Algae Microbiome: The Hidden World

Pressley Wilson, University of South Carolina Aiken

The Approach: In my previous post, I discussed (1) the importance of an organism’s microbiome in relation to its health and (2) the importance of algae in marine ecosystems due to their ability in producing oxygen, removing nitrogen and phosphorus from water, and exchanging inorganic carbon.

Considering the importance of these two variables, this summer I am researching the relationship between the algae microbiome and algae species in One’ula Beach, Honolulu, Hawai’i.  

DNA extraction in progress. Photo credit: Dr. Heather Fullerton.

The objectives of my research project are:

  • Identify relationship between algae microbiome and algae species
  • Identify relationship between the microbiome with algae’s morphology

Prediction

This study will predict there is a variation in the microbiome between algae species, due to the different species characteristics, such as calcification.

Sample Collection

The five algal species of different morphologies were hand-sampled by Dr. Heather Spalding at the intertidal region of One’ula Beach. The algae samples were rinsed with artificial saltwater to remove dirt and loosely associated bacteria. After cleaning, each species were placed into (1) a micro-centrifuge tube with 0.5 mL of RNA-later or (2) a 15 milliliter conical tube with 1.5 mL RNA-later. The RNA-later is a DNA preservation agent, was used to stabilize the algae DNA. The samples were stored at 4°C overnight. This overnight incubation allowed the RNA-later to penetrate the bacterial and algal cells to the DNA. After this incubation all tubes were frozen at -20°C and shipped overnight on dry ice to the College of Charleston, South Carolina, where they were stored in  -80°C freezer until DNA extraction.

Sample Analysis a

A completed gel electrophoresis.

A MoBio Fast DNA Spin Kit was used to extract the DNA from the algal samples. This DNA is then tested by PCR to determine if bacteria are present on the algae. To determine the number of bacteria present, qPCR is used. This molecular biology technique is used to quantify specific genes in a sample.

The PCR samples will be analyzed using gel electrophoresis, a molecular biology procedure that uses an electrical current to separate the components of the sample DNA by size. The qPCR data will be compared to a known DNA standard to determine the number of bacteria in our samples and calculations will be performed using excel.

Acknowledgements

I would like to thank Dr. Heather Fullerton for her guidance and support with this project and Dr. Heather Spalding for her sample collection. This project is supported by the Fort Johnson REU Program, NSF DBI-1757899. 

Meddling with Mysterious Macroalgae

Pressley Wilson, University of South Carolina Aiken

The problem: If you have ever been in the ocean, you have probably come across a piece of seaweed, which is a type of macroalgae. Macroalgae are simply algae that can be seen without a microscope. These organisms undergo photosynthesis, produce carbon, and can reduce the levels of phosphates and nitrates in water (Champagne et al. 2015).

Although algae are one of the most important parts of marine ecosystems, the algae microbiome (the bacteria that live in and around algae) is highly unknown and further research is needed to uncover this critical macroalgae information. Is there a relationship between bacteria and algal species? Is there a relationship between the algae’s physical features and the bacteria? Or is the microbiome the same throughout the algae, regardless of variation in species and physical features?

In order to answer these questions, I am conducting a research project this summer looking at the bacteria that are associated with intertidal macroalgae from One’ula Beach, Hawai’i.

Intertidal region of One’ula Beach, Hawaii

The five species below were chosen from the intertidal region of One’ula: Asparagopsis taxiformis (1), Avrainvillea sp (2), Halimeda discoidea (3), Padina sanctae-crucis (4), and Dictyota sandviscensis (5). These species were chosen because they range from red, brown, and green algae; have varying physical features; and all currently grow on the intertidal region of One’ula Beach.

Macroalgae from One’ula Beach, Hawaii (Photo credit: Dr. Heather Spalding)

Asparagopsis, Avrainvillea, and Dictyota are uncalcified, Halimeda is calcified, and Padina is lightly calcified. Asparagopsis has fluffy upright filaments, Avrainvillea and Padina have a fan-shaped thallus, Halimeda has flattened segments, and Dictyota has dichotomous branches. All species are native to One’ula Beach, Hawaii, except Avrainvillea which is an invasive species, meaning it is not native to the area. These species represent a diverse array of brown algae (Padina and Dictoyta), green algae (Avrainvillea and Halimeda) and one red alga (Asparagopsis).

This research will lead to a better understanding of algae, which could lead to a better understanding of all photosynthetic marine organisms. Furthermore, this research will be used as preliminary results for Dr. Heather Spalding’s work in the Northwestern Hawaiian Islands determining if there is a relationship between spatial patterns and the algae microbiome, beginning in August.

Acknowledgements

I would like to thank Dr. Heather Fullerton for her guidance and support with this project and Dr. Heather Spalding for her sample collection. This project is supported by the Fort Johnson REU Program, NSF DBI-1757899. 

References

Champagne P, Hall G, Liu X, Wallace J, Yin Z. 2015. Determination of Algae and Macrophyte Species Distribution in Three Wastewater Stabilization Ponds Using Metagenomics Analysis. MDPI – Water. 7(7): 3225-3242.