The Southern Ocean plays a significant role in absorbing around one-third of global carbon dioxide through the biological carbon pump and the solubility pump. The biological carbon pump system is regulated by the presence of the essential micronutrient iron, with some evidence of potential iron-manganese co-limitation. Iron and manganese are essential trace metals that have a crucial effect on the functioning of photosynthetic proteins in metabolic processes and the study of their biogeochemical cycles is of great interest. Within the Southern Ocean are regions such as island wakes, which are recognized for their high productivity, usually depicted by phytoplankton blooms, a phenomenon known as the “land mass effect”, where the presence of land might contribute to increased availability of trace metals. However, the majority of observations are mostly focused on islands such as South Georgia, Crozet Island, and Kerguelen Island, whereas no observations have been made on the islands situated in the Atlantic sector of the Southern Ocean (Gough Island). This hampers our understanding of the land mass effect on significant micronutrients, as the islands differ from one another in terms of topography and the currents surrounding them, thus resulting in different distribution patterns of trace metals.
To address this gap, trace metal samples were collected during the 2023 and 2024 Gough Island cruises. These samples were collected upstream and downstream of Gough Island and were analyzed at Stellenbosch University. The data collected from these islands was utilized to examine the interplay between dissolved and particulate forms of trace metals and their distribution patterns. The chlorophyll-a distribution showed low concentrations, and furthermore, the climatology of geostrophic current velocity around the island indicated that water movement strongly influences the surrounding waters, with relatively high flow leading to continuous transport and dispersal of trace elements, weakening the chlorophyll signal typically associated with the Island Mass Effect.