MEPS 387:109-123 (2009)  -  DOI: https://doi.org/10.3354/meps08093

Interspecific variation in the elemental and stable isotope content of seagrasses in South Florida

Justin E. Campbell1,*, James W. Fourqurean1,2

1Department of Biological Sciences, Florida International University, Marine Sciences Program, 3000 NE 151 Street, North Miami, Florida 33181, USA
2Center for Tropical Plant Conservation, Fairchild Tropical Botanic Garden, 11935 Old Cutler Road, Coral Gables, Miami, Florida 33156, USA

ABSTRACT: The elemental (C, N, and P) and isotope (δ13C, δ15N) content of leaves of the seagrasses Thalassia testudinum, Halodule wrightii, and Syringodium filiforme were measured across a 10000 km2 survey of the seagrass communities of South Florida, USA, in 1999 and 2000. Trends at local and broad spatial scales were compared to examine interspecific variation in the seagrass characteristics often used as ecological indicators. The elemental and stable isotope contents of all species were variable and demonstrated marked interspecific variation. At broad spatial scales, mean N:P ratios were lowest for T. testudinum (36.5 ± 1.1) and S. filiforme (38.9 ± 1.3), and highest for H. wrightii (44.1 ± 1.8). Stable carbon isotope ratios (δ13C) were highest for S. filiforme (–6.2 ± 0.2‰), intermediate for T. testudinum (–8.6 ± 0.2‰), and lowest for H. wrightii (–10.6 ± 0.3‰). Stable nitrogen isotopes (δ15N) were heaviest for T. testudinum (2.0 ± 0.1‰), and lightest for H. wrightii (1.0 ± 0.3‰) and S. filiforme (1.6 ± 0.2‰). Site depth was negatively correlated to δ13C for all species, while δ15N was positively correlated to depth for H. wrightii and S. filiforme. Similar trends were observed in local comparisons, suggesting that taxon-specific physiological/ecological properties strongly control interspecific variation in elemental and stable isotope content. Temporal trends in δ13C were measured, and revealed that interspecific variation was displayed throughout the year. This work documents interspecific variation in the nutrient dynamics of 3 common seagrasses in South Florida, indicating that interpretation of elemental and stable isotope values needs to be species specific.


KEY WORDS: Seagrass · Elemental content · Stable isotopes · Interspecific variation · Carbon acquisition


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Cite this article as: Campbell JE, Fourqurean JW (2009) Interspecific variation in the elemental and stable isotope content of seagrasses in South Florida. Mar Ecol Prog Ser 387:109-123. https://doi.org/10.3354/meps08093

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