Rhodes students named Broadcom MASTERS semifinalists

Three young scientists from the Rhodes School were named semifinalists in the Broadcom MASTERS, the nation’s most prestigious STEM competition for middle school students. Rhodes eighth grader Alexandra Orczyk and Rhodes graduates Katrina Ordway and Alexa Infelise were named in the top 300 out of 6,000 students nationwide. In the last 12 years, Rhodes and science teacher Roxanne Hunker have had six national finalists in the competition.

Alexa, whose family has moved out of state, was honored for her eighth grade project “Impacts of the Decoy Effect on Promoting Positive Choices in an Academic Setting.” Alexandra won for her seventh grade project “Investigating Impacts of Human Intrusion on Lottia gigantea Tide Pool Populations” and Katrina, now a freshman in high school, won for her eighth grade project “Effects of Quercus engelmannii on Native vs. Invasive Plant Species.”

“I was really surprised because I didn’t think I had much of a chance,” said Alexandra, who is also a pianist and a published poet.

Just to apply for Broadcom MASTERS was a four- to six-hour process, with required essays and a lot of personal and innovative-thinking questions to answer.

“I’m really happy for the amount of effort that I put into this project,” Katrina said.

Both Alexandra’s and Katrina’s projects were inspired by time spent outdoors in San Diego, enjoying nature and the coastal environment.

Alexandra’s project focused on tide pools in Point Loma.

“I always saw so many visitors and I wondered what kind of impact all these visitors had on the inter-tidal environment,” Alexandra said.

In science class she had learned about the intertidal animal the owl limpet (Lottia gigantea), a species of sea snail, and how it was at risk due to poaching.

“What makes the problem worse is that owl limpets start out as juveniles with no gender and once they grow larger they become male and then later in life become female. Poachers tend to take the larger owl limpets which are the females so this creates a skew in the ratio of male to females,” Alexandra said.

She contacted local marine biologist Dr. Keith Lombardo and he told her about the surprising drop in number of owl limpets throughout the state — she wanted to investigate further. From Lombardo, she received maps of tide pool zones — zone one has 200,000 visitors annually and zone two has only 20,000 annually — her project would compare the two zones to see how much of an impact the visitors had.

Alexandra started researching in late September 2015 and collected data over several trips. Because she only had a few days’ worth of research, she also received and organized 80 pages of raw data from 1990-2013 to compare her results.

“Surprisingly, there was no statistically significant difference in sizes or numbers of owl limpets between the two zones,” Alexandra said, noting she also compared the high-tide zones to middle-tide zones to see limpet recruitment — many juveniles are born in high tide and replace the females dying off in middle-tide zone. On average, the limpets are smaller in high tide than middle tide and Alexandra thought recruitment could explain the large drop-off and hopefully predict that as they grow larger the population will go up again.

“I think these visitors didn’t make much of an impact because the tide pools are protected and the visitors are more well-informed,” Alexandra said. “The average visitor would be well-informed enough to know to not pry an owl limpet off a rock. If we protect more intertidal areas and educate visitors we can help protect owl limpets even more.”

Her project placed first in animal sciences at the Greater San Diego Regional Science and Engineering Fair and earned professional awards from the National Oceanic and Atmospheric Association and the San Diego Audubon Society. In the California State Science Fair, she took second place in zoology.

Katrina’s interest in her science project stemmed from the number of hikes she takes throughout San Diego — she always paid attention to different types of plants and trees and wondered about their impacts on the environment.

“I was really interested in one particular type of tree because it seemed to have no shrubbery growing around it underneath or very little invasive species growing around it, while other types of oaks seemed to have more invasive vegetation,” Katrina said of the Engelman Oak tree (Quercus engelmannii).

Katrina found that the allelopathic properties of the Engelmann Oak had never been explored and her project was set. As she explained, allelopathy is the chemical inhibition of one plant that hinders other plants from growth.

For her experimentation she went on many different hikes and measured the distance in a 10-meter and 5-meter radius to the trunk and created log forms that would document the approximate number of each species found, whether native or invasive. She also documented the air temperature, the percent relative humidity, the lux (sunlight), the soil moisture, the soil pH and the soil temperature.

She then compared those graphs to see differences and possibly spot to whether the oak was effective in inhibiting the growth of invasive species.

“As the second part of my project, I collected leaf litter and used the leaf litter to create my own form of natural herbicide that would hopefully prevent the invasive species from growth and not harm the native species,” Katrina said.

She conducted tests for eight weeks and recorded growth patterns, in addition to observing the trees in nature.

“I was able to find in the log forms that I wrote down during the hikes that I took, that there were close to no invasive species in the 5- to 10-meter radius of the oak tree other than small, unidentifiable grasses. With the native species they were able to grow more abundantly around the trunk which showed me that perhaps the Engelmann Oak tree did possess the allelopathic properties,” Katrina said.

Her controlled test with the herbicide she created produced similar results. She applied the herbicide to five different native and five different invasive plants and after eight weeks, the invasive were wilting and dying while the native were “growing in a healthy matter and perhaps even stimulated by natural herbicide,” Katrina said.

At the county science fair, Katrina won first place in plant biology and the runner up sweepstakes award, as well as a professional award from the San Diego Zoo. In the state fair, she received first place in plant biology.

Honker, who has been at Rhodes for 30 years, said she ignites students’ interest in science as early as kindergarten. She shows all grades the connections between physics, chemistry, biology and math, and tries to incorporate a lot of phemomena and make science real and relatable to students.

“I think that’s important. And I think they, as young scientists, realize that they can also explore and contribute to scientific knowledge,” Honker said.

“For me, Ms. Honker would always make it fun,” Katrina said. “That was one of the big things about it, that I actually found myself really enjoying science which made me want to do more science.”

“It’s true, we have a lot of fun,” Honker agreed.

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