Marine vertebrates impact the bacterial community composition and food webs of Antarctic microbial mats

• Published in: Frontiers in Microbiology
• Main Authors: Almela, Pablo, Velázquez, David, Rico, Eugenio, Justel, Ana, Quesada, Antonio
• Other Authors: Ministerio de Economía y Competitividad (España), Ministerio de Ciencia e Innovación (España)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers 2022
• Subjects: Antarctica; Bacterial community; Microbial mat; Nitrogen; Penguins; Phosphorus; Trophic relationships; Biología y Biomedicina; Economía; Matemáticas; Zoología; Antarctic; Antarctic Peninsula; The Antarctic; Antarc*
• Online Access: http://hdl.handle.net/10016/37277; https://doi.org/10.3389/fmicb.2022.841175

The biological activity of marine vertebrates represents an input of nutrients for Antarctic terrestrial biota, with relevant consequences for the entire ecosystem. Even though microbial mats assemble most of the biological diversity of the non-marine Antarctica, the effects of the local macrofauna on these microecosystems remain understudied. Using 16S rRNA gene sequencing, 13C and 15N stable isotopes, and by characterizing the P and N-derived nutrient levels, we evaluated the effects of penguins and other marine vertebrates on four microbial mats located along the Antarctic Peninsula. Our results show that P concentrations, C/N and N/P ratios, and δ15N values of “penguin-impacted” microbial mats were significantly higher than values obtained for “macrofauna-free” sample. Nutrients derived from penguin colonies and other marine vertebrates altered the trophic interactions of communities within microbial mats, as well as the relative abundance and trophic position of meiofaunal groups. Twenty-nine bacterial families from eight different phyla significantly changed with the presence of penguins, with inorganic nitrogen (NH4+ and NO3–) and δ15N appearing as key factors in driving bacterial community composition. An apparent change in richness, diversity, and dominance of prokaryotes was also related to penguin-derived nutrients, affecting N utilization strategies of microbial mats and relating oligotrophic systems to communities with a higher metabolic versatility. The interdisciplinary approach of this study makes these results advance our understanding of interactions and composition of communities inhabiting microbial mats from Antarctica, revealing how they are deeply associated with marine animals. This work was supported by the Spanish Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER), Grants PID2020-116520RB-I00, CTM2016-79741-R, and PCIN-2016-001. PA was supported by a FPI-contract fellowship (BES-2017-080558) from MINECO.