The model predicts that, under pulsed conditions, specialization is beneficial when the metabolic cost of an additional uptake system is more than ~0.5% of the total metabolic cost, which is a reasonable estimate and illustrates that this is a plausible hypothesis. According to Ferdi Hellweger, an associate professor of civil and environmental engineering at Northeastern, microbial pollution represents one of the most significant problems for our lakes, rivers, and estuaries. A simple mathematical model encompassing the relevant mechanisms is developed and parameterized realistically based on the literature. The field of microbial individual-based ecology, or IBE (Kreft et al., 2013), is grounded in the notion that to truly understand the interactions of microorganisms with their biotic and abiotic environment, one cannot ignore the scales at which such interactions occur. When the bacteria are not growing, the added cost also reduces the fitness of the generalist species. Wilhelm2 Harmful cyanobacteria are a global environmental problem, yet we lack actionable understanding of toxigenic versus nontoxigenic strain ecology and toxin production. Consequently, the specialist strategy is beneficial, which is consistent with observations from laboratory experiments. During nutrient-replete growth the metabolism is saturated and assimilating additional substrates does not increase the growth rate, but carrying the assimilation system constitutes a cost. Rather they switch between non-growing and nutrient-replete states. Earlier this month, the New England Region of the Environmental Protection Agency honored him with an Environmental Merit Award for his effort.

They may live in an ecologically nutrient-limiting environment, but they are rarely in a biologically nutrient-limited state. Since joining the Northeastern faculty in 2004, environmental engineering associate professor Ferdi Hellweger has been working to make the river swimmable again. My research interests are in surface water quality, microbial ecology and systems bioecology (the combination of systems biology and systems ecology).

Water turbidity was surveyed using a boat-mounted optical sensor (YSI) at 5 m spatial resolution, resulting in about 4,000 data points. This apparent discrepancy can be resolved by realizing that bacteria in the natural aquatic environment encounter nutrients as high-concentration patches. Wilhelm2 Harmful cyanobacteria are a global environmental problem, yet we lack actionable understanding of toxigenic versus nontoxigenic strain ecology and toxin production. The usability of high-resolution satellite imagery for estimating spatial water quality patterns in urban water bodies is evaluated using turbidity in the lower Charles River, Boston as a case study. Tristan Horner, Faculty, Woods Hole Oceanographic Institution. This seemingly contradicts a large body of literature from laboratory experiments under nutrient-limiting conditions, where mixed substrate use is the rule. Ferdi Hellweger, Faculty, Northeastern University. Recent observations of natural bacterial communities show high genetic diversity in organic carbon uptake systems (microdiversity) and specificity in substrate species taken up.

Ferdi hellweger