Water Quality Benefits and Tolerances of Shellfish Reef Restoration: Unlocking a Natural Business Model for Waste-Water Remediation and re-use of Shell Waste
Background: The Dornoch Firth is Scotland’s least industrial Firth and a Marine Protected Area. Native oysters (Ostrea edulis) were fished-out in Europe in the 1800’s and are now a rare “missing” shellfish habitat of high nature conservation importance. Blue mussel (Mytilus edulis) populations may also have recently declined. The case for bivalve shellfish restoration has never been greater1 and the restoration of shellfish habitats uses waste shell material as ‘clutch’ to promote settlement.
Heriot Watt University, the Glenmorangie Company and the Marine Conservation Society have developed an innovative partnership called the Dornoch Environmental Enhancement Project (DEEP: 2): a project that seeks to restore oysters to the Dornoch Firth, Glenmorangie’s brand-home, for the first time in over 100 years. The Glenmorangie Company has invested in an Anaerobic Digestion system that will reduce its organic discharge by removing 95% of the Chemical Oxygen Demand. Allied to this, the DEEP restoration of native oysters will remove the final 5% because shellfish are excellent bio-filters: ingesting organic materials and nutrients whilst enhancing water quality and biodiversity. This business case needs a rigorous foundation because unlocking predictable outcomes will pave the way to the re-use of waste shell in restoration projects; reduced treatment costs / value creation and also bolster the populations of commercially valuable species.
DEEP has shown that oysters were historically present in the Dornoch Firth and modern-day conditions for restoration are suitable1. Test oysters show 86% survival and growth (Sanderson unpubl. data). In the next 2 years DEEP will begin to focusing on optimising oyster reef creation using waste shell and varying oyster stocking. One of the strategic aims of DEEP R&D is to unlock investment potential across Europe and the world to generate environmental engineering and oyster supply-chain jobs linked to circular economy and knowledge economy that will be ‘winning for Scotland’.
Aim: To quantify the extent to which native oyster and blue mussel restoration contributes to waste water management and the stresses that might constrain this.
Most ‘filter-feeders’ are not simple ‘on-off’ organisms and consume either more detritus or more phytoplankton whilst reacting avidly to preferred food and changes in available resources. The role shellfish play in water quality improvement, and modelling this, are the basis of an emerging market for restoration projects.
Objectives: 1. To establish what Ostrea edulis and Mytilus edulis can eat and therefore the potential they have for assimilating waste material. Examining potential niche partitioning. 2. To evaluate the role waste water exposure has on shellfish health. Will inform the trade-off between food from discharges (1 above) and stress induced mortality (2,3) in the siting of restoration projects. 3. To evaluate how much carbon and nutrients oysters and blue mussels consume. This will use up-take and depositional experiments in the laboratory and field (4) to quantify the consumption of oysters and mussels in response to different scenarios. 4. To establish what difference shellfish restoration will make to water quality monitoring metrics. This will use models developed based on ‘1’ and ‘2’ above to predict outcomes relevant to government. 5. To determine the unit values-added and recovered in shellfish restoration, as derived from: A. shellfish tissue growth and sale, B. Waste shell re-use in habitat creation, C. resilience of coastal systems and nutrient management off-set.
The Hydro Nation Scholars Programme is an open competition for PhD Scholars to undertake approved projects, hosted within Scottish Universities and Research Institutes.
Full funding is available from the Scottish Government (to host institutions via the Scottish Funding Council). The funding available will be in line with the UKRI doctoral stipend levels and indicative fees.
Applicants should have a first-class honours degree in a relevant subject or a 2.1 honours degree plus Masters (or equivalent). Shortlisted candidates will be interviewed in February 2019. A more detailed plan of the studentship is available to candidates upon application.
1. Fariñas-Franco …& Sanderson (2018). Missing native oyster (Ostrea edulis L.) beds in a European MPA…Biological Conservation. 2018;221:293-311 (https://www.sciencedirect.com/science/article/pii/S0006320717308030).
2. Dornoch Environmental Enhancement Project (http://www.theglenmorangiecompany.com/about-us/deep/)
3. Coughlan, Hartl, et al. (2002). Detecting genotoxicity ..of Manila clam ..to polluted estuarine sediments. Mar. Poll. Bull.;44(12):1359-65.
4. Kent FE, Last KS, Harries DB, Sanderson WG (2017). In situ biodeposition measurements on a Modiolus modiolus (horse mussel) reef provide insights into ecosystem services. Estuarine, Coastal and Shelf Science. 2017;184:151-7.
Al‐Shaeri ….& Hartl. Potentiating toxicological interaction … carbon nanotubes ... Env. tox. and chemistry. 2013;32(12):2701-10.
Beck et al., (2011), Oyster reefs at risk and recommendations for conservation, restoration and management. BioSci., 61(2): 107-116.
Kent ….. & Sanderson (2017). Commercially important species associated with horse mussel … reefs: ……. Mar. Poll. Bull.
Martínez-Córdova et al. Studies on the bioremediation …of the adult black clam, ... Rev. biol. marina y oceanografía. 2011;46(1):105-13.
Rees, Sanderson et al. (2008). Small-scale variation … Crevice, sediment infauna and epifauna... J. Mar. Biol. Ass. UK, 88(1), 151-156.
Rodriguez-Perez ....& Sanderson WG. (2019). Conservation and restoration of a keystone species: Understanding the settlement preferences of the European oyster (Ostrea edulis). Marine Pollution Bulletin;138:312-21 (https://www.sciencedirect.com/science/article/pii/S0025326X18308099).
Wang. Managing shrimp pond water to reduce discharge problems. Aquacultural engineering. 1990;9(1):61-73.
Zu Ermgassen et al. (2012) Historical ecology with real numbers….. Proc. R. Soc. B., 288: 1803, 1-8.