Variability in phenotypic tolerance to low oxygen in invasive populations of quagga and zebra mussels

Abstract

Species level identifications of morphologically simple marine algae have undoubtedly caused biodiversity assessments to be an arduous task. The green algal genus Ulva L., 1753, is notorious for morphological plasticity and cryptic speciation. We used two chloroplast-encoded (rbcL and tufA) molecular markers and the nuclear internal transcribed spacer 1 (ITS1) of the ribosomal cistron to detect Ulva ohnoi M. Hiraoka and S. Shimada, 2004, a species known for forming green tides in Japan, as a new record for the Western Atlantic, including the Gulf of Mexico (GoMX) and Atlantic coast of Florida. All rbcL sequences from this investigation were identical to reports for U. ohnoi. The Western Atlantic isolates showed relatively low genetic diversity in tufA and ITS1 sequences, which suggests that this species is not native to the GoMX and Atlantic Florida. Furthermore, we have identified U. ohnoi as the species that formed an ephemeral, localized overgrowth during July of 2013 in Biscayne Bay, Florida, an area with a persistent bloom of two other green algal species, Anadyomene stellata J. V. Lamouroux, 1812, and Anadyomene sp., due to eutrophication from anthropogenic nutrient loading near canals. A tissue nutrient analysis of samples from this overgrowth of Ulva showed that this species has a high affinity for nitrogen, especially ∂15N, which suggests anthropogenic sources of N. Further investigations are needed to assess the geographical ranges of this species in this region as well as the potential invasiveness of this alga in the Western Atlantic. It is highly recommended to monitor the abundance of this species in response to nutrient discharges in Biscayne Bay.

Does eutrophication-driven evolution change aquatic ecosystems?

“…The results suggest an evolved behavioural response to avoid hypoxia, allowing the adapted population to persist and perhaps thrive (as hypoxic conditions may provide a refuge from fish predation) despite the adverse environmental conditions caused by eutrophication. Physiological adaptation to tolerate hypoxic conditions has also been documented in invasive Dreissena mussels [16].…”

Differential tolerance to nickel between Dreissena polymorpha and Dreissena rostriformis bugensis populations

“…However, De Ventura et al . 47 evidenced that local adaptation to fluctuating environmental parameters can rapidly occur even in newly established populations, and showed that D. r. bugensis is better adapted to fluctuating oxygen levels than D. polymorpha . This adaptability might thus exist, for both species, regarding physico-chemical parameters.…”

“…To our knowledge, there is only one study dealing with both inter-populational and inter-specific differences in relation to pollution 10 . The others are generally relative to hypoxia 47 or salinity 48 effects and even heritability of heat tolerance 49 . However, these works are mainly focused on predicting the invasiveness of dreissenid species in contrasting habitats, not on their potential use as biomonitors.…”

Mussel as a Tool to Define Continental Watershed Quality

“…The two species are indeed characterized by differential physiological performances. They disclose different temperature, salinity and low oxygen tolerance levels, byssal thread attachment, growth, respiration rates, assimilation efficiency, or reproduction [87][88][89]. Quagga mussels reveal a lower tolerance to high temperature, although there is a better adaptability to lower temperature, allowing a development in deeper waters.…”