The Great Barrier Reef is in trouble. There are a whopping 45 reasons why

A helicopter view of Bait Reef in the Great Barrier Reef Marine Park.
Justin Blank/AAP

Jon C. Day, James Cook University and Scott Heron, James Cook University

When the managers of the Great Barrier Reef recently rated its outlook as very poor, a few well-known threats dominated the headlines. But delve deeper into the report and you’ll find that this global icon is threatened by a whopping 45 risks.

The most publicised main threats relate to climate change and poor water quality, and are unquestionably the most damaging.

However, many of the 45 threats are not well known or understood. All but two are happening now – and most are steadily getting worse. Collectively, it means the Great Barrier Reef is heading for a “death by a thousand cuts”.

Flood plume extending 60 kilometres offshore from the Burdekin River to Old Reef after an extreme monsoon weather event, February 2019.
Matt Curnock

The last prognosis was bad. Now it’s worse

The Great Barrier Reef Marine Park Authority produced the 2019 Outlook Report, required by law every five years. It shows the total number of threats has increased from 41 in 2014 to 45 now.

Click here for the authority’s list of all 45 threats.

All of these threaten the Great Barrier Reef’s World Heritage values – the factors that make it globally outstanding. Of the 45 threats, 42 threaten its remarkable ecosystem.

The new threats include the loss of cultural knowledge, especially by the Indigenous traditional owners, and the potential negative impacts of genetic modification which are not well understood but could occur when modified organisms are released into the wild.

The table below shows the most alarming 21 risks to the Great Barrier Reef ecosystem. It is becoming clear that many of the risks are serious, and the situation is getting worse.

Author provided/The Conversation, CC BY-ND

Click here for a version of the above table including additional data.

The threats you may not have heard of

The likelihood and consequences of many lesser known threats are increasing.

The ten threats leading to “very high” risks are of greatest concern, especially as all are considered “almost certain” to occur. They include:

• The modification of coastal habitats from continued urban and industrial development. Vegetation clearing damages important ecosystem services for many marine species.

• Illegal fishing and poaching elsewhere are impacting global fish stocks. This will increase the incentive for such activity on the Great Barrier Reef, with major consequences for some species and habitats.

• Altered weather patterns are predicted as climate change accelerates, including more frequent and/or intense cyclones, floods and heatwaves. These weather events are natural processes in tropical regions, but when severe can prolong recovery times of coral ecosystems by up to 20 years.

At least 6 of the 11 “high” risks are worsening, including:

• Disease outbreaks in corals, turtles and coral trout were of “minor” consequence in 2009 but “major” consequence in 2019.

• The likelihood of altered ocean currents and their flow-on effects has been revised from “unlikely” in 2014 to “almost certain” in 2019. An increase in speed and the southern extent of the East Australian Current has already been observed. Such changes could irreversibly affect how eggs, larvae and juvenile organisms are naturally distributed.

Cyclone Yasi wrought havoc along the Queensland coast, including Port Hinchinbrook (pictured) in 2011. Severe events are expected to become more frequent, potentially damaging the Great Barrier Reef and communities.
AAP

---

Read more:
The Barrier Reef is not listed as in danger, but the threats remain

---

• The likelihood of problems from artificial light emitted from shipping and coastal development has increased from “likely” in 2014 to “almost certain” in 2019. This is known to affect turtle hatchlings and may be detrimental to seabirds and fish behaviour.

Many of the threats to the reef ecosystem occur simultaneously, and can act together to exacerbate the impacts. These cumulative effects are not all well understood and have not been adequately addressed in the Outlook Report, so this is further cause for concern.

Don’t forget the main threats – with catastrophic consequences

We cannot forget the problems that loom largest for the Great Barrier Reef: climate change and poor water quality.

The report rates the potential consequences of climate change-related sea temperature increase and ocean acidification as catastrophic.

A photo depicting two threats to the Great Barrier Reef: coal ships anchored near Abbot Point and a flood plume from the Burdekin River (February 2019); such plumes can carry pollutants and debris to the Great Barrier Reef.
Matt Curnock

• Sea temperature increase is certain to continue, leading to further bleaching and possible death of corals and other organisms that will damage the entire reef ecosystem.

