Horizontal patchiness in zooplankton populations in two Ontario kettle lakes

Malone, Ben; McQueen, Donald J.

doi:10.1007/bf00015039

Cited by 102 publications

(67 citation statements)

References 54 publications

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“…Jeppesen et al, 1990). Moreover, it has become increasing clear that aquatic environments are not as homogenous as previously assumed, but that many zooplankton and phytoplankton populations show a high degree of patchiness in their distributions (George & Edwards, 1976;Harris, 1980), with, as was reported by Malone & McQueen (1983) differences of upto a factor three in chlorophyll content within a distance of a few meters. This implies that a slight horizontal or vertical movement of the daphnids could lead to different feeding conditions rather rapidly.…”

Section: Discussionmentioning

confidence: 87%

Offspring size in Daphnia: does it pay to be overweight?

Boersma

1997

Cladocera: The Biology of Model Organisms

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Variation in offspring size and number has been described for a wide range of organisms. In this study I investigated the relationship between resource level of the mother and size of her offspring in the cladoceran Daphnia magna, in order to assess whether offspring produced at different food levels are optimal in size for these food levels. Optimal offspring size was defined as the size of offspring that yields the highest parental fitness (i.e. offspring of optimal size have the highest juvenile fitness per unit maternal effort invested in them). I observed that especially at the higher food levels, daphnids produced offspring that are larger than the computed optimal offspring size at these food levels. I interpret this as a mechanism to avoid starvation of neonates in the case of suddenly deteriorating food conditions.

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Section: Discussionmentioning

confidence: 87%

Offspring size in Daphnia: does it pay to be overweight?

Boersma

1997

Cladocera: The Biology of Model Organisms

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“…Our understanding of zooplankton populations has been impeded because zooplankton are known to be extremely patchy, and the patterns of distribution have been difficult to discern with conventional sampling methodology. Patchy zooplankton distributions have been found wherever people looked for them (Whiteside 1974;Malone andMcQueen 1983), andDowning (1991) concluded that zooplankton, although transported passively by water movements, are as spatially aggregated as most other groups of aquatic organisms.…”

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confidence: 99%

Spatial distributions of zooplankton during coastal upwelling in western Lake Superior

Megard

Kuns

Whiteside

et al. 1997

Limnology & Oceanography

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Zooplankton distributions during coastal upwelling in western Lake Superior were mapped with a high-frequency (192~kHz) sonar system that consists of an echosounder and a navigation receiver connected to a microcomputer. An acoustic transect after a September storm revealed a sloping sound-scattering layer, traceable more than 5 km offshore, in the thermocline between an upwelling water mass and a returning front of surface water. Interfacial shear produced short internal waves on the scattering layer, and regularly spaced plumes of high backscattering in the surface layer were attributed to stream lines of eddies that were transporting sound scatterers from aggregations in the thermocline to the lake surface. The sloping sound-scattering layer was due to high concentrations (up to lo5 ind. m-3) of copepods, chiefly Leptodiuptomus sicilis. Backscattered sound (volume-scattering strength) was highly correlated with concentrations of microcrustacea in samples collected with nets, consistent with Rayleigh scattering theory for ideal elastic spheres the size of adult L. sicilis (target strength = -123 dB).Acoustic sampling revealed a skewed frequency distribution; low animal concentrations (< 1,000 m-j) occupied most (65%) of the zooplankton space, but a small proportion (105 m-3) with concentrations several orders of magnitude larger than the median, Infrequent patches of very high densities are probably a general feature of zooplankton populations, because the patchiness inferred from sound backscattering is similar statistically to distribution patterns in lakes and oceans sampled with conventional methods, The densest aggregations are likely to be the most important for foraging fishes but are so infrequent they are unlikely to be detected with conventional sampling methods.Spatial distribution influences virtually every aspect of the ecology of populations. In the zooplankton, spatial heterogeneity is thought to influence predation and mortality rates, reproduction, feeding, and species diversity (Cryer and Townsend 1988; Priddle et al. 1990; Saiz et al. 1993). A demographic process such as mortality, for example, is likely to be very different qualitatively and quantitively in a dense aggregation than it is where population density is very low. Our understanding of zooplankton populations has been impeded because zooplankton are known to be extremely patchy, and the patterns of distribution have been difficult to Acknowledgments

