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Remment ter Hofstede

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4 records found

The coral engine

The way for local communities to sustainably produce corals for Reef Rehabilitation at a large scale

Conference paper - Remment ter Hofstede, Jesper Elzinga, H. Carr, M van Koningsveld

Traditionally, marine infrastructure development is regarded to have a negative impact on the ecosystem in or near which it occurs. As a consequence, a whole industry has been treated as a threat and the ingenuity of companies in this industry was forced to focus on minimizing potential negative impacts. Recent trends are to also consider potential positive spin-offs, by including nature-based components in the designs. In this context, Dutch dredging and marine contractor, Van Oord, launched its Coral Rehabilitation Initiative in 2010. A mobile laboratory, named ReefGuard, was developed, to be operated anywhere in the world for sexual reproduction and rearing corals at a large scale (Van Koningsveld et ah, 2017). ReefGuard is used to initiate 'Coral Engines': large scale nurseries with corals obtained through sexual reproduction as well as from fragmentation. These Coral Engines guarantee the long term and large-scale supply of genetically diverse corals for reef creation and rehabilitation. Having coral 'in stock' furthermore allows reefs to be repaired quickly following harmful events such as hurricanes. The involvement of local stakeholders in its setup and operation foresees in sustainable opportunities for research, education and awareness, and local employment. Since 2010 ReefGuard has been applied in five large scale field applications (Australia 2014, 2015, The Bahamas 2015, 2016, 2017) (Van Koningsveld et al, 2017; Robijns et al, 2018; Schutter et al, 2018) producing thousands of sexual recruits consistently. In 2017 a first Coral Engine was delivered with several tens of thousands newly settled coral recruits, and hundreds of one year old recruits and fragments. This paper explains the concept of the Coral Engine in more detail and shares perspectives for future implementation along marine construction projects across the world. Marine infrastructure projects thus become opportunities for coral reef rehabilitation with essential financial and logistical capacity on site, and often also a legislative requirement for compensation of harmful environmental impact.@en

Testing Industrial-Scale Coral Restoration Techniques

Harvesting and Culturing Wild Coral-Spawn Slicks

Journal article - Christopher Doropoulos, F.J. Vons, F.J. Vons, Jesper Elzinga, Remment ter Hofstede, Kinam Salee, M. van Koningsveld, M. van Koningsveld, Russell C. Babcock

Accelerating the recovery of marine coastal ecosystems is a global challenge that has been attempted on many systems around the world. Restoration efforts have shown varying levels of success at localized-scales, but developing techniques for large-scale application are still in ...

Optimizing industrial‐scale coral reef restoration

Comparing harvesting wild coral spawn slicks and transplanting gravid adult colonies

Journal article - Christopher Doropoulos, Jesper Elzinga, Remment ter Hofstede, M. van Koningsveld, M. van Koningsveld, Russell C. Babcock

Accelerating coral reef restoration is a global challenge that has been attempted around the world. Previous attempts show varying levels of success at localized‐scales, but comparisons of cost and benefits to evaluate large‐scale reef restoration approaches are lacking. Here, we ...

RECRUIT: Recovery of reefs using industrial techniques for coral spawn slick harvesting and release

Abstract - Christopher Doropoulos, Jesper Elzinga, Remment ter Hofstede, M. van Koningsveld, M. van Koningsveld, Russell C. Babcock

Accelerating the restoration and recovery of coral populations is a global challenge that has been attempted on many coral reefs around the world. Previous approaches have shown varying levels of success at localised scales, but the comparison of cost and benefits to develop large scale restoration concepts has so far been lacking. Here, we compare two large scale restoration approaches: the harvesting, development, and release of wild coral spawn slicks and the transplantation of fully fecund adult coral colonies. Comparisons incorporate the best available information on the demographic rates to estimate coral population growth beginning at settlement to maturity five years following deployment. Cost effectiveness is also considered in a coarse manner. This contribution elaborates on the apparent optimal approach for large scale application in the current context of the Great Barrier Reef: coral spawn slick harvesting and release. The coral spawn slick harvesting and release approach 27 appears optimal because it achieves large scale restoration of coral communities with low impact technology and at lower cost per colony. Overall, it has the potential to (1) transport billions of thermally tolerant larvae up to 1000s of km’s that (2) are relevant to coral restoration efforts at the geographical scales of the Great Barrier Reef while (3) benefitting from the use of technology that likely has extremely low impact on wild populations and (4) retaining the natural genetic and species diversity needed to enhance the resilience of restored coral communities. The proposed technology and application of using industrial techniques for large scale coral spawn slick harvesting and release is presented. Our contribution also provides valuable insights into critical elements of each concept. We highlight information gaps and the relative sensitivities of different approaches to parameter uncertainties such as levels of larval retention, which could result in different assessments of cost effectiveness. @en

Contributed

2 records found

Oyster broodstock structure

On the design of oyster broodstock structures for nature enhancement in offshore wind farms

Master thesis - V.A. van Rie, M. van Koningsveld, P.M.J. Herman, P. Taneja, Remment ter Hofstede, T. Raaijmakers

Over the recent years, the Dutch Continental Shelf has seen the erection of various wind farms in an effort to counter climate change by replacing fossil-based power plants. Since the majority of these sites use scour protections which have a substantial impact on the surroundings, the Dutch government increasingly stimulates and requires ecological enhancement of such structures in order to restore the natural habitat and maintain the marine ecosystem of the North Sea. Oyster enhancement has been one of the methods used for the ecological enhancement of offshore wind farm scour protections. However, studies report that a successful structure for the harbouring of an oyster population is yet to be developed. Existing structures were found to be unstable or unable to provide a suitable habitat for the oysters (Bouma, Belze, et al., 2013; Stokes et al., 2012). The study at hand aims to develop a successful design for oyster broodstock structures for nature enhancement in offshore wind farms. It was conducted for Van Oord as part of project Ecoscour. To establish design criteria for the oyster broodstock structures, oyster habitats and the Borssele V site were analysed and a brainstorm session with partners from project Ecoscour was set up. The final criteria concerned: ecology; structural integrity; commissioning & construction; and monitoring. The design criteria were used to develop several viable structure designs. In order to rapidly assess the strength and stability of potential designs, a Python-based open source tool was built named Econstruct. With this tool, geometries can easily be evaluated under various influences, accounting for the effect of marine fouling. This could be used for quick investigations of loads, stability and structural integrity. The Econstruct tool was validated and analysed for sensitivity for the input parameters, of which the input radius and current velocity had the highest influence on stability. Using the environmental input parameters that hold for the Borssele V wind farm, a terraced design was proposed. After consultation with the manufacturer of the structure, D & M engineers, this proposal was altered to account for manufacturing limitations. The definitive design was evaluated using the Econstruct tool and found to be stable. It was then manufactured, and ultimately placed in Borssele V in October 2020. Several recommendations are made for future research and the design of ecological enhancement structures for offshore wind farms. Most importantly, the Econstruct open source tool can be used in the future for the design of structures for other ecological enhancement projects such as coral reef restorations.

Nature-enhancing design of scour protection for monopiles in the North Sea

Master thesis - O.D. Groen, M. van Koningsveld, Tom Wilms, Bas Hofland, G.M. Smith, Remment ter Hofstede

A combination of the growth of the offshore wind energy sector and the decline in both species richness and species abundance in the North Sea has inspired the goal to use the scour protection in wind farms as a means to enhance marine life. Present research has focused on genera ...