Patrick Saldana, a Ph.D. candidate at the University of Florida (UF), is studying macroalgae decomposition and the effects on dissolved oxygen and nitrogen cycling in shallow environments with a focus on Matlacha Pass in partnership with SCCF’s Marine Lab.

Macroalgae, commonly referred to as seaweeds, are a natural and common component of seagrass ecosystems, but recent algal blooms have smothered seagrass beds in Charlotte Harbor. In addition to having negative consequences for seagrasses, an important habitat-forming species within these systems, the decomposition of macroalgae can also initiate hypoxic events when combined with local tidal circulation patterns. 

Saldana’s advisor is Andrew Altieri, Ph.D., who has studied hypoxia and its effects on marine life in New England and Panama. Together they will be deploying oxygen sensors to monitor and quantify how dissolved oxygen levels are affected by recent macroalgae blooms. Saldana’s research addresses macroalgae in Matlacha Pass.

He has set up several manipulative experiments with several common macroalgal species to examine differences in algae decay rates, uptake, and release of nitrogen, and will be working with UF biogeochemist Ashley Smyth, Ph.D., to collect core samples to study microbial transformations of biogeochemical processes in subtidal sediments as a result of algae decomposition.

Although macroalgae can smother seagrasses and cause immediate changes in habitat quality, their effects on sediment characteristics such as sulfide levels, oxygen flux, and grain size may have long-lasting implications for seagrass recovery in Charlotte Harbor.

Saldana hopes that his research will contribute to our broader understanding of seaweed ecology from a trait-based perspective and provide insight for the management and restoration of Charlotte Harbor’s subtidal ecosystems following algal blooms.