Ocean Plant Life in Decline海洋植物數(shù)量銳減
1.Scientists have discovered plant life covering the surface of the world's oceans is disappearing at a dangerous rate. This plant life called phytoplankton is a vital resource that helps absorb the worst of the "greenhouse gases" involved in global warming. Satellites and ships at sea have confirmed the diminishing productivity of the microscopic plants, which oceanographers say is most striking in the waters of the North Pacific—ranging as far up as the high Arctic. "Whether the lost productivity of the phytoplankton is directly due to increased ocean temperatures that have been recorded for at least the past 20 years remains part of an extremely complex puzzle", says Watson W. Gregg, a NASA biologist at the Goddard Space Flight Center in the USA, but it surely offers a fresh clue to the controversy over climate change. According to Gregg, the greatest loss of phytoplankton has occurred where ocean temperatures have risen most significantly between the early 1980s and the late 1990s. In the North Atlantic summertime, sea surface temperatures rose about 1. 3 degrees Fahrenheit during that period, while in the North Pacific the ocean's surface temperatures rose about 0.07 of a degree.
1、科學(xué)家們發(fā)現(xiàn)覆蓋海洋表面的植物數(shù)量正在快速消失。這種被稱為“浮游植物”的生物能夠吸收導(dǎo)致全球變暖的危害的“溫室氣體”。衛(wèi)星和海上船舶確認(rèn)了這種細(xì)微生物正在減少。海洋研究者認(rèn)為這種生物在北太平洋里的消亡速度最快，甚至擴(kuò)展到了北極圈。“浮游植物的減少是否是過去的20 年間海洋溫度的升高直接導(dǎo)致的，這依然是一個(gè)未解之迷。”在美國的Goddard空間飛行中心的NASA生物學(xué)家Watson W.Gregg如是說。但他表示，這確實(shí)提供了一個(gè)解決氣候變化爭議的全新線索。Gregg認(rèn)為，從80年代初到90年代末，海洋溫度明顯升高的地方往往是浮游植物大量減少的地方。在北大西洋的夏季，海洋的表面溫度在那段時(shí)間里升高了1.3華氏度，在北太平洋海洋表面，溫度升髙了0.07度。
2.While the link between ocean temperatures and the productivity of plankton is striking, other factors can also affect the health of the plants. They need iron as nourishment, for example, and much of it reaches them in powerful winds that sweep iron-containing dust across the oceans from continental deserts. When those winds diminish or fail, plankton can suffer. According to Gregg and his colleagues, there have been small but measurable decreases in the amount of iron deposited over the oceans in recent years.
2、雖然海洋溫度的升高和浮游植物數(shù)量之間的關(guān)系密不可分，但是其他 因素也會(huì)影響這種海洋植物的健康。比如說它們需要鐵來當(dāng)做養(yǎng)料，這種養(yǎng) 料來自于大陸上含鐵的沙塵。大風(fēng)把這些沙塵吹向海洋，當(dāng)這些風(fēng)減弱或者 消亡，浮游植物的生存就會(huì)面臨危脅。Gregg和他的同事認(rèn)為，近年來海洋中 的鐵含量有所下降，盡管幅度較小，但是已經(jīng)能夠通過儀器測量出來。
3.The significant decline in plankton productivity has a direct effect on the world's carbon cycle. Normally, the ocean plants take up about half of all the Carbon dioxide in the world's environment because they use the carbon, along with sunlight, for growth, and release oxygen into the atmosphere in a process known as photosynthesis. Primary production of plankton in the North Pacific has decreased by more than 9 percent during the past 20 years, and by nearly 7 percent in the North Atlantic, Gregg and his colleagues determined from their satellite observations and shipboard surveys. Studies combining all the major ocean basins of the world have revealed the decline in plankton productivity to be more than 6 percent.
3、浮游植物數(shù)量明顯減少對(duì)全球碳循環(huán)有著直接的影響。通常，這種海洋植物吸收了全球大約一半的二氧化碳，因?yàn)樗鼈兘柚趸家约瓣柟鈦砩L，并把氧氣釋放到大氣中，這就是我們熟知的光合作用。浮游植物的主要生長區(qū)域是北太平洋，那里的浮游植物數(shù)量在過去的20年里降低了9%以上，在北大西洋降低了約7%,這是Gregg和他的同事利用衛(wèi)星觀察和船舶測量得出的結(jié)論。對(duì)世界上主要海洋盆地的研究表明，浮游植物的數(shù)量下降了6%以上。