Artificial light, biological clock disruptions, increase breast cancer risk, study finds

Employment as a flight attendant has been found to be related to an increased risk of breast cancer. Credit: © dmitrimaruta / Fotolia

The disruption of a person's circadian rhythm -- their 24-hour biological clock -- has been linked to an increased risk of breast cancer, according to new University of Georgia research. The culprit, in this study in particular, is artificial light.

"Exposure to artificial light leads to a significantly higher risk for developing breast cancer," said Chunla He, a biostatistics graduate student in the UGA College of Public Health. "To decrease the use of artificial light, people should avoid working at night and implement earlier bed times."

Her research, published in the International Archives of Occupational and Environmental Health, examined key studies that included risk factors for developing breast cancer.

"A large body of related research about circadian rhythms and breast cancer exists," He said. 

"However, these studies are inconsistent and have a variety of limitations."

Under the mentorship of Sara Wagner Robb, assistant professor of epidemiology in the College of Public Health, He turned to previous studies to see what the research revealed.

In addition to other relevant exposures, He examined studies on breast cancer and flight attendants, who typically work both day and night shifts. The flight attendants represented a group of workers particularly susceptible to disrupted circadian rhythms, which are heavily influenced by light.

In her analysis, He found that employment as a flight attendant was related to an increased risk of breast cancer.

"People naturally secrete the hormone melatonin, which helps to regulate the circadian rhythm," He said. "When the sleep-wake cycle is disrupted by artificial light, melatonin secretion is adversely affected."

Robb recommends spreading this information to shift workers so they understand the harms in disrupting their circadian rhythms.

"Individuals engaging in this type of work should be aware of these risks and may make efforts to adjust their circadian rhythms," she said. "Although additional studies are certainly needed, scientists are becoming increasingly aware of the health risks associated with night workers and others exposed to circadian-disrupting behaviors."

Robb and He also advise that future research needs to examine social constraints -- which may foster disruption of circadian rhythms -- on shift workers. Additionally, shift workers should contact their primary care physicians for personalized treatment and options.

"This information tells us the harm in disrupting our natural cycle," He said. "With this new analysis, we must be cautious in our exposure to artificial light."

The article was co-authored by Sonia Taj Anand, a former graduate student in the College of Public Health; Mark H. Ebell, professor of epidemiology; and John E. Vena, Medical University of South Carolina.

Source: University of Georgia

Managing reefs to benefit coastal communities

Fishing. Credit: Josh Cinner

Coral reefs provide a range of benefits, such as food, opportunities for income and education, but not everyone has the same access to them, according to a new study conducted by the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

The researchers examined how people from 28 fishing communities in Madagascar, Kenya, Tanzania and Seychelles benefit from the marine environment.

For many years conservation in developing countries has been based on the assumption that improvements in ecosystem conditions, such as increasing coral reef fish biomass, will benefit the community as a whole.

But Dr Christina Hicks, a social scientist, says this is approach is too simplistic.

"Increased supply tends to benefit the elite, not the community as a whole," Dr Hicks says.

"We need to look at the social and economic access mechanisms that would enable a wider group of people to benefit from reefs and then develop policies based on that information," she says.

Study co-author Professor Josh Cinner from the Coral CoE says the focus on increasing the supply of benefits isn't enough.

"We need to pay more attention to how that benefit is distributed and how it is accessed by different people within a community," Professor Cinner says.

The researchers argue that policy makers need a more inclusive approach to managing coral reefs, which includes a focus on improving wellbeing.

"We tend to focus on economic growth because it is easy to measure, but this should be greatly expanded to include the way people can share in the benefits that flow from reefs," Dr Hicks says.

Source:  ARC Centre of Excellence in Coral Reef Studies.

You can hear the coral reefs dying, experts say

A lionfish in an Indonesian reef. Credit: Image courtesy of University of Essex

You can hear the sound of former bustling coral reefs dying due to the impact of human activity, according to new research from the Universities of Essex and Exeter.

