, Volume 363, Issue 1–3, pp 241–251 | Cite as

Biochemical composition of particulate organic matter and bacterial dynamics at the sediment–water interface in a Mediterranean seagrass system

  • Roberto DanovaroEmail author
  • Norberto Della Croce
  • Mauro Fabiano


The seagrass Posidonia oceanica is the most productive system of theMediterranean Sea. In order to gather information on the temporal andspatial variability of the suspended particulate matter in relation tobacterial dynamics, water samples were collected at 10 cm above thesediments over a period of 13 months in the Prelo Bay (Ligurian Sea, NWMediterranean). Measurements of seston concentration, as well as theelemental (POC and PON) and biochemical composition (lipids, proteins,carbohydrates and nucleic acids) of particulate matter were carried out toassess the origin, composition and bacterial contribution to the foodpotentially available in the seagrass system to consumers. Lipids andproteins were the main biochemical classes of organic compounds, followed bycarbohydrates. Despite the highly refractory composition of the seagrassleaves, particulate organic matter was mostly composed of labile compounds(69.9% of POC). POM temporal patterns were controlled by currentspeed at the sediment–water interface that resuspended only smallparticles largely colonised by bacteria after an intensive process offractionation and aging. In the seagrass system, the POM appears to bedominated by bacteria (density ranging from 0.7 to 2.5×109 cells l™1, representing more than48.3% of POC and 68.7% of the biopolymeric carbon, as the sumof lipid, protein and carbohydrate carbon). This feature was characteristicof the seagrass system since much lower bacterial densities were foundoutside the Posidonia meadow. Bacteria were negatively correlated with theconcentration of nitrite and nitrate suggesting a selective utilisation ofinorganic nutrients to support their growth.

particulate organic matter composition bacteria sediment-waterinterface Posidonia oceanica 


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Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  • Roberto Danovaro
    • 1
    Email author
  • Norberto Della Croce
    • 2
  • Mauro Fabiano
    • 2
  1. 1.Facoltà di ScienzeUniversità di AnconaAnconaItaly
  2. 2.Istituto Scienze Ambientali MarineUniversità di GenovaGenovaItaly

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