Green Stuff: eco-news
New discoveries about reefs, pinniped evolution, and climate change.
Canadian Museum of Nature/AP
Reef resilience found in no-fishing zones
A new study supports an emerging consensus among marine biologists: If a reef is off limits to fishing, it recovers from disturbances, human-caused or otherwise, more quickly than if itâ€™s fished. The study, which appears in the online journal Aquatic Conservation: Marine and Freshwater Ecosystems, identified certain â€śsuper reefsâ€ť off East Africa â€“ a triangle between Madagascar, northern Mozambique, and southern Kenya â€“ as especially resilient and a potential focus for conservation efforts.
When high temperatures hit in 1998, 45 percent of the regionâ€™s corals died. But while fished areas remain degraded, Tanzaniaâ€™s reefs, which were off limits to fishing, have recovered. The study also found that reefs with more complex structures and greater variation in water temperature and currents recovered more quickly than more uniform sites. Complexity leads to resilience, the authors conclude.
Fossil find may be missing link to seal, sea lion, walrus
Researchers from the United States and Canada have found the fossil skeleton of a newly discovered carnivorous animal, Puijila darwini. New research suggests Puijila is a â€śmissing linkâ€ť in the evolution of the group that today includes seals, sea lions, and the walrus. The April 23 issue of the journal Nature contains the analysis of the skeleton and support for the hypothesis that the origins of these pinnipeds â€“ fin-footed, semimarine mammals â€“ can be found in the Arctic.
Modern seals, sea lions, and walruses all have flippers, limb adaptations for swimming in water. These adaptations evolved over time, as some terrestrial animals moved to a semiaquatic lifestyle. Until now, the morphological evidence for this transition from land to water was weak.
Critical turning point can trigger abrupt climate change
Ice ages are the greatest natural climate changes in recent geological times. Their rise and fall are caused by slight changes in the Earthâ€™s orbit around the sun due to the influence of the other planets. But we donâ€™t know the exact relationship between the changes in the Earthâ€™s orbit and the changes in climate.
New research from the Niels Bohr Institute at the University of Copenhagen indicates that there can be changes in the levels of carbon dioxide in the atmosphere that suddenly reach a critical turning point and trigger dramatic climate changes. The results are published in Paleoceanography, a journal of the American Geophysical Union.