Spatio-Temporal Scale Assessment of an "Upwelling Shadow" in Northern Monterey Bay, California

Graham, William M.

doi:10.2307/1352766

Cited by 46 publications

(41 citation statements)

References 29 publications

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“…Recent studies (Storlazzi et al 2003, Drake et al 2005) document that alongshore and cross-shore currents show a much more complex response to wind stress than previously suggested. However, sites near the bay's northern shore show the highest windtemperature coherence, and the recent studies were generally consistent with earlier observations that a front is established between the cool water in the southern and eastern sections of the bay and a warmer region of water in the northern bay (Graham 1993, Graham & Largier 1997. This warm region of water (Fig.…”

Section: Monterey Peninsulasupporting

confidence: 90%

Spatial variability of recruitment in the sand crab Emerita analoga throughout California in relation to wind-driven currents

Diehl¹,

Toonen²,

Botsford³

2007

Mar. Ecol. Prog. Ser.

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We compared recruitment of the sand crab Emerita analoga over 2 yr at 17 sites distributed along > 800 km of the California coastline. We hypothesized that larvae of benthic invertebrates are retained by water circulation near headlands, and then redistributed alongshore north of the promontories during synoptic-scale relaxation in upwelling winds. We tested for a negative relationship between recruitment and distance north of 4 headlands: Point Arena, Point Reyes, Monterey Peninsula, and Point Conception. We also examined patterns of recruitment at sites east of Point Conception, within the Southern California Bight (SCB). Recruitment magnitude was predictable at a given site within a recruitment season (June through October), but not between the 2 years at each site. Recruitment of E. analoga north of Point Conception was negatively correlated with site distance north of a headland in 1998, but not in 1999. Upwelling indices in 1998 were not significantly different from the long-term average either north of Point Conception or within the SCB; in contrast, during 1999, upwelling was stronger than the 54 yr average at all sites north of Point Conception, but not at those within the SCB. Thus, the upwelling-relaxation mechanism appeared to operate effectively from Point Arena to Point Conception in 1998, when upwelling and wind stress were within long-term average levels, but not in 1999, when upwelling and wind stress were anomalously high. However, in the SCB, we observed similar magnitude and spatial patterns of recruitment in both years. One implication of our results is that the California coast may be composed of separate retentive cells of populations separated by headlands, which enhances population persistence, but the extent of larval loss from these cells remains unknown.

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Section: Monterey Peninsulasupporting

confidence: 90%

Spatial variability of recruitment in the sand crab Emerita analoga throughout California in relation to wind-driven currents

Diehl¹,

Toonen²,

Botsford³

2007

Mar. Ecol. Prog. Ser.

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“…Under upwelling conditions, circulation dynamics cause water in the northern part of the Bay to become separated from the inner-bay, creating an upwelling shadow (Graham, 1993;Graham and Largier, 1997). The water in the upwelling shadow is characterized by long residence times, and is sheltered from wind-induced mixing by local topography, leading to pronounced stratification (Graham, 1993). At periods of 15 to 40 days, the winds can lessen (< 3 m s -1 ) or reverse direction (Rosenfeld et al, 1994); these periods are termed 'relaxation' periods (Fitzwater et al, 2003).…”

Section: Study Areamentioning

confidence: 99%

Hidden thin layers of toxic diatoms in a coastal bay

Timmerman

McManus

Cheriton

et al. 2014

Deep Sea Research Part II: Topical Studies in Oceanography

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ACKNOWLEDGEMENTSiii ABSTRACTHarmful algal blooms (HABs) can threaten animal and human health through the production of toxins such as domoic acid. These blooms have become more frequent and toxic over the last few decades. In this study, we investigate the role that nutrients play in a toxic, subsurface bloom of Pseudo-nitzschia in northeastern Monterey Bay, California.Profilers and towed instruments were deployed and laboratory analyses of discrete water samples were conducted to describe the physical and biogeochemical conditions of the sampling site and to characterize the bloom. The Pseudo-nitzschia bloom occurred within a well-defined subsurface layer, containing high levels of domoic acid. In situ images taken within the layer revealed diatom flocs -indicators of nutrient stress. Nutrient ratios and alkaline phosphatase activity, commonly used to determine the nutritional status of phytoplankton, suggest that the Pseudo-nitzschia cells were phosphate stressed, and we speculate that this physiological stress led to increased toxicity of the bloom.Understanding how frequently blooms such as these are characterized by nutrient stress could improve our ability to predict the occurrence of HABs. With increased anthropogenic input of nutrients, such blooms could occur more often and with greater degrees of toxicity in the future.iv

