植物和河流的二重奏,演繹了一段今天九曲十八彎的河道,令貧瘠之地貌郁郁蔥蔥;今天的科學(xué)小品告訴你!詼諧的語言,生動的內(nèi)容,一分鐘快速掌握科技最新動態(tài)。
What was around the bend in rivers hundreds of millions of years ago? It’s a trick question—because there weren’t any bends. Ancient rivers were typically just wide, sheet-like flows of water. New reports in the journals Geology and Earth-Science Reviews say we can thank the very first land-lubbing plants for putting the turn in the river. Researchers from Dalhousie University examined dozens of sites, from the Channel Islands off France to Death Valley. They say that well before dinosaurs or, really, much of anything roamed the earth, rivers were just vast expanses of water heeding only gravity and heading straight to sea. The first vascular plants took advantage of the abundant water, and put down roots. The roots began to hold sediment in place. Thus the riverbank was born and waterways began to get thinner and more defined. The communities of Paleozoic plants congregated at the water’s edge and began to colonize the earth’s surface. Over the next 50 million years this co-evolution of flora and flow led to the meandering rivers we know today, and a barren landscape made lush. And, also, the seven dollar toll to cross the Hudson on the George Washington Bridge.
幾億年前,河灣周圍會有些什么呢?這是個很狡猾的問題—因為那時并不存在什么河灣,遠(yuǎn)古時代的江河里都是一馬平川似的流水。《地質(zhì)與地球科學(xué)評論》雜志中最新的報道稱:我們要感謝最早期的固定水土的植物根系,正是它們造就了今天的河灣。 從遠(yuǎn)離法國的海峽群島到死亡之谷,達(dá)荷西大學(xué)的研究人員勘察了幾十個地方,他們稱:遠(yuǎn)在恐龍出現(xiàn)或確切地說,在地球上出現(xiàn)可以走動的生物之前,江河中大量的水僅受重力的影響并徑直流入海中。 首批出現(xiàn)的維管植物利用了這豐富的水資源,扎根于此,而后,河中沉淀物就開始沉積在維管植物根部,由此產(chǎn)生了河堤,水路也開始變得愈發(fā)狹窄,水流方向更加明確。不斷聚集在水邊的古生代植物群開始侵占地球表面。 其后的5000萬年中,植物群體和水流的共同演變開創(chuàng)了今天九曲十八彎的河道,令貧瘠之地貌郁郁蔥蔥,當(dāng)然,為此,我們還要付出7美元的過橋費,以通過哈德遜河上的喬治華盛頓大橋。