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Earth & Climate

The Hidden Threat to Kelp Forests: How Competition from Algae is Reshaping the Gulf of Maine

New research shows how rapidly proliferating turf algae are waging ‘chemical warfare’ to inhibit the recovery of kelp forests along Maine’s warming coast.

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The Gulf of Maine, once home to thriving kelp forests that provided a haven for marine life, is now facing an unprecedented threat. Climate change has led to warming waters, causing kelp forests to collapse and turf algae species to take over. This shift from dense canopies of tall kelp to low-lying mats of turf algae is driving biodiversity loss and altering the flow of energy and nutrients through reef ecosystems.

New research published in Science has revealed that turf algae release chemicals that can kill young kelp, creating a feedback loop where more turf algae means more harmful chemicals, further inhibiting recovery and reinforcing kelp forest collapse. This chemically-mediated interaction, known as allelopathy or chemical warfare, highlights an indirect way climate change is reshaping ocean ecosystems.

The study, led by researchers at Bigelow Laboratory for Ocean Sciences, involved a collaboration with experts from the University of Maine, University of California Riverside, University of Tübingen, Perry Institute for Marine Science, and Harvard University. They conducted extensive field surveys, advanced chemical analysis, and novel lab experiments to understand the complex interactions between kelp forests and turf algae.

The research showed that once turf algae are established, they can inhibit kelp recovery by taking up space on the reef or harboring small grazers that eat baby kelp. In tropical ecosystems, similar changes in the chemical environment have been shown to prevent recovery of foundational species.

The study’s lead author, Shane Farrell, a UMaine doctoral candidate, emphasized that this shift from kelp to turf is analogous to a terrestrial forest transitioning into a grassland. With the loss of kelp forests, biodiversity, productivity, and ecosystem services provided to humans are decreased.

While previous work has shown that ocean warming is the primary driver of kelp forest decline in the Gulf of Maine, these new findings highlight the complexity of the issue. The researchers found that the chemical environment of a kelp forest is distinct from a turf-dominated reef, with less than 2% of the chemical features identified.

The study’s senior author, Doug Rasher, emphasized that this research is powerful because it moves logically from describing a pattern in nature to revealing the chemical landscape of kelp forests and pointing out that turf algae prevent kelp recruitment.

The experiments conducted by the researchers showed that gametophyte survival declined dramatically when exposed to chemicals released by turf algae, confirming that the new chemical environment is directly responsible for kelp mortality.

This study has significant implications for promoting kelp forest recovery in the Gulf of Maine. Once turf algae are established, simply curbing global carbon emissions and reversing ocean warming will not bring back the kelp forests. Local interventions to remove the turf algae before kelp will actually recover are necessary.

The research was supported by various organizations, including the NSF Established Program to Stimulate Competitive Research, the Louise H. & David S. Ingalls Foundation, the PADI Foundation, and the German Research Foundation.

Air Quality

Unlocking the Secrets of Environmental DNA: A Powerful Tool for Wildlife and Human Surveillance

Environmental DNA from the air, captured with simple air filters, can track everything from illegal drugs to the wildlife it was originally designed to study.

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Dublin, a city known for its warm welcome and lively traditional music, has an unsuspecting secret – the air is teeming with DNA from various species. From cannabis to bobcats, even magic mushrooms – at least their DNA – are floating on the breeze. A new study reveals that this phenomenon can be leveraged to track wildlife, viruses, and other substances in unprecedented ways.

David Duffy, Ph.D., a professor of wildlife disease genomics at the University of Florida, has developed innovative methods for deciphering environmental DNA (eDNA). His lab has been studying sea turtle genetics using eDNA from water samples. Expanding on this research, they’ve created tools to study every species – including humans – from DNA captured in environmental samples like air filters.

“What we’re finding is that you can get intact large fragments of DNA from the air,” Duffy said. “That means you can study species without directly having to disturb them.” This approach opens up vast possibilities for tracking all species in an area simultaneously, from microbes and viruses to vertebrates like bobcats and humans.

A proof-of-concept experiment demonstrated that researchers could pick up signs of hundreds of different human pathogens from the Dublin air, including viruses and bacteria. This surveillance method can aid scientists in tracking emerging diseases. Additionally, it can track common allergens, such as peanut or pollen, more precisely than current methods allow.

In another test, Duffy’s lab identified the origin of bobcats and spiders whose DNA was collected from air filters in a Florida forest. This technique allows researchers to track endangered species without having to lay eyes on them or gather scat samples – all while knowing their exact origin is crucial for conservation efforts.

This powerful analysis is paired with impressive speed and efficiency, as demonstrated by the team’s ability to process DNA for every species in as little as a day using compact, affordable equipment, and software hosted in the cloud. This quick turnaround is orders of magnitude faster than was possible just a few years ago, making advanced environmental studies more accessible to scientists worldwide.

