MERCES WEBINAR, on Moving to Industrial-Scale Coral Habitat Restoration-6 March 2020
The fifth and final MERCES webinar was held on Friday 6 March 2020, between 15:00-16:00 CET. The webinar was hosted by GRID-Arendal using ZOOM. The webinar featured new methods for the restoration of coral habitats in both tropical and temperate seas, including coastal, continental shelf and deep-water coral communities. A major unknown at the start of the MERCES project was whether restoration measures could be undertaken at a meaningful scale to make a significant difference to the sharp declines in the distributions of many different ecosystems. This webinar addressed some of the methods that might be used in restoration of coral habitats and their applicability at larger scales.
The webinar was introduced by David Billett highlighting 1) the many MERCES deliverables on marine ecosystem restoration being finalised in the final months of the MERCES project and 2) how the webinar series was intended to bring together businesses, policy makers, decision takers and scientists with an interest in marine ecosystem restoration.
The core of the webinar included two talks of 20 minutes each, followed by a discussion with the audience. The speakers were:
- Jesper Elzinga, Van Oord Dredging and Marine Contractors [Van Oord] on ‘The Recovery of Reefs Using Industrial Techniques for Slick Harvesting and Release (RECRUIT)’
- Joaquim Garrabou, Spanish Research Council (CSIC), Barcelona on ‘Lessons Learned from Coral Restoration in Shallow and Deep Environments’
Both speakers referred to the multidisciplinary and trans-national teams engaged in the work they described. Joaquim Garrabou included details of research by other MERCES partners, most notably from Dr Cristina Linares (University of Barcelona) and Dr Marina Carreiro Silva (IMAR, University of the Azores).
Jesper Elzinga explained how Van Oord is integrating innovative environmental management approaches into the company’s core business interests in dredging, reclamation, offshore wind parks, pipelines and subsea rock installations. Through the company’s ‘Marine Ingenuity’ programme, Van Oord has teamed up with the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia, and the University of Delft, to address methods by which coral abundance on the Great Barrier Reef might be boosted at very large scales. The project, called RECRUIT (RECovery of Reefs Using Industrial Techniques), aimed to scale up tropical coral rehabilitation efforts by 2 to 3 orders of magnitude from current practices.
The approach was to use a workboat with a large aft deck equipped with 12 large-volume tanks (4500 L). The boat was used to sample slicks of coral eggs from multiple species spawned during mass fertilisation events. The slicks were located through hydrodynamic modelling and direct airborne observations. A portion of the slicks seen were concentrated within a boom usually used as part of dredging activities. Having pumped the eggs and embryos on board, the embryos and subsequent developing larvae were incubated through to settling competency. The RECRUIT project aimed to determine whether 1) the slicks could be located, concentrated and pumped onto the ship, and 2) the embryos could be held in tanks on board the ship until the larvae developed to a stage where they could settle onto the seabed. The project was successful in all of these aspects. Several papers have been published from the work in the journals Restoration Ecology and Frontiers in Marine Science.
The full scale application of the method would only sample < 1% of the reproductive slicks and therefore have a negligible effect on the ability of the natural corals to maintain their populations in the region, but at the same time very high concentrations of competent larvae could be incubated and maintained for seeding back into degraded and destroyed areas than might occur through natural processes. Further research is planned to study the efficacy of the method in repopulating corals over large areas affected by coral bleaching and other impacts.
A major benefit of the approach is that a wide variety of coral species which broadcast spawn can be reintroduced to degraded environments at the same time. Different methods, such as transplantation, would have to be devised for brooding species. The method offers up the possibility of translocating larvae from healthy reefs to damaged reefs, perhaps over hundreds of kilometres using the mother vessel, and for facilitating ecological connectivity between populations that may have become isolated through coral bleaching. The method also offers a way in which heat-tolerant coral strains might be selected on board the vessel and translocated to new sites where environmental conditions have changed. It may also be possible to introduce heat-tolerant Symbiodiniumcommensals to the corals if this is considered to be beneficial.
Joaquim Garrabou focused on how temperate coastal, continental shelf and deep-water corals differed from the tropical corals featured in Jesper Elzinga’s presentation. The temperate corals live in low-light environments, or depths where no light penetrates, and so do not harbour photosynthetic symbionts. They generally have much slower life-history dynamics and characteristics than shallow tropical coral species. However, the temperate corals play an equally important ecological role as habitat-forming species. The temperate corals are also being impacted by marine heat waves, depending on the depths at which they occur, and direct impacts from fishing and other industries. These species have lower levels of reproductive output, slower growth rates and may live for hundreds of years, which makes them particularly sensitive to repeated impacts.
