About This Project
Seagrass viability assessments rely on light attenuation alone, assuming 15% subsurface irradiance ensures survival. This threshold ignores epiphytic biofouling, which can block up to 60% of photosynthetic light. We will combine optical light profiling with 18S eDNA metabarcoding in three estuaries (Santander Bay, Urdaibai, Villaviciosa) to characterise and quantify epiphytic bio-load and set an effective light threshold, reducing false alarms and improving habitat protection.
Ask the Scientists
Join The DiscussionWhat is the context of this research?
Under the EU Water Framework Directive (WFD), estuarine ecological status assessments evaluate the viability of seagrass meadows (Zostera noltii and Zostera marina) using a single physical indicator: the water-column light attenuation (ref. 1-9). This framework assumes that photosynthetically active radiation (PAR) depends exclusively on water transparency, omitting the optical attenuation caused by the leaf epiphytic biofouling (micro-algae, diatoms, and encrusting organisms), which can block up to 60% of PAR from reaching chloroplasts (ref. 10-12).
This physical-biological disconnect creates severe predictive failures: unflagged light starvation in clear, nutrient-loaded estuaries, and false alarms in naturally turbid zones. This project couples underwater optical radiometry with 18S rRNA eDNA metabarcoding to establish an effective light attenuation threshold (K_deff), transforming static management models into high-precision ecological forecasting tools.
What is the significance of this project?
Estuarine Zostera meadows are vital blue carbon ecosystems and nursery habitats, but current monitoring is flawed because it treats light availability as a purely physical property of the water column (ref. 13,14). This 10-month proof-of-concept explores how the taxonomic composition of leaf-surface epiphytes quantitatively alters the photon flux reaching chloroplasts. By combining epiphyte eDNA concentrations and taxonomic relative abundances with paired optical light readings, the generated dataset will be mathematically integrated using optical absorption weights to formulate an Epiphytic Bio-Load Index (EBLI). The resulting preliminary conversion factors will offer a practical starting point for upgrading standard light attenuation models. This open-access resource will give regional water managers an open-access data package and a tested workflow to explore how molecular data can refine future estuarine monitoring strategies.
What are the goals of the project?
This project aims to establish a bio-calibrated light monitoring framework for estuarine seagrasses (Zostera noltii and Zostera marina) across Northern Spain by improving static water-quality thresholds. Its primary goals are to: (1) execute paired optical profiling and 18S rRNA eDNA metabarcoding across Santander Bay, Urdaibai, and Villaviciosa estuaries to construct an Epiphytic Bio-Load Index (EBLI); (2) integrate EBLI into Beer-Lambert equations to reformulate the physical light limit (K_d) into an effective light attenuation threshold (K_deff) reflecting true PAR reaching chloroplasts; (3) validate K_deff against historical regional monitoring datasets (such as URA) to reduce false alarms in predicting seagrass decline; and (4) deliver an open-access, FAIR-compliant workflow to deploy these updated thresholds within EU Water Framework Directive reporting cycles.
Budget
Field Gear & Consumables ($1,550): Digital PAR meter to measure the quantity of light photons in the 400 to 700 nm, Inflatable kayak to get to the sampling sites, filters, gloves, sterile tubes, zip bags, sample conservation reagents, DNA extraction reagents, spectrophotometric reagents.
NGS Sequencing ($3,500): Covers 18S rRNA V4 region primers, library preparation, and Illumina MiSeq 2x300 bp sequencing for 70 targeted field samples and controls.
Travel & Logistics ($500): Covers road travel, fuel, and car rental for 6-8 sampling trips across Santander Bay (Cantabria), Urdaibai (Basque Country), and Villaviciosa (Asturias).
Open Access ($2,500): Covers open access publication fees.
Data analysis ($1,200): Covers computational power
Platform & Processing Fees ($800): Covers Experiment's standard 8% platform fee ($800).
Endorsed by
Project Timeline
Project success relies on aligning with Zostera seasonal growth: early sensor calibration is critical to capture baseline spring conditions before peak summer epiphyte blooms. Field sampling carries the highest risk due to weather dependencies on canopy development, which we mitigate using alternative pre-identified stations. Bioinformatic processing and validation against URA data form the core experiment. Results will be shared with backers via Lab Notes and Instagram (@la_biodivertida).
