9,000 Larvae Later…

Jaclyn Caruso, Salem State University

Me UrchinFindings: In my previous post, I talked about how counting larval stages and measuring their skeletons could help us determine the lethal and sublethal effects of preservatives used in cosmetics and other personal care products on development. What we found was pretty surprising.

After two days of development in normal conditions, sea urchin larvae should be in the pluteus stage and have 2 or 4 arms. The arms are important because they are surrounded by bands of cilia that help the larva swim and feed. In the controls and at the lowest concentrations that we tested (0.1, 1, and 10 parts per million), the majority of the larvae successfully reached this stage. However, things got interesting at about 32 ppm.

We found that at concentrations at and above 32 ppm, the larvae generally grew shorter arms, had a smaller body size, and were more asymmetric. Any of these abnormalities could potentially have fatal consequences for the larvae. We also found that at high enough concentrations of the preservatives, development will fail completely. At concentrations of 1000 ppm, almost 100% of the fertilized eggs that we added to the jars didn’t develop past the early cleavage stages. This means that development was stopped almost instantly.

If you remember back to my first post, we wanted to test how parabens compared to the newer alternatives they were replaced with. Of the three preservatives we tested, the paraben caused changes in growth and failure of development at the lowest concentrations. The other two preservatives fared slightly better, suggesting that the personal care products industry may have made a good decision by switching. However, because we saw harmful effects in all three preservatives, we can’t say that they are completely safe for marine life at these concentrations.

This summer has taught me a ton about scientific research. I always expected it to require a lot of time, patience, and dedication, and my expectations were absolutely confirmed. In total, we counted and categorized 8,919 larvae and measured 2,224. That’s a lot of long hours at the microscope, and a lot of data to analyze. But, our results were definitely worth it, and I’m greatly looking forward to my next research experience!

Larval Stages

Left: normal preserved plutei in the 4- or 2-arm stage. Right: abnormal preserved individuals with incorrectly shaped skeletons or at early stages of development. Jaclyn Caruso, 2018


Acknowledgements

Thank you to Dr. Bob Podolsky (CofC) for his mentorship, Dr. Cheryl Woodley (NOAA) for providing her procedures and resources, and Pete Meier (CofC) for teaching me the ropes of setting up aquaria. This project is supported by the Fort Johnson REU Program, NSF DBI-1757899.

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Is “Paraben-Free” the Way to Be?

Jaclyn Caruso, Salem State University

Me-WetLab Edit

In the wet lab, we wear a lei to remember to shut off the tank valve. Photo: Jaclyn Caruso, 2018.

The problem: Have you brushed your teeth today? Washed your hair? Put on deodorant, perfume, makeup, or lotion? If you (hopefully) have, you’ve used a cosmetic. According to the FDA, anything that is applied to your body with the intention of cleansing or beautifying it is a cosmetic (FDA, 2018). Because this category covers such a wide variety of products, it’s easy to imagine just how many are used worldwide on a daily basis.

Like anything people use, cosmetics are eventually washed off, and often end up in the ocean from sewage drains and wastewater treatment plants. The problem with this pollution is that cosmetics contain preservatives. Although these components prevent the growth of bacteria and mold, their actions when introduced to natural systems are not tested at great lengths when considering their frequent use. Until a few years ago, the most common preservatives were a group of chemicals called parabens.

But, you’ve probably heard of at least one product that claims to be “paraben-free.” This aversion to parabens followed a landmark study in 2004 which showed that parabens have the potential to accumulate in human breast tumors (Darbre et al., 2004). The authors explicitly stated that the source of the parabens (methylparaben, mainly) was unknown, but many people were shaken by the findings. Cosmetics manufacturers began changing their formulations by using newer, “safer” preservatives like 2-phenoxyethanol and chlorphenesin (Bressy et al., 2016). However, these alternative preservatives have not been extensively tested for their effects on marine animals, which may be at risk when these chemicals enter the ocean.

Me with Urchin

Collecting sea urchins at Breach Inlet! Photo: Dr. Podolsky, 2018.

My research this summer aims to explore the effects that these alternative preservatives have on marine animal development. We will use the local sea urchin Arbacia punctulata as a model, because it is easily collected in the wild and reared in the lab. Like many marine animals, A. punctulata is a broadcast spawner—males and females release their sperm and eggs into the water column. After fertilization, the embryos develop into free-floating larvae, which are highly sensitive to pollutants.

We will expose the sea urchin larvae to various concentrations of each chemical to test whether larval development is affected negatively by the chemicals. Such negative effects could inhibit the ability of sea urchins to develop properly, leading to death or inability to mature to adulthood. If we see effects in sea urchins, there is a possibility of similar effects in other species that may be more directly important to humans, like fish and crustaceans.

Our ultimate goal is to explore whether products that are safer for people are safer for the marine environment. If they are—great! If not, we need to think critically about the products we use that end up in the ocean, because human and ocean health are inextricably linked. Healthy oceans, for example, provide us with food, medications, recreation, and more (NOAA, 2018).

