Dr. John Valentine
Professor, University of South Alabama
Executive Director, Dauphin Island Sea Lab
Ph.D. 1989, University of Alabama
Emphasis: Experimental Marine Ecology, Plant-animal interactions, Habitat Linkages, Human-Dominated Ecosystems.
My current research interests examine the role of biotic processes, and human perturbations, in controlling the flow of energy among trophic levels both within and between marine habitats, with emphasis on submerged vegetated habitats. This research is being conducted in diverse locations ranging from the lower reaches of the Mobile Bay Delta to the Marine Protected Areas of the northern Florida Keys. Much of the emphasis of this work is on
1) experimental assessments of grazing intensity in seagrass habitats,
2) responses of seagrasses to this grazing, and
3) the role of omnivory in controlling trophic cascades in marine systems.See More
Newly funded work will examine
1) the degree to which marine production can subsidize the diets adult freshwater piscivorous fishes in oligohaline vegetated habitats in the northern Gulf of Mexico,
2) the relative value of infaunal functional groups to demersal fish growth, also in the northern Gulf of Mexico and
3) the indirect effects of the removal of large predatory fishes on the base of seagrass food webs in the Florida Keys.
Finally, one planned project will be to investigate the degree to which seagrass detritus can subsidize the productivity of macroinvertebrates in nearby unvegetated habitats.
The overall significance of this research lies in its attempt to understand the processes that control the distribution and productivity of submerged vegetated habitats throughout the western Atlantic Ocean. Because of the widespread occurrence of these habitats, the extraordinary productivity and richness of their associated biota, an understanding of the factors controlling their distribution and the degree to which they subsidize the productivity of nearby less productive habitats is essential to our understanding of how the overall productivity of nearshore waters is determined.
Selected Current Research Grants
Lead PI - Alabama Center for Ecological Resilience. Gulf of Mexico Research Initiative (2015-2018). - $6,497,054
Food & Drug Administration (FDA) and MESC/Dauphin Island Sea Lab Collaboration - $790,000
National Science Foundation - "Collaborative Proposal: Gulf Coast ADVANCE: Cross Institutional Synergy for Women Scientist - $44,652.00
Valentine, J.F. and K. L. Heck, Jr. Herbivory in Seagrass Meadows: an Evolving Paradigm.
Estuaries and Coasts (2020). https://doi.org/10.1007/s12237-020-00849-3
Martin, C.W., K.A Lewis, A.M. McDonald, T.P. Spearman, S.B. Alford, R.C. Christian, and J.F. Valentine. Disturbance-driven changes to northern Gulf of Mexico nekton communities following the Deepwater Horizon oil spill: evidence for the need for expanded coastal monitoring systems. Marine Pollution Bulletin. 155: 111098. DOI: 10.1016/j.marpolbul.2020.111098.
Martin, C.W. and J.F. Valentine. Invasion of Eurasian Milfoil Myriophyllum spicatum Lead to a “Trophic Dead End” and Reduced Food Web Complexity in Gulf of Mexico Estuarine Food Webs? Front. Environ. Sci. doi.org/10.3389/fenvs.2019.00166
Seubert, E.A., N.E. Hussey, S.P. Powers, J.F. Valentine, and J.M. Drymon. Assessing trophic flexibility of a predator assemblage across a large estuarine seascape using blood plasma stable isotope analysis. Food Webs. In Press.
Martin, C.W. and J.F. Valentine. Eurasian milfoil in Gulf of Mexico estuaries: does invasion of complex submerged vegetation lead to a “trophic dead end” in estuarine food webs? PeerJ Preprints. 6:e27454v1. doi.org/10.7287/peerj.preprints.27454v1.
Kauffman, T.C., C.W. Martin, and J.F. Valentine. Hydrological alteration exacerbates the negative impacts of invasive Eurasian milfoil Myriophyllum spicatum by creating hypoxic conditions in a northern Gulf of Mexico estuary. Marine Ecology Progress Series. 592: 97-108.
Bearden, B., J. Valentine, P. O'Neil, and S. Jones. Emerging Water Policy Issues in Coastal Alabama. The Wave. Volume 37. Number 3. 15-23.
Steele, L. and J. Valentine. 2015. Seagrass deterrence to mesograzer herbivory: evidence from mesocosm experiments and feeding preference trials. Marine Ecology Progress Series. 524: 83-94.
Martin, C.W., and J.F. Valentine. 2014. Tolerance of Embryos and Hatchlings of the Invasive Apple Snail Pomacea maculata to Estuarine Conditions. Aquatic Ecology 48: 321-326.
