National Oceanic and Atmospheric Administration

Atlantic Oceanographic and Meteorological Laboratory

Physical Oceanography Division

Dr. Elizabeth ("Libby") Johns


4301 Rickenbacker Causeway,
Miami, FL 33149, USA
Phone: (305) 361-4360

Research Interests

  • Investigation of circulation, water properties, and connectivity in the Caribbean Sea, Gulf of Mexico, and south Florida coastal waters using interdisciplinary shipboard surveys, moored instruments, and satellite-tracked surface drifters.
  • Analysis of episodic oceanographic events such as red tides and black water intrusions, algal blooms, remote river plumes and extremes in temperature and salinity, and their effects on regional coastal ecosystems such as coral reefs.
  • Studies of the circulation, transport, and watermass variability of the western boundary current system from the equator to Cape Hatteras, including the North Brazil Current, the Caribbean Current, the Loop Current, the Florida Current, the Antilles Current, and the Gulf Stream, as well as the Deep Western Boundary Current.

Current Work

Dr. Johns is currently using 15 years of shipboard survey data (1998-2012) in south Florida coastal waters including NOAA's Florida Keys National Marine Sanctuary (FKNMS), Florida Bay, and Biscayne Bay, to analyze the means, climatologies, and variability of sea surface temperature, salinity, and chlorophyll. This work will provide a valuable baseline for these parameters that will allow a better ability to detect future change, and will assist other interdisciplinary south Florida researchers to put their observations in a quantitative oceanographic context.

In addition, Dr. Johns is working collaboratively with scientists from NOAA's Southeast Fisheries Science Center (SEFSC) to quantify the abundance, variety, and distribution of larval reef fish populations of the US and British Virgin Islands, and how the oceanographic conditions influence the observed patterns. For example, a large Amazon River plume caused an anomalous "green water" event in the northeastern Caribbean during the spring of 2009, which was captured by a research cruise aboard the NOAA Ship Nancy Foster. This event caused temporary but significant changes in the larval reef fish populations from what had previously been observed in the area.

More recently, Dr. Johns has been part of a research team that is using a variety of observational techniques, including shipboard profiling and remote sensing, to develop an optical characterization of south Florida coastal waters including NOAA's (FKNMS). This new work is important because there have not previously been systematic in situ observations of the underwater light environment over the FKNMS coral reefs, yet how light is transmitted through the water column to the benthos is known to be a factor in the health of the ecosystem.


Cannizzaro, J.P, C. Hu, K.L. Carder, C.R. Kelble, N. Melo, E.M. Johns, G.A. Vargo, C.A. Heil, 2013: On the accuracy of SeaWiFS ocean color data products on the west Florida shelf. J. Coastal Res., in press.

Muhling, B., R.H. Smith, L. Vasque-Yeomans, J. Lamkin, E.M. Johns, L. Carrillo, E. Sosa-Cordero, and E. Malca, 2013: Larval fish assemblages and mesoscale oceanographic structure along the Mesoamerican Barrier Reef System. Fish. Ocean., 22(5):409-428, doi: 10.1111/fog.12031.

Zhao, J., C. Hu, B. Lapointe, N. Melo, E.M Johns, and R.H Smith, 2013: Satellite-observed black water events off Southwest Florida: Implications for coral reef health in the Florida Keys National Marine Sanctuary. Remote Sens., 5:415-431, doi:10.3390/rs5010415. [pdf]

Johns, E.M., and T.N. Lee, 2012: Tropical Connections: South Florida's marine environment. Chapter 2, Oceanographic Connectivity, "Weather and climate strongly influence salinity, water quality, and circulation of south Florida coastal waters and bays". Kruczynski W.L., Fletcher P.J., (eds.). ISBN 978-0-9822305-3-4. [pdf]

Keller, B.D., and E. Johns, 2012: Tropical Connections: South Florida's marine environment. Chapter 2, Oceanographic Connectivity, "Strong ocean currents connect geographic regions". W.L. Kruczynski and P.J. Fletcher (eds.). IAN Press, University of Maryland Center for Environmental Science, Cambridge, MD, 15. [pdf]

Manzello, D.P., I.C. Enochs, N. Melo, D.K. Gledhill, and E.M. Johns, 2012: Ocean Acidification Refugia of the Florida Reef Tract. PLoS ONE, 7(7):e41715. doi:10.1371/journal.pone.0041715. [pdf]

Smith, R. H., and E. M. Johns (2012). Tropical Connections: South Florida's marine environment. Chapter 2, Oceanographic Connectivity, "Oceanographic data are collected in many different ways". Kruczynski W.L., Fletcher P.J., (eds.). ISBN 978-0-9822305-3-4. [pdf]

Gramer, Lewis J., E. M. Johns, J. C. Hendee, and C. Hu (2009). Characterization of biologically significant hydrodynamic anomalies on the Florida Reef Tract, In Dodge, R., ed., /Proceedings of the 11th International Coral Reef Symposium/, Ft. Lauderdale, FL, July 7-11, 2008, 470-474.

Lee, T.N., N. Melo, E. Johns, C. Kelble, R.H. Smith, and P.B. Ortner, 2008: On water renewal and salinity variability in the northeast subregion of Florida Bay. Bull. Mar. Sci., 82(1):83-105. [pdf]

Kelble, C.R., E.M. Johns, W.K. Nuttle, T.N. Lee, R.H. Smith, and P.B. Ortner, 2007: Salinity patterns of Florida Bay. Estuarine, Coastal, and Shelf Science, 71(1-2):318-334. [pdf]

Lee, T.N., E. Johns and P. Ortner, 2007: Chapter 4: Physical Processes, in Florida Bay Science Program: A Synthesis of Research on Florida Bay, J. Hunt (ed). Florida Marine Research Institute (FMRI), 41 pp.

Lee, T.N., E.M. Johns, N. Melo, R.H. Smith, P.B. Ortner, and N. Smith, 2006: On Florida Bay hypersalinity and water exchange. Bull. Mar. Sci., 79(2):301-327. [pdf]

Hu, C., F.E. Muller-Karger, C. Taylor, K.L. Carder, C. Kelble, E. Johns, and C. A. Heil, 2005: Red tide detection and tracing using MODIS fluorescence data: A regional example in SW Florida coastal waters. Remote Sens. Environ., 97(3):311-321. [pdf]

Hu, C., J.R. Nelson, E. Johns, Z. Chen, R.H. Weisberg, and F.E. Muller-Karger, 2005: Mississippi River water in the Florida Straits and in the Gulf Stream off Georgia in summer 2004. Geophys. Res. Lett., 32(14):L14606, doi:10.1029/2005GL022942. [pdf]

Hu, C., F.E. Muller-Karger, G.A. Vargo, M.B. Neely, and E. Johns, 2004: Linkages between coastal runoff and the Florida Keys ecosystem: A study of a dark plume event. Geophys. Res. Lett., 31(15):L15307, doi: 10.1029/2004GL020382. [pdf]

Schmid, C., Z. D. Garraffo, E. Johns, and S. L. Garzoli, 2003: Pathways and Variability at intermediate depths in the tropical Atlantic. ed. by G. J. Goni and P. Malanotte-Rizzoli. EOS,, 68:233-268. [pdf]

Lee, T.N., E. Williams, E. Johns, W.D. Wilson, and N.P. Smith, 2001: Transport processes linking south Florida coastal ecosystems. In The Everglades, Florida Bay, and Coral Reefs of the Florida Keys: An Ecosystem Sourcebook, K.G. Porter and J.W. Porter (eds.). CRC Press (ISBN 0849320267), 309-342.

