Epiphytes mediate the trophic role of sea urchins in Thalassia testudinum seagrass beds

Marine Ecology Progress Series

Just Cebri#xe1n¹  Jose Luis S#xe1nchez-Lizaso¹  Patricia Prado¹  Kenneth L. Heck¹  Candela Marco-M#xe9ndez¹ 

关键词: Food choice;    Lytechinus variegatus;    Thalassia testudinum;    Epiphytes;    Isotopes;   

DOI  :  10.3354/meps09781

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: The trophic role of the sea urchin Lytechinus variegatus (Lamarck) and the importance of epiphytes as mediators of trophic interactions were evaluated in a Thalassia testudinum meadow, St. Joseph Bay, Florida, in fall 2010. Tethering experiments were deployed within the meadow to assess consumption rates, and food choice experiments, with combinations of different types of T. testudinum leaves, green leaves and detached (decayed) leaves, both with and without epiphytes, were carried out with individual urchins in 4 different 24 h feeding trials. Lytechinus variegatus had higher consumption rates on decayed (12.15 ± 1.3 mg DW shoot⁻¹ d⁻¹; mean ± SE) compared to an undetectable consumption of green seagrass leaves, and consistently chose epiphytized leaves of both type. Therefore, consumption rates were highest for decayed leaves with epiphytes. This choice may be related to the significantly higher epiphytic biomass on decayed (3.64 ± 0.28 mg DW cm⁻²) than on green leaves (2.11 ± 0.25 mg DW cm⁻²). Stable isotope analyses pointed to epiphytes and green leaves as the main sources of nitrogen and carbon in L. variegatus diet. These results suggest that epiphytes mediate trophic interactions between sea urchins and turtlegrass. Therefore, changes in epiphytes and decayed leaf biomass can regulate sea urchin foraging and its impact on the trophic dynamics of the meadows.

【 授权许可】

Unknown