Rubble Stabilization in Coral Reef Restoration

Many reef areas around the world have been subjected to damage from dragging boat anchors and fishing nets. Physical damage to the reef breaks the coral skeletons and forms broken rubble fields. These rubble areas host very little life and erode neighbouring areas of reef with their mobile substrate. The rubble “killing fields” expand with little chance of recovery.

A coral restoration site needs to first have the rubble stabilized before coral can be transplanted to the area. Without a stable substrate to grow upon, young corals will smother and die. So the basic steps of active reef restoration are:

  1. Structural stabilization of the rubble substrate

  2. Transplant a selection of suitable coral species

  3. Encourage other species of a reef ecosystem to inhabit the area

Blue Corner Marine Research has conducted experiments to determine different methods for stabilizing rubble. At the coral restoration project in Nusa Penida we have used the following methods:

Metal wire mesh: Mesh is rolled across the seafloor to stop rubble from moving and eroding. The mesh allows rubble to become trapped long enough for sponge, soft corals, and coralline algae to bind the rubble together. This method of biostabilization can be effective in areas of reef slope.

Rebar frames: Modular frames are placed across the rubble field to reduce the amount of rubble movement. Rubble is slowly trapped against the frames and then becomes colonized with reef organisms.

Coral Ropes: between frames young corals are grown on ropes a short distance off the seafloor. As these corals grow bigger they increase the coverage of living coral and create terraces to increase reef topography.


To learn more about coral restoration methods read our project summary of the Nusa Penida coral restoration project. Or join one of our training programs:

Scholarships for Indonesian Women

Each year Blue Corner runs a scholarship program to train Indonesian women as PADI Divemasters in order to increase gender equality and opportunities in the marine tourism industry. Gender equality is not only a fundamental human right, but a necessary foundation for a peaceful, prosperous and sustainable world. Blue Corner is committed to doing our part to fulfill the United Nations Sustainable Development Goals - including gender equality (SDG 5).

This year we hosted a scholarship training program for 3 Indonesian women - Cat, Yas & Emma. They spent three months living at Blue Corner learning from our professional PADI dive instructors training to become part of Indonesia’s elite group of professional Divemasters themselves!

We also expanded this scholarship from previous years so that these women could have additional training opportunities in the field of marine conservation. The three Indonesian scholarship candidates also participated in our full marine conservation internship program.

Following the training program they are assisted with work placement and offered jobs in the ecotourism industry.

These amazing women chose to stay on and join us as staff members here at Blue Corner! Yas joined Blue Corner Marine Research as one of our full-time biologists helping supervise interns and maintain our coral restoration site. Cat joined Blue Corner Dive Lembongan as a full-time divemaster guiding international tourists on dives in the Nusa Penida Marine Park. Emma has chosen to continue her path studying marine conservation and is working on a research project recording sound on reefs - comparing un-restored and restored coral reefs.

We believe in providing opportunities for women to achieve gainful employment in the ecotourism and marine conservation industry. If you (or someone you know) is interested in applying for our 2024 scholarship program reach out to us!

Coral Restoration Training - Bahasa Indonesia (Restorasi Terumbu Karang)

This year we welcomed Egi, our local Indonesian marine biologist, to the team. One of our important goals for outreach and expanding coral restoration efforts is to provide accessible training programs and opportunities here in Indonesia.

The following coral restoration programs and training materials are now available in Bahasa Indonesia:


Tahun ini kami menyambut Egi, ahli biologi kelautan lokal Indonesia, ke dalam tim. Salah satu tujuan penting kami untuk menjangkau dan memperluas upaya restorasi karang adalah untuk menyediakan program dan peluang pelatihan yang dapat diakses di Indonesia

Program dan materi pelatihan restorasi karang berikut sekarang tersedia dalam Bahasa Indonesia:


Site monitoring shows increasing hard coral coverage

Since the start of the coral restoration project in Nusa Penida, the Blue Corner team has been conducting monitoring of the Restoration site. Monitoring methods involved Reef Check surveys which count fish and invertebrates present as well as percentage cover of various reef substrate - including rubble and hard coral. To measure substrate coverage divers conducted several replicate transects at each site with a point-intercept method. These surveys were done every few months - and continue to take place as part of our on-going monitoring of the project.

