Using palaeoecological techniques to understand the impacts of past volcanic eruptions

Abstract

Large volcanic eruptions may have major impacts on ecosystems through their physical, chemical and climatic affects. These impacts are stochastic and because the largest, most damaging volcanic events have not occurred in the recent past there is considerable interest in past eruptions as an analogue for possible future events. Palaeoecology is an essential tool to understand the environmental consequences of eruptions in the past. Here we review the processes by which volcanic eruptions affect ecosystems, how palaeoecological research can enhance our knowledge of palaeo-volcanic impacts and some of the challenges which such studies face. We focus particularly on tephropalaeoecological studies which address changes in the abundance of microfossils (e.g. pollen, diatoms, testate amoebae) across tephra layers preserved in sediments. In our discussion we stress the importance of impacts from volcanic tephra, volatiles and volcanically-induced climate change, which are likely to be the most spatially extensive impact mechanisms. We highlight the importance of considering the taphonomy of tephra and microfossils when attempting to identify volcanic impacts. We discuss the extent to which it is, and is not, possible to distinguish volcanic impacts from non-volcanic processes and random variability. The focus of this special issue is the Mediterranean and we conclude by discussing the particular issues which may apply in this region, including the availability of suitable archives and preservation conditions.

Geography Field Study: the 21st Century Learning Innovation

“…These impacts are stochastic because the largest and most damaging volcanic events have not occurred recently. Thus, there is considerable interest in past eruptions as an analogue for possible future events [22].…”

Forests protect aquatic communities from detrimental impact by volcanic deposits in the tropical Andes (Ecuador)

“…Dashed lines represent the moment of the volcanic event (tephra deposition in the lake catchment), being double in Laguna Baños (original and secondary). Taxa included for defining pollen and chironomids' assemblages are listed in Tables S3, S4 and S5 C o r e D e v e l o p m e n t T e a m 2 0 1 5 ) : ( i ) D e t r e n d e d Correspondence Analysis (DCA) was performed using the package 'vegan' version 2.3-5 (Oksanen et al 2013); (ii) Rates of Change (RoC) between contiguous samples were calculated using the package 'rioja' (Juggins 2017); and (iii) Chord distance dissimilarity coefficient between samples previous and after the disturbance (Overpeck et al 1985;Payne and Egan 2019) was calculated using the 'analogue' package (Simpson 2007). For these analyses, the dataset used was the percentage data after square root transformation and down weight of rare taxa.…”

A multidisciplinary study of an exceptional prehistoric waste dump in the mountainous inland of Calabria (Italy): Implications for reconstructions of prehistoric land use and vegetation in Southern Italy

“…Until very recently, tephra from the Pompeii eruption had not been described for Calabria, which is somewhat surprising considering the thickness of the tephra layer encountered at site RB073, whose origin was earlier established by Sevink et al (2016) based on 14 C datings. Its thickness is such that it may have had a serious impact on the coeval environment, since tephra holds toxic elements and is physically harmful to humans and animals (see, for example, Blong, 2013;Payne and Egan, 2019;Riede, 2019). An explanation for the low number of recorded occurrences might be that the tephra consists of very loose and easily erodible fine material and, if reworked, may not be recognized without microscopic analysis, similar to the earlier tephra (AP2) at site RB073.…”