• Ocean acidification (decreasing ocean pH levels) is reducing the capacity of corals and other calcifying organisms to build skeletons and shells, which reduces their capacity to create habitat.

The federal government is failing to meaningfully address Australia’s contribution to climate change, especially as the scale of the problem is much greater than the scale of interventions to date.

---

Read more:
The Great Barrier Reef outlook is ‘very poor’. We have one last chance to save it

---

Runoff containing sediment, nutrients and pesticides, mainly from agriculture, is causing poor water quality which can stifle the growth of coral and seagrass, and encourage outbreaks of the damaging crown-of-thorns starfish.

Despite substantial investment of human and financial resources to address the problem, the Queensland Government’s latest water quality report card this month gave the reef a rating of “D” overall and warned that high sediment loads “will continue to be transported to, and remain in, the region”.

So where to now?

It is clear that despite management efforts at local, regional and national levels, a significant number of threats to the reef are getting worse. The evidence leading to the ‘derived trend’ arrows on the right-hand side of the above table indicates ongoing concerns.

Adani’s Abbot Point coal terminal, and the Caley Valley wetlands. Critics say the coastal development is damaging the surrounding environment.
Gary Farr

Much more effort is required to effectively address complex threats such as climate change. But to ensure that the Great Barrier Reef survives as a healthy, resilient ecosystem, we must also ensure the lesser known risks are addressed.

This requires greater efforts by the community, industries, traditional owners and non-government organisations together with strong leadership from governments and their agencies. Unless this happens, the prognosis for the Great Barrier Reef is worse than “very poor” – and the ecological, social, economic and cultural impacts of that will be devastating.

---

Support for the aerial images by Matt Curnock was provided by TropWATER JCU, the Marine Monitoring Program – Inshore Water Quality through the Great Barrier Reef Marine Park Authority, the Queensland Government, the Landholders Driving Change project led by NQ Dry Tropics, CSIRO and the National Environmental Science Program Tropical Water Quality Hub.

Jon C. Day, PSM, Post-career PhD candidate, ARC Centre of Excellence for Coral Reef Studies, James Cook University and Scott Heron, Senior Lecturer, James Cook University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Advertisement

The world’s coral reefs are in trouble, but don’t give up on them yet

Terry Hughes, James Cook University and Joshua Cinner, James Cook University

The world’s coral reefs are undoubtedly in deep trouble. But as we and our colleagues argue in a review published today in Nature, we shouldn’t give up hope for coral reefs, despite the pervasive doom and gloom.

Instead, we have to accept that coral reefs around the world are transforming rapidly into a newly emerging ecosystem unlike anything humans have experienced before. Realistically, we can no longer expect to conserve, maintain, preserve or restore coral reefs as they used to be.

This is a confronting message. But it also focuses attention on what we need to do to secure a realistic future for reefs, and to retain the food security and other benefits they provide to society.

The past three years have been the warmest on record, and many coral reefs throughout the tropics have suffered one or more bouts of bleaching during prolonged underwater heatwaves.

A bleached coral doesn’t necessarily die. But in 2016, two-thirds of corals on the northern Great Barrier Reef did die in just six months, as a result of unprecedented heat stress. This year the bleaching happened again, this time mainly on the middle section of the reef.

Reefs are being degraded by global pressures, not just local ones.
Terry Hughes, Author provided

In both years, the southern third of the reef escaped with little or no bleaching, because it was cooler. So bleaching is patchy and it varies in severity, depending partly on where the water is hottest each summer, and on regional differences in the rate of warming. Consequently some regions, reefs, or even local sites within reefs, can escape damage even during a global heatwave.

Moderate bleaching events are also highly selective, affecting some coral species and individual colonies more than others, creating winners and losers. Coral species also differ in their capacity to reproduce, disperse as larvae, and to rebound afterwards.

This natural variability offers hope for the future, and represents different sources of resilience. Surviving corals will continue to produce billions of larvae each year, and their genetic makeup will evolve under intense natural selection.

