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.

Research Interests

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. 


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


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.

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