Dissertation Research
My dissertation research was on how nutrients, namely nitrogen and phosphorus, cycle through and contribute to blooms in the northern Indian River Lagoon (IRL) system. This estuary has experienced several large and long lasting blooms of various nano and pico-plankton species since the so-called "Superbloom" in 2011. These blooms have had many ecological and economic impacts, most noticeably the substantial loss of important seagrass habitat.
My research questions addressed the following:
My research questions addressed the following:
- What forms of nutrients (N & P) are preferred by bloom-forming species?
- Can water-column processes such as N-fixation contribute to blooms?
- From a nutrient perspective what, ultimately, has changed in the IRL to allow for large blooms?
- The bloom-forming species (pico-cyanobacteria and nano-eukaryotic phytoplankton) preferred "reduced" N (ie ammonium and organic N) over "oxidized" N (ie nitrate); bloom-formers also were able to uptake organic P
- While N species appears to have selected for the specific bloom-forming phytoplankton, there was a significant shift in dissolved phosphorus prior the the 2011 Superbloom, and consequently N:P ratios have shifted downward
- There is significant albeit sporadic potential for biological nitrogen fixation (BNF) activity in the IRL; measured BNF rates appear to be highly correlated with dissolved P concentrations
- The community of fixers was almost exclusively heterotrophic bacteria, not cyanobacteria, and was diverse throughout all of the IRL basins
- Ultimately, this research suggests both N and P need to be managed in the IRL system and that BNF should be considered as a significant source of N in IRL nutrient budgets
SELECTED PUBLICATIONS
2020-
Papacek, J., Smyth, A., Abeels, H., Betancourt, A. Climate Change and Florida: Frequently Asked Questions. Accepted as University of Florida Institute of Food and Agricultural Sciences EDIS publication.
Papacek, J.R., Phlips, E.J., Lasi, M. & Inglett, P.W. Nitrogen and phosphorus uptake kinetics in cultures of two novel picoplankton groups responsible for a recent bloom even in a subtropical estuary (Indian River Lagoon, Florida). In Preparation for submission to Frontiers in Marine Science.
Papacek, J.R., Phlips, E.J., Lasi, M., Strauss, S.L. & Inglett, P.W. Evidence of nitrogen fixation in the watercolumn of a subtropical estuary (Indian River Lagoon, Florida). In review at Limnology & Oceanography.
Doron, M., Inglett, P.W., Papacek, J.R., Albertin, A.R., Cichra, M.F., & J. Hendirckson. N sink or source: Nitrogen fixation in shallow, subtropical Lake George, Florida, USA. In preparation for submission to Biogeochemistry.
Contributions to Technical Reports
IRL Plankton Investigations – Algal nutrient uptake dynamics and nitrogen fixation, microzooplankton grazing, and bacterioplankton/zooplankton quantification. October 2013-September 2016. PIs: Phlips, E.J. & P.W. Inglett. Final report submitted to St. Johns River Water Management District.
Papacek, J., Smyth, A., Abeels, H., Betancourt, A. Climate Change and Florida: Frequently Asked Questions. Accepted as University of Florida Institute of Food and Agricultural Sciences EDIS publication.
Papacek, J.R., Phlips, E.J., Lasi, M. & Inglett, P.W. Nitrogen and phosphorus uptake kinetics in cultures of two novel picoplankton groups responsible for a recent bloom even in a subtropical estuary (Indian River Lagoon, Florida). In Preparation for submission to Frontiers in Marine Science.
Papacek, J.R., Phlips, E.J., Lasi, M., Strauss, S.L. & Inglett, P.W. Evidence of nitrogen fixation in the watercolumn of a subtropical estuary (Indian River Lagoon, Florida). In review at Limnology & Oceanography.
Doron, M., Inglett, P.W., Papacek, J.R., Albertin, A.R., Cichra, M.F., & J. Hendirckson. N sink or source: Nitrogen fixation in shallow, subtropical Lake George, Florida, USA. In preparation for submission to Biogeochemistry.
Contributions to Technical Reports
IRL Plankton Investigations – Algal nutrient uptake dynamics and nitrogen fixation, microzooplankton grazing, and bacterioplankton/zooplankton quantification. October 2013-September 2016. PIs: Phlips, E.J. & P.W. Inglett. Final report submitted to St. Johns River Water Management District.