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Invertebrates Sleep

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Transparent octopus larvae showing the brain, the white cloudy stuff between its eyes.  My science-geek book club just finished reading Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness by Peter Godfrey-Smith. This got me going down the rabbit hole, not of consciousness exactly, but sleep.    Since Octopods are wicked smart, the expectation is that their sleep patterns would be akin to those of vertebrates, most of which are kind of smart, while other lowly  dumb  invertebrates would exhibit different sleep patterns. On the other hand, since sleep is an ancient process, maybe braininess does not influence the pattern.   Jellys and flatworms have sleep-like states and lack a centralized nervous system, suggesting that sleep appeared early in the history of animal life. Thus sleep appears to be a fundamental biological function for all animals; well, maybe not sponges. It’s very hard to tell if a sponge is sleeping. We know some reasons...
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Quiet Oceans

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H. ampullatus , the Northern bottlenose Whale As pointed out in one of the most important papers for marine science in decades (Duarte et al. 2020), during World War I and  II, an unexpected benefit was observed: Fish populations rebounded after fishing boats were withdrawn from the oceans. The hiatus allowed fish stocks to replenish, likely delaying their collapse by decades.  This recovery of marine life demonstrates the resilience within these communities. There is hope for the ocean yet.    Did COVID create a similar situation? It turns out that the slowdown in shipping and ocean traffic generally quieted the oceans. What effects did this quieting have on overall ocean ecosystems?   In areas like the Hauraki Gulf Marine Park in New Zealand, boat traffic almost completely stopped, and underwater noise dropped by about 2/3 within 12 hours . This  reduction expanded the communication ranges of fish and dolphins by up to  65% . Dolphins' calls can trav...
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Death comes to the Amazon

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 Death comes to the Nile Amazon Amazon River Dolphin (modified from Scientific American). Hot temperatures are again hitting the Amazon River and its tributaries. In 2023, temperature spikes in and around Lago Tefé killed hundreds of river dolphins. Tefé is located in the heart of Amazonas, approximately 400 miles up the Amazon River from Manaus, the capital of the region. As a whole, the region is sparsely populated, as Manaus is one of the two cities that have a large population of over 1 million.  Once again, temperatures are rising, and combined with regional droughts, this has created another deadly zone. In November, the lake's waters reached 41 degrees Celsius (105.8 degrees Fahrenheit). David Hannah said, "Drought conditions often coincide with high atmospheric temperatures, and such trends will become more intense and frequent with climate change." Additionally, droughts have lowered the lake levels, leading to new problems. The issue extends beyond just one lak...
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Have a Heart

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  Figure 1. Shark Heart (author's original image) Hearts have been on my mind lately.    We, humans that is, of course, have a four-chambered heart. We have two atria and two ventricles. The right side carries blood low in oxygen, and the left side, having just returned from the lungs, carries blood high in oxygen. We share this heart anatomy with the other mammals, birds, and crocodiles.    Found in most amphibians and some reptiles is a three-chambered heart with two atria and one ventricle, which allows mixing of oxygenated and deoxygenated blood. That is a bit freaky in my view: oxygenated blood and deoxygenated blood mix in the central chamber; whoever thought this was a good design?    Most animals in the kingdom do not have hearts with 3 or 4 chambers. The most speciose vertebrates, scaly fishes, have a two-chambered heart. Suppose we follow the blood flow in 18-spined sculpin (AKA long-horned sculpin),  Myoxocephalus octodecimspinosus...
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