Over a two year period we focused on transplanting hard coral out onto an area of degraded reef. At the beginning of the project the site was predominantly dead rubble (95% coverage) with only a low coverage of hard coral (2%). However with the help of many volunteers over many restoration dives, the amount of hard coral cover began to increase with each survey until the latest survey in Dec 2020 showed 35% coverage of hard coral at the site. During the same time the amount of rubble began decreasing as stabilization methods have trapped moving rubble allowing soft corals, sponges and other living substrates to begin to colonize upon the rubble.

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New Coral Restoration eLearning Course Launched

We have put together the theory of our popular coral restoration workshop into an eLearning course!

Students now have the chance to learn all the details of coral reef restoration at home. This is a great option for people who want to join one of our workshops but have not yet decided when they will be able to make the trip to our site in Bali. The course can be done as a stand-alone online training course ($45). If students decide after taking this eLearning course that they would like to continue on with the hands-on workshop, then the price they have already paid for the eLearning course will be discounted off the workshop fees!

The Coral Restoration eLearning course is a scientific-based training program which goes though the following topics:

  • Coral Reef Ecology

  • Restoration Ecology

  • Developing a Coral Restoration Plan

  • Physical Restoration Efforts

  • Biological Restoration Efforts

  • Coral Transplantation

  • Restoration Site Monitoring

  • Case Study: Nusa Islands Restoration Project

Blue Corner Marine Research conducts regular Coral Reef Restoration Workshops throughout the year. Learn more about these hands-on training workshops here:

Increasing coral cover in rubble using nursery ropes

Coral reef restoration projects often have the challenge of needing to grow coral on an area that has become dead rubble. These rubble fields usually do not recover naturally, but rather expand and erode neighbouring areas of healthy coral because the broken coral skeletons are unstable and move around in currents. Any attempts for young corals to try to establish themselves in these areas are unsuccessful - as the small corals quickly become smothered and buried in the rubble.

Using Active Coral Restoration Methods

In our restoration project we are using a few different methods to try to stabilize the rubble substrate in order to allow natural settlement of corals. As well as using low-lying structures to transplant corals upon above the rubble.

In an attempt to increase the amount of hard coral coverage across the rubble, we tested a new technique one year ago. We used mature ropes from our nursery (8 months old) in which the attached corals had grown to about football-sized. With these ropes we pinned them along the bottom across areas of rubble (between some of our coral-frames).

acropora coral rope across substrate

Improving Techniques for Increasing Coral Cover

After one year, our trial plot using this technique showed decent results. Although the colonies had only about 50% survivorship, the rope had acted as a barrier for rubble erosion and allowed for natural settlement of new corals. This technique had promising results, as long as we were able to improve the survivorship of the corals upon the ropes. We attributed the relatively low coral survivorship to the constant moving action of the coral colonies across rubble. To improve this technique we started using shorter ropes so that the span between anchors was not as far. In March 2020 we anchored several more mature nursery ropes out across the rubble, so we hope after a few months we can see some growth and stabilization - which will increase the coral coverage at the site.

coral nursery rope on rubble

The ecological basis and background of our coral reef restoration project in Nusa Penida

Over the last 2 years we have been working at restoring an area of coral reef on the northern coastline of Nusa Penida. The project is led by marine biologist Andrew Taylor who is a Certified Ecological Restoration Practitioner and director of Blue Corner Marine Research. Together with his team of students, volunteers and ocean warriors they have been restoring an area of degraded coral reef measuring 200m x 20m.

The following video outlines the coral reef restoration project as well as describes the scientific principles which the project is based upon.

  1. Restoration Site Description

  2. Highlighting a Need for Restoration

  3. Developing a Restoration Plan

  4. Structural Reef Restoration

  5. Biological Restoration of the Coral Reef Community

  6. Monitoring the Restoration Site

Stabilization of rubble using wire mesh to promote reef recovery

Marine biologist Andrew Taylor and the Blue Corner Marine Research team use multiple coral reef restoration techniques including structural stabilization with wire mesh. In an effort to stabilize the shifting rubble substrate and reduce erosion at the coral reef restoration site, they added a novel restoration approach of using metal wire mesh across areas of degraded rubble reef.

