Chemical and C and N stable isotope compositions of three species of epiphytic Tillandsia in a Caribbean coastal zone: air pollution sources and biomonitoring implications

ABSTRACT

We characterized the elemental and C and N stable isotope compositions of Tillandsia fasciculata Sw., Tillandsia balbisiana Schult. & Schult.f. and Tillandsia recurvata (L.) L. samples collected in Cienfuegos (Cuba). Results showed high enrichment factors for S, Hg, Cd, Pb, P, Zn, Cu, Mo, Sb and Ca in all Tillandsia species, indicating inputs from local anthropogenic activities (road traffic, industries and cement production). Carbon concentrations and δ¹³C varied from 38.3–47.7 % and –20.4 to –13.4 ‰ within the three species, respectively. δ¹³C showed seasonal dependence with the dry and wet periods and more ¹³C-depleted values in urban/industrial areas, coherent with the input of anthropogenic emissions. Nitrogen concentrations (0.4–1.3 %) and δ¹⁵N values (–9.9–4.4 ‰) exhibit larger variations and are positively correlated in the three species. The most positive δ¹⁵N in T. recurvata (–0.2–4.4 ‰) are attributed to contributions from industrial activities and road traffic. In fact, both δ¹⁵N and total nitrogen (TN) values increase in sites with higher road traffic and show significant correlations with typical road traffic and industrial tracers. Finally, we calculate an average total nitrogen deposition rate of 4.4 ± 2.3 kg ha^–1 a^–1 from N content in T. recurvata, similar to the existing values determined in the region by field measurements, but higher than the global terrestrial average.

KEYWORDS:

• Air quality biomonitoring
• carbon-13
• Cuba
• heavy metals
• nitrogen-15
• Tillandsia species
• pollution sources
• stable isotope tracer & methodology

Acknowledgments

The authors express their gratitude to the analytical staff of the environmental laboratories at the Centro de Estudios Ambientales de Cienfuegos (CEAC) and Laboratorio Ambiental de Calidad Ambiental (LICA, Universidad de Navarra) for its assistance. The authors also wish to thank Orlando Viera Ribot for his support during sampling campaigns.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

Yasser Morera-Gómez: Conceptualization, Methodology, Validation, Formal analysis, Investigation, Data Curation, Writing – Original Draft, Writing – Review & Editing, Visualization. Alejandro Armas-Camejo: Investigation, Data Curation, Writing – Original Draft. Jesús Miguel Santamaría: Conceptualization, Resources, Writing – Review & Editing, Supervision. Carlos Manuel Alonso-Hernández: Conceptualization, Supervision, Writing – Review & Editing, Project administration. Esther Lasheras: Formal analysis, Data Curation, Writing – Review & Editing. David Widory: Original Draft, Writing – Review & Editing, Supervision. David Elustondo: Conceptualization, Resources, Writing – Original Draft, Writing – Review & Editing, Supervision.

Data availability

Primary data related to this work is provided in the Supplemental online material.

Additional information

Funding

This research has received funding from ‘la Caixa’ Banking Foundation. The study was also supported by the IAEA TC Project CUB/7/008 “Strengthening the National System for Analysis of the Risks and Vulnerability of Cuba’s Coastal Zone Through the Application of Nuclear and Isotopic Techniques” and National Program PNUOLU /4-1/ 2 No. /2014 of the National Nuclear Agency of Cuba.