Aquatic Sciences Meeting, Albuquerque 2001

SS15 Biomechanics: Making the Connection Between Physics and Biology at the Organismal Level (Disciplinary Connections)

Date: Wednesday, February 14, 2001, Time: 4:30:00 PM

Location: Mesilla

Moisander, P, H, Univ. of North Carolina at Chapel Hill, Inst. of Marine Sciences, Morehead City, USA, moisande@email.unc.edu

Kononen, K, , Finnish Institute of Marine Research, Helsinki, Finland, kaisa.kononen@nessling.fi

Paerl, H, W, Univ. of North Carolina at Chapel Hill, Inst. of Marine Sciences, Morehead City, USA, hans_paerl@unc.edu

EFFECT OF COUETTE FLOW ON FILAMENTOUS CYANOBACTERIA FROM THE BALTIC SEA

Hepatotoxic, diazotrophic cyanobacteria Nodularia spp. and Aphanizomenon spp. dominate the late summer blooms in the Baltic Sea. Nitrogen fixation and photosynthesis of Nodularia spp., isolated from the open Baltic Sea, were reduced when exposed to shear. Filament length of N. spumigena was not affected by shear in culture experiments where shear rates ranged 2.2-18 rad s-1, while N. sphaerocarpa filament length decreased. In shipboard experiments in the Baltic Sea, filaments of Aphanizomenon and Anabaena spp. were significantly shorter in response to shear treatment, while Nodularia filament length was not affected. Baltic Sea Aphanizomenon and Anabana may be more sensitive to shear than Nodularia. A shear level of 2.2 rad s-1 decreased productivity within 12 hours during the Baltic Sea cyanobacterial blooms. Direct mechanical stress imposed by turbulence may in part control Baltic Sea cyanobacterial blooms.

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Aquatic Sciences Meeting, Albuquerque 2001

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