Sue Leskiw, Sierra Club
For the 15th year, North Group Sierra Club sponsored awards for the best projects relating to environmental issues at the annual Humboldt County Science Fair, which was held virtually in mid-March. Three cash prizes were awarded. Two of the three projects North Group judges selected competed in the California State Science Fair in April!
“Benthic Macroinvertebrates in Jacoby Creek” by Jacoby Creek School eighth-grader Genevieve Caruso was awarded first prize. She investigated the presence of benthic macroinvertebrates (insects that live along the bottom of a water body and are visible to the naked eye) to serve as an indicator of stream health. She placed two sample bags each at four locations along Jacoby Creek, collecting them after two weeks to sort and count macroinvertebrates. Genevieve also looked for a correlation between the types and amounts of macroinvertebrates and creek turbidity and flow, plus a correlation between increased flow and turbidity, by checking turbidity data twice a week. Her sites included two residential areas (upstream – South Quarry and Brookwood), adjacent to a farm, and along a busy road (downstream – Old Arcata). Collecting between January 1 and 16, at South Quarry, Genevieve trapped five different taxa (including one that is intolerant of polluted water); at Brookwood, four taxa; at Farm, four taxa (ranging from intolerant to very tolerant); and at Old Arcata, four taxa. The lack of rain may have affected macroinvertebrate collection during her second sampling block, January 16-30. Her prediction that macroinvertebrate numbers and diversity would increase as turbidity decreased was not supported, but she was correct that turbidity did correspond with flow levels. She noted that Jacoby Creek contains many salmon redds. Genevieve competed at the State level, winning third place in the junior division of Earth & Environment. Her project also won a first place award from Friends of the Arcata Marsh in the Humboldt County Science Fair.
Second place went to Jacoby Creek seventh-grader Zoe Cappuccio for “Cellulase Activity in Environmental Samples.” (She had won a third-place award from North Group in 2021.) Her research question was “What environmental sample — garden compost, cow compost, or chicken coop compost — has the most active cellulose-degrading bacteria?” She hypothesized that garden compost, where plants are more broken down into soil, would have the most cellulose activity, rather than cow and chicken coop compost, which still have visible plant matter. Her experiment investigated conversion of mass: cellulosic biomass doesn’t disappear, but is slowly broken down by cellulose-degrading enzymes. After growing bacteria from the three types of compost on media plates, she transferred colonies onto plates having no agar food source, only carboxymethylcellulose (CMC) to enrich cellulose-degrading bacteria. Following a 24-hour incubation, Zoe measured the areas where bacteria had eaten the CMC. Garden compost-sourced bacteria cleared the largest area (34 square millimeters), with 50 percent of the samples showing cellulose activity, while chicken coop compost bacteria cleared the least (13 square millimeters, with only one of eight samples showing activity), supporting Zoe’s hypothesis. She noted that cellulosic biomass (non-edible plant matter) has the potential to replace ethanol as the new primary liquid fuel, but enzyme efficiency to break down cellulose represents a barrier for large-scale processing. Zoe was selected to compete at the State level, where she won fourth place in the junior division of Microbiology.
Caroline Taylor, a sixth-grader at Jacoby Creek, was awarded third place for “Can Kelp Replace Plastic?” Her project examined whether kelp could be made into starter pots that could perform similarly to plastic ones. She theorized that kelp pots might even work better than plastic because the nutrients contained in kelp could slowly disperse into the soil and add “extra energy” to the growing sprouts. Caroline found that more pea seeds sprouted in the kelp pots, but they were shorter than those in the plastic pots. Her possible explanations were that while the kelp pots started out wet, they dried out more than plastic did after minimal watering of both or that the black plastic trapped more heat than the light green kelp, boosting winter growth. Caroline noted that native peoples living along the Pacific Coast have made baskets out of kelp for a long time and that the kelp pots she crafted weren’t very difficult or time consuming to make. “We don’t have to use plastic for everything we make. There are alternatives that could be more eco-friendly… I can’t wait to extend this project and find other green solutions to the overuse of plastic,” Caroline concluded.