In response to fishing, coastal development, pollution and four bouts of bleaching in 1998, 2002, 2016 and 2017, the Great Barrier Reef is already a highly altered ecosystem, and it will change even more in the coming decades. Although reefs will be different in future, they could still be perfectly functional in centuries to come – capable of sustaining ecological processes and regenerating themselves. But this will only be possible if we act quickly to curb climate change.

The Paris climate agreement provides the key framework for avoiding very dangerous levels of global warming. Its 1.5℃ and 2℃ targets refer to increases in global average land and sea temperatures, relative to pre-industrial times. For most shallow tropical oceans, where temperatures are rising more slowly than the global average, that translates to 0.5℃ of further warming by the end of this century – slightly less than the amount of warming that coral reefs have already experienced since industrialisation began.

If we can improve the management of reefs to help them run this climate gauntlet, then reefs should survive. Reefs of the future will have a different mix of species, but they should nonetheless retain their aesthetic values, and support tourism and fishing. However, this cautious optimism is entirely contingent on steering global greenhouse emissions away from their current trajectory, which could see annual bleaching of corals occurring in most tropical locations by 2050. There is no time to lose before this narrowing window of opportunity closes.

A crisis of governance

Reef governance is failing because it is largely set up to manage local threats, such as overfishing and pollution. In Australia, when the Great Barrier Reef Marine Park Authority was set up in 1976, the objective of managing threats at the scale of (almost) the entire Great Barrier Reef was revolutionary. But today, the scale of threats is global: market pressures for Australian reef fish now come from overseas; port dredging and shipping across the reef are spurred on by fossil fuel exports to Asia; a housing crisis in the United States can batter reef tourism half a world away; and record breaking marine heatwaves due to global warming can kill even the most highly protected and remote corals.

Increasingly, coral reef researchers are turning to the social sciences, not just biology, in search of solutions. We need better governance that addresses both local and larger-scale threats to coral reef degradation, rather than band-aid measures such as culling starfish that eat corals.

In many tropical countries, the root causes of reef degradation include poverty, increasing market pressures from globalisation, and of course the extra impacts of global warming. Yet these global issues desperately need more attention at just the time when some governments are reducing foreign aid, failing to address global climate change, and in the case of Australia and the US, trying to resuscitate the dying fossil fuel industry with subsidies for economically unviable projects.

Effective reef governance will not only require increased cooperation among nations to tackle global issues, as in the case of the Paris climate deal, but will also require policy coordination at the national level to ensure that domestic action matches and supports these larger-scale goals.

Quite simply, we can’t expect to have thriving coral reefs in the future as well as new coal mines – policies to promote both are incompatible.

Terry Hughes, Distinguished Professor, James Cook University, James Cook University and Joshua Cinner, Professor & ARC Future Fellow, ARC Centre of Excellence, Coral Reef Studies, James Cook University

This article was originally published on The Conversation. Read the original article.

Western Australia’s coral reefs are in trouble: we mustn’t ignore them

Christopher Doropoulos, CSIRO; Damian Thomson, CSIRO; Mat Vanderklift, CSIRO; Mick Haywood, CSIRO, and Russ Babcock, CSIRO

Last year’s record-breaking temperatures are having a devastating impact on the world’s coral reefs. For only the third time in recorded history, coral reefs are experiencing a global “bleaching” event (where corals turn white; some ultimately die).

Australia’s reefs are feeling the impact, too. The US National Oceanic and Atmospheric Administration (NOAA) is in charge of producing global bleaching forecasts. Surprisingly, it isn’t the Great Barrier Reef facing the greatest threat this year, but Western Australia’s less well-known coral reefs.

NOAA predictions for the Western Australia (WA) are about as severe as they get: there is a 60% probability of the most severe bleaching (“Alert 2”) for all of April 2016.

In comparison, the Great Barrier Reef on Australia’s east coast has a 60% probability of milder bleaching (“Alert 1”) for most of March 2016 – obviously still a major concern, but not as severe as for the west.

And bleaching is not the only threat facing Western Austraia’s reefs. While we are well aware of the troubles of the Great Barrier Reef, we must make sure we don’t ignore its less famous western cousins.

El Niño and the western reefs

Recent years have seen devastating marine heatwaves cause massive losses to the underwater kelp forests and corals of Western Australia.

