Acidification, predators pose double threat to oysters
New research reveals that the “once-booming, now struggling” West coast Olympia oyster may face a double threat from ocean acidification and invasive predators. The Olympica oyster population collapsed from overfishing in the late 1800s and never recovered. Now, many additional stressors will make recovery even less likely. When raised under ocean conditions predicted for the end of this century, the oysters were smaller but the invasive snails were not affected. In the simulated higher carbon dioxide conditions, the snails ate 20 percent more juvenile oysters compared to current conditions.
Key species of algae shows effects of climate change over time
A study of marine life in the northeast Pacific Ocean suggests that ocean acidification is altering biodiversity. Researchers examined the competitive dynamics among crustose coralline algae – a group of algae that grow skeletons made of calcium carbonate, similar to shelled organisms like oysters. As the ocean becomes more acidic, crustose coralline algae have a hard time producing their hard skeletons, which makes it a “poster organism” for studying ocean acidification. In previous studies where four species of crustose coralline algae were placed together to see how they would compete, one species (Pseudolithophyllum muricatum) ‘won’ nearly 100 percent of the time over the other three species because of its ability to grow a much thicker skeleton than the other species. Now, P. muricatum’s skeleton only grows half as thick, making it roughly equal to the three others because it has to use more energy combating the stress of changing ocean conditions.
Swimming dolphins don’t need to cheat
A paper published by Sir James Gray in 1936 stated that dolphins didn’t have the muscle to produce the thrust they need to swim as fast as they do. This concept was called “Gray’s paradox,” and has resulted in many studies trying to determine how dolphins reduce drag – knowledge which could be applied to improving torpedoes and even swimsuits. But a news study reveals that swimming dolphins “generate thrust just fine,” so there is no need for a paradox. Researchers filmed dolphins swimming through a curtain of tiny air bubbles. The shifts in bubble position let the researchers determine how much thrust the dolphins produced. At the end of the article there’s a short clip that shows the dolphin swimming…check it out!
Copyright © 2014 by Marine Science Today, a publication of Marine Science Today LLC.