The effects of irradiance levels and spectral composition on mating strategies in the snow alga, Chloromonas sp.-D, from the Tughill Plateau, New York State
✍ Scribed by Ronald W. Hoham; Erin M. Schlag; Jennifer Y. Kang; Andrew J. Hasselwander; Alissa F. Behrstock; Ian R. Blackburn; Rurik C. Johnson; Stephen C. Roemer
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 328 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0885-6087
No coin nor oath required. For personal study only.
✦ Synopsis
Studies have related changes in snow albedo to snow crystal structure and to the presence of surface debris (i.e. pine needles), but there has been less attention given to the existence of algae in snow. An increase in the number of snow algae could also decrease albedo and increase snowmelt rates. The primary purpose of this paper is to document how solar irradiance serves to control the developing stages of algae in snow. Snow algae do not appear near the surface until there is meltwater in the snowpack. Low levels of solar irradiance penetrate through the snowpack and germinate snow algal resting stages that lie underneath, and snow algal growth is enhanced by available gases and nutrients. Flagellate cells swim through the snowpack in the meltwater around the snow crystals, and cells are positioned according to irradiance and spectral dierences. In this study, Chloromonas sp.-D strains 582C and 582D, isolated from the upper 20 cm of snowpacks in the Tughill Plateau, Whetstone Gulf State Park, NY, were used to investigate mating strategies under dierent irradiance levels and spectral compositions in the laboratory, and the irradiance levels used in the experiments correlated with those recorded from the upper 20 cm of snow. Using similar irradiance levels, blue light regimes produced more matings than green and red light regimes. There were no trends in mating when comparing green and red light regimes. When red light regimes of higher photon irradiance (85 mmol m 72 s 71 ) were compared with those of blue light regimes of lower irradiance (30 mmol m 72 s 71 ), more mating occurred under red light. A photon irradiance of 95 mmol m 72 s 71 [photosynthetically active radiation (PAR) of 400±700 nm] produced the most mating under both wide-spectrum (WS) and cool-white (CW) regimes, but more mating occurred under CW in all irradiances tested. Mating pairs of three types were observed: oblong-oblong (o±o), oblong-sphere (o±s) and sphere-sphere (s±s). Cell packs that produced mating types and o±o mating pairs diminished through the eighthour time duration of the experiments. However, o±s and s±s mating pairs peaked at six to seven hours after the experiments began, while quadri¯agellate zygotes produced from the mating pairs continued to increase throughout the eight hours.