Read More

Coral Transplants showing promising growth!

We have had 12 of our modular reef structures out at the restoration site for over 17 weeks now and have already seen some good growth rates. 

The Scientific Diver interns have been out helping transplant and measure fragments of Acropora upon our structures. Each structure started with 30 x 10cm fragments in the following experimental design:

  • 3 x structures: Single Species with fragments from SAME parent colony
  • 3 x structures: Single Species with fragments from DIFFERENT parent colonies
  • 3 x structures: Two different species of fragments mixed
  • 3 x structures: Control with no transplants in order to monitor for natural settlement
Coral Restoration artificial reefs
coral growth rates.png

A Need for Coral Restoration in Nusa Lembongan?

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By now, most people know that coral reefs are under a severe ecological threat, mostly attributed to human activity. Climate change, overfishing, runoff and sedimentation are all menacing coral reef ecosystems’ ability to survive.

In the past year, we have seen great suffering from the Earth’s reefs. The obituary posted for the Great Barrier Reef brought international attention to the devastating mass bleaching in the largest living organism on the planet. But we are also collectively aware that if we continue ‘business as usual’, the Great Barrier Reef won’t be so great anymore.

Coral reefs are the building blocks of the ocean. They house tremendous biodiversity and produce provide us with bountiful economic wealth; from tourism to fishing to protection from severe weather.

It is so critical we start thinking about these pressures in the long term and not for short-term benefit as not only the environment but many people’s livelihoods are at stake!

The good news. (Wait you mean there’s good news in this????) All of the earth's environmental and even humanitarian issues are connected. Threats seems to come from every angle, but so do the solutions. Innovative technology combined with scientists, activists and most importantly passionate, conscious everyday people are the driving force of the conservation movement and there is much we can do to switch paths on our way to a greener future!

There are many things that we can do to help. Here we’re going to discuss a couple of ways Blue Corner is involved with coral conservation! But first, a bit of background as to what the heck is going on down there.

Coral Reef Systems: #Biology101

As most of us divers know, corals are animals. They are invertebrates and belong to the family Cnidaria. Mostly found in shallow, low nutrient tropical waters, these animals can only survive in very specific water temperatures. They need abundant sunlight in order for the symbiotic phytoplankton in their tissues to harness and convert sunlight energy into food for the coral! Neat. (Sidenote: This is why we have such a high tourism value on coral reefs; who doesn’t love to swim through 25 - 30 degrees Celsius, stunningly clear turquoise water fish playground??!)

 

So what’s the issue and why are the greenies freaking out?

Climate Change

Most people nowadays have heard of the greenhouse gas effect; carbon dioxide and methane gases from burning fossil fuels and cow farts (yikes) are warming the atmosphere. Forests around the world, that usually act as carbon sinks, are being cut down for agricultural purposes needed to sustain the exponentially increasing human population (You can get a live update here). These excess gases are being absorbed by the ocean, both increasing Sea Surface Temperature (SST) as well creating more acidic oceans. And yes it’s happening because of human activity …. If you are in climate denial, please feel free to educate yourself here.

What does this mean for coral reefs?

Corals are amazing complex animals, yet exceptionally sensitive to changes in their surrounding environment. A change of 1 - 2 degrees Celsius in SST can cause coral bleaching; whereby the coral expels the nourishing phytoplankton living within its tissues. Repeated or sustained events of coral bleaching will result in the eventual death of coral … #notcool. Literally. 

Overfishing

Is it estimated that by 2050, global fisheries may collapse due to current unsustainable fishing practices. Over 1 billion people rely directly on fish for their income and main protein source. Coral reef systems also rely on healthy fish populations as changes in the trophic system (where an organism sits in the food chain) can cause an overabundance of algae that smother reefs.

Shark fishing in Indonesia is a major threat to coral systems as sharks are vital apex predators to keep the reef fish in balance. There have been a few marine protected areas established in the area after a breakthrough in Manta Ray conservation, however many areas go unregulated and affect all levels of the oceanic ecosystem from the top predators to the macrofauna.

