Low oxygen in coastal waters impairs fish reproductionAugust 29, 2007University of Texas at Austin marine scientist finds hypoxia acts as endocrine disruptor PORT ARANSAS, Texas-Low oxygen levels in coastal waters interfere with fish reproduction by disrupting the fishes' hormones, a marine scientist from The University of Texas at Austin Marine Science Institute has found. Incidents of seasonal low levels of oxygen, known as hypoxia, have increased dramatically in coastal waters throughout the world over the past few decades, largely as a result of increased run-off from human agricultural and industrial activities. Hypoxia's long-term impact on marine animal populations is unknown. Dr. Peter Thomas found that both male and female fish collected from seasonally hypoxic waters in Florida's Pensacola Bay estuaries had little ovarian and testicular growth, low egg and sperm production, and low levels of reproductive hormones during a time a year when they would normally be increasing in preparation for reproduction. "This study provides the first clear evidence that a wild population of estuarine fish has experienced reproductive impairment through hypoxia," said Thomas, professor of marine science. "We rarely find such a dramatic reproductive impairment in both male and female fish collected from degraded environments, such as those contaminated with pollutants." Thomas' research was published online this week in Proceedings of the Royal Society B. Laboratory studies showed that hypoxia caused endocrine disruption through decreasing levels in the brain of a chemical important for brain function called serotonin. The decrease in serotonin was caused by a decrease in an enzyme that plays a role in the serotonin synthesis pathway. Atlantic croaker is one of the most common inshore fish species along the coasts of the southeastern Atlantic Ocean and Gulf of Mexico, and Thomas said that the croaker is representative of many inshore fish. "This study suggests that when persistent coastal hypoxia occurs, there is a potential long-term threat to fish populations and fishery resources," said Thomas. "With worldwide increases in hypoxia, it's something we must be concerned about, because so many people rely on fishing for their livelihood." Thomas' future studies will aim to further elucidate the effects of hypoxia on fish endocrine and reproductive systems at the molecular level. He is also pursuing similar work on reproductive impairment in croaker from hypoxic waters surrounding the so-called "Dead Zone" off the coast of Louisiana, which is an area of almost no oxygen that this year covered 7,900 square miles. University of Texas at Austin |
|||||||||||||||||||||
| Related Hypoxia Current Events and Hypoxia News Articles Active hearing process in mosquitoes A mathematical model has explained some of the remarkable features of mosquito hearing. In particular, the male can hear the faintest beats of the female's wings and yet is not deafened by loud noises. 1930s drug slows tumor growth Drugs sometimes have beneficial side effects. A glaucoma treatment causes luscious eyelashes. A blood pressure drug also aids those with a rare genetic disease. A woman in space In the early years of the "space race" (1957-1975) two men sought to test a scientifically simple yet culturally complicated theory: that women might be innately better suited for space travel than men. Diesel exhaust is linked to cancer development via new blood vessel growth Scientists here have demonstrated that the link between diesel fume exposure and cancer lies in how diesel exhaust induces the growth of new blood vessels that supply solid tumors. The researchers found that in both healthy and diseased animals, more new blood vessels sprouted in mice exposed to diesel exhaust than did in mice exposed to clean, filtered air. This suggests that previous illness isn't required to make humans susceptible to the damaging effects of the diesel exhaust. Chemotherapy resistance: Checkpoint protein provides armor against cancer drugs Cell cycle checkpoints act like molecular tripwires for damaged cells, forcing them to pause and take stock. Blood-flow metabolism mismatch predicts pancreatic tumor aggressiveness Researchers from Turku, Finland, have identified a blood-flow glucose consumption mismatch that predicted pancreatic tumor aggressiveness, according to results of a study published in Clinical Cancer Research, a journal of the American Association for Cancer Research. New light-emitting biomaterial could improve tumor imaging, study shows A new material developed at the University of Virginia - an oxygen nanosensor that couples a light-emitting dye with a biopolymer - simplifies the imaging of oxygen-deficient regions of tumors. Biologists ID molecular basis of high-altitude adaptation in mice Biologists have long known how adaptive evolution works. New mutations arise within a population and those that confer some benefits to the organism increase in frequency and eventually become fixed in the population. Unraveling how cells respond to low oxygen Gary Chiang, Ph.D., and colleagues at Burnham Institute for Medical Research (Burnham) have elucidated how the stability of the REDD1 protein is regulated. Holding Breath for Several Minutes Elevates Marker for Brain Damage Divers who held their breath for several minutes had elevated levels of a protein that can signal brain damage, according to a new study from the Journal of Applied Physiology. More Hypoxia Current Events and Hypoxia News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||