Algal turf assemblages of the northern Great Barrier Reef, Australia, were sampled to determine the nutritional value of detritus and algae. Samples were collected with a suction apparatus across an exposure gradient from (1) the reef crest at highly exposed outer barrier reefs, (2) the reef crest of moderately exposed midshelf reefs, and (3) the reef slope of sheltered midshelf reefs. The biomass of algae and detritus decreased from sheltered midshelf reefs to moderately exposed midshelf reefs to highly exposed outer barrier reefs. This decrease was significant only for detritus (P Ͻ 0.005). Wave energies were calculated across the exposure gradient with the wave model WAMGBR. Detrital mass was inversely correlated with predicted wave energies and fitted a polynomial relationship (P Ͻ 0.001) and explained 52.8% of the variation. A similar relationship was also found between algal mass and wave energy (P Ͻ 0.001) but only explained 30.0% of the variation. The nutritional value of samples in protein amino acids and starch was assessed. The amino acid composition of detritus and algae was similar and not considered nutritionally different, whereas the concentration of protein amino acids was significantly (P Ͻ 0.001) higher in detritus (21.2 Ϯ 2.0 mg g Ϫ1 ) than in algae (11.8 Ϯ 1.0 mg g Ϫ1 ). Starch content was significantly (P Ͻ 0.05) higher in algae (7.7 Ϯ 0.9 mg g Ϫ1 ) than in detritus (6.0 Ϯ 1.0 mg g Ϫ1). These results demonstrate that detritus is a potentially valuable food source to grazing fishes on coral reefs.Two predominant views of coral reef trophic biology are that shallow-water epilithic algal communities (EAC) are the major sites of primary production and that grazing fish and invertebrates are the predominant consumers of this resource (Hatcher 1997). Grazing fish are classified as herbivores and are assumed to derive the significant component of their nutrition through consumption, digestion, and assimilation of living turf algae

[1] Field observations of water temperature on the Australian North-West Shelf (Eastern Indian Ocean) with the support of numerical simulations are used to demonstrate that the injection of turbulence generated by the wave orbital motion substantially contributes to the mixing of the upper ocean. Measurements also show that a considerable deepening of the mixed layer occurs during tropical cyclones, when the production of wave-induced turbulent kinetic energy overcomes the contribution of the current-generated shear turbulence. Despite a significant contribution to the deepening of the mixed layer, the effect of a background current and atmospheric forcing are not on their own capable of justifying the observed deepening of the mixed layer through most of the water column. Furthermore, variations of a normally shallow mixed layer depth are observed within a relatively short timescale of approximately 10 hours after the intensification of wave activity and vanish soon after the decay of storm surface waves. This rapid development tends also to exclude any significant contribution by wave breaking, as small rates of vertical diffusivity for wave breaking-induced turbulence would require longer timescales to influence the depth of the mixed layer.

The concept of a constant-flux layer is usually employed for vertical profiling of the wind measured at some elevation near the ocean surface. The surface waves, however, modify the balance of turbulent stresses very near the surface, and therefore such extrapolations can introduce significant biases. This is particularly true for buoy measurements in extreme conditions, when the anemometer mast is within the wave boundary layer (WBL) or even below the wave crests. In this paper, field data and a WBL model are used to investigate such biases. It is shown that near the surface the turbulent stresses are less than those obtained by extrapolation using the logarithmic-layer assumption, and the mean wind speeds very near the surface, based on Lake George field observations, are up to 5% larger. The behavior is then simulated by means of a WBL model coupled with nonlinear waves, which confirmed the observations and revealed further details of complex behaviors at the wind-wave boundary layer.

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This paper presents the results of a wave hindcast of a severe storm in the Southern North Sea to verify recently developed deep and shallow water source terms. The work was carried out in the framework of the ONR funded NOPP project (Tolman et al. 2013) in which deep and shallow water source terms were developed for use in third-generation wave prediction models. These deep water source terms for whitecapping, wind input and nonlinear interactions were developed, implemented and tested primarily in the WAVEWATCH III model, whereas shallow water source terms for depth-limited wave breaking and triad interactions were developed, implemented and tested primarily in the SWAN wave model. So far, the new deepwater source terms for whitecapping were not fully tested in shallow environments. Similarly, the shallow water source terms were not yet tested in large inter-mediate depth areas Shell Global Solutions International B.V, Rijswijk, The Netherlands like the North Sea. As a first step in assessing the performance of these newly developed source terms, the source term balance and the effect of different physical settings on the prediction of wave heights and wave periods in the relatively shallow North Sea was analysed. The December 2013 storm was hindcast with a SWAN model implementation for the North Sea. Spectral wave boundary conditions were obtained from an Atlantic Ocean WAVEWATCH III model implementation and the model was driven by hourly CFSR wind fields. In the southern part of the North Sea, current and water level effects were included. The hindcast was performed with five different settings for whitecapping, viz. three Komen type whitecapping formulations, the saturation-based whitecapping by Van der Westhuysen et al. (2007) and the recently developed ST6 whitecapping as described by Zieger et al. (2015). Results of the wave hindcast were compared with buoy measurements at location K13 collected by the Dutch Ministry of Transport and Public Works. An analysis was made of the source term balance at three locations, the deep water location North Cormorant, the inter-mediate depth location K13 and at location Wielingen, a shallow water location close to the Dutch coast. The results indicate that at deep water the source terms for wind input, whitecapping and nonlinear four-wave interactions are of the same magnitude. At the inter-mediate depth location K13, bottom friction plays a significant role, whereas at the shallow water location Wielingen also depth-limited wave breaking becomes important.

The Australian marine research, industry, and stakeholder community has recently undertaken an extensive collaborative process to identify the highest national priorities for wind-waves research. This was undertaken under the auspices of the Forum for Operational Oceanography Surface Waves Working Group. The main steps in the process were first, soliciting possible research questions from the community via an online survey; second, reviewing the questions at a face-to-face workshop; and third, online ranking of the research questions by individuals. This process resulted in 15 identified priorities, covering research activities and the development of infrastructure. The top five priorities are 1) enhanced and updated nearshore and coastal bathymetry; 2) improved understanding of extreme sea states; 3) maintain and enhance the in situ buoy network; 4) improved data access and sharing; and 5) ensemble and probabilistic wave modeling and forecasting. In this paper, each of the 15 priorities is discussed in detail, providing insight into why each priority is important, and the current state of the art, both nationally and internationally, where relevant. While this process has been driven by Australian needs, it is likely that the results will be relevant to other marine-focused nations.

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