Coastal proximity, orientation, and precipitation amount drive spatial variability in δ34S values on the Caribbean island of Trinidad

Sparks, J. M., Crowley, B. E., Rutherford, M. G. and Jaggernauth, D. (2019) Coastal proximity, orientation, and precipitation amount drive spatial variability in δ34S values on the Caribbean island of Trinidad. Applied Geochemistry, 108, 104372. (doi: 10.1016/j.apgeochem.2019.104372)

Abstract

Coastal proximity, wind direction, and amount of precipitation can all influence the distribution of marine sulfur on land. However, the relative importance of these different factors to vegetation is not well constrained, and previous research has been geographically limited. Here we use sulfur isotope (δ34S) values for total sulfur in foliage to assess the spatial distribution of marine-derived sulfur (+15.6 to +21‰) on the island of Trinidad. We expected that plants that receive heavy precipitation and are located on windward coasts (along the east and north coasts) would have higher δ34S values resembling marine sulfur, whereas areas with low precipitation or on leeward coasts (i.e. the west and southwest) would have lower values. Samples were collected along an east-west transect that spanned the island's width, as well as 18 additional sites across the island. As anticipated, along the transect, plant δ34S values are highest on the windward coast (ca. +17.4‰). Values decline ca. 9‰ within 1.5 km, and another ca. 6‰ within 10 km from the east coast. Island-wide, plants from the north and northeast exhibit the highest δ34S values (+16.2 to +20.4‰), while those from the southwest have markedly lower δ34S values (ca. +9.6‰). Overall, we find that a marine sulfur signal is most pronounced for sites within 1.5 km of the ocean yet may still be detectable within 10 km of the ocean for sites that receive abundant precipitation or are on a windward coast. Our data also suggest that anthropogenically-derived sulfur is utilized by vegetation growing in roadside and urban settings on the island.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Rutherford, Mr Mike
• Authors: Sparks, J. M., Crowley, B. E., Rutherford, M. G., and Jaggernauth, D.
• College/School: University Services > Library and Collection Services > Museum and Art Gallery
• Journal Name: Applied Geochemistry
• Publisher: Elsevier
• ISSN: 0883-2927
• ISSN (Online): 1872-9134
• Published Online: 08 July 2019