BMA, our potential superheroes…pending

Connor Graham, Francis Marion University

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Findings: At the beginning of this summer my mentors and I had specific objectives and questions we wanted to answer regarding the biogeography of benthic microalgae and of course like any experimental hypotheses, things change. Our main objective was to identify the community structure on five barrier islands on South Carolina’s coast and see if there were differences. If there were differences were they because of geographic distance or environmental factors?  As the summer progressed our questions changed slightly to look more at community biomass instead. Of course our questions link back to the larger picture of using these diatoms as bioindicators for environmental health.

Community structure is composed of two main components: biomass and DNA composition. Biomass is the mass of the organisms present in a given area. Even though we collected samples for DNA, we had an allotted time which only allowed for analyzation of the biomass samples which were chlorophyll a. So, now our main questions were: Are there differences in community biomass among islands? Are those differences due to geographic distance or environmental factors like water temperature, nutrients, wind, pressure and so many more.

Based on the results from the data we have, biomass does indeed differ among islands, geographic distance is not the reason, but instead a few environmental factors. Those significant environmental factors are located in the table below. Still taking in account that we have pending analysis for DNA composition, nutrients and grain size, our original questions could be supported quite differently.

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The result of an ANOVA test which showed biomass differences among islands. The p-value was less than 0.0001.

 

 

 

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This p-value of 0.439 shows that Geographic distance is not correlated with community BMA biomass.

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These are the significant environmental factors that correlate with BMA biomass, with water temperature being the most significant with a p-value of 0.001.

However, if we do see that community structure is not affected by the differences in locations, then potentially there is no dispersal limitation on our microbes. Also, if community structure is also impacted by environmental like biomass, then we could potentially use this to measure bioindication by adding in a new factor.

As of now, we are not sure if diatoms can be used as bioindicators, and if they are the superheroes we need. However, we do know that more research is needed to find out and until then our great state awaits its savior.

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A picture of me covered in mud at Hunting Island after a day of sampling. Photo: Max Cook

Acknowledgements

I would like to thank my mentors: Dr. Craig Plante and Kristina Hill-Spanik (CofC). Also, I would like to thank my lab partner Max Cook (CofC). This project is supported by the Fort Johnson REU Program, NSF DBI-1757899.

 

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Bat-Signal? Have you heard about Diatom-Signal?​​

Connor Graham, Francis Marion University

IMG_0079The approach: In my previous post I talked about using benthic microalgae (BMA) as bioindicators for South Carolina’s coastline. If they are truly the “superheroes” we need, we will be able to use BMA to test water quality that affects commercial and recreational fishing, tourism, and even human health. My job in all of this is to determine whether or not these diatoms are actually present and similar in the sediments of the saltmarshes. If they are similar in similar unimpacted habitats then they can be used as biological signals. The bat-signal illuminates the sky to alert the citizens of Gotham City that there is a problem and in the same way diatoms could potentially be our signal for the environment.

My team and I have traveled to five barrier islands on South Carolina’s coast to gather samples from the mudflat regions. On each island, I had three main sites, 0,10, and 100 meters. From these sites, each had a letter, A, B, C where our samples were collected. At 10 meters, each letter has three sub-sites.

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Field Sampling Map. Created by: Connor Graham

Using BMA as bioindicators will require the community structure to be similar among islands. Previously, I mentioned when concerning microbes we assume they are everywhere because of their incredible abundance, however that is not the case. I will look at the BMA community structure on the various islands and see if there is any correlation between them and geographical distance. If there is a correlation between community variation this relationship is called beta diversity and geographic distance, then is it possible that factors other than environmental one also affects the relationship between regional and local BMA communities (i.e. dispersal limitation).

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Edisto Beach Sampling Site. Photo: Connor Graham

Some of the environmental factors that were measured at each site at each island are sediment, air and water temperature, amount of light and PAR, humidity, wind speed, pressure and the amount of dissolved oxygen. Current, and water salinity were also measured. If the communities are dissimilar these measurements could be our contributing factors.

