Preliminary Disease Risk Assessment in Giant Kelp Aquaculture on the US Pacific Coast

Our goal is to establish a preliminary assessment of disease risk associated with giant kelp Macrocystis pyrifera aquaculture. We predict that several diseases will affect kelp specimens and cause significant productivity loss, though we are likely to find algal varieties that are comparatively resistant to infection.

This project was a collaboration between Bowling Green State University, University of California: Santa Barbara, and University of Wisconsin: Milwaukee. Each of the institutions worked to connect studies surrounding productivity, epifauna disease rates, and kelp use for biofuel.

As the researchers from Bowling Green State University, it was our job to analyze photos of harvested kelp from the University of California: Santa Barbara so we could achieve our three main areas of study: disease characterization, kelp productivity loss determination, and resistant cultivar identification. These were summed up in our scholarly question. In order to achieve these areas of study, there were several steps. 

As stated above, the team had to identify the main disease and their infection characteristics. This was done by analyzing photos of the harvested kelp that the University of California Santa Barbara researchers took. After analyzing the photos for diseases, bryozoa, amphipods, and hydroids were determined to be the primary diseases we could consistently quantify with the data available. Other researchers on the team observed disease characteristics such as blade rot and frond and stipe twisting, but logistical constraints prevented their assessment in a comprehensive manner; for this reason we focused only on the primary diseases. After identifying the primary diseases and their characteristics we created a ranking scale for the amount of blade covered by diseases. This step bridged the main goal of identifying the disease characteristics and the other two main goals. In our scale, 0 was no coverage, 1 was less than 10 percent coverage, 2 was between 10 and 50 percent coverage, and 3 was attributed to plants with more than 50 percent overall coverage. Each plant was given a rank for each of the three diseases, and those ranks were used along with pre-measured data- provided by the UC Santa Barbara team- of the total weight, stipe weight, blade weight, blade count, pneumatocyst count, and individual count to determine kelp productivity loss and resistant cultivar.

The second two goals required the use of statistical tools such as PERMANOVA and Kruskal Wallis tests. These were required because our data was non-parametric and these tests are specifically for identifying statistically significant relationships in non-parametric sets. PERMANOVA tests were used to determine whether there were statistically significant relationships among several variables such as genotype, biomass, infection phenotypes, and infection rates. With the PERMANOVA, we determined the relationships between genotype, disease rates, and productivity. For clarification, productivity was a compounded multivariate variable consisting of total weight, stipe weight, blade weight, blade count, pneumatocyst count, and individual count. The findings of these analyses are listed below.

I have always wanted to be a marine biologist, so when I had the chance to join a research project about kelp, I dove right in! I was excited because this project was intended to focus on conservation of the environment and reducing the demand for fossil fuels. This was a massive ARPA-E project, and my team worked along with researchers at University of California: Santa Barbara (UCSB) and University of Wisconsin: Milwaukee (UWM). UCSB’s research concerned maximizing kelp productivity in aquaculture and UMW’s research focused on converting that kelp into biofuels. There was a critical link missing, though, which my team filled. This included analyzing the statistical relationships between genotype. Disease, and productivity. Kelp is prone to diseases, so minimizing infection will save aquaculturists time and money, and there may be a key component relating genotype to disease resistance. On the same note, genotype and productivity are likely related to mannitol production, which is the molecule UMW is researching for biofuel purposes. Participating in this research allows me to be a part of large-scale conservation efforts that have tangible impacts on global communities.

Our data analysis indicated that not all diseases or disease combinations would have statistical relationships with productivity, which I thought was very interesting. I would have expected overall increased pest presence to be related to decreased productivity, but that was only the case for two disease states: hydroids alone and the combined presence of amphipods and bryozoans. The latter could be a case of secondary infection, which will require further research in the future.

My CURS project focused on data analysis of many interrelated variables. When my partner and I received our data from California, coming up with methodology and appropriate analytical tests was challenging. Being the first to perform this kind of research made analysis particularly difficult because we did not have any references to follow. After careful consideration, we overcame this challenge by using multivariate analysis because there were multiple variables that interacted to influence the relationships, and a simple ANOVA test would not be sufficient. Therefore, we learned how to use the program R to perform specific tests called PERMANOVA and Kruskal-Wallis tests to analyze our data.

CURS provided me with opportunities to learn about the many uses of kelp, which range from biofuel to substitute fertilizer to carbon sinks! In addition, I learned about complex data analysis and programs like R, which are critical for researchers.

This research experience was so important to me because it showed me the critical nature of performing applicable research. This study will be applied to conservation on many fronts, which include reducing fossil fuel consumption and increasing environmental remediation.

CURS has given me an outlet to try out new modes of research that have real-life impacts. Trough this experience, I gained valuable skills that I will use far into the future. 

Applying for research funding may seem intimidating but taking this step may be the beginning of your journey to changing the world. Taking chances to apply for research experiences will be well worth your time, and you might even discover a new passion you never knew you had.

I am scuba diving certified, and my favorite dives have been night dives or dives with sharks!