Antarctic ascidians under increasing sedimentation: Physiological thresholds and ecosystem hysteresis
L Torre1, G Alurralde1, C Lagger1
1Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Av. Vélez Sarsfield 299, 5000, Córdoba, Argentina; Instituto de Diversidad y Ecología Animal (Consejo Nacional de Investigaciones Científicas y Técnicas), Córdoba, Argentina.
Marine Environmental Research
|March 17, 2021
Summary
Glacier melt alters Antarctic coastal ecosystems. Ascidians thrive in high sediment areas, suggesting a sediment threshold may maintain ecosystem stability in Potter Cove.
Area of Science:
- Marine ecology
- Antarctic research
- Benthic ecosystems
Background:
- Glacier melting introduces sediment into Antarctic coastal ecosystems.
- Sedimentation has been linked to shifts in benthic community structure in Potter Cove.
- Ascidian dominance in newly ice-free areas contradicts previous sedimentation-assemblage relationships.
Purpose of the Study:
- To investigate the relationship between total suspended particulate matter (TSPM) and ascidian feeding and energy reserves.
- To understand the factors influencing ascidian distribution in Potter Cove under varying sedimentation regimes.
- To explore the potential for a TSPM threshold in maintaining alternative stable states in benthic systems.
Main Methods:
- Comparison of gut content and energy reserves of three ascidian species.
- Sampling conducted at three stations with differing TSPM concentrations in Potter Cove.
- Analysis of organic matter (%OM) in gut contents.
Main Results:
- Ascidian species exhibited higher gut content with lower %OM in areas with high TSPM.
- A theoretical scope for growth model explained historical assemblage shifts but not current ascidian distribution.
- Findings suggest a potential TSPM threshold influencing ascidian dominance.
Conclusions:
- Sedimentation plays a complex role in Antarctic benthic community structure.
- A critical TSPM threshold might facilitate the coexistence of different ecological states in Potter Cove.
- Further research is needed to fully elucidate the mechanisms driving ascidian distribution and ecosystem stability.
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