Discipline: Biological Sciences
Subcategory: STEM Research
Alex Mercado-Molina - Florida International University
Co-Author(s): Joel Trexler
Periphyton is an association of autotrophs and saprophytes that is the primary source of energy and elements for many aquatic food webs. Periphyton-mat structure affects consumer access to food elements, also limiting resource transfer from basal to consumer portions of the food web. Few studies evaluate the relationship between environmental gradients and periphyton nutritional quality in wetlands, limiting our capacity to link it to population, and ultimately ecosystem, function. This work describes a field experiment evaluating the impact of increasing water velocity on resource quality and resource-consumer relationships in the Everglades. We created a food-web fragment within enclosures established at three locations experimentally differing in water velocity (0 cm/s, 3-4 cm/s, 5-7 cm/s). The food web consisted of primary producers (periphyton mats and biofilm), a grazer (Ramshorn snail), an omnivorous fish (Eastern Mosquitofish), and a carnivorous fish (Blue-Spotted Sunfish). The resource-consumer relationship across locations was evaluated using nutrient and fatty acid profiles, tools that relate the dietary sources of energy from basal resources to consumers. We found that in periphyton mats the percentages of phosphorous (P) and polyunsaturated fatty acids (PUFA) increased with water flow. In biofilm, P followed the same pattern as that of periphyton mats. Nevertheless, PUFA was highest under mid-velocity conditions. These results will be discussed within the context of the trophic relationship of the components of the food web.
Funder Acknowledgement(s): National Science Foundation; US Army Corps of Engineers
Faculty Advisor: None Listed,