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Study eyes global jellyfish populations

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Are jellyfish numbers increasing globally? One recent study suggests decadal fluctuations. Photo courtesy NOAA.

More long-term and widespread monitoring needed to pinpoint trends

By Summit Voice

FRISCO —Global jellyfish populations appear to fluctuate on a decadal basis, including an increase in the 1990s and early 2000s that has led to the current perception of an overall global increase in jellyfish abundance.

But reports that jellyfish are steadily increasing may be unfounded, according to a recent study led by researchers from the Dauphin Island Sea Lab in Alabama and the National Oceanography Centre, Southampton, UK, who concluded there is no robust evidence for a global increase in jellyfish over the past two centuries.

The researchers did find a hint of a slight increase in jellyfish since 1970, although this trend was countered by the observation that there was no difference in the proportion of increasing vs. decreasing jellyfish populations over time. Continue reading

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Jellyfish not taking over the world — yet

Recent reports on jellyfish proliferation may be overstated

Researchers hope to unravel some jellyfish mysteries with a global monitoring project. PHOTO COURTESY ANNA FIOLEK, NOAA.

By Summit Voice

SUMMIT COUNTY — Much to SpongeBob’s chagrin, reports that jellyfish are taking over the world’s oceans may be exaggerated and unsupported by any hard evidence or scientific analyses, according to a research team with expertise on gelatinous organisms.

A new global collaborative study conducted at UC Santa Barbara’s National Center for Ecological Analysis and Synthesis suggests that jellyfish populations fluctuate on a decadal scale, but that more research is needed to determine whether there are other factors in play, and whether there are long-term trends on a global or regional scale.

The researchers don’t deny that blooms of jellyfish have clogged fising nets and choked intake lines for power plants. But they say that widespread reporting of those incidents has created a perception that the world’s oceans are experiencing increases in jellyfish due to human activities such as global warming and over-harvesting of fish. Continue reading

Oil working its way up the Gulf of Mexico food chain

Scientists working in the Gulf of Mexico are tracking BP's spilled oil as it works its way up the food web, from bacteria to plankton. PHOTO COURTESY NOAA.

Measuring relative levels of carbon isotopes helps researchers determine how the oil may move through the marine ecoystem

By Summit Voice

SUMMIT COUNTY — Just a couple of days after biologists discovered a patch of oil-damaged coral a few miles from BP’s failed Macondo well, another round of research shows that non-toxic carbon from the oil is quickly working its way up the food chain, from bacteria to plankton, which forms the basis of the marine ecosystem as an important food source for larger animals.

“Recently, much has been made of where the oil went. Because of the magnitude of the spill, the fact that the oil seemed to have ‘disappeared’ so quickly made many people uncomfortable with the unprecedented use of chemical dispersants to move the oil from its floating form on top of the water to micro-droplets within the water,” said lead author Dr. Monty Graham.

“We showed with little doubt that oil consumed by marine bacteria did reach the larger zooplankton that form the base of the food chain. These zooplankton are an incredibly important food-source for many species of fish, jellyfish and whales,” Graham said.Graham and his co-researchers measured the impact of the oil by tracing carbon isotopes, according to a press release from the Dauphin Island Sea Lab. Continue reading

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