Environmental ecology of marine bryozoans (Phylum Bryozoa) and ascidians (Tunicata: Ascidiacea) under multistressor scenarios

Yepes-Narváez, Vanessa (2020) Environmental ecology of marine bryozoans (Phylum Bryozoa) and ascidians (Tunicata: Ascidiacea) under multistressor scenarios. Doctoral thesis (PhD), Manchester Metropolitan University.

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Abstract

Environmental stressors determine the extent of occurrence of marine species and modify their biology and ecology; understanding the tolerance range of marine fauna to disturbances is an important conservation tool that supports the development of better strategies to protect species and their ecosystem functions. Monitoring is key to understand the behaviour of species against current stressors, however, in order to analyse the species performance under predicted multi-stressor scenarios for the end of the century, controlled laboratory experiments also known as mesocosms are a good tool that allow us to modify environmental conditions and evaluate the degree of impact on the species biology and ecology. In this study, I collected and modelled environmental data and created mesocosms in order to evaluate the biological response of Bryozoans and Ascidians against current and future stressor scenarios. Firstly, I identified the diversity of bryozoans at different geographic and bathymetric ranges in the Colombian Caribbean with the purpose of complement the species record and to compare their distribution and ecology with the environmental variables in those areas. This allowed me to describe new species for science and their ecology in the Caribbean. I demonstrated that bryozoans modify their reproductive patterns and create habitat complexity in high disturbance areas in the Colombian Caribbean. Secondly, I developed controlled mesocosms in laboratory to test the effects of turbidity, ocean acidification, global warming and microplastic pollution on the biological functions of coastal ascidians. I discovered a novel behaviour in these Chordates of energetically expensive total evisceration after environmental stress, this behaviour allows the animals to create a new digestive system within two weeks but exposes them to further threats. In addition, I demonstrated that the ingestion of mic