Phenotypic plasticity and differentiation in an invasive freshwater microalga

TY - JOUR

T1 - Phenotypic plasticity and differentiation in an invasive freshwater microalga

AU - Sassenhagen, Ingrid

AU - Wilken, Susanne

AU - Godhe, Anna

AU - Rengefors, Karin

N1 - ;Data archiving: Property of Lund University bevestigd van Donk 2-8-2017

PY - 2015/1

Y1 - 2015/1

N2 - Recent studies show that both marine and limnic microalgal species often consist of several genetically distinct populations. This is also valid for the nuisance freshwater algae Gonyostomum semen, which originates from acidic, brown water swamp lakes, but can nowadays also be found in clearer lakes with close to neutral pH. We hypothesized that the observed genetic differentiation among G. semen lake populations, reported in earlier studies, is connected to adaptation to local environmental conditions. In the present study we performed controlled laboratory experiments to test whether 12 strains originating from five lakes varied in their response to five to six different pHs, light intensities and DOC concentrations. Overall, growth (0.01-0.37 day(-1)) was observed over a wide range of light intensities and pHs, demonstrating high potential for photoacclimation and extensive plasticity of individual strains. Moreover, we found similar growth rates and consistent growth optima for specific pHs by strains from the same lake, suggesting genetic differentiation of populations into distinct phenotypes. However, observed strain specific preferences did not always reflect environmental conditions in the lakes of origin and provided limited evidence for the hypothesized local adaptation. Instead, the observed phenotypic differentiation may indicate resilient effects of founder events. We suggest that the wide phenotypic plasticity in this species enables it to thrive in fluctuating and variable environments, and may play a role in its ability to colonize new habitats.

AB - Recent studies show that both marine and limnic microalgal species often consist of several genetically distinct populations. This is also valid for the nuisance freshwater algae Gonyostomum semen, which originates from acidic, brown water swamp lakes, but can nowadays also be found in clearer lakes with close to neutral pH. We hypothesized that the observed genetic differentiation among G. semen lake populations, reported in earlier studies, is connected to adaptation to local environmental conditions. In the present study we performed controlled laboratory experiments to test whether 12 strains originating from five lakes varied in their response to five to six different pHs, light intensities and DOC concentrations. Overall, growth (0.01-0.37 day(-1)) was observed over a wide range of light intensities and pHs, demonstrating high potential for photoacclimation and extensive plasticity of individual strains. Moreover, we found similar growth rates and consistent growth optima for specific pHs by strains from the same lake, suggesting genetic differentiation of populations into distinct phenotypes. However, observed strain specific preferences did not always reflect environmental conditions in the lakes of origin and provided limited evidence for the hypothesized local adaptation. Instead, the observed phenotypic differentiation may indicate resilient effects of founder events. We suggest that the wide phenotypic plasticity in this species enables it to thrive in fluctuating and variable environments, and may play a role in its ability to colonize new habitats.

KW - Gonyostomum semen

KW - Growth rate

KW - Phenotypic differentiation

KW - Plasticity

KW - pH

KW - Raphidophyte

KW - international

U2 - 10.1016/j.hal.2014.11.001

DO - 10.1016/j.hal.2014.11.001

M3 - Article

SN - 1568-9883

VL - 41

SP - 38

EP - 45

JO - Harmful Algae

JF - Harmful Algae

ER -