Day and night chemistries vary significantly due to different dominate radicals. Hydroxyl radical from daytime ozone and nitrate radical from nighttime dinitrogen pentoxide have different effects on the ocean’s sea-surface microlayer. The ocean is a complex system of biology and chemistry that greatly influences our atmosphere as the sea-surface microlayer composition greatly impacts sea spray aerosol (SSA) formation. The composition of SSAs are influenced by the biology and chemistry in the ocean. Further studies are needed to understand what comprises SSAs and how SSAs influence the atmosphere, specifically their effects on ice nucleation, cloud condensation, and radiative forcing. By using an originally developed micro mini Marine Aerosol Reference Tank (µ-miniMART), algae biology, lipase enzymatic activity, and diurnal atmospheric chemistry can be studied. A diurnal setup for synthesizing ozone and dinitrogen pentoxide was developed to understand the specific composition of SSA and their potential role in the atmosphere. Instrumentation including infrared and Raman spectroscopies will be used to understand the molecular interactions of diurnal chemistry in situ. Preliminary results suggest that the C=O stretch (1730 cm-1) and CH2 asymmetric stretch (2930 cm-1) of lipids and the amide band bend (1300 cm-1) of the proteins, like lipase, yield resolvable peaks which can be monitored throughout an algal bloom. It is predicted that these modes will change when reacted with different atmospheric gases. This diurnal cycle is important for understanding the changing surface chemistry of the ocean which influences SSML and SSA composition.

Diurnal cycle effects on ocean biochemistry during a mesocosmic algal bloom

2019 Fall National Meeting

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