Extreme storms cause rapid but short‐lived shifts in nearshore subtropical bacterial communities

Abstract

Summary Climate change scenarios predict tropical cyclones will increase in both frequency and intensity, which will escalate the amount of terrestrial run‐off and mechanical disruption affecting coastal ecosystems. Bacteria are key contributors to ecosystem functioning, but relatively little is known about how they respond to extreme storm events, particularly in nearshore subtropical regions. In this study, we combine field observations and mesocosm experiments to assess bacterial community dynamics and changes in physicochemical properties during early‐ and late‐season tropical cyclones affecting Okinawa, Japan. Storms caused large and fast influxes of freshwater and terrestrial sediment – locally known as red soil pollution – and caused moderate increases of macronutrients, especially SiO2 and PO43−, with up to 25 and 0.5 μM respectively. We detected shifts in relative abundances of marine and terrestrially derived bacteria, including putative coral and human pathogens, during storm events. Soil input alone did not substantially affect marine bacterial communities in mesocosms, indicating that other components of run‐off or other storm effects likely exert a larger influence on bacterial communities. The storm effects were short‐lived and bacterial communities quickly recovered following both storm events. The early‐ and late‐season storms caused different physicochemical and bacterial community changes, demonstrating the context‐dependency of extreme storm responses in a subtropical coastal ecosystem.

Picophytoplankton dynamics in a large temperate estuary and impacts of extreme storm events

“…A higher frequency of extreme precipitation events (tropical cyclones) and more precipitation associated with non-cyclone storm events between extensive droughts is predicted in the regions surrounding the NRE, but also other globally distributed systems—making precipitation frequency a regional to global concern 109 – 112 . This is particularly true for estuaries and coastal systems where plankton community structure and biomass are altered by storms of varying severity 113 – 115 . Based the data presented here and prior results from other estuaries 13 , 16 , 17 , reductions in total PicoP biomass and promotion of larger PEUK are expected in temperate/tropical estuaries poised to receive more precipitation via moderate to extreme storms.…”

Preparing Aquatic Research for an Extreme Future: Call for Improved Definitions and Responsive, Multidisciplinary Approaches

“…In addition, the adoption of novel molecular biomonitoring approaches (e.g., environmental DNA; Thomsen and Willerslev 2015 ) and high-throughput in situ imaging (e.g., camera traps; for a review, see Farley et al 2018 ) have more accurately recorded population and community shifts in response to major disturbance. These approaches have been successfully applied to collect data and assess the responses to extreme events across freshwater (e.g., Curtis et al 2020 , Mächler et al 2021 ) and marine (Anglès et al 2015 , Grossmann et al 2015 , Ares et al 2020 , DiBattista et al 2020 ) species that are challenging to identify or collect using conventional species-capture approaches. The empirical tools listed above, particularly when used in combination with conventional sampling approaches, can provide robust biological, chemical, and physical data to maximize the power and timeliness of ecosystem studies.…”

Coastal Microbial Communities Disrupted During the 2018 Hurricane Season in Outer Banks, North Carolina

“…For example, storm impacts could be controlled by proximity to urban or agricultural environments with potential for runoff, local topography and hydrology of the coastal region, and characteristics of the storm (e.g., intensity, duration, and path). Previous studies from different locations have shown variable degrees of impact from extreme storms toward microbial communities (Okinawa, Japan: Ares et al, 2020 ; Pamlico Sound, North Carolina: Paerl et al, 2001 ; Peierls et al, 2003 ; Oahu, Hawaii: De Carlo et al, 2007 ; Yeo et al, 2013 ; New Orleans, Louisiana: Sinigalliano et al, 2007 ; and Houston, Texas: Steichen et al, 2020 ). Increased understanding of geographic region-specific shifts in microbial community composition and functional potential following extreme storms is vital to interpreting disruptions to nutrient cycling processes and the overall health of a coastal ecosystem.…”