The North Pacific Subtropical Gyre (NPSG), as its name suggests, is a massive gyre located in the north Pacific Ocean. Gyres are areas of the ocean where currents rotate in a circular motion. This means that they effectively cut off delivery of nutrients from nearby coastal sources, and so we often consider these systems to be "oligotrophic" or nutrient-poor. However, this part of the ocean is very deep (almost 5 km), which means that there may actually be a wide range of conditions--including different levels of light, nutrients, and temperature--that select for different organisms throughout its vertical profile. Typically, the surface waters are warm and have plenty of light, but are nutrient-limited. The deeper waters, in contrast, are colder, nutrient-rich, and dark.
In the late 1980's, a multidisciplinary team set out to monitor the productivity and biogeochemical conditions of the NPSG. A Long-term Oligotrophic Habitat Assessment (ALOHA) project was established with the goal of increasing our understanding of the processes that control carbon cycling and the roles of microorganisms in the oceans. A new paper published in the journal Ecosystems provides an update on the ecology of the NPSG.
In the late 1980's, a multidisciplinary team set out to monitor the productivity and biogeochemical conditions of the NPSG. A Long-term Oligotrophic Habitat Assessment (ALOHA) project was established with the goal of increasing our understanding of the processes that control carbon cycling and the roles of microorganisms in the oceans. A new paper published in the journal Ecosystems provides an update on the ecology of the NPSG.
Over the past few decades since the initiation of ALOHA, we've seen an explosion in our understanding of microbial metabolism including many new "-omics" techniques for measuring these processes. Molecular and rRNA techniques have been applied to better understand the phytoplankton communities in the NPSG. Researchers have found that diatom species are vertically segregated in this area of the ocean despite the oligotrophic conditions. Another study has shown that with minor addition of nutrients, the phytoplankton community can shift dramatically from prokaryotes to eukaryotes with changes shown even in the metatranscriptome (the collection of RNA transcripts) of the community.