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.

Exploring the “Secret Garden”

Christine Hart, Clemson University

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On a walk along the beach, have you ever noticed the garden growing at the water’s edge? During low tide patches of green and gold speckle the sand, growing what researchers have called a “Secret Garden.”

The “Secret Garden” is made up of a variety of microorganisms like cyanobacteria, flagellates, and diatoms. These small, sand-dwelling organisms are collectively known as benthic microalgae (BMA). BMA are responsible for 50% of primary production in estuary systems through photosynthesis and an extracellular polymeric secretion. Though small, these photosynthetic powerhouses form the basis of ocean food webs. BMA are also important indicators of ecosystem health. Scientists have documented the response of BMA to a variety of environmental conditions. As humans change natural estuary conditions, BMA will serve as a bioindicator for changes in ecosystem health.

The visible patches of green and gold at low tide indicate an increasing density—or biomass—of BMA. Currently, researchers do not know the mechanism for the visible change in BMA biomass. Our study will focus on two possible mechanisms of biomass change. One mechanism may be the vertical migration of BMA to the top of the sand.  The increase in biomass could also result from growth among BMA species due to sunlight exposure.

In addition to the unknown mechanism, the particular BMA species associated with the green and gold sheen have not been well studied. Like plants in a garden, BMA species are diverse and serve their own roles in maintaining a healthy environment. To better use BMA as a bioindicator, we will characterize the type of BMA contributing to the visible biomass changes.

Our study will focus on the mechanism of changes in biomass during low tide, while also identifying changes in the presence of BMA species. The results from the study will give us a greater understanding of the BMA that are essential to estuary systems. This information will establish a basis of BMA dynamics that can be used as an indicator of the health of estuaries.

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Thank you to my mentor, Dr. Craig Plante, and my co-advisor, Kristina Hill-Spanik, for their support and guidance.  This project is funded through the National Science Foundation, and supported by The College of Charleston’s Grice Marine Laboratory.

 

Literature Cited

Lobo, E. A., Heinrich, C. G., Schuch, M., Wetzel, C. E., & Ector, L. (n.d.). Diatoms as Bioindicators in Rivers. In River Algae (pp. 245-271). Springer International Publishing. doi:10.1007/978-3-319-31984-.

MacIntyre, H.L., R.J. Geider, and D.C. Miller. 1996. Microphytobenthos: the ecological role of
 the “Secret Garden” of unvegetated, shallow-water marine habitats. I. Distribution, abundance and primary production. Estuaries 19: 186-201.

Plante, C.J., E. Frank, and P. Roth. 2011. Interacting effects of deposit feeding and tidal resuspension on benthic microalgal community structure and spatial patterns. Marine Ecology Progress Series 440: 53-65.

Rivera-Garcia, L.G., Hill-Spanik, K.M., Berthrong, S.T., and Plante, C. J. Tidal Stage Changes in Structure and Diversity of Intertidal Benthic Diatom Assemblages: A Case Study from Two Contrasting Charleston Harbor Flats. Estuaries and Coasts. In Review.

Underwood, G.J.C., and J. Kromkamp. 1999. Primary production by phytoplankton and 
microphytobenthos in estuaries. Advances in Ecological Research 29: 93-153.

 

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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Benthic Microalgae Research – A day at the beach

Jessica Lowry, Coker College

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I’m Jessie Lowry, a rising senior Biology major at Coker College, which is located in the tiny, homy town of Hartsville, SC. I am really excited to be here in my hometown this summer with opportunity to do research through the College of Charleston REU at Ft. Johnson. My research project this summer that I am working with Dr. Craig Plante on is investigating what factors influence the communities of benthic microalgae, or photosynthetic microorganisms in sediment.

Before we begin researching what species of diatoms make up the benthic microalgal communities, we need to do some preliminary sampling to measure things like pH, salinity, temperature, grain size, and moisture, at the three local beaches where I will be sampling at.

I’m not sure what I had envisioned for doing research this summer, but what I did not expect was for it to be like a day at the beach! Yesterday, Dr. Craig Plante and I went to Isle of Palms and Folly Beach, and today we are going to Kiawah.

My mentor, Dr. Craig Plante carrying research supplies out to the water at Folly Beach, SC.

We took several samples of seawater and sediment at each beach and we will do tests back at the lab. Unfortunately, I will not be spending every day researching at the beach. It was really great to get some sand, salt, and sun during a day of research.

Samples of seawater and sediment from Isle of Palms and Folly Beach that we collected to measure pH, salinity, grain size, and moisture.

Samples of seawater and sediment from Isle of Palms and Folly Beach that we collected to measure pH, salinity, grain size, and moisture.

Also, the temperature was in the 90s, the water was slightly warmer than the air, and the sand at one point at Folly Beach was a scorching 120° F! Dipping our feet in the water definitely felt great.

Funding

This research is funded by the National Science Foundation Reseach Experience for Undergraduates program at College of Charleston’s Grice Marine Lab.

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