My research takes an integrative approach to understanding the impacts of human-induced rapid environmental change on wildlife. Primarily my research focuses on the ecological effects of emerging chemical pollutants in aquatic ecosystems (but also includes noise pollution, thermal pollution, and invasive species). Environmental pollution with synthetic chemicals is recognised as one of the fastest-growing agents of global change, exceeding that of many well-recognised environmental megatrends (e.g. rising CO2 emissions, land loss to agriculture, and biodiversity loss). It is essential that we understand if, and how, emerging pollutants impact wildlife and ecosystems.
My key research themes are, as follows:
- Behavioural ecotoxicology
- The gut microbiome
- Evidence synthesis
Animal behaviour has emerged as a critical tool in measuring chemical-induced impacts. The growing use of behaviour in ecotoxicology is primarily a result of its sensitivity to chemical disruption and its direct link to population-level outcomes. Concerningly, many emerging pollutants—particularly pharmaceuticals (e.g. antidepressants, anxiolytics, and endocrine disruptors)—have the potential to alter the behaviour of exposed wildlife. Indeed, there is now a building body of evidence, including my own work, reporting that environmentally realistic levels of emerging pollutants can disrupt a range of important behaviours in wildlife. Within the research theme of behavioural ecotoxicology, there are three principal sub-themes around which I am building my research: behavioural variation, collective behaviour, and lab to field.
Behavioural variation: moving beyond the mean in ecotoxicology
To date, the vast majority of research in ecotoxicology has considered only mean-level effects on animal behaviour, neglecting the behavioural variation that exists within populations. That is, we often ignore the variation among and within individuals—treating it as noise in our data. However, behavioural variation among and within individuals has profound population- and community-level implications. Thus my research asks whether chemical pollution impacts some individuals more than others, and whether chemical pollution can homogenise/exacerbate individual differences.
- Polverino G, Martin JM, Bertram MG, Soman VR, Tan T, Brand JA, Mason RT, Wong BBM. (2021) Psychoactive pollution suppresses individual differences in fish behaviour. Proc. R. Soc. Lond. B Biol. Sci. https://doi.org/10.1098/rspb.2020.2294 | PDF
- Brand JA, Henry J, Melo G, Alton LA, Wlodkowic D, Wong BBM, Martin JM*. (In press) Moving beyond the mean: personality, plasticity, and predictability in a freshwater fish (Gambusia holbrooki). Behav. Ecol.
* Co-senior authors
Collective behaviour: can a single individual tell the collective story
Most animals live in a social environment, from highly structured societies, to loosely structured social groups, and anything in-between. Thus, social interactions are group formation are fundamental for the survival of many species. Despite this, the majority of research in ecotoxicology focuses on the behaviour of individual animals, and seldom considers how chemicals might affect animal collectives and the interactions between them. My work asks whether emerging pollutants can disrupt the formation and composition of animal groups, and how this might affect collective behaviour.
- Michelangeli M, Martin JM, Pinter-Wollman N, Ioannou- CC, McCallum ES, Bertram MG, Brodin T. Predicting the impacts of chemical pollutants on animal groups. (2022) Trends Ecol. Evol. https://doi.org/10.1016/j.tree.2022.05.009 | PDF
- Martin JM and McCallum ES. (2021) Incorporating animal social context in ecotoxicology: can a single individual tell the collective story? Environ. Sci. Technol. https://doi.org/10.1021/acs.est.1c04528 | PDF
Lab to field: injecting ecological complexity into behavioural ecotoxicology
One of the recent goals of my work is to understand how the effects of chemical pollution may manifest under more ecologically realistic conditions. Colleagues at SLU and I are incorporating technologies like acoustic telemetry and biologgers (e.g. heart rate, temperature and 3D acceleration), in combination with slow-release chemical implants to measure the impacts of pharmaceutical exposure on animals in the field. For example, we have investigated the effects of pharmaceutical exposure on predator-prey interactions in multi-fish communities across three lakes in Sweden.
The gut microbiome
The relationship between an animal host and its gut microbiome is a rapidly expanding area of research in the Life Sciences. Recent evidence has established strong links between the gut microbiome, host homeostasis, and behaviour. An animal’s microbiome resides at the interface between the host and its environment; in essence, the microbiome represents a buffer and first line of defence against contaminants and environmental stressors. A number of chemical pollutants (e.g. metals and antibiotics) have the potential to disrupt the microbiome of animals.
My most recent research theme is to understand the impacts of chemical pollution on the gut microbiome of exposed wildlife, and the consequences for their metabolism, growth, and behaviour. My preliminary results suggest that pharmaceutical exposure can cause perturbation of the gut microbial community at environmentally realistic levels, which appears to be linked to changes in neurotransmitter expression in the gut and brain.
In combination with my experimental research, I also employ evidence synthesis to understand the effects of emerging pollution on wildlife. Evidence synthesis is the process of collating and combining data from multiple sources to establish an evidence base, identify gaps in knowledge, and analyse overall or absolute effects. Typically this takes the form of systematic literature reviews and meta-analysis.
Evidence synthesis is particularly important for research measuring the impacts of pollution, as to accurately inform policymakers, we must first build a database and calculate the risk of pollutants in a repeatable and unbiased manner. One of the current evidence synthesis projects I am leading is a large-scale systematic map, addressing the effects of human and veterinary pharmaceuticals on aquatic animal behaviour. Once my team and I have completed metadata extractions for the primary research articles on this topic, it will be presented as a publicly available database for use in policymaking and for meta-analysis.
- Martin JM, Bertram MG , Blanchfield PJ, Brand JA,, Brodin T, Brooks BW, Cerveny D, Lagisz M, Ligocki IY, Michelangeli M, Nakagawa S, Orford JT Sundin J, Tan H, Wong BBM, McCallum ES. (2021) Understanding the impacts of pharmaceuticals on aquatic animal behaviour: a systematic map protocol. Environ. Evid. https://doi.org/10.1186/s13750-021-00241-z | PDF