Attack of the Killer Algae

Since 1991, French scientists and authorities have tried to destroy the seaweed by smothering the plants with salt, sucking them up with vacuum hoses, uprooting them by hand, and smothering them under tarps. In every case, the algae quickly grew back. Fortunately, eradication efforts in Southern California started early. Because both of the affected sites are located in nearly enclosed lagoons, scientists hope the seaweed can be completely wiped out before it spreads to the open ocean and beyond.

If the battle is successful, the next battle, believe it or not, will be with aquarium hobbyists who greatly prize the Caulerpa genus, which comprises 73 species, many of which are difficult to tell apart even for experts. When state legislators proposed a bill banning possession or sale of the entire genus, there was a nationwide outcry, saying that banning the entire genus would have dire effects on aquarium owners. In the end, legislators banned only nine Caulerpa species: three known to be invasive and six look-alikes. But many are concerned that the law will be unworkable because of the difficulty of telling Caulerpa species apart. The scientific consensus that all Caulerpas should be banned from the aquarium trade.

2 thoughts on “Attack of the Killer Algae”

  1. Um, just informing you of a somewhat confusing mistake in your article. This is a quote from it (the areas that need focus is in caps):
    “The SEAWEED NORMALLY DIES if the water temperature drops BELOW 21 DEGREES CELCIUS(70 degrees Fahrenheit). But specimens of the plant imported in the 1970’s by the Wilhelmina Zoo in Stuttgart, Germany somehow mutated in captivity, producing a strain that grows several times larger than normal, spreads much faster and can survive months in WATER AS COLD AS 50 DEGREES CELCIUS(10 degrees Fahrenheit)”.

    I don’t know how to convert to Fahrentheit, but I do know this: 50 degrees Celcius is over twice as hot as 21 degrees Celcius.

    Otherwise, cool article!

  2. Unfortunately you misunderstand the Celsius scale. 50 degrees Celsius is not even close to “twice as hot” as 21 degrees Celsius.  Absolute zero on the Celsius scale comes at -273.16 degrees (0 Kelvin). That means that 50°C is 323.16 K, and 21°C is 294.16 K, representing a temperature difference of just 9.86%, not two times. The starting (zero) point on the Celsius scale is simply the freezing point of water at normal atmospheric pressure; temperatures in Celsius cannot be used directly for “N times as hot” comparisons in the way you’ve described.

    It’s rather like if you and a friend went to a ballgame, and drove home in separate cars. Suppose you stopped for gas at the same gas station on the way home, 273.16 miles from the ballpark, and both reset your trip odometers to zero at that point. You then drive another 50 miles to get to your house, and your friend drives 21 another miles to get to his house. You can’t say that you live twice as far away from the ballpark as does your friend because your trip odometer reads 50 miles and his reads 21 in the end. You need to start measuring at the ballpark–at absolute zero–so you see that you live just 9.86% farther away, not two times.

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