Bourles, B., R.L. Molinari, E. Johns, W.D. Wilson, and K.D. Leaman, 1999: Upper layer currents in the western tropical North Atlantic (1989-1991). J. Geophys. Res., 104(C1):1361-1376. [pdf]

Johns, E., W.D. Wilson, and R.L. Molinari, 1999: Direct observations of velocity and transport in the passages between the Intra-Americas Sea and the Atlantic Ocean, 1984-1996. J. Geophys. Res., 104(C11):25,805-25,820. [pdf]

Johns, E., R. A. Fine and R. L. Molinari (1997). Deep flow along the western boundary south of the Blake Bahama Outer Ridge, J. Phys. Oceanogr., 27, 2187-2208.

Molinari, R. L., and E. Johns (1994). Upper layer temperature structure of the western tropical Atlantic, J. Geophys. Res., 99(C9), 18225-18233.

Wilson, W. D., E. Johns and R. L. Molinari (1994). Upper layer circulation in the western tropical North Atlantic Ocean during August 1989, J. Geophys. Res., 99(C11), 22513-22523.

Molinari, R. L., R. A. Fine and E. Johns (1992). The Deep Western Boundary Current in the tropical North Atlantic Ocean, Deep-sea Res., 39(11/12a), 1967-1984.

Molinari, R. L., E. Johns and J. F. Festa (1990). The annual cycle of meridional heat flux in the Atlantic Ocean at 26.5oN, J. Phys. Oceanogr., 20(3), 476-482.

Leaman, K. D., E. Johns and H. T. Rossby (1989). The average distribution of volume transport and potential vorticity with temperature at three sections across the Gulf Stream, J. Phys. Oceanogr., 19(1), 36-51.

Johns, E., D. R. Watts and H. T. Rossby (1989). A test of geostrophy in the Gulf Stream,J. Geophys. Res., 94(C3), 3211-3222.

[Other Publications]

Hunt, J. H., and W. Nuttle, eds. (2007). Florida Bay Science Program: A Synthesis of Research on Florida Bay. Fish and Wildlife Research Institute Technical Report TR-11, 148 pp. (Chapter 4: Physical Processes, authored by T. N. Lee, E. Johns, and P. B. Ortner.)

Johns, E. M., E. Malca, J. Lamkin, T. Gerard (2009). Collaborative Research Cruise Conducts Survey for the Coral Reef Ecosystem Research Program. University of Miami Rosenstiel School of Marine and Atmospheric Science, Soundings, May 2009.

Johns, E., P. B. Ortner, and T. N. Lee (2006), Interdisciplinary coastal ocean observations in the Florida Keys National Marine Sanctuary with real-time data links, In: 2002-03 Sanctuary Science Report: An Ecosystem Report Card after Five Years of Marine Zoning, B. D. Keller and S. Donahue, eds., 2006. U. S. Department of Commerce, National Oceanic and Atmospheric Administration, National Ocean Service, Office of National Marine Sanctuaries, Florida Keys National Marine Sanctuary, Marathon, FL.

Johns, E., T. N. Lee, and W. Nuttle (2003). Mixing it up in Florida Bay. Florida Bay News, published by the Everglades National Park, Summer 2003, 8 pp.

Johns, E., and T. N. Lee (2003). Red tides on the southwest Florida shelf: The effect of physical oceanographic and meteorological forcing on the onset, severity and persistence of Karenia brevis blooms. Report submitted to the Florida Fish and Wildlife Conservation Commission's Florida Marine Research Institute (FMRI), 4 pp.

Johns, E., T. N. Lee, and P. B. Ortner (2002). Surface currents connect south Florida and the Keys. Sounding Line, News of the Florida Keys National Marine Sanctuary (FKNMS). Winter 2002 issue, 4-5.

Lee, T. N., and E. Johns (2001). South Florida's Current's Concerns Require a Global View, Florida Bay Watch Report, a synthesis document of the Florida Bay and Adjacent Marine Systems Science Program, Florida Bay Education Project.

Lee, T. N., E. Johns, W. D. Wilson, and E. Williams (2000). Site characterization for the Tortugas region: Physical oceanography and recruitment, Tortugas 2000 Report, Florida Keys National Marine Sanctuary.