Coral reefs are amongst the noisiest environments on our planet and healthy reefs can be heard using underwater microphones from kilometres away.

However, scientists have found that coral reefs impacted by human activity, such as overfishing, are much quieter than protected reefs, which can have a big impact on the fish and invertebrates which rely on the reefs for survival.

Led by Dr Julius Piercy, from the University of Essex, the study, which also involved the University of Derby, involved taking acoustic recordings of coral reefs with different levels of protection around islands in the Philippines. The research found that the noise produced by the few remaining resident fish and crustaceans on unprotected reefs was only one third of the sound produced at bustling, healthy reef communities

This is particularly important to the larval stages of reef fish and invertebrates, which spend the first few days of their life away from reefs and use sound as an orientation cue to find their way back. With less sound being produced at impacted reefs, the distance over which larvae can detect habitat is ten times less, impacting on the replenishment of future generations needed to build up and maintain healthy population levels.

"In an environment where underwater noise plays such an important role in the population dynamics of coral reefs, it is alarming to find such a large effect of human impact on the natural acoustic environment," explained Dr Piercy. "This puts reef sound in the spotlight for the people who manage coral reef ecosystems on two counts. Firstly, that they might need to consider reef sound as an integral part of the design of marine protected area networks to ensure that there is sufficient recruitment of larvae within and between reserves and neighbouring reefs. Secondly, this study shows sound can be useful in monitoring the health of coral reefs."

With growing evidence demonstrating the direct impacts of human-made noise on aquatic life, these findings highlight additional indirect human impacts -- such as overfishing and landscape development -- on natural underwater sounds.

Dr Steve Simpson, from Biosciences at the University of Exeter, added: "Taking sound recordings is a cheap, fast and objective way to get a broad idea of whether a reef is in a good condition or not. While it cannot replace detailed visual surveys conducted by snorkelers or divers, it gives a good account of the cryptic and nocturnal species missed in visual census, and quickly provides a general picture of the state of coral reefs without requiring time-consuming surveys and extensive training."

The researchers also found that reef sounds can be detected further away than predicted, increasing previous estimates of the likely detection zone for recruiting larvae and increasing the potential importance of reef sound in attracting new fish and crustaceans to coral reefs.

The study highlights the need to further characterise reef soundscapes and identify acoustic cues that larvae tune into when seeking a suitable home. Dr Simpson said: "We still know very little about what sounds these animals are listening to and it is likely to be very different between species. Combined with recent findings that fish dislike the smell of impacted reefs (another homing cue used by the larvae), there is a real need to understand how human impacts can indirectly affect the success of future generations of reef organisms."

Source: University of Essex

Combatting illegal fishing in offshore marine reserves

Fishing boat. Credit: Henry Wolcott

Conservation scientists say there needs to be a new approach to protecting offshore marine reserves.

Illegal fishing in marine reserves will be a major focus at the IUCN World Parks Congress, which has opened in Sydney.

Researchers at the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University, who are attending the conference, have found a way to predict illegal fishing activities to help authorities better protect marine reserves.

Marine reserves are the most common strategy used to protect and maintain marine ecosystems around the world.

The International Convention of Biological Diversity aims to have 10 per cent of the world's marine areas protected by 2020.

Many countries are contributing to this target by protecting remote, offshore areas. For example, the United States recently created the world's largest fully protected marine reserve, covering almost 1.27 million square kilometres in the central Pacific Ocean.

But scientists are concerned that while a great deal of effort is being made to create reserves, many countries are simply not able to enforce the laws that are supposed to protect them.

fishing gear. Image: Todd Steiner, Sea Turtle Restoration Project
The majority of fishers obey the law, but some don't.

"The success of protected areas depends on whether people comply with the regulations," says Professor Joshua Cinner from Coral CoE.

