Ecosystem Metabolism and Primary Production

Ecosystem Metabolism

The Howarth-Marino lab has measured rates of primary production, ecosystem respiration, and net ecosystem production at the whole-ecosystem scale in several aquatic ecosystems. We have also written on the methodologies for making whole-ecosystem measurements of metabolism, and on the terminology for the various types of metabolism at the whole-ecosystem scale.

Our lab currently has an active research site at West Falmouth Harbor examining the impacts of N pollution on whole ecosystem biogeochemistry and ecosystem metabolism. Click here to view our project site.

Nutrient limitation of primary production

Net primary production in most estuaries is controlled by nitrogen, while phosphorus is more limiting in most productive lakes. This simple statement has long been controversial, yet the evidence for the difference is strong. The Howarth-Marino lab has written extensively on both the evidence for limitation by a particular nutrient in aquatic ecosystems and the mechanisms which can lead more towards nitrogen or phosphorus limitation in different types of ecosystems (both aquatic and terrestrial).

Respiration and decomposition processes in wetlands and aquatic ecosystems

Howarth’s Ph.D. thesis demonstrated that respiration and decomposition in salt marshes is dominated by the anaerobic process of sulfate reduction, and several other studies have evaluated anaerobic metabolism in other types of ecosystems and various aspects of respiration and decomposition controls in streams, rivers, and wetlands.