Fottea

Fottea 14(2): 121-127, 2014 | DOI: 10.5507/fot.2014.009

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

Samuel A. Drerup, Morgan L. Vis

Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, U.S.A.

The freshwater red algal species, Batrachospermum gelatinosum, is common in temperate/borea 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^-1) 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.

Keywords: Batrachospermum gelatinosum, freshwater, Ohio, red algae, river, seasonality

Received: February 4, 2014; Accepted: April 7, 2014; Published: September 1, 2014Show citation