC) areas, such as the Southern Ocean. After reviewing the pros and cons of iron fertilization, it was determined that iron fertilization should be considered to combat climate change, but it needs to undergo more testing and research. Areas for further study include toxic blooms, the amount of biomass that is reaches the seafloor (via sediment cores) and if ocean iron fertilization is legal or considered ocean dumping.

Phytoplankton Climate Regulation in Positive and Negative Feedback Systems: The CLAW and anti-CLAW hypotheses

Adam Stoer \ Oceans First, Issue 4, 2017, pgs. 43-52.  Download PDF

Abstract

The global climate crisis is bigger now than it has ever been before, pushing for much-needed research on the consequences of climate change. In 1987, Charlson, Lovelock, Andreae, and Warren proposed the CLAW hypothesis which stated that phytoplankton contribute to the production of a significant amount of cloud condensation nuclei (CCN) which in turn creates a negative feedback loop after there is an initial temperature rise. Many years later, in 2006, Lovelock proposed the anti-CLAW hypothesis, which argues that a similar process occurs except that it works as a positive feedback system. Both hypotheses have created much controversy about the effects phytoplankton has on climate and climate regulation. Research has shown that different types of phytoplankton tend to have higher growth rates within a temperature range. Coccolithophores are known for their contribution of DMSP, a compound that forms to make CCN as well as their carbon sequestration abilities. This type of phytoplankton typically function at a thermal niche where nutrient stratification is not strongly limiting, making them act like a buffer against further temperature rises in terms of the CLAW hypothesis. Based on the physiological capabilities of phytoplankton within their environment, both the CLAW and anti-CLAW mechanisms correlate strongly with coccolithophorid algae.

Electrolysis: Is it enough to save the coral?

Taylor Watts \ Oceans First, Issue 4, 2017, pgs. 53-60.  Download PDF

Abstract

Corals all over the world are diminishing quickly due to ocean acidification and from human causes. Future predictions state that coral calcification will decline by 78% by 2100 due to greenhouse gas emissions (Rinkevich. 2015); if the corals disappear our oceans will suffer. Once corals die or become damaged, healing and the rebuilding of their calcium carbonate structure takes far too long; this means corals are diminishing far faster than they are being replenished. A new scientific process called electrolysis has since been discovered that may be the only chance for corals to gain any ground in rebuilding themselves. Electrolysis is the process of using electric current to create environments with high concentrations of calcium and carbonate ions in order for natural calcification to occur. However, electrolysis is not a well-known practice, nor is it heavily experimented. This paper discusses the process of electrolysis and the benefits of such a practice. The main goal of this paper is to prove that the process of electrolysis to rehabilitate corals should be used on a global scale.

The Benefit and importance of Kleptoplasty to Sacoglossan Sea Slugs

Caleb Beck \ Oceans First, Issue 4, 2017, pgs. 1-8.  Download PDF

Abstract

Photosynthesis was first observed being performed by sacoglossan slugs in the 1960’s. However, there is still little known about the cellular processes that give sacoglossans their unique photosynthetic ability. In the past few decades the literature written about photosynthesis in sacoglossans has been contradictory regarding whether or not they are able to photosynthesize at all, and whether this is an example of horizontal gene transfer between the sacoglossans and their algal food source. The goal of this paper is to analyze existing literature on, and determine whether sacoglossans benefit from photosynthesis and if it is an example of horizontal gene transfer. This paper examines literature on six sacoglossan species and the impacts photosynthesis has on them. These impacts include; change in weight during starvation, survival rates, yield of offspring, and the influence of non-native algal food sources. Past sacoglossan research has focused on three or fewer species at a time. Lack of comparison between species and lack of data compilation caused the benefits of photosynthesis to sacoglossans not to be apparent. The benefits of photosynthesis become clear after data compilation, which shows that there is variation of photosynthetic abilities between sacoglossan species. In those sacoglossans that can photosynthesize it has been shown that they maintain plastids from their algal food source and that their photosynthetic abilities are an example of horizontal gene transfer.

The Effect of Melting Arctic Sea Ice on Arctic Whales

A. Paulin \ Oceans First, Issue 3, 2016, pgs. 1-9.

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Abstract: In the past few decades, Arctic sea ice has been experiencing some dramatic changes due in large part to climate change. Arctic sea ice is melting and decreasing in both surface area and thickness. Annual ice melt and freeze timings are being altered. These changes affect the precarious balance of the Arctic ecosystem from the microscopic organisms to its largest inhabitants, the Arctic whales. The factors influencing Arctic cetaceans include ultraviolet radiation exposure, invasive species, and killer whale predation. The reduced sea ice cover decreases the net reflectivity of the Arctic, increasing absorption of UV rays in Arctic waters which cause skin lesions in whales and reduce primary production. With reduced sea ice cover, invasive species – including predatory killer whales – have been extending their ranges northward, creating a possible competition for food with endemic Arctic species. Arctic whales are very susceptible to changes in their habitat and may not be able to survive the present rate of change in their environment. This review synthesizes data gathered from previous studies on the impacts of decreasing sea ice extent on Arctic cetaceans in an effort to better assess the conservation status of the three species.

