WWF's Conservation Innovation Awards

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Restoring the oceans abundance using seawater electrolysis- a marine conservation initiative

Seawater electrolysis or mineral accretion, utilises two things well known to many kiwis- no.8 wire and solar power! This simple technology truly aligns with the kiwi 'no.8 wire' mindset in its resourceful and inventive approach to restoring underwater ecosystems. It has proven very successful for restoration of coral reefs, shellfish beds and sea grass meadows in tropical climes- but how could it help our unique inshore areas here in NZ? It could quickly re-establish damaged underwater habitats and attract a wide range of calcifying organisms, crustaceans and fish. This would provide habitat, food sources and safety from predators to many organisms.

So how is all this possible? Well, lets get into the details:

Solar power is collected at the waters surface via a buoy fitted with a solar panel. This provides a very, very weak electrical current (~1.37V) that is passed through a steel wire structure located on the seafloor below. This causes a reaction with seawater that creates calcium carbonate to form (accrete) on the structure- the building block of the ocean in many respects. Many people know that coral is made from calcium carbonate but there are many other organisms that require it also, most notably shellfish (clams, mussels, oysters, urchins, some sea snails) and crustaceans (crabs, crayfish), but also coralline algae (an important benthic habitat for our paua), some seaweeds, many byrozoans (small animals with calcium carbonate skeletons) even through to microscopic phytoplankton.

Another major benefit of the reaction is that is raises the pH around the structure- this could prove especially helpful as a mitigation measure against ocean acidification by aiding in the conversion of CO2 into CaCO3. Cold water absorbs more CO2 from the atmosphere so providing effective resilience would be a game changer for the ocean. Seawater electrolysis has shown remarkable effects in aiding in the resilience of habitats to adverse conditions- i.e., tropical corals on these structures have not suffered from bleaching while surrounding areas have, organisms have also thrived on the structures in heavily polluted waterways, again, when everything else cannot. Ecosystems such as kelp forests naturally provide the higher pH levels that calcifying organisms require but these forests are diminishing- and fast.

So, finally, whats the idea?

My idea for NZ is to add to our marine conservation toolkit mostly consisting of marine reserves at present. While restricting fishing from certain areas provides a relatively passive form of conservation, solar powered structures could act as an 'active' attractant for marine species to marine reserves, enabling the formation of nursery habitats to many commercial and non-commercial fisheries. Artistic formations and the abundance of marine life has the added benefit of being a potential tourism draw card!

I want to trial this technology in a marine reserve setting to see if this is something we should be implementing on a wider scale throughout NZ. The success of the idea would be measured by abundance measures i.e. species abundance (no. of species/m2) and the Shannon and Simpson diversity indices. These measures would be compared against the abundance of an area without the technology implemented. With our unique marine flora and fauna there is no knowing how successful seawater electrolysis could be here, but my opinion is that we don't know until we try it!

What conservation problem are you trying to solve?

In a nutshell, if we do not provide adequate habitat for species to thrive in marine reserves the process of regeneration will take an extended period of time- if it is possible to regenerate at all. With this technology there is the opportunity to provide a natural looking benthic structure- adding hetergeneity back into the landscape. 

Marine reserves may not address the loss of habitat via previously destructive fishing techniques such as trawling. This results in a barren landscape, without the habitat so desperately needed for sea life to return to the area and thrive. This technology has the potential of speeding up the recovery of damaged marine ecosystems, enhancing the effectiveness of the protection provided by marine reserves in NZ. When it comes to marine conservation in NZ, we need to keep searching for ways to improve the status quo of marine conservation and not let it be an issue of 'out of sight, out of mind'.

How are you going to solve this conservation problem?

A steel wire structure that provides the largest amount of habitat options for NZ marine life will be designed (areas for sea grass/ mussel/ oyster beds, nooks and crannies for crayfish etc). This essentially provides 'instant habitat' for marine species. To test the efficacy of this technology in NZ marine reserves, one structure would be placed within a marine reserve and one in unprotected water to act as a control. Solar paneled buoys that sit on the ocean surface provide the weak electrical current to the wire structure on the seafloor- (note this current is so weak that even if a diver/swimmer touched it they wouldn't notice). It is important to note that no detrimental impacts have been observed by marine species that rely on electroreception (i.e., sharks and rays). Abundance measurements would be taken periodically and compared between the two sites to test its success, this would ideally be done over a few years (~3-5).

What makes your idea new and unique?

I love this idea in its combination of the kiwi 'can-do' attitude utilising no.8 wire and solar power. It is beautiful in its simplicity as a solution to helping restore abundance to our much depleted ocean. It is unique in that it has not been done in NZ before and could potentially be so beneficial. It could tick so many boxes in terms of enhancing conservation, creating nurseries for recreational and commercial fisheries and aiding in tourism, all of these aspects crucial to New Zealanders and the economy. Innovation will also be in the design of the structure. I aim to develop a structure that best replicates a local heterogenous benthic environment, derived from local and traditional knowledge on what once existed in the study area. This design will provide a range of conditions in which species can aggregate, shelter, source food, juveniles can settle etc.

