The offshore wind energy sector has rapidly expanded over the past two decades, providing a renewable energy solution for coastal nations. Sector development has been led in Europe, but is growing globally. Most developments to date have been in well-mixed, i.e., unstratified, shallow-waters near to shore. Sector growth is, for the first time, pushing developments to deep water, into a brand new environment: seasonally stratif...

The balance of physical and biological processes governing phytoplankton growth rates and the accumulation of biomass is widely debated in the literature, notably during the winter–spring transition. Here we show, in a temperate shelf sea that variability in the depth of the actively mixing surface layer is the leading order control. During a 2‐week period preceding the peak of the spring bloom we observe two distinct regimes;...

A 4‐month time series of water column temperature structure on the shelf of North Island New Zealand is used to calculate the energy in the internal tide as stratification evolved between spring and summer. Average total energy in the internal tidal wave was 200 J m −2 , with peaks reaching 600 J m −2 . Wave energy was weakly correlated with stratification ( r = 0.2) and with the spring‐neap cycle of tidal currents ( r = 0.17)...

Observations of vertical gradients in phytoplankton community structure were made through the water column of the seasonally stratified Celtic Sea, including within the thermocline. A deep chlorophyll maximum (DCM) was located within the thermocline at all stations, coupled to the nitracline. Vertical gradients in phytoplankton community composition were routinely observed within the thermocline. The cell abundance maxima for...

Dense surface blooms of toxic cyanobacteria in eutrophic lakes may lead to mass mortalities of fish and birds, and provide a serious health threat for cattle, pets, and humans. It has been argued that global warming may increase the incidence of harmful algal blooms. Here, we report on a lake experiment where intermittent artificial mixing failed to control blooms of the harmful cyanobacterium Microcystis during the summer of...

Measurements of the intra‐tidal and spring‐neap variation in the vertical flux of nitrate into the base of the sub‐surface chlorophyll maximum (SCM) were made at the shelf edge of the Celtic Sea, a region with strong internal mixing driven by an internal tide. The neap tide daily mean nitrate flux was 1.3 (0.9‐1.8, 95% confidence interval) mmol m ‐2 d ‐1 . The spring tide flux was initially estimated as 3.5 (2.3‐5.2, 95% confi...

Observations of the vertical structure of density, concentrations of chlorophyll a and nitrate, and turbulent dissipation rates were made over a period of 25 h in a well‐stratified shelf region in the Western English Channel, between neap and spring tides. Maximum turbulent dissipation at the base of the thermocline occurred almost 5 h after maximum tidal currents. This turbulence aids phytoplankton growth by supplying bottom‐...

Continuous time‐series of near‐bed and near‐surface currents and temperature were recorded, at the shelf edge and on the shelf of northeast New Zealand, between June 1994 and January 1996. Tidal analysis of the current records show that typical tidal currents in the region are dominated by the Mj constituent, with amplitudes between 5 and 10 cm s ‐1 . The amplitude of the M 2 tide varies in response to the existence of an inte...