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Section: Thin Zooplankton Layers and Stratificationmentioning

confidence: 99%

“…The nearshore waters in this area are characterized by cold subsurface waters and a warm surface layer (4 to 7 m). This causes the water column to be highly stratified (Graham 1993, Woodson et al 2007.It is important to note that the processes that lead to stratification in the water column in East Sound and in Monterey Bay occurred over time scales of days to weeks, while the processes that lead to stratification in Mamala Bay occurred over time scales of hours. In Mamala Bay, thin layer persistence was on average shorter than the layers in East Sound by a factor of 4, and shorter than the layers in Monterey Bay by a factor of 2.…”

mentioning

confidence: 99%

Effects of physical structure and processes on thin zooplankton layers in Mamala Bay, Hawaii

Sevadjian

McManus²,

Pawlak³

2010

Mar. Ecol. Prog. Ser.

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Vertically thin layers of zooplankton were found to be common and recurring features in Mamala Bay on the south shore of the island of Oahu, Hawaii. The formation, maintenance, and vertical displacement of these thin layers are, in part, a function of regional physical oceanographic processes. The purpose of this study was to quantify general thin zooplankton layer characteristics in Mamala Bay and the underlying physical environment in which they occurred. We utilized a 2 mo time series of acoustic backscatter measurements from a calibrated acoustic Doppler current profiler (ADCP) to identify thin scattering features; took biological samples; and collected vertical profiles of physical, optical, and biological characteristics of the water column. In general, thin zooplankton layers were associated with increased water column stability. Stratification at the study site was low relative to other coastal regions around the continental USA where thin layers have been observed. Instances of significant stratification were short-lived, and possibly as a result, thin layers were shorter in duration. Diurnal surface heating accounted for much of the observed stratification, and the breakdown of stratification during civil twilight corresponded with a decrease in thin zooplankton layer formation. Biological and optical measurements taken during a focused shipboard profiling experiment over the course of the study suggested a mechanism for zooplankton layer formation in which zooplankton converged to graze on a thin phytoplankton layer. 409: 95-106, 2010 changes in the underlying physical environment. Thin layers are often found in conjunction with vertical gradients of some physical property, such as water density or current velocity. Franks (1992) and Stacey et al. (2007) proposed a buoyancy-driven mechanism for thin layer formation in which non-motile, or passive, organisms settle at densities equal to their own density; therefore one would expect a higher concentration of organisms near large density gradients. This theory has been supported by observational work by Dekshenieks et al. (2001), who found that a large percentage (71%) of thin layers were associated with the pycnocline. Another purely physical mechanism that has been proposed to contribute to thin layer formation is strain by a sheared velocity profile (Franks 1995, Stacey et al. 2007. To this end, Ryan et al. (2008) found strong statistical relationships between shear in the water column and the presence of thin layers. Thus, an understanding of the regional physical processes that contribute to local stratification and shear may help to predict the occurrence of conditions that are favorable to thin layer development and maintenance. KEY WORDS: Thin layer · Physical processes · Stratification · Zooplankton Resale or republication not permitted without written consent of the publisher OPEN PEN ACCESS CCESSMar Ecol Prog SerIn addition, motile species of phytoplankton and zooplankton can actively converge into thin layers seeking nutrients, ...

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Spatio-Temporal Scale Assessment of an "Upwelling Shadow" in Northern Monterey Bay, California

Cited by 46 publications

References 29 publications

Spatial variability of recruitment in the sand crab Emerita analoga throughout California in relation to wind-driven currents

Spatial variability of recruitment in the sand crab Emerita analoga throughout California in relation to wind-driven currents

Hidden thin layers of toxic diatoms in a coastal bay

Effects of physical structure and processes on thin zooplankton layers in Mamala Bay, Hawaii

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