This paper presents a review of the past decade’s highlights of research on the isolation
and characterisation of particulate organic matter (POM) in the world’s oceans.
The emphasis is on chemical studies but, in keeping with the growing interdisciplinary
nature of marine science, advances in other disciplines are also discussed, particularly
those in biological sciences. Increasing evidence for the importance of
picoplankton, bacteria and viruses as POM constituents is highlighted, including the
recent recognition of large populations of autotrophic bacteria able to harvest light
for energy. The transport of POM to bottom waters was thought to be largely confined
to large, rapidly sinking faecal pellets. However, recent studies have highlighted
the importance of organic aggregates and flocs formed by diatoms such as Rhizosolenia
and other microalgae. Ascending particles have also been discovered, many of which
are lipid-rich. Several studies have shown that resuspension of bottom sediments and
lateral advection of material from continental shelves can lead to anomalously high
particle fluxes measured in sediment traps moored in deep water. Many new approaches
for characterizing POM have emerged, such as pyrolysis gas chromatography-
mass spectrometry and direct temperature-resolved mass spectrometry for analysis
of higher molecular weight materials and biopolymers. Lipid biomarker techniques
have also advanced, exciting new possibilities being raised by the ability to measure
stable and radioactive carbon isotopes for individual compounds. The techniques of
molecular biology, such as the polymerase chain reaction (PCR), are being increasingly
applied to provide complementary information to more conventional microscopy
and flow cytometry on the identity of organisms in the sea. The combination of these
techniques with advanced chemical analysis methods promises to greatly increase
our knowledge of the origins, transport and fate of organic matter in the oceans.
This paper presents a review of the past decade’s highlights of research on the isolation
and characterisation of particulate organic matter (POM) in the world’s oceans.
The emphasis is on chemical studies but, in keeping with the growing interdisciplinary
nature of marine science, advances in other disciplines are also discussed, particularly
those in biological sciences. Increasing evidence for the importance of
picoplankton, bacteria and viruses as POM constituents is highlighted, including the
recent recognition of large populations of autotrophic bacteria able to harvest light
for energy. The transport of POM to bottom waters was thought to be largely confined
to large, rapidly sinking faecal pellets. However, recent studies have highlighted
the importance of organic aggregates and flocs formed by diatoms such as Rhizosolenia
and other microalgae. Ascending particles have also been discovered, many of which
are lipid-rich. Several studies have shown that resuspension of bottom sediments and
lateral advection of material from continental shelves can lead to anomalously high
particle fluxes measured in sediment traps moored in deep water. Many new approaches
for characterizing POM have emerged, such as pyrolysis gas chromatography-
mass spectrometry and direct temperature-resolved mass spectrometry for analysis
of higher molecular weight materials and biopolymers. Lipid biomarker techniques
have also advanced, exciting new possibilities being raised by the ability to measure
stable and radioactive carbon isotopes for individual compounds. The techniques of
molecular biology, such as the polymerase chain reaction (PCR), are being increasingly
applied to provide complementary information to more conventional microscopy
and flow cytometry on the identity of organisms in the sea. The combination of these
techniques with advanced chemical analysis methods promises to greatly increase
our knowledge of the origins, transport and fate of organic matter in the oceans.
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