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We compared the mean normalized water-leaving radiances ([L W ¯(λ)] N ) of two in-water optical profilers, a compact optical profiling system (C-OPS) and a HyperPro II Optical Profiler (HP2), with modeled [L W ¯(λ)] N at five stations in Monterey Bay, California. Although C-OPS and HP2 [L W ¯(λ)] N s were mostly within one standard deviation, C-OPS and modeled [L W ¯(λ)] N showed the lowest absolute percent differences (≤25% for most wavelengths) at four of the stations. We attribute this to C-OPS's high vertical resolution (∼1  cm), which is important for detecting changes in optical layers and for measuring the upper 0-0.5 m of the water column. HP2's low vertical resolution (∼50  cm), low signal-to-noise ratio, and inability to measure the upper 0-0.5 m are problematic in Monterey Bay. Although a significant component of the [L W ¯(λ)] N differences between C-OPS and HP2 likely stems from fluctuating water mass's inherent optical properties, the 25% error in [L W (λ)] N s processed from HP2 casts, compared to <1% for C-OPS, is also important.

Most harmful algal blooms (HAB) originate away from the shore and, for them to endanger human health, they must be first transported to shore after which they must enter the surf zone where they can be feed upon by filter feeders. The last step in this sequence, entrance into the surf zone, depends on surf zone hydrodynamics. During two 30-day periods, we sampled Pseudo-nitzschia and particulate domoic acid (pDA) in and offshore of a more dissipative surf zone at Sand City, California (2010) and sampled Pseudo-nitzschia in and out of reflective surf zones at a beach and rocky shores at Carmel River State Beach, California (2011). At Sand City, we measured domoic acid in sand crabs, Emerita analoga. In the more dissipative surf zone, concentrations of Pseudo-nitzschia and pDA were an order of magnitude higher in samples from a rip current than in samples collected just seaward of the surf zone and were 1000 times more abundant than in samples from the shoals separating rip currents. Domoic acid was present in all the Emerita samples and varied directly with the concentration of pDA and Pseudo-nitzschia in the rip current. In the more reflective surf zones, Pseudo-nitzschia concentrations were 1-2 orders of magnitude lower than in samples from 125 and 20m from shore. Surf zone hydrodynamics affects the ingress of Pseudo-nitzschia into surf zones and the exposure of intertidal organisms to HABs on the inner shelf., (Copyright © 2016 Elsevier B.V. All rights reserved.)