However, Duffy and his collaborators have called for ethical guardrails due to the potential for sensitive human genetic data to be identified using these tools.

“It seems like science fiction, but it’s becoming science fact,” Duffy said. “The technology is finally matching the scale of environmental problems.” As researchers continue to explore the capabilities of eDNA, they must also address the challenges and implications of this rapidly developing field.

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Early Climate

First Direct Observation of Trapped Waves that Shook the World in 2023

A new study has finally confirmed the theory that the cause of extraordinary global tremors in September — October 2023 was indeed two mega tsunamis in Greenland that became trapped standing waves. Using a brand-new type of satellite altimetry, the researchers provide the first observations to confirm the existence of these waves whose behavior is entirely unprecedented.

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The article begins by describing an extraordinary global seismic signal that occurred in September 2023. A peculiar pattern of earthquakes was observed every 90 seconds over nine days, only to be repeated a month later. Initially, two scientific studies proposed that these anomalies were caused by massive tsunamis triggered in a remote East Greenland fjord due to the warming of an unnamed glacier. The resulting waves became trapped in the fjord system, creating standing waves (seiches) that undulated back and forth.

However, despite extensive research, no direct observations of these seiches existed until now. Not even a Danish military vessel visiting the fjord three days into the first seismic event was able to detect the wave responsible for the mystery signals.

A new study from researchers at the University of Oxford has employed cutting-edge analysis techniques on satellite altimetry data from the Surface Water Ocean Topography (SWOT) mission, launched in December 2022. The SWOT satellite measures ocean and surface water levels with unprecedented accuracy along a swath 30 miles wide using its Ka-band Radar Interferometer (KaRIn) instrument.

Utilizing KaRIn data, the researchers created elevation maps of the Greenland Fjord at various time points following the tsunamis. These maps showed clear, cross-channel slopes with height differences of up to two meters. Crucially, the slopes in these maps occurred in opposite directions, indicating that water moved backwards and forwards across the channel.

To confirm their theory, the researchers linked these observations to small movements of the Earth’s crust measured thousands of kilometers away, reconstructing weather and tidal conditions to rule out alternative explanations.

Lead author Thomas Monahan stated: “Climate change is giving rise to new, unseen extremes. These extremes are changing the fastest in remote areas, such as the Arctic, where our ability to measure them using physical sensors is limited. This study shows how we can leverage the next generation of satellite earth observation technologies to study these processes.”

Co-author Professor Thomas Adcock added: “This study is an example of how the next generation of satellite data can resolve phenomena that has remained a mystery in the past. We will be able to get new insights into ocean extremes such as tsunamis, storm surges, and freak waves. However, to get the most out of these data we will need to innovate and use both machine learning and our knowledge of ocean physics to interpret our new results.”

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Ancient DNA

The Tipping Point: Scientists Warn of West Antarctic Ice Sheet Collapse and its Devastating Consequences

Collapse of the West Antarctic Ice Sheet could be triggered with very little ocean warming above present-day, leading to a devastating four meters of global sea level rise to play out over hundreds of years according to a new study. However, the authors emphasize that immediate actions to reduce emissions could still avoid a catastrophic outcome.

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The fate of the West Antarctic Ice Sheet (WAIS) hangs precariously in the balance, with scientists warning that the next few years will be crucial in determining its future. A recent study published in Communications Earth & Environment has shed light on the alarming consequences of WAIS collapse, which could trigger a devastating four meters of global sea level rise over hundreds of years.

The researchers from the Potsdam Institute for Climate Impact Research (PIK), NORCE, and Northumbria University in the UK conducted extensive model simulations spanning 800,000 years to understand how the vast Antarctic Ice Sheet has responded to Earth’s climate fluctuations. Their findings revealed two stable states: one with WAIS intact, which is our current state, and another where the ice sheet has collapsed.

The primary driver of this collapse is rising ocean temperatures around Antarctica, which are mostly supplied by the ocean rather than the atmosphere. Once WAIS tips into the collapsed state, it would take several thousands of years for temperatures to drop back to pre-industrial conditions, reversing the damage.

“We have two stable states: one with WAIS intact and another where it has collapsed,” said lead author David Chandler from NORCE. “Once tipping has been triggered, it’s self-sustaining and seems very unlikely to be stopped before contributing to about four meters of sea-level rise. And this would be practically irreversible.”

The consequences of WAIS collapse would be catastrophic, with four meters of sea level rise projected to displace millions of people worldwide and wreak havoc on coastal communities.

However, there is still hope for a better outcome. Immediate actions to reduce emissions could avoid a catastrophic outcome, giving us a narrow window to act before it’s too late.

“It takes tens of thousands of years for an ice sheet to grow, but just decades to destabilise it by burning fossil fuels,” said co-author Julius Garbe from PIK. “Now we only have a narrow window to act.”

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