Algal Picoplankton from Marine and Freshwater Ecosystems: A Multidisciplinary Perspective

Abstract

The discovery of minute (0.2–2.0 μm) algal picoplankton in the late 1970's in both marine and freshwater ecosystems has led to a resurgence of research activity throughout the world, addressing questions related to taxonomy, distribution and abundance, physiology and biochemistry, and ecological considerations of their role in aquatic food webs. To many, their discovery provided the "missing link" in the controversial carbon supply–demand question in the world's oceans and gave further credibility to the emerging new paradigm on the importance of microbial food webs in energy transfer and nutrient recycling in aquatic systems. In this essay we provide the first comprehensive multidisciplinary review of phototrophic picoplankton in lake and ocean ecosystems, discussing what is currently known about their occurrence, taxonomy, physiology, and biochemistry and their role in primary production and aquatic food webs.