Seasonal contrast among bacterial, trophic, and biotic indicators in a multi-use coastal protected area
Çiftçi Türetken, P.S.; Demircan Akyasan, M.D.; Balcioglu, E.; Gönülal, O.; Tosun, D.D.; Ozturk, B. (2026). Seasonal contrast among bacterial, trophic, and biotic indicators in a multi-use coastal protected area. Aquat. Sci. 88(3): 86. https://dx.doi.org/10.1007/s00027-026-01324-0
In: Aquatic Sciences. Birkhäuser/Springer: Basel etc.. ISSN 1015-1621; e-ISSN 1420-9055, more
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| Author keywords |
Bacterial water quality · Salmonella · Fecal indicator bacteria · Trophic status (TRIX) · Biotic indices · Multi-use SEPA · Coastal management |
| Authors | | Top |
- Çiftçi Türetken, P.S.
- Demircan Akyasan, M.D.
- Balcioglu, E.
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- Gönülal, O.
- Tosun, D.D.
- Ozturk, B.
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| Abstract |
Monitoring programs in coastal ecosystems commonly combine microbial, trophic, and biotic indicators under the assumption that they provide a consistent picture of environmental status. Yet these indicators reflect processes operating at different temporal scales and may therefore respond differently to human pressures. In this study, we evaluated the responses of bacterial, trophic, and benthic assessment tools in a multi-use coastal protected area in the Eastern Aegean Sea (Karaburun–Ildır Special Environmental Protection Area (SEPA), Türkiye), where tourism and aquaculture coexist. Surface and bottom waters, together with benthic sediments, were sampled seasonally (May and September, 2022–2023) at stations representing aquaculture, tourism, and reference conditions. Bacterial indicators (fecal coliforms and intestinal enterococci) showed significant seasonal and activity-related variation (p < 0.001), reflecting periods of intensified human use. The detection of Salmonella increased during peak activity, pointing to episodic sanitary risks that were not captured by trophic or benthic metrics. By contrast, trophic index (TRIX) values were mainly shaped by seasonal dynamics and did not differ significantly among activity types. Similarly, benthic indices (BEnthic IndeX [BENTIX], MEDiterranean COastal Classifier [MEDOCC], Turkish Biotic Index [TUBI], Shannon diversity) remained relatively stable across space and time. These results indicate a divergence in seasonal responses between rapidly responding microbial indicators and more stable trophic and benthic assessments. The divergence does not imply methodological inconsistency; rather, it reflects the different ecological time scales represented by each indicator group. Our findings highlight the need for monitoring approaches that integrate short-term sanitary signals with longer-term ecological assessments in multi-use coastal systems. |
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