Blog 1 Photo

Left: A beautiful specimen of Arbacia punctulata. Scale bar = 1 cm. Right: Dr. Podolsky demonstrating how to induce spawning in sea urchins using a low voltage across the gonopores. Photos: Jaclyn Caruso, 2018.

 


Acknowledgements

Thank you to Dr. Bob Podolsky (CofC) for his mentorship and endless patience, Dr. Cheryl Woodley (NOAA) for graciously offering her procedures and resources, and Pete Meier (CofC) for teaching me the ropes of setting up aquaria. This project is supported by the Fort Johnson REU Program, NSF DBI-1757899.


References

Bressy, A. et al. (2016) ‘Cosmet’eau—Changes in the personal care product consumptionpractices: from whistle-blowers to impacts on aquatic environments’, Environmental Science and Pollution Research. Environmental Science and Pollution Research, 23(13), pp. 13581–13584. doi: 10.1007/s11356-016-6794-y.

Darbre, P. D. et al. (2004) ‘Concentrations of Parabens in human breast tumours’, Journal of Applied Toxicology, 24(1), pp. 5–13. doi: 10.1002/jat.958.

FDA (U.S. Food & Drug Administration) (2018) ‘Is It a Cosmetic, a Drug, or Both? (Or Is It Soap?)’ https://www.fda.gov/Cosmetics/GuidanceRegulation/LawsRegulations/ucm074201.htm (accessed Jul. 2, 2018).

NOAA (National Oceanic and Atmospheric Administration) (2018) ‘What does the ocean have to do with human health?’ https://oceanservice.noaa.gov/facts/ocean-human-health.html (accessed Jul. 2, 2018).

Are New Englanders more tolerant than Southerners? A test of latitudinal variation in Atlantic sea urchins

Kaelyn* Lemon, Macalester College/ Dr. Bob Podolsky and Grice Marine Lab

If you’re not a climate change denier, you know that global climate change, mainly driven by the increasing amounts of carbon dioxide that humans release into the atmosphere, has been raising the Earth’s average temperature and will continue to do so for the near future. If you are particularly well-versed in your environmental science, you know that these increasing amounts of carbon dioxide are also causing the oceans of the world to become more acidic (see: coral bleaching) (1). Unless you are a marine or climate scientist, though, you probably don’t know why climate change is causing ocean acidification or how this will affect ocean animals besides probably not being the best thing ever for them.

Our oceans actually absorb around 30% of the carbon dioxide we release into the air (2). This CO2 hangs around as a gas mixed into the water and goes through a series of chemical reactions that both release hydrogen ions (the H in pH), therefore lowering the pH of the water and making it more acidic, and reducing the amount of carbonate available in the water for ocean animals and other organisms to use (2). Animals like sea urchins that build shells or skeletons out of calcium carbonate (the main ingredient in limestone) find this task more difficult when there is less carbonate around.

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Ocean acidification due to greater amounts of carbon dioxide in the atmosphere leads to less carbonate in the water (from http://www.i-fink.com/ocean-acidification/)

While the thought of sea urchins will bring to mind their hard, spiny exterior, these animals (yes, there are body tissues inside those aquatic pincushions) are actually most affected by ocean acidification during their larval stage of life, when they build a skeleton that allows them to swim around and eat (3) (urchin larvae are like insect larvae in that they behave and look very different from the full-grown animals they will eventually become). When oceans become more acidic and less carbonate is available, urchin larvae are smaller, which makes it harder for them to eat at the same time as they are more at risk of being eaten themselves (3). Unfortunately, a world with a lot fewer urchins would be a world where seaweed would easily overgrow ocean habitats and predators of urchins (like the adorable fuzzy otters that lay on their backs in the ocean and hold hands- google it) might have more difficulty finding food.

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One of the sea urchins from South Carolina with some of the seaweed they like to eat (photo credit: Kaelyn  Lemon)

I’m looking into whether sea urchins (specifically the species Arbacia puntulata, which is found in the Atlantic ocean) from Massachusetts and South Carolina will react differently in higher acidity. If one group of urchins can produce larvae that maintain a larger body size under more acidic conditions than the other group, then we will know that there is some degree of variability within the species. This would be a positive result for the sea urchins (and therefore for oceans in general) because it would mean that these urchins may be able to adapt to acidified waters more easily than we can currently expect.

Sources:

1. IPCC, 2014: Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. IPCC, Geneva, Switzerland, 151 pp.

2. Clark D, Lamare M, Barker M. 2009. Response of sea urchin pluteus larvae (Echinodermata: Echinoidea) to reduced seawater pH: a comparison among a tropical, temperate, and a polar species. Marine Biology. 156: 1125-1137.

3. Sheppard Brennand H, Soars N, Dworjanyn SA, Davis AR, Byrne M. 2010. Impact of ocean warming and ocean acidification on larval development and calcification in the sea urchin Tripneustes gratilla. PloS One. 5:1-7.

Funding from the NSF and support from the College of Charleston

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