From River to Lake: Phosphorus partitioning and algal community compositional changes in Western Lake Erie

• DOI: 10.1016/j.jglr.2011.09.010
• Publication Date: 2011-11-07T18:33:08Z
• Authors: Thomas B. Bridgeman; Justin D. Chaffin; Douglas D. Kane; Joseph D. Conroy; Sarah E. Panek; Patricia M. Armenio
• Keywords: Microcystis; Bloom; Lyngbya; Lake ecosystem

article The Maumee River is an important source of phosphorus (P) loading to western Lake Erie and potentially a source of Microcystis seed colonies contributing to the development of harmful algal bloomsin the lake.Herein, we quan- tified P forms and size fractions, and phytoplankton community composition in the river-lake coupled ecosystem before (June), during (August), and after (September) a large Microcystis bloom in 2009. Additionally, we deter- mined the distribution and density of a newly emergent cyanobacterium, Lyngbya wollei, near Maumee Bay to es- timate potential P sequestration. In June, dissolved organic phosphorus (DOP) was the most abundant P form whereas particulate P (partP) was most abundant in August and September. Green algae dominated in June (44% and 60% of total chlorophyll in river and lake, respectively) with substantial Microcystis (17%) present only in the river. Conversely, in August, Microcystis declined in the river (3%) but dominated (32%) the lake. Lake phy- toplankton sequestered b6% of water column P even during peak Microcystis blooms; in all lake samples b112 μm non-algal particles dominated partP. Lyngbya density averaged 19.4 g dry wt/m 2 , with average Lyngbya Pc ontent of 15% (to 75% maximum) of water column P. The presence of Microcystis in the river before appearing in the lake indicates that the river is a potential source of Microcystis seedcolonies forlater lake blooms,that DOPisan impor- tant component of early summer total P, and that L. wollei blooms have the potential to increase P retention in nearshore areas.