Abstract

Harmful algal blooms are a reoccurring phenomenon in the Great Lakes, particularly Lake Erie and Ontario. During stages of algal proliferation, there is an excess pool of nutrients and dissolved metals available to the algae for sequestration. In algae, copper is vital for metabolic processes involved with photosynthesis and growth. Previous research has explored using algae to remediate wastewater by removing dissolved metals and better understand, the downstream effects on their metabolome, morphology and physiology. In this study, we expand on previous work to determine how algal species, Chlorella vulgaris and Tetradesmus obliquus, adapt to copper stress. Using a combination of inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy with an electron dispersive x-ray (SEM-EDX), Fourier transform infrared spectroscopy (FTIR), and liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-QTOF) analyses, we established links between algal physiological, morphological and metabolic changes. We observed significant differences in algal population across treatments and different species. SEM-EDX confirmed the sorption of copper to the surface, and results from FTIR showed notable changes within the chemical composition of the algal biomass and variation between both species. These preliminary results indicate that the response to added copper stress supports that algal species uptake and internalize copper within their environment.  The accumulation of contaminants such as copper in algae suggests that algal blooms represent an underrepresented fraction of copper. This provides an avenue of research for the recovery of copper by exploring extraction protocols that may be compatible with industrial processes. By accessing algal blooms, there is a potential to optimize recovery methods on small quantities and as they progress to scale procedures. Post-extraction, the copper recovered can later be refined, utilizing blooms as a renewable source of copper.