Kady wants to know how the bacteria and viruses – the microbiome communities – that live in the bodies of all animals may be influenced by pollution and what role that might play in evaluating the health of stingrays (and other sharks and rays) that often swim in contaminated waters. She is looking at the change in the microbiome community in stingrays across both polluted and unpolluted reaches of Georgia’s coastline in the USA.
It sounds like a cliché, but ever since I was little kid I have been fascinated by the ocean. My parents played a big role in supporting my interest from a young age by enrolling me in after-school marine programmes and taking me on many a trip to the beach. As a young adult, I became fascinated by the research on shark behaviour carried out by Dr Eugenie Clark, a maverick for her time as a woman in shark science. Many years later, my work as a young professional in shark research would earn me the honour of being the...
The project aim is to determine how habitat quality, based on the degree of anthropogenic contamination, may alter the microbial composition found on elasmobranch skin, gills, and digestive tracts. Our objective is to sample a variety of elasmobranch species along the Georgia (USA) coastline, which varies in anthropogenic influence.
Recognition of the role the microbiome plays in influencing individual health is gaining momentum; however, even baseline information in elasmobranchs microbiome composition is extremely limited. This project will be one of the first to take a multi-tissue, multi-species and multi-locality approach to characterizing and understanding factors that affect the microbiome communities in elasmobranchs. In addition, the coastline of Georgia is underdeveloped compared to adjacent states, enabling a unique opportunity for access to relatively “clean” and “impacted” shorelines within a small stretch of coastline. The continental shelf of Georgia has also recently been designated a Sylvia Earle Hope Spot. With this unique distinction, our project will generate baseline research necessary to understand how anthropogenic forces impact local marine environments so that appropriate steps can be taken to protect and preserve the coastline of Georgia. This project highlights how novel work can be conducted through multi-institutional collaborative efforts from three distinct sectors.
Mucus membranes delineate biological tissues from the surrounding environment, making them exposed to pathogenic and non-pathogenic microbes. In teleost fishes, the bacterial composition of these mucous membranes support digestion, essential nutrient production, waste processing, and defense against parasites and pathogens. Elasmobranchs also utilize mucus membranes at key sites such as the skin, gills and digestive tract, with unique adaptations that make them distinct compared to bony fishes. For example, compounds on elasmobranch skin are known to have unique healing properties that show promise for human wound healing applications.
Despite this potential, elasmobranch microbiome research lags behind teleost research, with only one peer-reviewed study on captive cownose ray skin microbiome and several unpublished Master theses. Given this paucity of research, it is critical to first characterize the normal bacterial flora associated with different tissues and then apply this knowledge to 1. describe and delineate species’ microbiomes and 2. determine how environmental factors, such as contaminant exposure, may impact that composition at the tissue-specific level (e.g. skin, gills, and gut).
Since mucus membranes are constantly exposed to the environment, there is potential for external factors to influence microbial composition. In particular, pollution is an insidious factor that can affect organisms at multiple levels. The complete spectrum of pollution impacts on elasmobranch physiology are not well understood, and even less is known about its influence on microbiomes. Being demersal, rays generally have more intimate contact with contaminated sediment than their shark counterparts. Thus, external microbiome communities on mucus membranes may be at more risk of direct exposure to contaminants in rays compared to shark species. Understanding how microbiome communities may be influenced by environmental factors, such as contaminant exposure, is important for evaluating species health from a holistic perspective.
Sushmita is working closely with fishers along the coast of West Bengal, from the border with Bangladesh to the mangroves of the Sundarbans, to collect information that will help her understand the catch composition of sharks and rays at fish landing sites. She hopes to fill the gaps in what is known of their life history and identify population dynamics of the elasmobranchs of the region, as well as potential threats to them.