Snow-Dependent Biogeochemical Cycling of Polycyclic Aromatic Hydrocarbons at Coastal Antarctica

Abstract

The temporal trend of polycyclic aromatic hydrocarbons (PAHs) in coastal waters with highly dynamic sources and sinks is largely unknown, especially for polar regions. Here, we show the concurrent measurements of 73 individual PAHs and environmental data, including the composition of the bacterial community, during three austral summers at coastal Livingston (2015 and 2018) and Deception ( 2017) islands (Antarctica). The Livingston 2015 campaign was characterized by a larger snow melting input of PAHs and nutrients. The assessment of PAH diagnostic ratios, such as parent to alkyl-PAHs or LMW to HMW PAHs, showed that there was a larger biodegradation during the Livingston 2015 campaign than in the Deception 2017 and Livingston 2018 campaigns. The biogeochemical cycling, including microbial degradation, was thus yearly dependent on snow-derived inputs of matter, including PAHs, consistent with the microbial community significantly different between the different campaigns. The bivariate correlations between bacterial taxa and PAH concentrations showed that a decrease in PAH concentrations was concurrent with the higher abundance of some bacterial taxa, specifically the order Pseudomonadales in the class Gammaproteobacteria, known facultative hydrocarbonoclastic bacteria previously reported in degradation studies of oil spills. The work shows the potential for elucidation of biogeochemical processes by intensive field-derived time series, even in the harsh and highly variable Antarctic environment.

Phytoplankton Biological Pump Controls the Spatiotemporal Bioaccumulation and Trophic Transfer of Antibiotics in a Large Subtropical River

“…In the Pearl River Estuary, a hydrological model has revealed that the discharge of erythromycin-H 2 O and sulfamethoxazole through outlets accounts for 30.8 and 6.74% of their environmental capacity, respectively . Humans can be exposed to antibiotics through seafood consumption, thus prompting the need for systemic investigation of bioaccumulation, hazard evaluation, and risk assessments in aquatic organisms. − Once in the water column, the biological pump and degradation largely determine the fate of organic pollutants. , Previous studies have demonstrated that the phytoplankton biological pump plays an important role in regulation of water column mass balance and burial of antibiotics in eutrophic ecosystems, which could further affect the fate and trophic transfer behaviors of antibiotics in food webs. , Consistently higher bioaccumulation factors (BAFs) of other organic pollutants, such as perfluorooctanoate (PFOA), in oceanic plankton have been found in large oligotrophic global oceans . A recent work indicated that the effects of the biological pump further enhanced the uptake of sediment-bound hydrophobic organic contaminants (HOCs) by benthos and phytoplankton could strengthen the benthic bioaccumulation of HOCs …”

“…6−9 Once in the water column, the biological pump and degradation largely determine the fate of organic pollutants. 10,11 Previous studies have demonstrated that the phytoplankton biological pump plays an important role in regulation of water column mass balance and burial of antibiotics in eutrophic ecosystems, which could further affect the fate and trophic transfer behaviors of antibiotics in food webs. 12,13 Consistently higher bioaccumulation factors (BAFs) of other organic pollutants, such as perfluorooctanoate (PFOA), in oceanic plankton have been found in large oligotrophic global oceans.…”