The temperate species do not spawn in mass events and so different methods will be required to restore these coral habitats. The MERCES project focused on transplanting corals and coral fragments 1) directly onto the seabed using scuba divers and 2) by attaching the coral clusters to artificial structures which were then placed on the seabed.
In the Azores archipelago scientists are working with local fishermen to take coral fragments captured as bycatch in fishing operations, and grow the fragments into larger coral clusters in the laboratory to reach a size that can then be attached to an artificial reef and lowered back to the seabed in deep waters (c. 700m). Survival in the laboratory aquaria was good. Survival of the transplanted corals on the artificial reefs on the seabed, though, varied between 15 and 100% after 2 years.
A similar method was adopted by CSIC and the University of Barcelona in the Mediterranean Sea continental shelf off the Catalan coast. Scientists were able to work with local fishermen to obtain coral fragments collected during fishing, for growing in the lab and then for reintroduction into areas with Marine Protected Areas, so that theoretically they would not be fished again. The experiment had an 87.5% success rate after 1 year. A second method was also employed for larger gorgonian fragments which were attached to rocks of a suitable size and weight and deployed over the side of the vessel, sinking to the seabed in the manner of a shuttlecock in the sport of Badminton. This method allows a wide area of sedimented seabed to be covered with recruits.
In water depths within reach of scuba divers transplantation methods have been applied also in a cost effective manner by engaging local diving centres. Fragments of gorgonians were attached to the seabed using epoxy resin. During a dive lasting 40 minutes, 14 people attached more than 400 gorgonian fragments to rocky surfaces on the seabed. However, survival at the time of the experiment was only 20% after 2 years owing to the impact of two marine heatwaves which were experienced in the study area during 2017 and 2018, leading to mass mortalities.
CSIC has also been using genetic methods to identify heat resistant populations of corals across the western Mediterranean Basin and on the Portuguese coast in the Atlantic Ocean in proximity to the Straits of Gibraltar. Heat resistant populations were detected off Italy and Portugal.
The work carried out in the MERCES Project indicates that transplantation is a successful technique for certain species when used at local scales and in environments where the original drivers of environmental degradation have been controlled or eliminated. Transplantation can also ensure that coral clusters can be sited at distances where reproductive processes between clusters can still occur. While the use of scuba divers and artificial reefs makes these methods difficult to use at a large scale they are very important in engaging with influential stakeholders and educating local communities in the benefits of ecosystem restoration. While transplantation may be used to restore corals in Marine Protected Areas (MPAs), the success of the method depends on how well the MPAs ae enforced by local authorities. The use of coral fragments, and perhaps many fragments from the original coral captured, could lead to a reduction in genetic diversity and further research is required on this aspect.
Prior to the webinar a large number of different organisations were contacted with details on the webinar and information on the wider MERCES project outputs. The contact list included MERCES Business Club members, focal points for the United Nations Environment Programme (UNEP), the EurOceans Network, EU Government contacts, coral interest groups on Twitter and Facebook, mailing lists of coral researchers and sports divers and the MERCES partnership, all with requests for them to publicise the webinar through their national networks.
The webinar was attended by 78 participants. It is possible participation was higher in places where several attendees shared one connection. Contact was made from universities in Colombia and Mexico for the webinar to be used as part of their courses in Marine Biology and it is likely this webinar, and previous ones, have been used by a wide variety of educational establishments worldwide. A total of 135 people registered for the webinar. All registrants were contacted following the webinar to inform them of where the archived webinar can be accessed.
European registrants for the webinar came from Belgium, Croatia, Cyprus, Denmark, France, Greece, Italy, Malta, Netherlands, Portugal, Spain, Sweden, Switzerland and UK. Additional registrants came from Argentina, Australia, Brazil, Colombia, Jamaica, Madagascar, Mexico, Sri Lanka and the USA.
A good discussion was developed using a wide variety of numerous questions posed by the attendees.
Of the registrants, 40 were representatives from companies, including environmental SME consultancies, coastal engineering, offshore oil and gas, dredging and financial interests. Seventeen of these came from non-European companies, including environmental consultancies in Colombia, Brazil, Argentina and Jamaica. A large number of registrants (50) were from educational establishments. Only 8 registrants came from Government Departments and organisations advising government policy. Five members of the European Commission registered. Fifteen registrants came from NGOs.
The webinar was archived and can be found in the following link: