TY - JOUR

T1 - Emission rates of C8-C15 VOCs from seaweed and sand in the inter-tidal zone at Mace Head, Ireland.

AU - Sartin, J. H.

AU - Halsall, Crispin J.

AU - Hayward, S.

AU - Hewitt, C. Nicholas

PY - 2002/11

Y1 - 2002/11

N2 - Emission fluxes for a range of C8–C15 volatile organic compounds (VOCs) were determined from the seaweed Fucus spiralis (spiral wrack) and an adjacent sand surface during low tide on the coastline of Mace Head, Ireland. These two surface types, assessed using dynamic flux chamber systems, are typical of the Mace Head inter-tidal zone. A range of n-alkanes and oxygenates were routinely identified in the measurement of chamber air. Examination of the odd/even n-alkane ratios and use of the carbon preference index (CPI) suggested a biogenic source for these compounds (CPIs >2 in for all samples). Fluxes of n-pentadecane, the most predominant n-alkane, ranged from 0.2 to 5.1 μg m−2 h−1 (0.9–24 nmol m−2 h−1), while oxygenates such as nonanal and decanal had fluxes ranging from <0.1 to 4.4 μg m−2 h−1 (<0.1–31 nmol m−2 h−1) and <0.1 to 4.6 μg m−2 h−1 (<0.1–30 nmol m−2 h−1), respectively. Seaweed emission rates for n-pentadecane were correlated with photosynthetically active radiation (PAR) (rs=0.94) while emissions from sand showed correlation with temperature (rs=0.85). This suggests a possible biochemical route controlling the release of n-pentadecane from spiral wrack, and temperature-driven volatilisation from sand. Volatilisation from residual seawater trapped in the sand may explain the comparable flux of both n-alkanes and oxygenates from this surface. Unlike the n-alkanes, oxygenate fluxes from sand correlate with PAR, suggesting a photodependent production from organic carbon residues present in seawater. Comparison with previous flux estimates from coastal seawater indicates that the two source types (Fucus spiralis and bare sand) are significant but not dominant sources of these VOCs.

AB - Emission fluxes for a range of C8–C15 volatile organic compounds (VOCs) were determined from the seaweed Fucus spiralis (spiral wrack) and an adjacent sand surface during low tide on the coastline of Mace Head, Ireland. These two surface types, assessed using dynamic flux chamber systems, are typical of the Mace Head inter-tidal zone. A range of n-alkanes and oxygenates were routinely identified in the measurement of chamber air. Examination of the odd/even n-alkane ratios and use of the carbon preference index (CPI) suggested a biogenic source for these compounds (CPIs >2 in for all samples). Fluxes of n-pentadecane, the most predominant n-alkane, ranged from 0.2 to 5.1 μg m−2 h−1 (0.9–24 nmol m−2 h−1), while oxygenates such as nonanal and decanal had fluxes ranging from <0.1 to 4.4 μg m−2 h−1 (<0.1–31 nmol m−2 h−1) and <0.1 to 4.6 μg m−2 h−1 (<0.1–30 nmol m−2 h−1), respectively. Seaweed emission rates for n-pentadecane were correlated with photosynthetically active radiation (PAR) (rs=0.94) while emissions from sand showed correlation with temperature (rs=0.85). This suggests a possible biochemical route controlling the release of n-pentadecane from spiral wrack, and temperature-driven volatilisation from sand. Volatilisation from residual seawater trapped in the sand may explain the comparable flux of both n-alkanes and oxygenates from this surface. Unlike the n-alkanes, oxygenate fluxes from sand correlate with PAR, suggesting a photodependent production from organic carbon residues present in seawater. Comparison with previous flux estimates from coastal seawater indicates that the two source types (Fucus spiralis and bare sand) are significant but not dominant sources of these VOCs.

KW - n-Alkanes

KW - Oxygenated organic compounds

KW - Coastal boundary layer

KW - Photosynthetically active radiation (PAR)

KW - Fucus spiralis (spiral wrack)

U2 - 10.1016/S1352-2310(02)00639-8

DO - 10.1016/S1352-2310(02)00639-8

M3 - Journal article

VL - 36

SP - 5311

EP - 5321

JO - Atmospheric Environment

JF - Atmospheric Environment

SN - 1352-2310

IS - 34

ER -