Nov 11, 2026
Project Launched
Feb 28, 2027
Field gear set up and sensor calibration
Apr 30, 2027
Spring Campaign Completion
Jun 30, 2027
Summer Campaign Completion
Jul 31, 2027
eDNA extractions finalized
Meet the Team
Affiliates
Konstantina Mitsi, PhD
Dr. Konstantina Mitsi is a molecular ecologist at the HADES group of the Santander Oceanographic Centre (IEO-CSIC). Her current research focuses on marine biodiversity monitoring in rocky infralittoral habitats under Spain’s Marine Strategies programme, with particular interest to seabed integrity. Previously, she studied the evolutionary origins of animal diversity, documented novel and undescribed species using molecular approaches, and investigated host–microbiota evolutionary dynamics. She has extensive experience optimising, adapting, and applying standard molecular protocols to non-model organisms. Her analytical toolkit spans phylogenomics, comparative genomics, metabarcoding, and metagenomics.
Lab Notes
Nothing posted yet.
Additional Information
References
1. European Commission (2000). Directive 2000/60/EC of the European Parliament and of the Council establishing a framework for Community action in the field of water policy. Official Journal of the European Communities, L 327, 1–72.
2. European Commission (2009). Common Implementation Strategy for the Water Framework Directive (2000/60/EC): Guidance Document No. 23 on Eutrophication Assessment in the Context of European Water Policies. Technical Report - 2009 - 030.
3. Basque Water Agency (URA) & AZTI (2021). Protocolos de redes de seguimiento del estado ecológico de las masas de agua de transición y costeras de la Comunidad Autónoma del País Vasco. Vitoria-Gasteiz: Uragentzia.
4. Borja, Á., et al. (2006). The European Water Framework Directive and the Basque Country monitoring network. Marine Pollution Bulletin, 53(1–4), 122–131.
5. Duarte, C. M. (1991). Seagrass depth limits. Aquatic Botany, 40(4), 363–377.
6. Ministerio para la Transición Ecológica y el Reto Demográfico (MITECO) (2021). Estrategias Marinas de España: Documento marco y evaluación del estado del medio marino en la Demarcación Noratlántica. Madrid: MITECO.
7. Dennison, W. C., et al. (1993). Assessing water quality with submersed aquatic vegetation: Habitat requirements as barometers of Chesapeake Bay health. BioScience, 43(2), 86–94.
8. Ralph, P. J., et al. (2007). Impact of light limitation on seagrasses. Journal of Experimental Marine Biology and Ecology, 350(1-2), 176–193.
9. Auby, I., et al. (2002). Long-term changes in seagrass beds (Zostera noltii and Zostera marina) in Arcachon Bay and adjacent estuaries (Bay of Biscay). Ifremer Open Archive.
10. Kemp, W. M., et al. (2004). Habitat requirements for submerged aquatic vegetation in Chesapeake Bay: Water quality, light attenuation, and epiphytes. Estuaries, 27(3), 363–377.
11. Brush, M. J., & Nixon, S. W. (2002). Direct measurement of light attenuation by epiphytes on eelgrass Zostera marina. Marine Ecology Progress Series, 238, 73–79.
12. Costa, M. M., et al. (2015). Epiphytes induce stress in Posidonia oceanica. Frontiers in Marine Science, 2, 111.
13. Costanza, R., et al. (1997). The value of the world's ecosystem services and natural capital. Nature, 387, 253–260.
14. Short, F. T., et al. (2011). Extinction risk assessment for the world's seagrass species. Biological Conservation, 144(7), 1961–1971.
15. Borrell, Y. J., et al. (2018). Metabarcoding and post-sampling strategies to discover non-indigenous species: A case study in the estuaries of the central south Bay of Biscay. Journal for Nature Conservation, 42, 67–74.
16. Thomsen, P. F., & Willerslev, E. (2015). Environmental DNA – An emerging tool in conservation for monitoring past and present biodiversity. Biological Conservation, 183, 4–18.
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