Varied phenologies of Batrachospermum gelatinosum gametophytes (Batrachospermales, Rhodophyta) in two low-order streams.

Abstract

Abstract:The freshwater red algal species, Batrachospermum gelatinosum, is common in temperate/boreal regions North America and Europe. In southeast Ohio, gametophytes of this taxon were observed to have two different phenologies; in one stream the gametophytes were present only during the spring months and in another stream they were present year-round. Therefore, the purpose of this study was to determine environmental parameters associated with occurrence, peak vegetative growth and reproduction for B. gelatinosum gametophytes in these two streams. Field sampling was conducted for 18 months with both streams being sampled every three to four weeks, when possible. Physical and chemical parameters of stream depth, current velocity, pH, conductivity and nutrients were measured each sampling date. Algal thalli were measured for changes in both vegetative and reproductive characters. In both streams, algal reproductive structures were positively correlated with stream depth (7-52 cm), but there was no correlation of vegetative characteristics with environmental variables measured. Algal cover (0-50%) in each stream was positively correlated with stream depth (7-52 cm), current velocity (BDL-1.08 m.s ) and day length (10.3-15.1 hrs). The site with the least canopy cover and greatest water depth had the highest algal cover and gametophytes present year-round; whereas the site with lower water depth had lower algal cover and gametophyte present only during spring and early summer. This result suggests that stream size and amount of riparian vegetation may play a role in determining phenologies observed. Contrasting phenologies have been reported for B. gelatinosum from sites that are geographically distant, but this study has found that local physical factors may produce differing phenologies in streams only a few kilometers apart.

Photosynthetic performance of two freshwater red algal species

“…Batrachospermum gelatinosum, like red algae in general, occurs in cold, clean running waters (7-14 °C), Kremer (1983), Vis et al (1996), Vis and Sheath (1997), Drerup and Vis (2014) and we also found under such conditions (Tab. 1).…”

“…Populations, as red algae usually, occur at cold temperatures (0-22 °C) in circumneutral (pH 6-8.5) waters with low conductivity (10-490 µS cm -1 ) (Kremer 1983, Vis et al 1996, Vis and Sheath 1997, Carmona et al 2011, Chiasson et al 2014, Drerup and Vis 2014. B. gelatinosum was also described in Central and South America, Australia and in the Middle East under similar conditions (Vis and Entwisle 2000, Jiménez et al 2004, Vis et al 2008, Barinova 2013.…”

Relative expression analysis of light‐harvesting genes in the freshwater alga Lympha mucosa (Batrachospermales, Rhodophyta)

“…In temperate regions, many streams have seasonal changes in light regimes related to deciduous tree canopy cover that affect red algal distribution and seasonality. For example, Drerup and Vis ( 2014 ) noted differences in the phenology of Batrachospermum gelatinosum from geographically close temperate streams with the gametophyte thalli being spring ephemerals in the smaller stream and perennial in the larger stream. The spring ephemeral seasonality was likely due to greater canopy cover and consequently a lack of sufficient light for basic photosynthetic requirements.…”