Bioluminescence Intensity Modeling and Sampling Strategy Optimization*

Abstract

The focus of this paper is on the development of methodology for short-term (1-3 days) oceanic bioluminescence (BL) predictions and the optimization of spatial and temporal bioluminescence sampling strategies. The approach is based on predictions of bioluminescence with an advection-diffusion-reaction (tracer) model with velocities and diffusivities from a circulation model. In previous research, it was shown that short-term changes in some of the salient features in coastal bioluminescence can be explained and predicted by using this approach. At the same time, it was demonstrated that optimization of bioluminescence sampling prior to the forecast is critical for successful short-term BL predictions with the tracer model. In the present paper, the adjoint to the tracer model is used to study the sensitivity of the modeled bioluminescence distributions to the sampling strategies for BL. The locations and times of bioluminescence sampling prior to the forecast are determined by using the adjoint-based sensitivity maps. The approach is tested with bioluminescence observations collected during August 2000 and 2003 in the Monterey Bay, California, area. During August 2000, BL surveys were collected during a strong wind relaxation event, while in August 2003, BL surveys were conducted during an extended (longer than a week) upwellingfavorable event. The numerical bioluminescence predictability experiments demonstrated a close agreement between observed and model-predicted short-term spatial and temporal changes of the coastal bioluminescence.

Bioluminescence to reveal structure and interaction of coastal planktonic communities

“…This was perhaps due to the intensification of the eddy, as suggested by the vertical distribution of BP, and to some degree fluorescence, on the last two sampling days (Figs. 8A and B) and the strength of the eddy (Shulman et al, 2005). The oscillations in depth distribu tions of the physical and biological parameters, for example inshore on transect ''a'' on the last night, are consistent with internal waves known to persist in this area (Petruncio et al, 1998).…”

“…The atmospheric forcing and physical dynamics in this region are well characterized for this time period. The time sequence of data collected by the REMUS catches a slow transition from a strong upwelling event to a relaxation condition (Shulman et al, 2005). Upwelling, affecting the study area, occurred along the coast north of the bay.…”

“…These measurements are becoming more prevalent and have now been conducted off ships, on profiling and undulating systems, on moorings, and on autono mous underwater vehicles (AUVs; Widder et al, 1993;Moline et al, 2001Moline et al, , 2005Herren et al, 2005). These efforts have provided new insight into the distribution of coastal bioluminescence at ecosystem scales as it relates to physical forcing and physiological rhythms (Widder et al, 1999;Shulman et al, 2003Shulman et al, , 2005Moline et al, 2005).…”

Sub-kilometer length scales in coastal waters

“…One possible explanation as to why we did not observe the same increased trend in Monterey Bay was because the entire transect was located within the bay and the dynamics and circulation patterns within the bay are known to be highly variable, particularly during times of upwelling (Drake et al, 2005). The 9 deployments in Monterey Bay coincided with the transition from a strong upwelling event to gradual relaxation (Shulman et al, 2005).…”

“…Monterey Bay is also a region characterized by strong spring and summer upwelling. During the time of this study (August 2001) the upwelling centers were at least 100 km away from the AUV deployment region (Shulman et al, 2005), nevertheless significant vertical variability existed in both density and FL. Interestingly there was no significant difference between one-depth and undulating CSVs for TB.…”