These are a particular case of blooms where high cell densities are located within a narrow depth interval (from some centimeters to a few meters), which can extend horizontally over several kilometers and persist for several days (Dekshenieks et al., 2001; ... A number of independent criteria have been proposed for their definition, most of which share three requirements: (1) the cells aggregation must be spatially and temporally persistent, i.e., TLP must be present in at least two consecutive vertical profiles (sampled within a few hours interval), (2) the layer thickness must not exceed a threshold (usually < 5 m), and (3) the maximum concentration must exceed a certain value (i.e., three times the background levels -average chlorophyll or cell abundance-in the water column) (Dekshenieks et al., 2001;Sullivan et al., 2010b). Nonetheless, the low POC:Chl a ratio observed at the DCM suggests the presence of photoacclimation mechanisms (Fennel and Boss 2003;Clegg et al. The swimming behavior of invertebrate larvae can affect their dispersal, survival, and settlement in the ocean. Irrespective, consumption by mesozooplankton had only minor impacts on water column phytoplankton and microzooplankton biomass, and production, and nutrient regeneration. The absence of DVM in the latter part of the infection cycle appeared to be associated with changes in phototaxic response and swimming speed of parasitized cells. Hence, density gradients may act as a barrier to vertical movement and not as a positive cue for area-restricted search behavior. Individual taxa often exhibited disparate patterns of vertical distribution, with some found throughout the water column, whereas others were restricted to narrow depth intervals. The paper is intended to serve as an homage to the (phytoplankton) ecologist Colin S. Reynolds. Six out eight of these events happened during summer-upwelling conditions, and according to a Principal Component Analysis (PCA) they were positively correlated with thermal stratification. For typical oceanic parameters, such as κv∼10-5m2s-1, α∼10-2s-1, and L0∼1000m the initial transient is about 3h and the layer achieves a minimum thickness of order 1m in a time of order 1 day. All too frequently, major gaps in our ability to identify, measure, and model the underlying biological and physical processes and their interactions over the appropiate temporal and spatial scales have prevented the quantitative assessment of the importance of these factors in causing past blooms and the development of predictive models of bloom dynamics and impacts. ... Relations between the threshold values for two depth-dependent parameters Ar(z) and Re(z)/Fr(z) in the density transition (Eqs. Sea lice (Lepeophtheirus and Caligus spp) are parasitic copepods that infect the external surfaces of fish hosts. The tank experiment was carried out in a 2.1 m PVC cylinder (0.29 m internal diameter) and lasted for 24 d. Initially, nitrate was replete throughout the water column (50 mu M) and the highly toxic cells formed a thin surface layer which persisted throughout the 14 h light:10 h dark cycle. Ocean color remote sensing utilizes the intensity and spectral variation of visible light scattered upward from beneath the ocean surface to derive concentrations of biogeochemical constituents and inherent optical properties within the ocean surface layer. The dominant rotation case is particularly studied. The daytime vertical migration that induce convective instabilities is well‐established. Energy dissipation rate was lowest in the central layer and increased in both top and bottom layers. The thickness of layers was not affected by fish presence. Strong stratification produced by late winter--early spring surface runoff results in the development of a stable pycnocline. Data also suggest that modification of host behavior by parasitism may contribute to vertical variations in phytoplankton species-composition and -abundance, particularly during epidemics when late-stage infections are prevalent. This condition, called positive assortment, is known to occur in spatially-structured viscous populations, where individuals typically have low mobility and limited dispersal. For over four decades, aggregations of phytoplankton known as thin layers have been observed to harbor large amounts of photosynthetic cells within narrow horizontal bands. Since the densities of detritus and algae as well as those of different algal species often overlapped, only 10 of the 100 samples processed in the course of the year showed a reasonable separation. The thin layers represent highly concentrated patches of phytoplankton, with a vertical extension from centimeters to meters, which could reach kilometers in the horizontal and persist hours either weeks, particularly in coastal areas (Sullivan et al., 2010). Here we report on the vertical distribution of bacteria, heterotrophic flagellates, ciliates and copepods at a permanent station in the Southern Kattegat during the bloom. Contrary to expectations, we found that mortality for Pacific hake (Merluccius productus) significantly decreased as storm events increased in the southern California Current Ecosystem. Retention of upwelled waters in bays allows for dense phytoplankton blooms that support productive bay ecosystems. The maximum rate of layer formation ranged from 0.46 to 0.94 d 21 , which is comparable to maximum reported growth rates of the most common phytoplankton taxa found in our samples. Application of this coupled approach can help identify fundamental ecosystem characteristics such as particle size spectra that affect primary production, trophic transfer, and export. Coinciding DCMs and DBMs can be found at the intersection of two opposite resource gradients, light from the surface, and nutrients from the bottom (Abbott et al. Mortality rates for northern anchovy (Engraulis mordax), Pacific sardine (Sardinops sagax), Pacific mackerel (Scomber japonicus), and jack mackerel (Trachurus symmetricus) had no relationship to storms, and no species’ mortality rates were related to the number of calm events. Using a mixed layer shape model, vertical velocity observations and turbulent dissipation estimates, we conclude that photoautotrophic bacteria continue their vertical migration at night. Surveys included microstructure profiles and high-resolution mooring measurements. These cyanobacteria, capable of regulating their vertical position, often flourish at the thermocline to form a deep chlorophyll maximum. In spite of vastly improved computing power and observational capabilities, the modeling approach has remained anchored to an old view that sees the microscales as unable to substantially affect larger ones. Studying the distribution of zooplankton in relation to their prey and predators is challenging, especially in situ. In this chapter, we consider the dispersion of pairs of particles passively advected by homogeneous, isotropic, fully developed turbulent type. This discrepancy may reflect a disparity between predictions from models developed for larger organisms in contrast to our microbe-centric model. Using multidisciplinary observations from regional- to small-scale, we examined the development of thin phytoplankton layers in water mass frontal zones of a coastal upwelling system. This mechanism was [CDATA[/* >