Interview with Associate Professor Aki Kato
 
Wakame (Undaria pinnatifida) and other seaweeds are generally served as daily food in Japan.When she saw these seaweeds as marine organisms, a career path opened up for her toward becoming a professional researcher.The world of marine algae spreading deep into the sea offers various potentials.
 
Becoming one of a few researchers in the field of phycology, inspired by an experience that turned her 180 degrees in the direction of her interest
 
  Dr. Aki Kato has been studying algae, primarily seaweeds, to clarify their species diversity and ecology. She was appointed to her present position as Assistant Professor at Hiroshima University in 2011. She is expected to be the first person in 34 years to work as a phycologist at the university since 1978, when a faculty member specializing in phycology was transferred to another university.

However, Dr. Kato has become who she is now because of an unexpected turn of events. She recalls that it was a university marine exercise that had greatly changed her future career path. “When I participated in a five-day maritime exercise using algae, I was surprised to discover the presence of this research field. I realized that I had never before thought of the category of algae as a possible research target,” she says.
 
Until then, she had wished to join a laboratory conducting biotechnology-related studies, such as plant breeding using genes. After the maritime exercise, however, she changed her mind in order to enter a laboratory of phycology. Dr. Kato says that when she saw seaweeds as marine organisms, she was surprised to find that here was a research discipline that was new to her, and that this surprise made her choose to pursue phycology.
 
While doing her graduation work as an undergraduate, she discovered a new seaweed species, to which she also gave a name. After accumulating these experiences, she decided to advance to the master’s and doctoral courses. Looking back on those days, she says, “I was so absorbed in studying taxonomy.”

After completing the graduate program, she continued studying the molecular phylogeny and systematics of seaweeds as a postdoctoral fellow and in other capacities. During that period, however, she found herself wondering about what seaweeds were like while they are alive. This could have been the moment she became aware that until then she had been studying dead subjects alone, despite the fact that she should have been pursuing biology.
 
 
She says, “At that time, I happened to have a chance to study at a laboratory I knew, which looked into how climate change, such as ocean acidification, could affect marine organisms. Since I was working on systematics of calcareous seaweeds in those days, I began conducting examinations to see what would happen if calcareous organisms were raised in acidified seawater.

In this manner, Dr. Kato started an attempt to “grow” organisms, an approach that was different from those she had taken until then. This triggered her interest in the relationship between species diversity and the environment.
 
Studies on coralline algae—a group of seaweed that become “living stones”—to classify them and clarify their ecology, and look into the relationship between coralline algae and the environment
 
  Currently, Dr. Kato is focused primarily on the study of coralline algae.

Coralline algae are, so to speak, “living stones,” with calcium carbonate accounting for approximately 90 percent of their body weight. In coral reefs, coralline algae produce chemical substances in addition to calcium carbonate, thereby helping larvae of the hermatypic coral to settle on the sea bottoms and undergo metamorphosis. In this manner, coralline algae contribute to the formation of coral reefs both directly and indirectly.
 
Dr. Kato says, “Hermatypic corals can grow in sea bottoms where sufficient sunlight penetrates. In waters deeper than 50 meters, the coverage of coralline algae is larger than that of hermatypic corals.” While coralline algae contribute to the settlement on the sea bottoms and metamorphosis of sea urchin and shellfish larvae, she points out, “Unlike in the case of coral reefs, coralline algae can cause a problem in the temperate zone.”
 
This problem is called a “barren ground,” a phenomenon in which a macroalgal bed, i.e. a forest of seaweeds, has deteriorated such that there are few seaweeds on the sea bottom. If this problem occurs, at the sea bottom we can often observe an area whose overall surface is covered with crustose coralline algae (nongeniculate coralline algae), and find a high density of sea urchin population. In such areas, almost all the seaweeds are consumed by sea urchins, which have thrived due to the dominance of coralline algae.

“Now we are studying the species and ecology of nongeniculate coralline algae occurring in coralline flat areas, using the Bungo Channel, which includes rich macroalgal beds and coralline flat areas,” says Dr. Kato.
 
 
On the other hand, the study of coralline algae has another aspect as well. In the process of the growth of nongeniculate coralline algae, they develop something like “tree rings” that can be utilized in “restoring the paleo-environment.” Past studies have thus far confirmed plant species more than several hundreds of years old.
 
  Dr. Kato explains, “We have not yet fully understood what kinds of species comprise coralline algae. By surveying their morphology and genetic variations, if we can recognize the presence of a certain species, we will be able to investigate their ecology and physiological characteristics. The accumulation of such research results will be useful in considering their applicability as environmental indicators.”

There are only a limited number of experts in systematics of coralline algae in the world. Dr. Kato has therefore received requests to deliver lectures and conduct joint researches, from an academic society of fossilology, earth scientists, and other researchers inside and outside Japan.
 
Dr. Kato is positive about responding to these requests, indicating in her remarks, “It is very interesting to work with people conducting research in different scientific fields.” She expects that such collaborative opportunities will expand her research even more in the future.
 
To break free from stereotypes
 

  During the first year after she began working at Hiroshima University, Dr. Kato devoted herself to surveys of seaweeds growing in the region surrounding the Takehara Marine Science Station, and confirmed the monthly occurrence of approximately 150 species that year. Among the surveys of this floristic study were ones conducted when the spring tide was at low tide. In winter, her team had to start these surveys before dawn. Despite such difficulty, she remembers the surveys with a smile on her face, saying, “It was truly enjoyable.” These study efforts led to the establishment of the Osaki-Kamijima Town Food Culture and Seaweed Study Group (Kaiso-jyuku), an organization for promoting and raising awareness of local seaweeds, in collaboration with the residents of Osaki-Kamijima, the largest isolated island in the Seto Inland Sea, located on the shore opposite the Takehara Marine Science Station. The Study Group is smoothly carrying out its activities, and has acted as a catalyst for successful commercialization of local seaweed products.

She expresses her aim, saying, “In the future, I want to study marine algae diversity thoroughly, especially focusing on calcareous algae in the world and local seaweeds in the Seto Inland Sea.”

Asked about what her goal is as a researcher, she replied, “What we take for granted is derived from the knowledge accumulated through many people’s experiences. In the ocean, there are many things that people have not yet experienced. I would be very happy if I could only discover any one of these things,” she says as her eyes brightened.
 
Dr. Kato sends the following message to young people who are thinking about their future path.

“As I mentioned before, when I participated in the maritime exercise, which was a compulsory subject, I found it unexpectedly interesting. Therefore, I hope that you also will actively enjoy experiencing everything you can choose to do at university. I advise not to narrow the scope of what you want to do based on the limited knowledge that you have now, but to take on various challenges.

“Not a few people say that they do not know what they want to do. Even so, you should begin with addressing a theme currently in front of you. It may turn out to be more interesting than you have expected. In fact, many sources of interest can be found anywhere around you.”
 
Aki Kato
Associate Professor, Laboratory of Aquatic Field Science

In April 2003, Dr. Kato was appointed as a COE Postdoctoral Fellow at Hokkaido University. She then served as a JSPS Postdoctoral Fellow at Kobe University, and as a COE Postdoctoral Fellow at the University of the Ryukyus. Since February 2011, she has been in her present position as Assistant Professor of the Takehara Marine Science Station, Graduate School of Biosphere Science, Hiroshima University.
January 1, 2017 – Associate Professor of the Takehara Marine Science Station, Graduate School of Biosphere Science, Hiroshima University.

Posted on Aug 2, 2016