Martin, C.W., and J.F. Valentine. 2014. Sexual and asexual reproductive strategies of invasive eurasian milfoil (Myriophyllum spicatum) in estuarine environments. Hydrobiologia. 727: 177-184.See More
Blackmon, D., and J.F. Valentine. 2013. Recurring nocturnal benthic emergence along the coral reef-seagrass interface in the Florida Keys National Marine Sanctuary: evidence of a possible novel prey escape response. Journal of Experimental Marine Biology and Ecology. 448: 220-227.
Peterson, B.J., J.F. Valentine and K.L. Heck, Jr. 2013. The Snapper-Grunt pump: habitat modification and facilitation of the associated benthic plant communities by reef resident fish. J. Experimental Marine Biology and Ecology. 441: 50-54.
Rozas, L.P., C.W. Martin and J.F. Valentine. 2013. Effects of reduced hydrological connectivity on the nursery function of shallow estuarine habitats within a river delta. Marine Ecology Progress Series. 492: 9-20.
Shepard, A., J.F. Valentine, C. F. D’Elia, D.W. Yoskowitz, D. E. Dismukes. 2013. Economic impact of Gulf of Mexico: integrating ecosystem service values into restoration decision-making. Gulf of Mexico Science. 31: 10-27
Martin, C.W., K.M. Baya, and J.F. Valentine. 2012. Establishment of the invasive island apple snail Pomacea insularum (Gastropoda: Ampullariidae) and eradication efforts in Mobile, Alabama, USA. Gulf of Mexico Science. 30: 30-38.
Puntila,R.I., C.W. Martin, and J.F. Valentine. 2012. Measuring predation with a new design of submersible chronographic timer. Bulletin of Marine Science 88: 1115-1122.
Steele, L., and J.F. Valentine. 2012. Idiosyncratic responses of seagrass phenolic production following sea urchin grazing. Marine Ecology Progress Series. 466:81-92.
Lemoine, N.P., and J.F. Valentine. 2012. Structurally complex habitats provided by Acropora palmata influence ecosystem processes on a reef in the Florida Keys National Marine Sanctuary. Coral Reefs. 31: 779-786
Martin, C.W. and J.F. Valentine. 2012. Eurasian milfoil invasion in Mobile Bay, Alabama: evidence that disturbance can reduce the proliferation of an aquatic nuisance species. Marine Ecology Progress Series. 449:109-119.
Hayworth, J.S., T.P. Clement, and J.F. Valentine. 2011. Deepwater Horizon oil spill impacts on Alabama beaches. Hydrol. Earth Syst, Sci. Discuss. 8: 6721-3741.
Martin, C.M. and J.F. Valentine. 2011. Impacts of a habitat-forming exotic species on estuarine structure and function: an experimental assessment of eurasian milfoil. Estuaries and Coasts. 34: 364-372.
Martin, C.M., M. Valentine and J.F. Valentine. 2010. Competitive Interactions between Invasive Nile Tilapia and Native Fish: the Potential for Altered Trophic Exchange and Modification of Food Webs. PLoSONE. 5:1-6
Chaplin, G. and J. F. Valentine. Secondary production of macroinvertebrates in the
tidal influenced Mobile Bay Delta. Estuaries and Coasts 32:319 -332.
Goecker, M., J. F. Valentine, S. S. Sklenar and G. Chaplin. Influence from hydrological modification on energy and nutrient transference in a deltaic food web. Estuaries and Coasts. 32: 173 -187.
Valentine J. F., K. L.Heck, Jr., D. Blackmon, B. J. Peterson, M. E. Goecker, J. Christian, R. M. Kroutil, M. A. VanderKlift , K. D. Kirsch, and M. Beck. Exploited species impacts on trophic linkages along reef -seagrass interfaces in the Florida Keys. Ecological Applications 18:1501 -1515.
Heck, K. L., and J. F. Valentine. The primacy of top-down effects in shallow benthic ecosystems. Estuaries and Coasts 30:371-381.
Vanderklift, M. A., J. How, T. Wernberg, L. D. MacArthur, K. L. Heck, Jr ,and J. F. Valentine. Proximity to reef influences the density of small predatory fishes while type of seagrass influences intensity of predation on crabs. Marine Ecology Progress Series 340:235 -243.
Fioravanti. G. and J. F. Valentine. Impacts of reef architecture and fishing on food webs in back reef environments of the upper Florida Keys National Marine Sanctuary. Florida Scientist 70:120 -136.
