Histopathological, behavioral and reproduction biomarkers in marine amphipods exposed to emerging pollutants

Abstract

Biomarkers are effective tools to monitor the consequences of introducing contaminants into the environment, including into the oceans. Several types of biomarkers can be used for this purpose, including histopathological, behavioral, and reproductive. Used together, they can give an overview of the impact that the pollutant causes on the organism. However, much remains to be studied in order to optimize them for several key species that could serve as bioindicators of the marine ecosystem and that methodologies can be standardized so that the results obtained by different researchers could be compared with reliability. Histopathological changes due to exposure to contaminants provide basic information about the damage that the toxic agent can cause to the tissue structure of organisms, which can lead to functional disorders. Behavioral studies, in turn, are fundamental for establishing the link between physiological disturbances and ecological impacts, since behavioral responses integrate from cellular processes to survival and reproduction of the organism. Finally, reproductive biomarkers can provide indications about the consequences of individual changes in population maintenance. Fertilization is a key step to reproductive success and contaminants in the marine environment have the potential to affect the conditions necessary for successful fertilization. Amphipods are essential components of marine ecosystems as they occupy several trophic niches and also serve as food for fish and birds, among others. They are, for various reasons, good candidates to be used as model organisms to assess the potential impacts that pollutants may have on the environment. Two ecologically important species that are being extensively studied and used in laboratory trials are Parhyale hawaienses and Echinogammarus marinus. Among different aspects of studies, the effort to understand the impact that emerging pollutants can cause to the marine environment is noticeable, with emphasis on nanoparticles, pharmaceutical compounds and plastics. They are defined as synthetic or natural substances that are not monitored but may cause adverse effects on human or ecological health. The knowledge of the effects of these emerging pollutants on organisms is still incipient and they need to be better studied. For the reasons outlined above, amphipods are a good group to evaluate the toxicological effects of these compounds. Histopathological, behavioral, and reproductive biomarkers may encompass a wide variety of physiological and cellular aspects related to their mode of action, both from the individual point of view and their populations in the ecosystem. (AU)