Beach Shading: A tool to mitigate the effects of climate change on sea turtles

D. Burke \ Oceans First, Issue 3, 2016, pgs. 10-16

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Abstract: Climate change may greatly impact sea turtles as rising temperatures can have negative effects on their development and survival. Primary sex ratios may become female dominated, with no males being produced. Higher female sex rations are correlated to other factors of hatchling survival such as: succession, emergence, size, and locomotive abilities. There are lower rates of succession and emergence in hatchlings that developed in lower temperatures due to mutations and disorientation, resulting in death. Smaller and weaker hatchlings are being produced in high temperatures, resulting in turtles that are easy prey for predators. Increased temperatures also cause turtles to be slower crawlers and take longer to self-right themselves, further extending the time they are exposed to predators. Currently, shading is the most studied method to reverse the negative effects of increasing temperature on sea turtles. By balancing the sex ratio, increasing succession, emergence, size, and locomotive abilities there will an increase in the turtle population while maintaining an even sex ratio. This review synthesizes the effects of climate change on sea turtles and how to mitigate them with shading, to provide working tactics for future conservation.

Flocs are not Spheres: A new Theoretical Approach for Treating Beam Attenuation as a Proxy for Suspended Particulate Mass

L. Hachey \ Oceans First, Issue 3, 2016, pgs. 17-22

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Abstract: Visibility in water is affected by suspended particles within. One way to assess suspended particulate mass (SPM) is to measure the attenuation (Cp) of a light beam calibrated for a specific size range of particles. The relationship between SPM and Cp has consistently been linear throughout the literature, but Baker and Lavelle (1984) found disagreement between the common Mie theoretical predictions and the relationship from experiments. Here, a summary of a new theoretical understanding based on considering particles as aggregates is presented. These aggregates have a fractal dimension of non-solid gaps which constrain the Cp:SPM to particles size. This is why transmissometers have been able to produce adequate estimates of SPM throughout the literature. Experiments are presented which confirm the aggregate nature of particles, and show how size distribution co-varies with beam attenuation. This consideration does not completely explain variation between different particle types, but a validated theoretical framework allows for previous experiments to be useful for the advancement of the field of aquatic optics.

The Cost of Lookin’ Good: A Review on Microplastics in Cosmetics and Their Impacts on Marine Life

A. Simons \ Oceans First, Issue 3, 2016, pgs. 23-30

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Abstract: Microplastic debris in oceans around the world has been accumulating over the last decade, with concentrations reaching over 100 000 microplastics per m3 in some areas. Though microplastics are defined as pieces of plastic debris measuring less than 5 mm in diameter, they are possibly the most harmful litter found in the ocean. Microplastics cause injury and death to marine birds, mammals, fish, and reptiles. These small pieces of litter not only block feeding appendages and obstruct the passage of food through the intestinal tract, they are also vectors for toxic chemicals that end up in the stomachs of marine animals and bioaccumulate through the trophic levels. Banning microbeads from all cosmetics, a primary source of microplastics, is a good start to eliminating them from the earth’s waterways. Each year, 80 tonnes of microplastics from cosmetics such as exfoliates and toothpastes end up in the ocean. Microbeads found inside cosmetics are not vitally important to the function of the product and make up a significant portion of the microplastics found in the ocean. The most effective way to immediately decrease the accumulation of microplastics in the ocean would be to eliminate them from all cosmetics.

Trophic Explanations for Non-Recovery of Atlantic Cod (Gadus morhua) in the Northwest Atlantic

R. Steele \ Oceans First, Issue 3, 2016, pgs. 31-37

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Abstract: In the early 1990s, the Atlantic cod stock in the Northwest Atlantic collapsed due to overexploitation by the Atlantic cod fishery. Since then, the stock has failed to recover to its natural population. This paper explores how a trophic cascade brought about from the initial removal of the cod from the Northwest Atlantic ecosystem can explain the cod’s inability to recover. The reduction in cod population allowed the abundance of harp seals and grey seals (natural predators of cod), to increase due to a reduction in competition for the role of apex predator. Furthermore, key cod prey species in capelin and zooplankton suffered a decrease in abundance due to the collapse of the cod population. As a result, cod face increased predation, a limited amount of available prey, and increased competition for their ecological niche. This has undoubtedly slowed the recovery of Atlantic cod in the Northwest Atlantic.