Coastal pollution limits pelagic larval dispersal.

Area of Science:

• Marine Ecology
• Population Genetics
• Environmental Toxicology

Background:

• The ecological effects of large coastal human populations on marine ecosystems are not well understood.
• Marine species face increasing anthropogenic pressures from coastal development and pollution.

Purpose of the Study:

• To investigate the population structure of the bat star (Patiria miniata) in the Southern California Bight.
• To correlate genetic distances with anthropogenic inputs, specifically stormwater runoff and wastewater effluent.
• To assess the impact of pollution on marine species' genetic diversity and connectivity.

Main Methods:

• Examined population structure of Patiria miniata using genetic markers.
• Modeled genetic distances based on flow rates and proximity to pollution sources.
• Utilized multivariate analyses to correlate genetic structure with anthropogenic variables.
• Performed regressions between allelic richness and distance to pollution sources.

Main Results:

• Overall genetic connectivity in Patiria miniata populations is high (F(ST)~0.005).
• Genetic structure is significantly correlated with anthropogenic inputs from stormwater and wastewater.
• Pollution sources explained a substantial portion (26.55–93.69%) of the observed genetic structure.
• Populations near pollution sources exhibit reduced genetic diversity (allelic richness).

Conclusions:

• Anthropogenic runoff and effluent act as barriers to larval dispersal for Patiria miniata.
• Pollution effectively isolates populations of a species with naturally high gene flow.
• Human activities significantly impact marine ecosystem connectivity and genetic diversity, even in species with minimal direct human interaction.