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NASA Responds to California’s Evolving Drought

By Guest PostFebruary 26, 2014Sciencebay area, california, central valley, drought, dwr, earth, evolving drought, flood control, freshwater, groundwater, icesat 2, jeanine jones, michael freilich, NASA, nasa satellite, san francisco, san joaquin valley, usgs, water cycle

NASA is partnering with the California Department of Water Resources (DWR) to develop and apply new technology and products to better manage and monitor the state’s water resources and respond to its ongoing drought.

NASA scientists, DWR water managers, university researchers and other state resource management agencies will collaborate to apply advanced remote sensing and improved forecast modeling to better assess water resources, monitor drought conditions and water supplies, plan for drought response and mitigation, and measure drought impacts. (more…)

Ancient sharks reared young in prehistoric river-delta nursery

By Guest PostJanuary 9, 2014Nature, Scienceadult bandringa, ancient, ancient sharks, bandringa fossils, bandringa sharks, electroreceptors, fossilized egg, freshwater, hawaii, illinois state museum, journal, lauren sallan, long snouted, marine, mazon creek, mechanoreceptors, michael coates, ohio, paddlefish, paleontologist, Pennsylvania, prehistoric, river delta nursery, river delta system, saltwater shark migration, sawfish, sensory organs, shark migration, shark nurseries, tiger sharks, university of chicago, university of michigan, upper midwest, vertebrate paleontology

ANN ARBOR — Like salmon in reverse, long-snouted Bandringa sharks migrated downstream from freshwater swamps to a tropical coastline to spawn 310 million years ago, leaving behind fossil evidence of one of the earliest known shark nurseries.

That’s the surprising conclusion of University of Michigan paleontologist Lauren Sallan and a University of Chicago colleague, who reanalyzed all known specimens of Bandringa, a bottom-feeding predator that lived in an ancient river delta system that spanned what is today the Upper Midwest. (more…)

An Ancient Biosonar Sheds New Light on the Evolution of Echolocation in Toothed Whales

By Guest PostMay 9, 2013Natureaarhus university, acoustic monitoring, ancient biosonar, aquatic mammals, Bangladesh, biosonar signals, bottlenose dolphin, denmark, earth, evolution of echolocation, evolutionary process, frants havmand jensen, freshwater, freshwater cetaceans, freshwater dolphins, ganges river dolphins, hole, low frequent click, mangrove forest, marine dolphins, marine environments, oceanographic institution, oldest species, peter teglberg madsen, platanistidae family, river habitats, river systems, toothed whales, woods

Some thirty million years ago, Ganges river dolphins diverged from other toothed whales, making them one of the oldest species of aquatic mammals that use echolocation, or biosonar, to navigate and find food. This also makes them ideal subjects for scientists working to understand the evolution of echolocation among toothed whales.

New research, led by Frants Havmand Jensen, a Danish Council for Independent Research | Natural Sciences postdoctoral fellow at Woods Hole Oceanographic Institution, shows that freshwater dolphins produce echolocation signals at very low sound intensities compared to marine dolphins, and that Ganges river dolphins echolocate at surprisingly low sound frequencies. The study, “Clicking in shallow rivers,” was published in the journal PLOS ONE. (more…)

Yale Study Reveals New Family Tree for Ray-Finned Fish

By Guest PostAugust 7, 2012Natureage of fishes, alex dornburg, bass, bonefishes, bonytongue fish, devonian period, dinosaurs, eels, evolutionary birthday, family tree, fishes, fossil record, freshwater, genetic analysis, kristen l kuhn, lineages of fish, mammals, ray finned fish, ron i eytan, salmon, second age, teleost fish, teleost lineages, teleosts, thomas near, tropical, tuna, yale university

The most common lineages of fish found today in oceans, lakes, and rivers evolved about the same time as mammals and birds, a new Yale University-led study shows.

The comparative genetic analysis of more than 200 fish species, reported the week of Aug. 6 in the Proceedings of the National Academy of Sciences, gave an earlier than expected evolutionary birthday to well-known teleost — or ray-finned — fish such as salmon, bass, or tuna.

The analysis also shows that the very earliest lineages of living teleost fish were eels and bonefishes, not tropical freshwater bonytongue fish as some scientists had proposed. (more…)

Tag Archives: freshwater

NASA Responds to California’s Evolving Drought

Ancient sharks reared young in prehistoric river-delta nursery

An Ancient Biosonar Sheds New Light on the Evolution of Echolocation in Toothed Whales

Yale Study Reveals New Family Tree for Ray-Finned Fish