The word observatory usually conjures up images of a huge telescope on a lonely hill, pointed at
enormous celestial bodies in space. Over the years, these images have fueled mankind's spirit of adventure and desire to learn about the unknown. NASA successfully met the challenge to travel into space, and
along the way many scientific and engineering advances were born, including the production of heat resistant materials, mobile communications, ultrasound scanners and laser surgery. Space observatory images
capture hundreds of thousands of tiny specks of light, odd shapes and colors that leave us awestruck. But the earth's inner space – its
oceans, soils and basalts – hosts a myriad of mysteries and marvels too. The Oceanic Microbial Observatory at BBSR turns the focus, quite literally, from outer space to the earth's inner space… the ocean.
Using a powerful microscope rather than a telescope, we can capture images of marine microbes that at first glance look quite similar to scenes of the heavens and produce similar feelings of wonder and
intrigue. However, this celestial view is dominated by bodies that are less than one millionth of a meter in diameter and whose identity and individual functions remain largely unknown.Structurally, life
on earth can be broken down into two vast groups of organisms: those without internal membrane bound organelles – the prokaryotes – and those with membrane bound organelles, like humans – the eukaryotes. Our
planet houses an estimated 14 million species, of which only about 12 percent have been identified. The vast majority of the uncharacterized species are prokaryotes. These prokaryotes are unicellular and
invisible to the naked eye, and all are independent stand-alone biological systems. It is somewhat surprising that so little is known about the organisms that are the oldest living residents of our, or
should I say their, planet (3.8 billion years). However, advances in culturing techniques, the introduction of molecular techniques based on ribosomal RNA sequences, and cloning have launched an explosion of
microbiological research. New discoveries are constantly being made. It was only 30 years ago that a completely independent domain of life, the Archaea, was recognized. It was just 20 years ago that
biological oceanographers discovered prochlorophytes, a previously unrecognized photosynthetic bacteria found to be a major contributor to primary production in the oceanic gyres. It was just a couple of
years ago that a gene for proteorhodopsin, a protein that assists prokaryotes in harvesting light energy, was discovered in bacterioplankton – a discovery that has vast implications for microbial ecology and
biogeochemistry in our oceans. This past year, we have seen the first successful attempt to grow
SAR11, the ocean's most ubiquitous group of bacteria, in culture. In a world that appears to be dominated by big stuff (i.e., things we can see),
why should we care about microbes – don't they just make us sick? The fact is that only a small percentage of microbes are pathogenic; most are beneficial to life on earth. The living biomass and processes
that drive the earth's biosphere are really in the hands of the microbes. They are incredibly diverse in terms of phylogeny (evolutionary relationship) and metabolic strategies. They have developed
strategies to persist in almost any environmental niche found on the planet, and some thrive in conditions that would be considered completely inhospitable to higher organisms. Over geologic time,
microbes have altered the chemical nature of the earth's environment, allowing for the evolution of plants and animals. Without them, we would have no oxygen to breathe, organic matter would not be degraded,
and the cycling of life's essential nutrients would cease. Scientists have a basic understanding of how microbes control and influence nutrient cycling in one of the earth's largest ecosystems, the ocean.
However, we have little understanding of how microbial diversity is linked to biogeochemical mechanisms. There is much we can learn from these organisms.
Dr. Craig Carlson, of the University of California, Santa Barbara, examines
marine microorganisms in BBSR's Oceanic Microbial Observatory lab |
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In 1999, the National Science Foundation initiated a program to better understand the role of microbes in natural systems. One of the sponsored projects was the Oceanic Microbial Observatory, a
collaborative effort between Dr. Stephen Giovannoni, of Oregon State University, and me. BBSR plays a critical role in this program by providing state-of-the-art
research facilities for intensive field visits, laboratory facilities for day to day operations overseen by BBSR research technician Rachel Parsons, at-sea sample collection, and, of course, access
to one of the world's most intensely studied oceanic sites, the Bermuda Atlantic Time-series Study
(BATS) site. BATS has been a test-bed for the development of advanced molecular techniques for measuring microbial diversity, and is the site of the
longest-running time-series study of oceanographic variables, making it an ideal site for an intensive study of microbial biodiversity and its interaction with biogeochemical processes.
The Oceanic Microbial Observatory focuses on one of the largest microbial ecosystems on the planet, the ocean surface layer (to a depth of 250 meters), as well as deeper portions of the water column.
Microorganisms in the ocean surface layer play an integral role in carbon transport from the atmosphere to the deep ocean. This "biological
carbon pump" has global significance for scientific understanding of the ocean's role in climate change. The Oceanic Microbial Observatory combines the expertise of
oceanography, biogeochemistry and an understanding of large-scale microbial processes with the expertise of molecular biology and environmental genomics. Our main goal is to better understand how
elemental cycling and energy flux have been partitioned among species by evolutionary processes. More focused objectives include:
- comprehensive efforts to bring the unculturable bacterioplankton – some of the planet's most abundant and elusive species – into culture
- development of new techniques, such as in situ rRNA probes and genomic DNA chromosomal paints, to identify and study the distribution of functionally significant species and implement them
into regular field sampling
- controlled experiments that combine molecular biology with precision chemical analyses to investigate how quality and source of organic substrates control microbial diversity, and in turn how
microbial processes affect the chemical nature of their substrates
- use of information gained from the Oceanic Microbial Observatory in educational and outreach activities, including several graduate and undergraduate level programs at BBSR.
Success stories from the Oceanic Microbial Observatory include a better understanding of the way prokaryotic community structure (diversity)
changes over depth and its potential connection to the dissolved organic carbon cycle at BATS; the largest time-series data record of prokaryotic
DNA and RNA that demonstrates temporal and spatial variability in an open ocean site; the first quantitative assessment of SAR11, one of the
most ubiquitous organisms in the sea; and the first open-ocean time series of virioplankton. These success stories present even further questions that may have
profound impacts on society. What role do these organisms play in the regulation of global climate? Do they possess properties with human health benefits, possibly through development of pharmaceutical
products? Will the next big scientific discovery come from the Oceanic Microbial Observatory? We'll keep looking. |
