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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…)

Suggested Explanation for Glowing Seas–Including Currently Glowing California Seas

By Guest PostOctober 20, 2011Environment, Scienceabundance of protons, bioluminescence, blue flashes, california waters, channels in membranes, coastal california waters, dinoflagellates, electrical events, electrical impulses, Environment, j woodland hastings, luciferase, marine environments, mechanical stimulation, organism, potential mechanism for bioluminescence, produce toxins, protein, scintillons, unicellular plankton, vacuole, voltage gated proton channels

*Potential mechanism for dazzling blue flashes of light in oceans identified*

It has long been known that spectacular blue flashes–a type of bioluminescence–that are visible at night in some marine environments (currently including coastal California waters) are caused by tiny, unicellular plankton known as dinoflagellates. However, a new study has, for the first time, detailed the potential mechanism for this bioluminescence.

The study, which was partially funded by the National Science Foundation, is reported by Susan Smith of Emory School of Medicine, Thomas DeCoursey of Rush University Medical Center and colleagues in the Oct. 17, 2011 issue of the Proceedings of the National Academy of Sciences (PNAS). (more…)

Study Assesses Nations’ Vulnerabilities to Reduced Mollusk Harvests from Ocean Acidification

By Guest PostAugust 7, 2011Environmentatmosphere, carbon dioxide emissions, carbonate shells or skeletons, changes in ocean chemistry, CO2, co2 levels, corrosive environment, fossil fuel, gambia, haiti, hauke kite powell, industrial revolution, Madagascar, marine ecosystems, marine environments, marine fisheries, mollusk aquaculture, mollusk harvests, mollusks, mozambique, noelle lucey, ocean acidification, ph, sarah cooley, scott doney, senegal, shellfish, transition decade, whoi, woods hole oceanographic institution, world oceans

Changes in ocean chemistry due to increased carbon dioxide (CO2) emissions are expected to damage shellfish populations around the world, but some nations will feel the impacts much sooner and more intensely than others, according to a study by scientists at Woods Hole Oceanographic Institution (WHOI).

As CO2 levels driven by fossil fuel use have increased in the atmosphere since the Industrial Revolution, so has the amount of CO2 absorbed by the world’s oceans, leading to changes in the chemical make-up of seawater. Known as ocean acidification, this decrease in pH creates a corrosive environment for some marine organisms such as corals, marine plankton, and shellfish that build carbonate shells or skeletons. (more…)

UF Pine lsland Pollen Study Leads to Revision of State’s Ancient Geography

By Guest PostMarch 3, 2011Scienceavon park formation, calusa indian village, david jarzen, deep injection well, early eocene, evolution of mammals, florida, flowering plants, fort myers, fossils, fredrick rich, geologic history, gray lignitic clay, jonathan bloch, limestone, marine environments, oligocene epoch, paleontologist, phytoplankton, pine island, pollen, sea level

GAINESVILLE, Fla. — A new University of Florida study of 45-million-year-old pollen from Pine Island west of Fort Myers has led to a new understanding of the state’s geologic history, showing Florida could be 10 million to 15 million years older than previously believed.

The discovery of land in Florida during the early Eocene opens the possibility for researchers to explore the existence of land animals at that time, including their adaptation, evolution and dispersal until the present. (more…)

Tag Archives: marine environments

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

Suggested Explanation for Glowing Seas–Including Currently Glowing California Seas

Study Assesses Nations’ Vulnerabilities to Reduced Mollusk Harvests from Ocean Acidification

UF Pine lsland Pollen Study Leads to Revision of State’s Ancient Geography