"Enforcement and compliance issues for large off-shore marine parks are fundamentally different to near-shore protected areas," Professor Cinner says.

He explains that the biggest problems facing countries trying to enforce offshore marine reserves is their distance from land and the difficulty and cost of patrolling large tracts of ocean.
"The distances to these areas can be very large. They are a long way from prying eyes and quite often the regulations are such that you have to actually catch people illegally fishing to prosecute them," Professor Cinner says.

"It can be extremely difficult for authorities to catch illegal fishers in the act."

In a bid to combat the problem, researchers at Coral CoE examined five years' worth of data collected from the World Heritage-listed Cocos Island National Park, a unique marine protected area in the Pacific Ocean about 500 kilometres off the west coast of Costa Rica.
From the records they were able identify illegal fishing patterns and predict both when and where illegal fishing was likely to happen.

They found that illegal fishing was concentrated in a few 'hotspots' and really ramped up during specific lunar phases of some months.

Professor Bob Pressey, also from Coral CoE, says authorities could use this knowledge to match patrols to the time and place when illegal fishers are most likely to be in action.
"Using a targeted approach helps authorities catch and deter illegal fishers, while saving money on patrols," Professor Pressey says.

"Rather than just hoping you can catch illegal fishers effectively by random patrols, we have used previous patrols to look for patterns which tell us when and where people fish illegally," adds Professor Cinner.

Study lead author, Coral CoE PhD candidate, Adrian Arias says the model of predicting illegal patterns from old records can be used to increase the success of patrols in other locations.

"Our research in Costa Rica showed how a systematic and periodic analysis of patrol records can help to increase the probability of catching illegal fishers. This could be done pretty much anywhere that patrol data are available," he says.

Professor Cinner adds that by better targeting limited resources, authorities have a greater chance of successfully protecting marine parks.

"Targeting resources is particularly important for developing countries such as Costa Rica, which have taken on the conservation challenge but don't have the same funding to ensure compliance as a country such as Australia."

Source: ARC Centre of Excellence in Coral Reef Studies

Cooling ocean temperature could buy more time for coral reefs

A Red Sea coral reef. Credit: Image by Elena Couce

Limiting the amount of warming experienced by the world's oceans in the future could buy some time for tropical coral reefs, say researchers from the University of Bristol.

The study, published by the journal Geophysical Research Letters, used computer models to investigate how shallow-water tropical coral reef habitats may respond to climate change over the coming decades.

Elena Couce and colleagues found that restricting greenhouse warming to three watts per square metre (equivalent to just 50-100 parts per million carbon dioxide, or approximately half again the increase since the Industrial Revolution) is needed in order to avoid large-scale reductions in reef habitat occurring in the future.

Shallow-water tropical coral reefs are amongst the most productive and diverse ecosystems on the planet. They are currently in decline due to increasing frequency of bleaching events, linked to rising temperatures and fossil fuel emissions.

Elena Couce said: "If sea surface temperatures continue to rise, our models predict a large habitat collapse in the tropical western Pacific which would affect some of the most biodiverse coral reefs in the world. To protect shallow-water tropical coral reefs, the warming experienced by the world's oceans needs to be limited."

The researchers modelled whether artificial means of limiting global temperatures -- known as solar radiation 'geoengineering' -- could help. Their results suggest that if geoengineering could be successfully deployed then the decline of suitable habitats for tropical coral reefs could be slowed. They found, however, that over-engineering the climate could actually be detrimental as tropical corals do not favour overly-cool conditions. Solar radiation geoengineering also leaves unchecked a carbon dioxide problem known as 'ocean acidification'.

Elena Couce said: "The use of geoengineering technologies cannot safeguard coral habitat long term because ocean acidification will continue unabated. Decreasing the amount of carbon dioxide in the atmosphere is the only way to address reef decline caused by ocean acidification."

Dr Erica Hendy, one of the co-authors, added: "This is the first attempt to model the consequences of using solar radiation geoengineering on a marine ecosystem. There are many dangers associated with deliberate human interventions in the climate system and a lot more work is needed to fully appreciate the consequences of intervening in this way."

Source: University of Bristol

A global surge of great earthquakes from 2004-2014 and implications for Cascadia

The last ten years have been a remarkable time for great earthquakes. Since December 2004 there have been no less than 18 quakes of Mw8.0 or greater -- a rate of more than twice that seen from 1900 to mid-2004. Hundreds of thousands of lives have been lost and massive damage has resulted from these great earthquakes. But as devastating as such events can be, these recent great quakes have come with a silver lining: They coincide with unprecedented advances in technological and scientific capacity for learning from them.

"We previously had very limited information about how ruptures grow into great earthquakes and interact with regions around them," said seismologist Thorne Lay of the University of California at Santa Cruz. "So we are using the recorded data for these recent events to guide our understanding of future earthquakes. We've gained a new level of appreciation for how one earthquake can influence events in other zones."

High on the list of areas ripe for a great quake is Cascadia, the Pacific Northwest, where the risk for great quakes had long been under appreciated. Evidence began surfacing about 20 years ago that there had been a great quake in the region in the year 1700. Since then the view of the great quake risk in Cascadia has shifted dramatically.

"We don't know many details about what happened in 1700," said Lay. There were no instruments back then to observe and record it. And so the best way to try and understand the danger and what could happen in Cascadia is to study the recent events elsewhere.

Over the last decade Lay and his colleagues have been able to gather fine details about these giant earthquakes using data from an expanded global networks of seismometers, GPS stations, tsunami gauges, and new satellite imaging capabilities such as GRACE, InSAR, and LandSAT interferometry. Among the broader conclusions they have come to is that great quakes are very complicated and idiosyncratic. Lay will be presenting some of those idiosyncrasies at the meeting of the Geological Society of America in Vancouver on Oct. 21.

"What we've seen is that we can have multiple faults activated," said Lay. "We've seen it off Sumatra and off Japan. Once earthquakes get going they can activate faulting in areas that were thought not physically feasible."

The great Sumatra-Andaman earthquake of Dec. 26, 2004, for instance, unzipped a 1,300 kilometer long segment of the subduction zone and unleashed one of history's most destructive, deadly tsunamis. Much of the rupture was along a region with very limited plate convergence. In Japan, the Kuril Islands, and the Solomon Islands, great mega-thrust ruptures have ruptured portions of the subduction zones that were thought too warm or weak to experience earthquakes.

"These earthquakes ruptured right through areas that had been considered to have low risk," said Lay. "We thought that would not happen. But it did, so we have to adjust our understanding."

Perhaps the best recent analogy to Cascadia is off the coast of Iquique, Chile, said Lay. There had been a great quake in 1877, and a conspicuous gap in quakes ever since. Like the 1700 Cascadia earthquake, there is little data for the 1877 event, which killed more than 2,500 people. In both subduction zones, the converging plates are thought to be accumulating strain which could be released in a very large and violent rupture. On April 1 of this year, some of that strain was released offshore of Iquique. There was a Mw8.1 rupture in the northern portion of the seismic gap. But it involved slip over less than 20 percent of the region that seismologists believe to have accumulated strain since 1877.

"We have no idea why only a portion of the 1877 zone ruptured," said Lay. "But clearly, 80 percent of that zone is still unruptured. We don't have a good basis for assessment of how the rest will fail. It's the same for Cascadia. We don't know if it always goes all at once or sometimes in sequences of smaller events, with alternating pattern. It is prudent to prepare for the worst case of failure of the entire region in a single event, but it may not happen that way every time."

What is certain is that studying these recent big earthquakes has given geophysicists the best information ever about how they work and point to new ways to begin understanding what could be in Cascadia's future.

Source: Geological Society of America