Valentine, J. F., K. L. Heck, Jr., D. Blackmon, M. E. Goecker, J. Christian, R. M. Kroutil, K. D. Kirsch, B. J. Peterson, M. Beck and M. A. Vanderklift. Food web interactions along seagrass -coral reef boundaries: effects of piscivore reductions on cross -habitat energy exchange. Marine Ecology Progress Series. 333: 37-50.
Park, K., J. F. Valentine, K. R. Weis, and M. R. Dardeau. Effects of Hurricane Ivan on Mobile Bay, Alabama. Journal of Coastal Research 23:1332 -1336.
Heck, K. L. and J. F. Valentine. Plant-herbivore interactions in seagrass meadows. Journal of Experimental Marine Biology and Ecology 330:420 -436.
Goecker, M., J. F. Valentine and S. Sklenar. Effects of exotic submerged aquatic vegetation on waterfowl in the Mobile-Tensaw Delta. Gulf of Mexico Science 24:68 -80.
Heck, K. L., Jr., J. F. Valentine, J. R. Pennock, G. Chaplin and P. M. Spitzer. Effects of nutrient enrichment and grazing on shoal grass (Halodule wrightii) and its epiphytes: Results of a field experiment. Marine Ecology Progress Series. 326: 145 -156.
Heck, K. L., J. F. Valentine, J. R. Pennock, G. Chaplin and P. M. Spitzer. How herbivores can mediate the effects of nutrient enrichment on seagrass meadows: unexpected results of a field experiment. Marine Ecology Progress Series 326:145 -156.
Valentine, J. F. and J. Emmett Duffy. The Central Role of Grazing in Seagrass Ecology. In: SEAGRASSES: BIOLOGY, ECOLOGY AND CONSERVATION. Pp. 463 -501. Springer, Dordrecht.
Valentine, J. F. and K. L. Heck, Jr. Interaction strength at the coral reef-seagrass interface: has overfishing diminished the importance of seagrass habitat production for coral reef food webs. Coral Reefs 24:209 -213.
Valentine, J. F. and K. L. Heck, Jr. Perspective review of the impacts of overfishing on coral reef food web linkages. Coral Reefs 24 (2): 209 -213.
Goecker, M. E., K. L. Heck, Jr. and J. F. Valentine. Effects of nitrogen content in turtlegrass, Thalassia testudinum, on consumption by the bucktooth parrotfish, Sparisoma radians. Marine Ecology Progress Series 286:239 -248.
Valentine, J. F., E. F. Blythe, S. Madhavan and T. D. Sherman. Effects of stimulated herbivory on nitrogen enzyme levels, assimilation and allocation in Thalassia testudinum. Aquatic Botany 79:235 -255.
Spitzer, P.M., K.L. Heck, Jr. and J.F. Valentine. Then and now: a comparison of patterns in blue crab post-larval abundance and post-settlement mortality during the early and late 1990s in the Mobile Bay system. Bull. Mar. Sci. 72: 435 -452.
Kirsch, K.D., J.F. Valentine, and K.L Heck, Jr. Parrotfish grazing in turtlegrass Thalassia testudinum: evidence for the importance of seagrass consumption in food web dynamics of the Florida keys national Marine Sanctuary. Marine Ecology Progress Series 227: 71 -85.
Aronson, R. B., K. L. Heck, Jr. and J. F. Valentine. Measuring predation with tethering experiments. Marine Ecology Progress Series 214: 311 -312.
Valentine, J. F., K. L. Heck, Jr., K. K. Kirsch and D. Webb. The role of leaf nitrogen content in determining turtlegrass (Thalassia testudinum) grazing by a generalist herbivore in the northeastern Gulf of Mexico. J. Exp. Mar. Biol. Ecol. 258: 65 -86.
Heck, K. L., Jr., J. R. Pennock, J. F. Valentine, L. D. Coen and S. S. Sklenar. Effects of nutrient enrichment and large predator removal on seagrass nursery habitats: an experimental assessment. Limnology and Oceanography.
Valentine, J. F. and K. L. Heck, Jr. Seagrass herbivory: evidence for the continual grazing of marine grasses. Marine Ecology Progress Series 176:291 -302.
Valentine, J.F., M. Dardeau, M. Zolkewitz and G. Crozier. An environmental assessment of the health of Mobile Bay using benthic infaunal organisms: A report to the Gulf Coast Industrial Environmental Forum. 32 p.