Who will use your idea, and how will they benefit?

The results from this trial will be published in an open access scientific journal- this means that absolutely anyone can access the findings. This technology would ideally be used in co-management arrangements between DOC and local communities/ iwi. With local engagement, the use of citizen science could aid the strengthening of connections between communities living close to marine reserves. Additional benefits to local communities are in the form of diving tourism ventures, flourishing oceans and spillover effects leading to better fishing outside of the reserve.

This technology could additionally provide a much needed monitoring tool of abundance nationwide in marine reserves- monitoring that could aid in identifying areas that are flourishing, areas that need more help and- of course, it could aid in securing more funding in providing results and reports easily presentable to interested funding bodies.


What tasks or activities do you need investment for? How would you spend a $25,000 grant?

This incredible grant would provide the much needed finances to trial the technology in NZ and publish the results. Costs are detailed as follows:

  • Dive workshop in Indonesia-this covers the design, manufacture, installation and maintenance of seawater electrolysis structures ~$5,000
  • 2 x Solar buoys- the largest cost to the project. Additional monitoring devices would be added to the buoy within the budget constraints i.e., remote sensing camera, monitors for temperature, pressure, pH etc. Off preliminary research into solar buoys prices I budget these at around $10,000 each.
  • A wire structure would be welded together at a relatively low cost.
  • Lastly, finances are needed for the man hours required in installation, regular visits and publishing the results.

Are you a New Zealand citizen or resident?


I have read and agree to the Crowdicity Terms of Use, the Conservation Innovation Awards 2017 Supplemental Terms and Conditions, and the Crowdicity Privacy Policy


List five other ideas posted in the challenge that excite you. Why?

1. Subscribe to a marine reserve- I see the ability of this idea to work in tandem with mine in providing updates to people that are interested on the progress of their favourite marine reserve. Any initiative that helps strengthen our relationship with the ocean gets my tick of approval.

2. The baleen filter- another marine initiative and a good one in that it is dealing with a major issue at the cause. Plastics in our oceans are of increasing concern to many people worldwide and the issue needs urgent action.

3. Compost and catch- this excites me as we all know how much decaying food attracts vermin, this technology is piggybacking the compost as an attractant (no expensive bait needed!) and dealing to pests particularly in urban environs.

4. Swimming with E-coli- real time monitoring on whether our waterways are safe to swim in is an absolute must. We shouldn't have to do this but it has reached the point where people need this information.

5. Thermal imaging- a great new tool to add to pest monitoring, bringing monitoring up to the current century in terms of technology.

How could you improve your idea?

The use of citizen science has been suggested in the comments and would be crucial to the success of this project. I have already received messages from individuals interested in helping out.

There is also a wealth of information available in the form of local ecological knowledge and traditional ecological knowledge on the shores of the chosen study site. This will help establish qualitative information on past abundances, what species were/are present, what changes have occured etc.

Involving local iwi in the project would be done from the outset and research would be done only with their permissions to do so.

edited on Oct 14, 2017 by Shannon Weaver

Tara Weaver Sep 26, 2017

Great idea!


Megan Somerville Sep 26, 2017

Hi. I am interested to see if you had identified potential places for this? And if so, how might iwi perspectives and understanding of the specific marine environment assist? Also wondering if you had considered how to involve the wider community as a citizen science approach?
this link below shows how aboriginal knowledges are supporting work on the Great Barrier Reef: http://www.abc.net.au/am/content/2008/s2451908.htm


Shannon Weaver Sep 26, 2017

Hi Megan thanks so much for your comments- in a perfect world for a good experimental set up I'd want ones on the east and west coasts of the North Island and South Island but this would be more of a first off trial run. Sites would have to be chosen with a few considerations e.g., length of time as a marine reserve, size, accessibility, approval, other inputs such as high boat or swimmer traffic, water depth to name a few that come to mind. My potential considerations at the moment are Goat Island (but I am concerned about the heavy commercial fishing right on the boundary), Whanganui-a-Hei, Te Wharawhara or Põhatu in the South Island. I think its good to be pretty open minded to sites at the moment as approval may largely dictate where it happens. I am super keen on involving the public in every aspect of the project from design input, to construction and installation to citizen science help with abundance monitoring. Iwi knowledge of the chosen site would be crucial to the project and my project (and conservation as a whole) assists in our ability to enact kaitiakitanga. I have previously done research involving traditional ecological knowledge as well as local ecological knowledge so understand well the value these perspectives hold.


Azura Lane Sep 27, 2017

You're amazing and so is this!


