![]() Rowe received funding from the National Research Council Research Associate program and Cooperative Institute for Limnology and Ecosystems Research (CILER) through the NOAA Cooperative Agreement with the University of Michigan. Eric Anderson, Henry Vanderploeg, Steven Pothoven, Ashley Elgin and Jia Wang of GLERL), and an expert in satellite remote sensing (Foad Yousef of UCLA). The project team included experts in ecology and lake hydrodynamics (Dr. Biophysical models that simulate location-specific impacts of nutrient levels have the potential to be an important tool for informing lake management decisions. With decreased offshore productivity in Lake Michigan, it has become increasingly important to understand how nearshore productivity supports the food web and fisheries. Although not simulated by the model, increased nutrient loads in the presence of mussels may lead to increased nuisance algae on the lake bottom. When the model simulated increased phosphorus from tributary inputs, lake productivity increased despite the presence of mussels. Some of the phosphorus was stored in the tissue of living mussels, and some was likely transferred to the sediment. This result suggested that quagga mussels have reduced lake productivity both by filter feeding and by removing phosphorus from the water. The model showed that changes to lake productivity averaged over the year were small when the amount of phosphorus stayed the same, despite the mussels filtering phytoplankton from the water. Manipulating the amount of nutrients available to phytoplankton in the computer simulation shed more light on the mussel-phytoplankton relationship. ![]() See Biophysical Model Simulations of Lake Michigan here. These maps show that mussels deplete the spring phytoplankton bloom when nutrient loads are present (C, D), and that nutrient loads enhance nearshore spring phytoplankton blooms when mussels are present (C, E). C-E: Maps derived from biophysical model simulations are able to separate the effects of mussels and nutrient loads on phytoplankton abundance. But during summer and winter when this vertical mixing is weak, phytoplankton is separated from filter feeders living on the bottom.Ī, B: Satellite-derived maps from two different sources (SeaWiFS, CPA ) show the combined effects of mussels and nutrient loads on phytoplankton abundance (chlorophyll a). These new model simulations showed that quagga mussels can deplete phytoplankton in the overlying water during spring and fall, when strong vertical mixing carries surface water to the bottom and vice versa. ![]() It is based on first principals such as conservation of mass, energy, and momentum, and a lower food web whose productivity is limited by phosphorus. Rather than depending on statistical association, the biophysical model is a mathematical computer simulation of lake temperature, currents, and the lower food web (plankton). (2017) applied a biophysical model to the problem. This study showed, for the first time, a statistically significant association between locations of high mussel filter feeding intensity and reduced phytoplankton blooms observed in satellite imagery.īuilding on this evidence of a direct link between quagga mussel filter feeding and reduced spring phytoplankton blooms, a more recent study by Rowe et al. Rowe and others mapped the location of quagga mussels in Lake Michigan by applying a geostatistical model to lake bottom (benthic) survey data. ![]() red arrows).įor the past two years, CIGLR Assistant Research Scientist Mark Rowe has been developing sophisticated models to understand the mussel-plankton association and help guide management decisions. The results showed an association between the location of mussel filter feeding intensity and decreased chlorophyll a in April, when the lake is vertically well-mixed (e.g. (2015) combined maps of quagga mussel abundance with estimates of filter-feeding rate and lake depth to estimate the fraction of the water column that is cleared per day by filter feeding. Prior to the quagga mussel invasion, there was a spring phytoplankton bloom that peaked in April. Chlorophyll a is a pigment specific to phytoplankton, which can be used as a measure of phytoplankton abundance and productivity. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |