Jellyfish blooms have finding their way into the media recently – clogged nets for fishermen, stinging waters for tourists, even choked intake lines for power plants – creating a perception that the world’s oceans are experiencing increases in jellyfish due to human activities such as global warming and overfishing.

A new study conducted at UC Santa Barbara’s National Center for Ecological Analysis and Synthesis (NCEAS) and published in the latest issue of BioScience questions this view. The study’s authors note that while there have been jellyfish blooms in certain areas (notably Giant Jellyfish in Japan), other regions have seen jellyfish declines or fluctuations. As noted in the press release,

Increased speculation and discrepancies about current and future jellyfish blooms by the media and in climate and science reports formed the motivation for the study. “There are major consequences for getting the answer correct for tourism, fisheries and management decisions as they relate to climate change and changing ocean environments,” says Duarte. “The important aspect about our synthesis is that we will be able to support the current paradigm with hard scientific data rather than speculation.”

The study has also led to the formation of the improbably named JEDI (Jellyfish…

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Three new studies looking at ocean acidification have shed light on some of its effects on marine organisms.

Since the beginning of the industrial revolution, human activities have accelerated the release of carbon dioxide into the atmosphere as carbon dioxide mixes with water. The two molecules combine to become carbonic acid, making seawater more acidic. As billions of molecules combine and go through this process, the overall pH of the oceans decreases, causing ocean acidification.

The first study, from Australia’s ARC Centre of Excellence for Coral Reef Studies and published Nature Climate Change, documents the the effects of rising CO2 emissions on the nervous systems of coral fishes. Based on several years of observations of how baby coral fishes react to an environment with high levels of dissolved CO2, researchers have found that elevated acidity levels directly interfere with fish neurotransmitter functions, impeding their ability to hear, smell, turn and evade predators. Prof. Philip Munday, one of the study’s authors, noted that:

“We’ve now established it isn’t simply the acidification of the oceans that is causing disruption – as is the case with shellfish and plankton with chalky skeletons – but the actual dissolved CO2 itself is damaging the fishes’…

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A group of 19 scientists from five research organizations have conducted the broadest field study of ocean acidification to date using sensors developed at Scripps Institution of Oceanography, UC San Diego.

It is an important step toward understanding how specific ecosystems are responding to the change in seawater chemistry that is being caused as the oceans take up extra carbon dioxide produced by human greenhouse gas emissions, said its authors. “These data represent a critical step in understanding the consequences of ocean change: the linkage of present-day pH exposures to organismal tolerance and how this translates into ecological change in marine ecosystems,” the authors wrote.

“These pH time series create a compelling argument for the collection of more continuous data of this kind.” Ocean acidification research is a relatively new study topic as scientists have only appreciated the potential extent of acidification within the last decade. As greenhouse gas emissions have accelerated in the past century, the oceans have taken up about a third of the carbon dioxide produced by human activities. That excess beyond natural levels increases amounts of carbonic acid in seawater. Acidification also limits the amount of carbonate forms that are needed by marine invertebrates such as…

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SOSF-sponsored marine podcast Naked Oceans is back for a second series, with this month’s episode focusing on life and death in the ancient seas. Listen in to learn about how life emerged from the oceans – and how it almost came to an end, as well as what the past can tell us about the future of life in the seas. As always, you can download the episodes for free at the Naked Oceans website or on iTunes.

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In July 2012, the 12 th ICRS will welcome over 2,500 delegates from around to world to the tropical city of Cairns, Australia, to attend 1,500 talks and posters presenting the latest research on the world’s coral reefs. The Reef Sharks and Coral Reefs mini-symposium will focus on research into the ecological roles of reef sharks in coral reef ecosystems; the environmental, biological, ecological and behavioural factors affecting the strength and dependence of these interactions; techniques for studying reef shark ecology; and methods to monitor reef shark populations. The mini-symposium will also explore the implications of reef shark declines, and the ramifications of recent research for their conservation and management.

Registration opens: 1 August 2011. Deadline for abstract submission: 1 February 2012. Early-bird registration closes: 1 March 2012. Click here to visit the website for the 12th International Coral Reef Symposium.

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The first 12-episode season of SOSF-sponsored podcast Naked Oceans, from Cambridge University-based Naked Scientists, has drawn to a close. We’re happy to announce that a second series is already in the works, but in the meantime, here is a recap of all the episodes so far:

1. July 2010. The problem of oil spills

We investigate the impacts of oil spills on the marine environment, hunting down the hidden world of microbes in Louisiana wetlands, tracing the fingerprint of oil in open oceans plankton communities, and we discuss the likely fallout from the Deepwater Horizon oil spill in the Gulf of Mexico. And 14 years on, we head to the south coast of Wales to find some of the survivors of the Sea Empress Oil Spill.

2. August 2010. Climate change and the oceans

One of the most pervasive problems in the oceans today, we dive into the science of climate change to find out what changes are we already seeing and what the prospects are for the future. We call in on the Arctic and the Antarctic to find out what’s going on in some of the most vulnerable parts of the…

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A high-level international workshop on the state of the world’s oceans took place at the University of Oxford earlier this year, where 27 participants from 18 organisations in 6 countries concluded that if the current trajectory of damage continues, the world’s ocean is at high risk of entering a phase of extinction of marine species unprecedented in human history.

The scientific panel looked at the latest research focusing on the primary threats to the marine environment and came to some stark conclusions:

The combination of stressors on the ocean is creating the conditions associated with every major extinction of species in the Earth’s history. The rate of degeneration in the ocean is far faster than anyone has expected. Many of the negative impacts previously identified are worse than anyone had predicted. Although difficult to assess because of the unprecedented speed of change, the first steps to globally significant extinction may have begun with a rise in the extinction threat to species such as reef-forming corals.

Dr Alex Rogers, Scientific Director of the International Programme on the State of the Ocean (IPSO) which convened the workshop said:

“The findings are shocking. As we considered the cumulative effect…

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