Typhoons initiate predictable change in aquatic bacterial communities

Abstract

We explored patterns of change in bacterioplankton and phytoplankton community composition in response to typhoons in a subtropical, subalpine freshwater humic lake in Taiwan. Thermal profiles with depth, nearsurface dissolved oxygen, and meteorological conditions were measured at high temporal resolution using an instrumented buoy. We collected samples across a time series spanning two typhoon seasons and assessed bacterial community composition at each time point using a fingerprinting technique targeting the internal transcribed spacer region of the ribosomal RNA operon. Wind and rain associated with the typhoons mixed the otherwise stably stratified water column. After each of six typhoon-induced mixing events, the bacterial community composition was reset to similar conditions, revealing a surprisingly deterministic pattern of recovery that was reminiscent of secondary succession following large infrequent disturbances in terrestrial ecosystems. Distinct bacterial assemblages were associated with epilimnion and hypolimnion samples collected more than 80 d after a mixing event. These assemblages were also distinct from the communities observed in the generally unstratified water column within 7 d after a typhoon. Our results were surprising since bacterial communities are not expected to respond in such predictable ways because of their immense complexity and diversity. In contrast, phytoplankton communities did not recover in a predictable way after typhoons.

Stochasticity, succession, and environmental perturbations in a fluidic ecosystem

“…Lake mixing increases the oxygen concentration in the anoxic hypolimnion, which likely stresses the anaerobic hypolimnion communities, explaining the measured decrease in microbial diversity (26). Similarly, all of the hypolimnion microbial communities recovered following perturbation by typhoons (49), oxygen addition or mixing (50), and whole-ecosystem mixing (26). The high degree of resilience of the hypolimnion microbial communities is consistent with the prediction of scenario B.…”

“…The experimental results with lake epilimnion microbial communities (26,(48)(49)(50)(51) also support scenario A. Generally, lake mixing increases nutrient input to the nutrient limited epilimnion (50), which should stimulate microbial diversity.…”

“…Several studies have also examined the resilience of lake microbial communities after disturbances (26,(48)(49)(50)(51). The experimental results with lake epilimnion microbial communities (26,(48)(49)(50)(51) also support scenario A.…”

“…The results showed that the β-diversity of the communities (animals and plants) in the drought ponds were significantly less than that in the permanent ponds, indicating that drought decreased the stochasticity in the dry ponds. For another example, the experimental results on the lake hypolimnion microbial communities from the lake mixing studies also appear to support scenario B (26,49,50). Lake mixing increases the oxygen concentration in the anoxic hypolimnion, which likely stresses the anaerobic hypolimnion communities, explaining the measured decrease in microbial diversity (26).…”

Networked lake science: how the Global Lake Ecological Observatory Network (GLEON) works to understand, predict, and communicate lake ecosystem response to global change

“…GLEON has been opportunistic about "natural experiments," such as quantifying the response of lakes to typhoons and tropical storms (Jones et al 2008, Tsai et al 2011, Klug et al 2012. Recognition of the importance of such events on lake ecosystems has inspired new sampling campaigns, such as "Blitzs."…”