Fluvial seeding of cyanobacterial blooms in oligotrophic Lake Superior
| Autor: | Sandra Brovold, Brenda Moraska Lafrancois, Robert W. Sterner, Kaitlin L. Reinl |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
Cyanobacteria Watershed Fluvial Plant Science 010501 environmental sciences Aquatic Science 01 natural sciences Algal bloom Nutrient Propagule Rivers Abundance (ecology) Trophic state index 0105 earth and related environmental sciences Shore geography geography.geographical_feature_category biology 010604 marine biology & hydrobiology biology.organism_classification Lakes Oceanography Environmental science Seasons |
| Zdroj: | Harmful algae. 100 |
| ISSN: | 1878-1470 |
| Popis: | Lake Superior has recently begun experiencing cyanobacterial blooms comprised of Dolichospermum lemmermannii near the Apostle Islands and along the southern shore of the western arm. Little is known about the origin of these blooms. Experiments were conducted during the summers of 2017 and 2018 to identify sources of propagules and characteristics of sites that were potential sources. The 2017 experiments were conducting using a factorial design with three source zones (Harbor, River, and Lake), two nutrient conditions (high and low N:P), and three temperatures (15, 20, and 25 °C). At the end of the experiment, cyanobacteria were most abundant from the ‘River’ and ‘Harbor’ zones at low N:P and 20 and 25 °C, with D. lemmermannii most abundant at 20 °C. Subsequently in 2018 we evaluated 26 specific inland locations from three waterbody types (Coastal, Lake/Pond, and River) and explored similarities among those sites that produced cyanobacteria in high abundance when samples were incubated under optimal conditions (low N:P and 25 °C). Under these growing conditions, we found high cyanobacteria abundance developed in samples from river sites with low ambient temperatures and high conductivity. Field monitoring showed that Lake Superior nearshore temperatures were higher than rivers. These observations suggest that blooms of D. lemmermannii in Lake Superior are initiated by fluvial seeding of propagules and highlight the importance of warmer temperatures and favorable nutrient and light conditions for subsequent extensive cyanobacterial growth. We argue that the watershed is an important source of biological loading of D. lemmermannii to Lake Superior, and that when those cells reach the nearshore where there is warmer water temperatures and increased light, they can grow in abundance to produce blooms. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect