What’s living in the sand?

Jessie Lowry, Coker College

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Visible microalgae seen on the surface of wet sand at Folly Beach.

Next time you go to the beach this summer, I want you to think about the sand that you are walking on. Did you know that there are tons of microscopic photosynthetic organisms, aka microalgae, that live on the surface of sand? Before this summer, I didn’t know about these organisms either. Here is a picture of visible microalgae on the surface of the sand. Look for this next time you’re at the beach!

Microalgae communities in sand are made up of single-celled eukaryotic algae and cyanobacteria living in the top several millimeters of the sand (Miller et al., 1996). These organisms play important roles in ecosystem productivity and food chain dynamics, as well as in sediment properties, such as erodibility (Miller et al., 1996).

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Dr. Craig Plante and Jessie Lowry collect samples of sediment from Folly Beach. Photo credit: Kristy Hill-Spanik.

I am studying these microalgal communities and what factors influence community structure. For example, does pH, salinity, nutrients, or grain size shape microalgal community structure? Or does geographic distance shape communities? To answer these questions, I am collecting samples from Kiawah Island, Folly Beach, Isle of Palms, and Pawley’s Island, SC. We are measuring environmental variables at each location, and using molecular tools to study microalgal community structure.

I am extracting the DNA from samples collected, amplifying specific regions from these samples using polymerase chain reaction (PCR), and then we will be getting these regions sequenced using Ion Torrent technology. We will then use QIIME to determine how similar these benthic microalgal communities are.

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Jessie Lowry preparing samples for PCR, or polymerase chain reaction, which is used to make millions of copies of a piece of DNA.

Diatoms, a group of microalgae, have been proposed as bioindicators of environmental health (Desrosiers et al., 2013). Bioindicators are really cool because instead of telling a snapshot of an environmental condition, such as pH, temperature, or amount of oxygen in an environment, biological indicators reflect those changes and can give an idea of how the ecosystem is being affected. This research will further our knowledge of what factors shape benthic microalgal communities, and give a better understanding of these organisms as a potential bioindicator. In addition, this research will add to knowledge about the distribution of microorganisms, which is also not fully understood.

Learn more:

http://web.vims.edu/bio/shallowwater/benthic_community/benthic_microalgae.html

http://www.aims.gov.au/docs/research/water-quality/runoff/bioindicators.html

References

Desrosiers, C., Leflaive, J., Eulin, A., Ten-Hage, L. (2013). Bioindicators in marine waters: benthic diatoms as a tool to assess water quality from eutrophic to oligotrophic coastal ecosystems. Ecological Indicators, 32, 25-34.

Miller, D.C., Geider, R.J., MacIntyre, H.L. Microphytobethos: The ecological role of the “Secret Garden” of unvegetated, shallow-water marine habitats. Estuaries, 19(2A): 186-212.

Acknowledgements

Thank you so much to my mentors Dr. Craig Plante, and Kristy Hill-Spanik. This research is funded through the National Science Foundation and College of Charleston’s Grice Marine Lab.

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The real beauty of coral reefs

Nina Sarmiento, Binghamton University

The beauty of a coral reef is undeniable. Over four thousand species of fish, 800 species of coral, invertebrates, and large macro fauna coming together in one place is sure to create a thrilling visual experience. You might be surprised to learn that these remarkable places filled with twenty five percent of marine life, constitute less than one percent of the ocean floor.1 But you don’t have to be lucky enough to travel to a coral reef to fully appreciate its beauty. The real value of reefs comes from their unsuspecting roles in sustaining life as we know it.

photo cred: fmap.ca

photo cred: fmap.ca

Fish from approximately half of our global fisheries, at one point spent a part of their life in coral reefs.2 The unique habitat hard corals provide is perfect for spawning and juvenile life for many species, which may later end up in other parts of the ocean. Fishermen make their livelihood from these reefs, harvesting an average of fifteen tons of seafood annually per square kilometer.3

As for people living on our tropical coastlines, reefs play a crucial role in protecting life on land. It is in the beauty of the long braches of Copra palmata, among other corals, that dangerous storms and waves are softened. Corals roughness and their shallow locale dissipate wave energy, and we have a natural barrier that safeguards our homes.4

Acropora palmata – “Elkhorn coral” Photo cred: coral.aims.gov.au

Acropora palmata – “Elkhorn coral”
Photo cred: coral.aims.gov.au

The importance and intrigue of coral reefs has led to studying many of the organisms and interactions there, leading to new understandings of many aspects of organism biology and evolution. Additionally research has uncovered new medicine from extracting compounds unique species have, giving reefs an importance in future medical interests.

The paradox is that, of all the reasons why we appreciate coral reefs, it is we, the human species that are not having a good effect on them. In fact we are seeing reef decline in many parts of the world because of our actions.5

This summer I am delving into studying one of the possible reasons for this decline; a chemical threat to coral that may not be obvious at first, but could have significant implications on their ability to survive and reproduce.

Stay tuned to hear about my project and the amazing opportunity I have to be a part of the effort to preserve these beautiful communities.

References:

1 Spalding MD, Ravilious C, Green EP. 2001. United Nations Environment Programme, World Conservation Monitoring Centre. World Atlas of Coral Reefs. University California Press: Berkley. 416.

2 US Coral Reef Task force. 2000. The National Action Plan to Conserve Coral Reefs. Washington DC: US Environmental Protection Agency. 34.

3 Ceasr H. 1996. Economic Analysis of Indonesian Coral Reefs. Washington DC: The World Bank.

4 Lowe JR, Falter JL, Bandet MD, Pawlak G, Atkinson MJ, Momismith SG, Koseff JR. 2005. Spectral wave dissipation over a barrier reef. Journal of Geophysical research. 10: C04001.

5 Nystrom M, Folke C, Moberg F. 2015. Coral reef disturbance and resilience in a human-dominated environment.

Funding for my research comes from the National Science Foundation in partner with The College of Charleston and the National Oceanic and Atmospheric Administration

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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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