Volatile organic compounds (VOCs) are produced by macroalgae in response to environmental stresses. A novel approach using Solid Phase Microextraction (SPME) was used to quantify the production of several VOCs from eight common intertidal algal species from the UK (Ascophyllum nodosum (Linnaeus) Le Jolis, Fucus vesiculosus (Linnaeus), Fucus serratus (Linnaeus), Laminaria digitata (Hudson) Lamouroux, Ulva lactuca (Linnaeus), Ulva intestinalis (Linnaeus), formerly known as Enteromorpha, Palmaria palmata (Linnaeus) Kuntze and Griffithsia flosculosa (J. Ellis) Batters). The volatile compounds included halogenated, sulphur containing, aldehydes, non-methane hydrocarbons (NMHC) and oxygenated species. Overall, the production of VOCs by these algae was not considerably different under illumination or in darkness; this suggests that the VOC production occurs during both algae photosynthesis and in other metabolic processes such as respiration or osmoregulation. Desiccation played an important role in the production of VOCs with greater production by macroalgae after desiccation. This production was related to the alga's normal position within the intertidal zone; there was a lower production of VOCs for species growing near the high water mark and a greater production for algae taken from the low tide position. There were also species differences in the VOC profiles and quantities released. For example, chlorinated and oxygenated compounds were principally released by the brown alga Ascophyllum nodosum, while green algae such as Ulva lactuca and Ulva intestinalis released greater amounts of brominated, sulphur containing compounds, aldehydes and non-methane hydrocarbons than the other algae tested. The kelps (e.g. Laminaria digitata) had the greatest release of iodinated compounds such as diiodomethane. These processes make significant contributions to the VOCs in seawater and, by transfer to the atmosphere, in the coastal atmosphere.

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Volatile Organic Compounds (VOCs) in the marine environment are produced by biogenic sources (marine macroalgae, phytoplankton, sediments, etc.) as well from anthropogenic sources. The temporal variation of such VOCs was studied together with their relationship to biological, meteorological and physico-chemical factors. Sixty four different VOCs were quantified including halogenated (

A new method of determining the composition of sediment/soil gases and their volatile organic compound (VOC) content is described. VOCs were collected in situ from intertidal sediments in the Menai Strait and surrounding areas. The sampling was performed using a portable sampler comprising a funnel coupled to a SPME fibre. Gases were extracted from the sediments using a small vacuum pump pulling 100 mL min(-1) at atmospheric pressure. Sixty one different compounds were detected in the samples, and their fluxes and concentrations were determined. The compounds were classified into groups: halogenated, sulfur containing compounds, aldehydes, BTEXs (benzene, toluene, ethyl benzene and xylene) and aliphatic hydrocarbons. Results of principal component analysis (PCA) showed that the chemical composition of extracted gas was influenced primarily by sediment type. Muddy anoxic sediments were dominated by halogenated and sulfur containing compounds and sandy sediments had more aldehydes and BTEXs.