The collected samples from the salt marshes will also undergo an array of measurements that are also considered ecological factors. For example, each sample will be measured for the moisture content, organic matter, and chlorophyll. Moisture content data allows me to again compare the different mudflats to identify similarity. The same is for organic matter and chlorophyll. Chlorophyll a measurements, in particular, will allow my team and me to quantify the total mass of diatom species (biomass) of each island.

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Field supplies ready for the first day at Folly Beach. Photo: Connor Graham

The idea of microorganisms displaying geographical patterns is debatable. Some believe that patterns are based on ecological factors alone, while others believe that the community diversity geographical patterns are based on ecological factors plus historical factors such as dispersal limitation or competition (Soininen 2012). Either way, we will finally be closer to knowing whether diatoms can be the signals we are looking for. If they are will we be able to see the “Diatom Signal” warning us about the health of our coast and what will we do about it?

Acknowledgments

I would like to thank my mentors: Dr. Craig Plante and Kristina Hill-Spanik (CofC). Also, I would like to thank my lab partner Max Cook (CofC). This project is supported by the Fort Johnson REU Program, NSF DBI-1757899).

Literature Cited

Soininen J. (2012) Macroecology of unicellular organisms – patterns and processes. Environmental Microbiology Reports, 4(1): 10-22.

Not all superheroes wear capes!

Connor Graham, Francis Marion University

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The problem: When you think of superheroes, does the man in the red cape and ‘S’ on his chest come to mind? That’s understandable, but could it be possible that our greatest protectors are embedded in the sediment along our saltmarshes? Well, it is and these potential protectors are known as Benthic diatoms.

Benthic diatoms, plant-like microorganisms, are bioindicators, which means they can be used to determine the health of an environment. In South Carolina, environmental health is crucial to the prospering tourist areas, booming commercial fishing, and overall human health of the year-round residents. Poor environmental health could lead to a decline in economic benefits, decrease in seafood-and-shellfish heavy diets, and the fitness of the human population living in those areas. Benthic microalgae (BMA) are considered to be great bioindicators because of they have a short lifespan, they are abundant, easy to sample, sessile, and respond to specific stimuli (Desrosiers et al. 2013). But the question is can we use diatoms as bioindicators for South Carolina’s various salt marshes? Are they the superheroes we did not even know we had?

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Sampling site at Folly Beach. Photo: Max Cook.

My project this summer consists of sampling saltmarsh mud on at least five barrier islands along South Carolina’s coast to better understand the biogeography of BMA and assess their potential as bioindicators for saltmarshes. Barrier islands are land areas that are now inhabited by humans that protect inland territories from natural disasters.

I am comparing the community structure of the BMA’s on the various islands. If there is little to no variation in the benthic microbial communities gathered from the islands, bioindication can be used to determine their health. To use them as bioindicators will require the community structure to be similar on all the islands.

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Measuring the amount of light at Folly Beach. Photo: Max Cook.

Whether or not the community structure is similar or different will then be compared to the geographical distance of the sample sites and islands. Looking at the biogeography (geographical distribution of living things) of the BMA community has not been a priority, because we assume “everything is everywhere” (Baas-Becking 1934, as cited in Janne Soininen 2012) when speaking of microorganisms. Hopefully, by determining the diatoms’ community diversity on the islands, South Carolina is one step closer to thriving.

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Kristina, Max, and I in the clean room at Hollings Marine Lab analyzing grain sizes of sediment samples. Photo: Jennifer Ness.

Acknowledgments

I would like to thank my mentors: Dr. Craig Plante and Kristina Hill-Spanik (CofC). Also, I would like to thank my lab partner Max Cook (CofC). This project is supported by the Fort Johnson REU Program, NSF DBI-1757899.

Literature Cited:

Desrosiers, C., J. Leflaive., A. Eulin. and L. Ten-Hage. (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.

Soininen J. (2012) Macroecology of unicellular organisms – patterns and processes. Environmental Microbiology Reports, 4(1): 10-22.