Photophysiology data from smooth cordgrass (Sporobolus alterniflorus) measured in a North American saltmarsh using pulse amplitude modulated (PAM) fluorescence

Coastal saltmarshes play an important role as an interface between terrestrial and marine environments. <i>Sporobolus alterniflorus</i> (smooth cordgrass) occurs naturally along the east coast of North America, from Texas to Quebec, where it often forms extensive monospecific stands. <i>Sporobolus alterniflorus</i> is highly productive and is often the dominant plant in terms of biomass. This data set presents variable chlorophyll fluorescence measurements made <i>in situ</i> from the leaves of <i>Sporobolus alterniflorus</i> growing in a tidal saltmarsh ecosystem (North Inlet, South Carolina, United states). Measurements were made using pulse amplitude modulated (PAM) fluorescence. The data include raw measurements of variable fluorescence (<i>F_t</i> ) and maximum fluorescence (<i>F'_m</i> ) made at 12 different actinic photosynthetic photon flux densities (PPFD). These data were used to calculate the quantum yield of photosystem II <i>(Φ_PSII</i> ) and estimate electron transport rates (ETRs). Rapid light curves (RLCs) were fitted to the ETRs to parametrize the relationship between ETR and PPFD in <i>S. alterniflorus</i> under different environmental conditions. Measurements were made from <i>S. alterniflorus</i> culms growing at different positions on the shore and at different times of the day. These data provide a resource for researchers interested in the photophysiology and photosynthesis of <i>Sporobolus alterniflorus</i>, and saltmarsh ecology and management.