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“…Previous studies have documented zooplankton-phytoplankton interactions through correlation analysis, but the trophic consequences of such interactions were not quantified (Mackas and Boyd 1979;Star and Mullin 1981;Malone and McQueen 1983). Studies have also shown that zooplankton spatial patterns can differ depending on body size (Martin and Srokosz 2002), especially if these patterns are wind-driven (Blukacz et al 2009).…”

Section: Discussionmentioning

confidence: 99%

Evaluating the effect of wind‐driven patchiness on trophic interactions between zooplankton and phytoplankton

Blukacz

Sprules

Shuter

et al. 2010

Limnology & Oceanography

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We measured spatial patterns of zooplankton and chlorophyll concentration (a proxy for phytoplankton) with continuous sensors along horizontal transects that were repeatedly sampled (n 5 150) under varying wind conditions throughout a growing season in two basins (South Arm and Annie Bay) of Lake Opeongo, Ontario, Canada. Spatially explicit in situ simulations that included activity costs associated with feeding were used to examine the effects of chlorophyll patchiness on the energy gain in different zooplankton communities. Simulations were repeated for several zooplankton size classes (small, large, and bulk) and two communities (all copepods and all cladocerans). For each simulated combination, a spatial energetic differential (SED) was estimated by contrasting the energy that zooplankton could gain using observed spatial patterns in chlorophyll and water temperature with the energy they could gain using uniform concentrations of chlorophyll and water temperature. Large zooplankton showed the greatest SED range across all communities, from a decrease of 8% to a maximum increase of 20%, assuming relatively low costs associated with feeding activity. Small zooplankton had the narrowest SED range. Zooplankton energy gain is sensitive to both the degree of zooplanktonchlorophyll spatial overlap and energetic costs associated with zooplankton feeding activity. SED values as high as 485% can occur under plausible estimates of activity costs. Wind-driven increases in spatial overlap between predator and prey can be large enough to substantially alter planktonic trophic interactions.In marine and freshwater ecosystems, both phytoplankton and zooplankton have patchy distributions that occur over a wide range of spatiotemporal scales. Although there is general agreement that the predominant drivers of spatial heterogeneity in phytoplankton distributions are physical (e.g., wind-driven currents), the relative importance of physical vs. biological drivers for zooplankton spatial distributions has been the subject of more debate (Martin 2003). Recent work is shifting this view by demonstrating that physical drivers, by themselves, are insufficient to explain the observed spatial structure across all scales (Martin 2003). The ''multiple driving forces hypothesis '' (Pinel-Alloul 1995) contends that physical drivers have strong control of zooplankton patchiness at large scales, but that the strength of biological drivers increases at small scales.Zooplankton play an important role in trophic interactions as they prey on phytoplankton and serve as food for fish. To gain a better understanding of such interactions, many researchers have used computer simulations (Martin 2003). Most simulations to date have estimated predator (zooplankton) consumption using statistical distributions, rather than observed data, to generate the predator patchiness, the prey (phytoplankton) patchiness, or both (Martin 2003). A few studies have computed consumption directly from observed data (Mullin and Brooks 1976; Sprules 2000). Mull...

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Horizontal patchiness in zooplankton populations in two Ontario kettle lakes

Cited by 102 publications

References 54 publications

Offspring size in Daphnia: does it pay to be overweight?

Offspring size in Daphnia: does it pay to be overweight?

Spatial distributions of zooplankton during coastal upwelling in western Lake Superior

Evaluating the effect of wind‐driven patchiness on trophic interactions between zooplankton and phytoplankton

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