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Acidification and Low Oxygen Put Fish in Double Jeopardy
http://newsdesk.si.edu/releases/acidification-and-low-oxygen-put-fish-double-jeopardy[font face=Serif][font size=5]Acidification and Low Oxygen Put Fish in Double Jeopardy[/font]
[font size=4]Chesapeake Fish More Likely To Die When Acidification and Low Oxygen Combine[/font]
May 10, 2016
[font size=3]Severe oxygen drops in the water can leave trails of fish kills in their wakes, but scientists thought adult fish would be more resilient to the second major threat in coastal waters: acidification. A new study published Tuesday from the Smithsonian Environmental Research Center (SERC) shows that is not entirely true—where fish are concerned, acidification can make low oxygen even more deadly.
Low oxygen and high acidity almost always go hand in hand. In coastal waters, nutrient pollution fuels the growth of algae and other organisms. As microbes, plants and animals take up oxygen through respiration, oxygen levels plummet to low levels or even zero. At the same time, acidity spikes as those same organisms release carbon dioxide. Worldwide, both low oxygen and acidity are expected to worsen as ocean temperatures rise. But until now, most research on how well fish cope has focused on either oxygen or acidification alone. This new study shows the consequences of the double threat: Fish exposed to low oxygen and high acidity can die at higher oxygen levels, suggesting the low-oxygen thresholds considered “safe” might not be as safe as once thought.
“Those dissolved oxygen limits actually might not be as protective as we thought they were,” said Seth Miller, postdoctoral fellow and lead author of the study published in Marine Ecology Progress Series.
Even more surprising was the discovery that acidity hurt adult fish. While past research had uncovered dangers for juvenile fish and larvae, adults were thought to be more resilient to increases in acidity by virtue of the fact that their growth has slowed and they have stopped developing.
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[font size=4]Chesapeake Fish More Likely To Die When Acidification and Low Oxygen Combine[/font]
May 10, 2016
[font size=3]Severe oxygen drops in the water can leave trails of fish kills in their wakes, but scientists thought adult fish would be more resilient to the second major threat in coastal waters: acidification. A new study published Tuesday from the Smithsonian Environmental Research Center (SERC) shows that is not entirely true—where fish are concerned, acidification can make low oxygen even more deadly.
Low oxygen and high acidity almost always go hand in hand. In coastal waters, nutrient pollution fuels the growth of algae and other organisms. As microbes, plants and animals take up oxygen through respiration, oxygen levels plummet to low levels or even zero. At the same time, acidity spikes as those same organisms release carbon dioxide. Worldwide, both low oxygen and acidity are expected to worsen as ocean temperatures rise. But until now, most research on how well fish cope has focused on either oxygen or acidification alone. This new study shows the consequences of the double threat: Fish exposed to low oxygen and high acidity can die at higher oxygen levels, suggesting the low-oxygen thresholds considered “safe” might not be as safe as once thought.
“Those dissolved oxygen limits actually might not be as protective as we thought they were,” said Seth Miller, postdoctoral fellow and lead author of the study published in Marine Ecology Progress Series.
Even more surprising was the discovery that acidity hurt adult fish. While past research had uncovered dangers for juvenile fish and larvae, adults were thought to be more resilient to increases in acidity by virtue of the fact that their growth has slowed and they have stopped developing.
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