「ロサンゼルス・タイムズ」紙の報道では、藻で覆われた面積は今年すでに約2万8900平方キロメートル。米マサチューセッツ州の面積を凌ぐ広さだ。[岩手県の約2倍。前回の大発生は2008年で、その際は1万3000平方キロメートルだったという]
厚い藻のなかを泳ぐ人々。2013年7月3日撮影。
自然現象[海面温度の高さ]だと説明する者もいるほか、青島市の南部沿岸では、海に浮かべたイカダでノリの養殖が行なわれており、そこに集まってくる藻が海岸にも押し寄せたのだとする研究者もいる。また、農地やゴルフコースからの排水に含まれる肥料[窒素やリン酸]が原因だという説もある。
一般的にはこの藻が人間に害を与えることはないものの、放置されて腐敗すれば有毒ガスを発する可能性もある、とロサンゼルス・タイムズ紙は伝えている[海面が覆われると水中の酸素濃度に影響し、海洋生態系に悪影響を及ぼす恐れがあると指摘されている]。
[問題になっているのは、アオサ属の藻「スジアオノリ」（Enteromorpha prolifera）の大量発生（緑潮）。日本でも水質汚濁が進んだ1970年代以降に顕著化し、千葉県の三番瀬・谷津干潟や横浜市、愛知県などで報告されている]
[(English) 日本語版：遠藤康子/ガリレオ]
関連記事
The Earth From Above
Sandy Cay(01 of15)
This astronaut photograph taken on Nov. 27, 2010, provides a view of tidal flats and channels near Sandy Cay, on the western side of Long Island, and along the eastern margin of the Great Bahama Bank, on the islands of Bahamas. The continuously exposed parts of the island are brown, a result of soil formation and vegetation growth. To the north of Sandy Cay, an off-white tidal flat composed of carbonate sediments is visible; light blue-green regions indicate shallow water on the tidal flat. (credit:NASA / AFP / Getty Images)
Lake Nasser(02 of15)
Egypt\'s Lake Nasser was photographed in January 2005 from the International Space Station. (credit:NASA)
Sahara Desert(03 of15)
Tassili n\'Ajjer National Park, part of the Sahara Desert, has a bone-dry climate with scant rainfall, yet it doesn\'t blend in with Saharan dunes. Instead, the rocky plateau rises above the surrounding sand seas. This image from 2000 was made from multiple observations by the Landsat 7 satellite, using a combination of infrared, near-infrared and visible light to better distinguish among the park\'s various rock types. (credit:NASA)
Hydrogen Sulfide and Dust Plumes on Namibia's Coast(04 of15)
Cloudless skies allowed a clear view of dust and hydrogen sulfide plumes along the coast of Namibia in early August 2010. Multiple dust plumes blow off the coast toward the ocean, most or all of them probably arising from stream beds. Unlike the reddish-tan sands comprising the dunes directly south of the Kuiseb River, the stream-channel sediments are lighter in color. Wind frequently pushes dust plumes seaward along the Namibian coast. (credit:NASA)
Egypt(05 of15)
The Nile River and its delta look like a brilliant, long-stemmed flower in this astronaut photograph of the southeastern Mediterranean Sea, as seen from the International Space Station on Oct. 28, 2010. The Cairo metropolitan area forms a particularly bright base of the flower. (credit:NASA / AFP / Getty Images)
Islands of Four Mountains(06 of15)
The snow-capped volcanoes composing the Islands of the Four Mountains in Alaska\'s Aleutian Island chain look suspiciously like alien worlds in this August 2010 image from the ASTER camera aboard NASA\'s orbiting Terra satellite. (credit:NASA)
Aurora Australis(07 of15)
This NASA image shows the aurora australis observed from the International Space Station on May 29, 2010. This aurora image was taken during a geomagnetic storm that was most likely caused by a coronal mass ejection from the sun on May 24. (credit:NASA / AFP / Getty Images)
Sarychev Volcano(08 of15)
Astronauts at the International Space Station captured this striking view of the Sarychev volcano on Russia\'s Kuril Islands in an early stage of eruption on June 12, 2009. Sarychev Peak is one of the most active volcanoes in the Kuril Islands chain. (credit:NASA)
Arctic Eclipse(09 of15)
NASA\'s Terra satellite was rounding the top of the globe -- making its way from the eastern tip of Siberia and across the Arctic Ocean toward northwest Russia -- when it captured this unique view of a total solar eclipse on Aug. 1, 2008. In the area shown in the image, the sun was obscured for about two minutes. As Earth rotated, the shadow moved southeast across the surface. At the same time, the satellite crossed the Arctic with its path nearly perpendicular to the eclipse.\r\n (credit:NASA)
Fargo(10 of15)
The Advanced Land Imager on NASA\'s Earth Observing-1 satellite shows a snowy blanket over Fargo, N.D., on Dec. 12. (credit:NASA)
Mount Everest(11 of15)
Astronauts captured this image highlighting the northern entry to Mount Everest from Tibet on Jan. 6. Climbers travel along the East Rongbuk Glacier, shown on the lower left, to camp at the base of Changtse mountain. (credit:NASA / AFP / Getty Images)
Island Beauty(12 of15)
The south end of Eleuthera Island in the Bahamas shimmers in turquoise waters in this 2002 photo from the International Space Station. (credit:NASA)
Massive Sandstorm(13 of15)
A massive sandstorm sweeps over Qatar as it races south toward southeastern Saudi Arabia and the United Arab Emirates on Feb. 15, 2004. A major upper-level, low-pressure system over southwestern Asia led to a series of storms sweeping through the area. The crew of the International Space Station captured this image with a digital camera using a 50-millimeter lens. (credit:NASA)
Lake Naivasha, Kenya(14 of15)
Flowers grow year round in sun-drenched Kenya, and nowhere are they more plentiful than Lake Naivasha, shown here. In this view from space, bright white squares mix with fields of green, tan and purple along the shores of the lake. Sunlight glints off the long rows of glass greenhouses, turning them silvery blue and white. Fallow fields are tan and pink, while growing plants turn the ground bright green. Roses, lilies and carnations are the most common flowers grown in the greenhouses and fields scattered around the lake. (credit:GSFC / METI / ERSDAC / JAROS / NASA)
Cumulonimbus Cloud Over Africa(15 of15)
High above the African continent, tall, dense cumulonimbus clouds, meaning \"cloud heap\" in Latin, are the result of atmospheric instability. The clouds can form alone, in clusters or along a cold front in a squall line. The high energy of these storms is associated with heavy precipitation, lightning, high wind speeds and tornadoes. (credit:NASA)