Rachel Morrison Sep 27, 2017

Hi I am a marine Science student in Tauranga and i am ery interested in this. I would like to get involved if i can? Thanks


Shannon Weaver Sep 27, 2017

Hi Rachel, yes that'd be great! I can keep you in the loop with progress but I am aiming to start on the project this coming summer. I'll find you on facebook


Stew Robertson Sep 27, 2017

Hi Shannon, could this technology be used on larger objects such as steel ship hulls acting as artificial reefs? I am working on a reef proposal at the moment, it would be interesting to chat..


Shannon Weaver Sep 30, 2017

Hi Stew, I have just read your proposal and it highlights another aspect of my research i'd need to factor in- an identical structure that has no power source to test the effect of structure alone. It would be great to talk I will email you so you have my details.


Becky Wilson Oct 2, 2017

The idea has been progressed to the next milestone


Leigh Nicholson Oct 3, 2017

Interesting concept!


Shannon Weaver Oct 4, 2017

Thanks Leigh, I have been looking into it for about two years now and am really looking forward to implementing it soon!


Shannon Weaver Oct 4, 2017

Kia ora, tēnā koutou for the incredible support for this idea. I want to expand on how the money will be used and what is next:

-The awards would provide some of the much needed capital to trial this innovation in NZ. As a scientist I would publish the results in a peer reviewed journal with full public access. I would provide presentations to local councils, public groups or other parties that would be interested in learning more and having the technology in their area.

-If the trial proves successful, my first step would be to create a charity, entirely not-for-profit to aid expanding the technology throughout marine reserves in NZ. I have already started looking into the registration process for a charity and have worked with multiple charities in the past in which I can go to for assistance. This is an initiative I want all New Zealanders to get behind and be a part of, by donating, volunteering, spreading the word and more. It is about enhancing our connection with our oceans and our marine reserves whilst providing the ability for abundance to return to our coastal areas.


Fiona Edwards Oct 9, 2017

Kia ora Shannon
I just wanted to check is the innovation aspect of this proposal that it would be used for the first time in NZ? Or the first time in temperate waters?


Shannon Weaver Oct 9, 2017

Hi Fiona, thanks for the question- the answer is that it is an innovation in both the senses you have suggested. The technology is an innovation that has not been trialed in New Zealand. With our unique marine flora and fauna there is no knowing how successful seawater electrolysis could be here, but my opinion is that we don't know until we try it. Innovation will also be in the design of the structure, an aspect of seawater electrolysis that has never been tested. Designs in tropical environments have been varied in form, i.e., cyclinders, squares, through to ornate art installations- these are fantastic but what about their efficacy? Why do they resemble shapes not usually seen in a natural marine scape? I aim to develop a structure that best replicates a local heterogenous benthic environment, derived from local and traditional knowledge on what once existed in the study area- this will best represent the habitat lost and so desperately needing to be restored. This design will provide a range of conditions in which species can aggregate, shelter, source food, juveniles can settle etc. Lastly the innovation is in opening up the discussion- and trial- of more active methods of marine conservation and that we continue to evolve our conservation techniques on from the passive marine reserve approach as our knowledge grows.


Fiona Edwards Oct 9, 2017

Thanks Shannon, I appreciate your clarification. Good luck with your project.


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Shannon Weaver Oct 9, 2017

Here are some images of a basic seawater electrolysis system, the amount of accretion that can occur and the solar buoy at the surface


Joanne Jackson Oct 12, 2017

Will your device interfere with bio-electromagnetic fields produced by living marine organisms?


Shannon Weaver Oct 12, 2017

Hi Joanne- good question! The answer is no- past research has shown that no adverse reactions occur from organisms that rely on electroreception (sharks and rays) or other animals such as turtles or dolphins.


Joanne Jackson Oct 12, 2017

Thanks for your reply Shannon. It is good to know that it doesn't appear to show adverse reactions as there is already a lot going on, down there. Does the device change the pH within it's field?


Shannon Weaver Oct 13, 2017

Hi Joanne, it does- this is probably the most important part of seawater electrolysis. The change in pH around the cathode (the wire structure) results in the mineral deposition onto the structure. This higher pH is what aids calcifying organisms that settle on or around the structure to grow faster (but importantly this doesn't mean a weaker shell)- particularly beneficial for juveniles to move out of the more vulnerable life stages. This system is replicated for example in kelp forests where photosynthesis leads to the higher pH environment calcifiers love. Unfortunately kelp forests in NZ are disappearing due to sedimentation, warming waters etc. Seawater electrolysis may provide a 'surrogate' to the many species that rely on kelp forests, potentially also aiding restoration of this vital ecosystem. It has shown pretty remarkable effects in aiding resilience of habitats to adverse conditions- i.e. tropical corals on these structures in other experiments have not suffered from bleaching while surrounding areas have, organisms have also thrived on the structures in heavily polluted waterways, again, when everything else cannot. Of course we have very unique marine ecosystems in NZ but without any evident adverse effects from seawater electrolysis elsewhere in the world, I am of the opinion that we need to give this a go and see if its something we should be considering as a longer-term wider-scale marine conservation tool.


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