Transport of the copepod, Calanus finmarchicus, in the northwest Atlantic during diapause

The copepod Calanus finmarchicus is the most important and biomass dominant mesozooplankter in the temperate-boreal North Atlantic. C. finmarchicus has an overwintering phase, termed diapause, during which it descends to great depths (300-2000m) and is metabolically quiescent for up to ten months. Changes in the currents at depth due to climate variation may influence the spring distribution and abundance of C. finmarchicus. We evaluated the potential transport of C. finmarchicus during diapause in the Labrador Sea and the Scotian Shelf under positive and negative North Atlantic Oscillation (NAO) index conditions with a coupled bio-physical individual-based model (IBM). The physical simulation was a basin-scale ROMS model using mean forcing for 1980-1993 (1962-1971) from NCEP/NCAR re-analysis fields to generate idealized positive (negative) NAO conditions. The biological IBM consisted of a particle-tracking model with simulated biological behavior. We modeled four mechanisms that have been proposed for diapause emergence: an external, photoperiod-dependent emergence trigger and three internal, temperature-controlled lipid consumption triggers. Copepods were seeded in the Labrador Sea and the Scotian Shelf for positive and negative NAO climatic conditions. An internal, lipid-based diapause emergence trigger based on Saumweber and Durbin (2006; Deep Sea Res. II, 53 (23-24), 2597-2617) best reproduced field observations of the dates of C. finmarchicus appearance at the surface following diapause. The phase of the NAO had an effect on potential transport distance of C. finmarchicus during diapause on the Scotian Slope, and in the northeastern Atlantic. In the Labrador Sea, the phase of the NAO had little effect on potential transport and duration of diapause

Inhibition of Barnacle (\u3cem\u3eAmphibalanus amphitrite\u3c/em\u3e) Cyprid Settlement by Means of Localized, Pulsed Electric Fields

The increasing needs for environmental friendly antifouling coatings have led to investigation of new alternatives for replacing copper and TBT-based paints. In this study, results are presented from larval settlement assays of the barnacle Amphibalanus (= Balanus) amphitrite on planar, interdigitated electrodes (IDE), having 8 or 25 mum of inter-electrode spacing, upon the application of pulsed electric fields (PEF). Using pulses of 100 ms in duration, 200 Hz in frequency and 10 V in pulse amplitude, barnacle settlement below 5% was observed, while similar IDE surfaces without pulse application had an average of 40% settlement. The spacing between the electrodes did not affect cyprid settlement. Assays with lower PEF amplitudes did not show significant settlement inhibition. On the basis of the settlement assays, the calculated minimum energy requirement to inhibit barnacle settlement is 2.8 W h m(-2)

Hybrid Xerogel Films as Novel Coatings for Antifouling and Fouling Release

Hybrid sol-gel-derived xerogel films prepared from 45/55 (mol ratio) n-propyltrimethoxysilane (C3-TMOS)/tetramethylorthosilane (TMOS), 2/98 (mol ratio) bis[3-(trimethoxysilyl)propyl]-ethylenediamine (enTMOS)/tetraethylorthosilane (TEOS), 50/50 (mol ratio) n-octyltriethoxysilane (C8-TEOS)/TMOS, and 50/50 (mol ratio) 3,3,3-trifluoropropyltrimethoxysilane (TFP-TMOS)/TMOS were found to inhibit settlement of zoospores of the marine fouling alga Ulva (syn. Enteromorpha) relative to settlement on acid-washed glass and give greater release of settled zoospores relative to glass upon exposure to pressure from a water jet. The more hydrophobic 50/50 C8-TEOS/TMOS xerogel films had the lowest critical surface tension by comprehensive contact angle analysis and gave significantly greater release of 8-day Ulva sporeling biomass after exposure to turbulent flow generated by a flow channel than the other xerogel surfaces or glass. The 50/50 C8-TEOS/TMOS xerogel was also a fouling release surface for juveniles of the tropical barnacle Balanus amphitrite. X-ray photon electron data indicated that the alkylsilyl residues of the C3-TMOS-, C8-TEOS-, and TFP-TMOS-containing xerogels were located on the surface of the xerogel films (in a vacuum), which contributes to the film hydrophobicity. Similarly, the amine-containing silyl residues of the enTMOS/TEOS films were located at the surface of the xerogel films, which contributes to the more hydrophilic character and increased critical surface tension of these films

Antifouling Character of \u27Active\u27 Hybrid Xerogel Coatings with Sequestered Catalysts for the Activation of Hydrogen Peroxide

Halide-permeable xerogel films prepared from sols containing 50 mol% aminopropyltriethoxysilane (APTES)/50 mol% tetraethoxysilane (TEOS) or 10 mol% APTES/90 mol% TEOS and 0.015 M selenoxide or telluride catalyst in the sol gave reduced settlement of cypris larvae of the barnacle Balanus amphitrite and larvae of the tubeworm Hydroides elegans in the presence of artificial seawater (ASW) and hydrogen peroxide (5-100 μM) relative to glass controls. Settlement of Ulva zoospores was lower on both the 50 mol% APTES/50 mol% TEOS and 10 mol% APTES/90 mol% TEOS xerogel formulations in comparison with glass controls with or without the added catalyst. The 50 mol% APTES/50 mol%TEOS xerogel containing telluride catalyst gave reduced settlement of Ulva zoospores in the presence of 100 μM H2O2 in ASW compared with the same coating without added peroxide. Scanning electron microscopy and XPS data suggest that exposure to H2O2 does not lead to chemical or morphological changes on the xerogel surface