Fecal Filtration

Although biofilters, a form of green stormwater infrastructure, have the capability of increasing water quality, the filtration of human pathogens and antibiotic resistance genes (ARGs) that are found in water sourcing from stormwater runoff is not well reported. Researchers from UC Santa Barbara’s Bren School of Environmental Science & Management — Marina Feraud, Dong Li, Patricia Holden, Laurie Van De Werfhorst and Timnit Kefela — have studied the efficiency of a breakthrough field-scale biofilter in Southern California. The researchers tested its ability to remove microbial markers and bacterial and viral pathogens from exposed water. They observed high variability in the removal of different microbial contaminants and ARGs. The biofilter significantly removed 14 of the 17 microbial markers when introduced to a 50:50 mixture of untreated sewage and stormwater. In contrast, no significant removal was documented in the other three markers: GenBAc3, Campylobacter and HF183. The results recorded in this study pose further research potential and questions about using human-associated fecal source markers as tools for pathogen removal. 

Ghost Gear

Abandoned, lost and discarded fishing gear (ALDFG) have long been obstacles in the field of marine conservation and continue to pose a threat to both marine organisms and field researchers.The adverse consequences of ALDFG are vast and range from the potential transport of invasive species to the distribution of harmful microalgae. They further include the obstruction of marine vessel navigation and “ghost fishing.” Ghost fishing is a process in which discarded fishing nets and other gear continue to catch and kill organisms long after fishermen have abandoned them, and is one of the most infamous results of derelict fishing gear. 

The extent of the environmental impact, however, depends on the drivers (i.e., the fisheries) which, in turn, depend on the region and scale of their work as well as the characteristics of the gear they are using, such as gear type and material. Therefore, any viable solutions must be context-specific. Six researchers, including UCSB Bren School of Environmental Science & Management adjunct professor Jono Wilson, compiled comprehensive databases in order to help streamline the development of solutions to these problems. The databases include various ALDFG causes, potential mitigation methods and “enabling conditions” to effectively manage these problematic marine debris items. This study and the databases will allow stakeholders to identify mitigation approaches that can be matched to distinct, local situations so that solutions are fishery-specific. It is hoped that these databases will direct the allocation of resources in order to effectively combat this incredibly damaging phenomenon. 

Food to Fumes

Aquaculture and mariculture are methods of food cultivation that are becoming increasingly important for food supplies across the globe. While these methods have led to greater accessibility to food sources, their expansion has resulted in an increase in greenhouse gas (GHG) emissions. The influx of these gases, including methane and carbon dioxide, are large contributors to climate change. With China being the leading producer of agricultural and mariculture cultivation, UCSB Bren School of Environmental Science & Management visiting scholar Kangshun Zhao worked with researchers from the Institute of Hydrobiology, Chinese Academy of Sciences to conduct a study that quantified GHG emission levels that were directly from aquaculture and mariculture production in China. They analyzed the carbon footprint of the four phases of the production process (feed, energy use, nitrous oxide and fertilizers) over the course of 10 years to show the spatial distribution of the emissions. The findings showed that feed production was the greatest contributor to GHG emissions as a result of crop energy use, crop land-use changes, fertilizer production and rice methane production. The regional gross domestic product was positively correlated with emissions in every province, with a correlation coefficient greater than 0.6. These results revealed that China’s aquaculture had a lower emission intensity compared to the findings of Macleod et al (2020) due to the higher percentage of bivalve (an aquatic mollusk) production. The results suggest that China’s carbon footprint can be reduced by adjusting the relative proportion of species-group production and decreasing the amount of energy use.