Does the diatom record of Lake Vico reflect a recent history of degraded water quality from hazelnut farming in the watershed?

Abstract

Lake Vico, Italy has experienced water quality issues in modern times due to the advent of hazelnut plantations and increased agriculture around the lake. Anthropogenic activity has affected the lake’s trophic state, and this study analyzed whether this was reflected in the diatom record, indicating that the lake’s flora are sensitive so such changes in the water quality. Enumeration of diatoms and multivariate were conducted to determine whether taxonomic differences presented themselves within the sediment record of the lake for the past millennium. Cluster analysis and broken stick modeling indicate that there are 4 distinct diatom zones within top 98cm of the lake core, with the uppermost zone representing anthropogenic activity over the last 50 years. Paleochlorophyll data indicate that the trophic state in 2012 may have improved some from the late 1990’s. While the recent eutrophication signal is apparent in the diatom flora, considerable down core variation was also noted in the older parts of the core which were analyzed to provide background data. This indicates that the diatom assemblages from the older part of the core could record an interesting paleoenvironmental record.