These events typically occur on the west coast during La Niña years (when the ocean is hotter off the west coast), but during the last year the Pacific Ocean has officially returned to El Niño.

This has sparked some hope for the marine environments in WA, because water temperatures are usually cooler in El Niño than La Niña years.

But water temperatures over the past 12 months have been recorded at 1-3°C warmer than long-term summer averages. While this may seem insignificant, global coral mortality previously occurred at these temperatures in 1998 and was observed in all ocean basins in 2015.

Acropora corals during a bleaching event.
Christopher Doropoulos

NOAA’s bleaching alert spans most of WA’s coastline. This includes the major coral reef systems of the Abrolhos Islands, reefs in the Pilbara (including Barrow Island, the Montebello Islands, and Onslow) and the Kimberley (including the Rowley Shoals and Scott Reef).

The alert also surprisingly includes the World Heritage-listed Ningaloo Reef. We say “surprisingly” because Ningaloo normally avoids bleaching: it fringes the Western Australian coast and usually receives cooler water welling up from the deep, and from a cool northward flowing current.

That said, Ningaloo experienced massive bleaching in 2011 at Bundegi, on the western side of Exmouth Gulf, where live coral cover crashed from 80% to 6% – almost all the adult coral was killed.

Map of major coral reefs in Western Australia
Mick Haywood

Reefs in danger

WA’s coral reefs are unusual because most are isolated from major human populations. They are world renowned for the abundance of unique and iconic fauna they host, a stark contrast to the red deserts they directly neighbour.

Unfortunately, the last few years has seen a series of major environmental disturbances that have compromised the health of these coral reefs.

We recently undertook surveys of reefs from the Dampier Archipelago and Montebello Islands to the Muiron Islands and what struck us most was the depauperate state of the reefs. We saw a mosaic of impacts depending on where we surveyed.

Some places are still recovering from two major rounds of coral bleaching – the event of 2010-11 and another in the Pilbara in 2013. Some were beset by crown-of-thorns outbreaks, and some had high cover of dead branching Acropora (the most abundant coral that builds reefs) that were smothered in sediment, mostly from nearby dredging projects.

Crown-of-throns starfish eating remnant Acropora colony.
Christopher Doropoulos

Ironically this region’s isolation is a double-edged sword — the severity of the situation, which could lead to long-term collapse of reef ecosystems, has gone largely unnoticed.

Isolation and the absence of human impacts might help coral reefs recover after coral bleaching. But it also means that few people are familiar with the region’s prolific coral reefs.

Without this understanding, there might not be sufficient public awareness to drive the action required to protect these areas in the face of mounting environmental pressures.

The future for WA’s coral reefs

Coral reefs rely on a range of ecological processes that keep the system resilient and able to function: processes such as the arrival of coral larvae, and removal of algae by herbivores.

However, human or environmental pressures can destabilise or weaken the system, and the ecosystem can swiftly collapse. Once a reef’s ecosystem processes have failed, they are much more difficult to restore than they were to remove, slowing the reef’s return to its optimal state.

Corals are archetypal ecosystem engineers: they provide the foundation for the diversity and abundance of all the other species in coral reef ecosystems. Greenhouse gas increases are contributing to more frequent and intense bleaching events.

Therefore, reefs need every chance to stay resilient by removing local human impacts and being actively restored. After all, without the foundation, there are no coral reefs.

It is time for the coral reefs of Australia’s west coast to be afforded the level of attention and resources devoted to the better known Great Barrier Reef. The system needs time to recover.

Christopher Doropoulos, OCE Postdoctoral Fellow, CSIRO; Damian Thomson, Experimental Scientist, CSIRO; Mat Vanderklift, Senior research scientist, CSIRO; Mick Haywood, Marine ecologist, CSIRO, and Russ Babcock, Senior Principal Research Scientist, CSIRO

This article was originally published on The Conversation. Read the original article.

Coral Reefs in Trouble

A recent report has highlighted the disturbing threats faced by the earth’s coral reefs, with 75% now threatened by various issues including global warming, pollution and overfishing.

For more visit:
http://saveourseas.com/blog/75_of_worlds_coral_reefs_threatened