Photosynthesis is the hallmark of the do-it-yourself crowd. Organisms that rely on it need only light, carbon dioxide, and some inorganic nutrients to grow. There are exceptions, of course, such as carnivorous plants that live in low-nutrient habitats. And here's a new one: microscopic algae that eat free-floating bacteria in the open ocean.rnThe smallest of the marine phytoplankton are unicellular algae less than one-tenth the width of a hair. They grow almost exclusively by photosynthesis, or so most scientists thought. But working aboard a research vessel in the North Atlantic, and using isotopes to track the fate of nutrients in samples of seawater, Mikhail V. Zubkovrnof the National Oceanography Centre in Southampton and Glen A. Tarran of the Plymouth Marine Laboratory, both in England, have determined that the tiny algae obtain about a quarter of their bio-mass from bacteria. So abundant are the little algae that they alone devour between 40 percent and 95 percent of all the bacteria eaten in the top, sunlit layer of the ocean-the rest succumb to other kinds of unicellular beings.rnThat algae should depend to such an extent on bacterivory came as a surprise. Perhaps it's more efficient to assimilate nutrients concentrated in bacteria than diffused in seawater, Zubkov and Tarran suggest. Whatever the reason, ecologists will have to revise their models of marine food chains to account for algal appetites.
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机译：光合作用是自己动手的人群的标志。依靠它的生物只需要光，二氧化碳和一些无机养分即可生长。当然，也有例外，例如生活在低营养生境中的食肉植物。这是一个新的例子：在海中吞噬自由漂浮细菌的细微藻类。最小的海洋浮游植物是单细胞藻类，不到头发宽度的十分之一。大多数科学家认为，它们几乎只能通过光合作用生长。但是在北大西洋的一艘研究船上工作，并使用同位素来追踪海水样品中养分的命运，南安普顿国家海洋学中心的Mikhail V. Zubkovrnof和英格兰普利茅斯海洋实验室的Glen A. Tarran已经确定微小藻类从细菌中获取了大约四分之一的生物量。小藻类是如此丰富，以至于它们一个人吞食了在阳光照射下的最高层的细菌中的40％至95％，其余的则屈服于其他种类的单细胞生物。细菌来了一个惊喜。 Zubkov和Tarran建议，吸收细菌中集中的养分比吸收海水中的养分更有效。无论出于何种原因，生态学家都必须修改其海洋食物链模型以考虑藻类的食欲。
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