Tracing 30 years of genetic diversity changes along pollution gradients in brown algae: A pool-sequencing approach

Authors:

Pacín, C., Boquete, M.T., Aboal, J.R., Fernández, J.A., Cronholm, B., Wernberg, T., Starko, S.

Congress:

Book of Abstracts – Posters - of the XX International Botanical Congress (IBC 2024), 21-27 July 2024, Madrid, España. P.0168, p. 604.

Studying the temporal evolution of genetic diversity is crucial for predicting adaptative potential and mitigating future ecological changes, particularly in ecosystem engineer species like the brown algae Fucus vesiculosus. This alga serves as a foundational species in the North Atlantic coastal environments, making its genetic health vital for the entire ecosystem. In this study we analyzed samples of F. vesiculosus vesiculosus from an environmental specimen bank to investigate changes in genetic diversity over a 30-year period across a pollution gradient. Specifically, we examined samples from five populations of F. vesiculosus (~50 thalli per population) collected in 1990, 2005 and 2021 in the North Atlantic Ocean (Galicia, NW Spain), assessing genetic variation and their pollutant concentrations. Levels of the latter in F. vesiculosus vesiculosus tissues ranged from 0.31 to 2.4 to mg kg-1 for Cd, from 0.22 to 6.5 mg kg-1 for Pb and from 7.2 to 372.5 µg kg-1 for Hg during the 30- year period. We hypothesize that populations in polluted areas have could experienced a loss in genetic diversity as a result of chronic pollutant exposure, and that populations from areas that varied from polluted to unpolluted have not recovered genetic variability yet. The ongoing pool-sequencing analysis will allow us evaluate the impact of anthropogenic activities on genetic variability. Loss of genetic diversity can limit adaptative potential, which is particularly relevant in the context of global change and in this specie given its essential roles in coastal ecosystems. By elucidating temporal patterns of genetic diversity, we gain valuable insights into the mechanisms driving evolutionary processes. This study highlights the broader implications of utilizing environmental specimen banks to understand genetic temporal patterns to offer valuable contributions to ecological and evolutionary research under a reliable and cost-effective method.

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Other project progress.

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Marine ecosystems and the impact of heavy metal pollution (HM).

Marine ecosystems, especially those in coastal areas, are particularly vulnerable to heavy metal (HM) pollution since they are subject to both land- and ocean-based pollution sources. Due to their toxicity, persistence, and capacity to biomagnify in the food chain, HMs pose an important threat through lethal and sub-lethal effects at the individual level that might have far-reaching consequences at higher hierarchical levels: populations, communities, and even entire ecosystems.

The cascading effects of pollution can thus jeopardize ecosystems' integrity and undermine their resilience, especially when they impact species with critical ecosystem roles, like macroalgal foundation species.