Runoff & Sedimentation

Remember, all rivers lead to the ocean. Agricultural land practices, including the use of pesticides and fertilisers, cause nutrient runoff into rivers and pollute our ocean systems. This increased amount of nutrients in our oceans lead to dead zones and algal blooms, which as we mentioned before, then smother reefs and cause reef mortality. Other threats include chemicals and pollutants in our everyday products, particularly sunscreens. These wash into and are absorbed by the ocean, all battering the reefs ability to withstand pressure (Stay tuned for more info about sunscreen + coral + what you can do to help next month!). 

 

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NOAA. How does climate change affect coral reefs? National Ocean Service website, https://oceanservice.noaa.gov/facts/coralreef-climate.html, 10/10/17

Should we be freaking out in Nusa Lembongan?

#Oceanography101

Luckily enough, we are situated in the convergence zone of two major oceans - the Pacific and the Indian. The reason we have amazing diving is that the currents and characteristics of the converging oceans draw species such as Molas and Mantas. Upwellings of deep cool water keep the ocean relatively cool and less at risk to mass bleaching events occurring elsewhere.

Seriously, we have an abundance of healthy coral still in existence!

Coral reefs are super resilient. They can withstand a lot of pressure and have been shown to bounce back to normal after a bleaching event. That being said, when faced with multiple threats in concurrence like raised Sea Surface Temperature AND excess nutrients/chemicals in the water, they are in danger of being killed completely. The above threats are imminent and conservation measures need to be addressed in order to keep the reefs stable!

Sooo, you ask, what can we do about it to ensure our reefs aren't further compromised?

Education And Ecotourism.

Be an eco-tourist. Check where you’re going first and ask yourself whether you are supporting a business that is eco and ethical. Choose an eco operator. Though do be careful - often the word eco is misused in company names, so you might need to do some research to see what sort of practices they may be involved in and guidelines they have around animal interactions. Never be afraid to ask.

Do we ride the turtles? Nope. Do we touch the mantas? Probably shouldn’t do that. Do we want our divers sending coral crumbling as far as the eye can see? Mmmmm...‘kay no. Do your certification with a company (ahem #BlueCorner) with excellent standards to have as minimal impact on the reef as possible.

We no longer serve any plastics in our restaurant because we try and make it as easy as possible for our customers to be ‘eco’ too and reduce our environmental footprint.

Ongoing Long-Term Reef Health Monitoring & Practical Restoration Work

Reef health monitoring is a vital way to measure impacts to reefs over time and space. These can be conducted by marine biologists and are performed to survey coral health and key indicator species. 

 

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Enter Andrew. Blue Corner’s co-founder, in-house Marine Biologist and ocean adventurer. He is in the early phases of testing for a major island-wide coral restoration project.

After his Master's project on the Great Barrier Reef, Andrew worked in environmental consulting as a scientific diver in Canada. His diving skills, in addition to his marine expertise, led him to start his own scientific diver program out of Blue Corner Dive. Components of the 4-week course he teaches range from marine ecology theory to advanced dive technique certifications necessary when working for environmental consulting agencies or NGO’s.

In addition to the scientific diver skills learnt during the course, participants get to be involved in his signature coral restoration project.

After taking part and seeing good results in similar coral projects (elsewhere), Andrew has designed his own study to see how these innovative coral growing techniques could be applied here in the Nusa islands.

Through a process called coral fragmentation, coral transplants are fixed to rebar structures by trained divers in damaged sites. 

 

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Over the next 6 months, he aims to study how coral growth is best aided in order to set up an islandwide mass coral restoration program. The goal is to establish a coral foundation in damaged areas to restore resilience and biodiversity that has been lost.

In this day and age, it is important to give back to the environment. As divers, we get to experience the total epic-ness of life underwater. And whether we like it or not, our livelihoods and business also depend on, not only surviving but thriving coral reef ecosystems.

Andrew’s project and Scientific Diver Course allows him to share the knowledge and skills he has attained to help save coral reefs and equip other divers with the skills needed to help in the journey towards sustainability.

If you are interested in learning more or becoming a part of the #teamscience feel free to inquire at info@bluecornerdive.com.