Quantitative analysis of the importance of wind‐induced circulation for the spatial structuring of planktonic populations

Abstract

SUMMARY1. Several studies have shown that wind-induced water movements have an important effect on the spatial distribution of crustacean zooplankton. However, few attempts have been made to quantify the effect of physical processes on these broad-scale patterns. Much of our understanding of this spatial structure has been based on the results of isolated surveys which do not capture the dynamic nature of the pelagic environment.2. In this study, we have used a combination of high-speed sampling (at a spatial resolution of 240 m) and spatial data analysis to quantify the factors influencing the horizontal spatial structure of the Daphnia galeata population in Windermere.3. The results show that lake-wide circulation patterns, as indicated by water temperature, account for 29 -47% of the basin-scale spatial variance in D. galeata abundance. However, these patterns are highly dynamic and change in response to the prevailing weather. This lack of temporal persistence means that the results of single-survey sampling campaigns must be interpreted with caution.3

Assessing Potential Algal Blooms in a Shallow Fluvial Lake by Combining Hydrodynamic Modelling and Remote-Sensed Images

“…However, their sign and the trend of the values over the four cases are meaningful to understand the underlying mechanisms relating the two processes. Elaborate statistical models e.g., [8,15] would better describe the complex, composite and, to a large extent, site-specific relations of the Chl-a concentrations to the hydrodynamic variables. Yet, such an analysis would overcome the purpose of the present research article, which is to demonstrate the feasibility of the use of a hydrodynamic model to forecast the extension and location of the areas of most probable phytoplankton accumulation and the consequent environmental risks in shallow fluvial lakes.…”

“…Microorganism arrangement is also the vector through which hydrodynamically induced patchiness is transferred to higher trophic levels [14]. Biological processes are hence relevant only over multi-daily time scales or over very small spatial scales [15].…”

“…In this frame, biological dynamics can be used to estimate hydrodynamic patterns e.g., [26]: for example, remote-sensed images of Chl-a distribution can be used to validate wind-induced circulation models [7], while numerical model results can be used to assess the correlation between plankton distribution and hydrodynamic variables [8]. Thackeray et al [15] pointed out that given the responsive nature of plankton distribution to wind variations, the results of field surveys taking many hours or days to complete cannot describe properly the distribution dynamics. In this sense, remote-sensed images are the most appropriate tool, as they capture instantaneously the whole water body.…”

Lake‐wide distributions of temperature, phytoplankton, zooplankton, and fish in the pelagic zone of a large lake

“…Dominant factors explaining spatial variations are windinduced circulations (Lacroix and Lescher-Moutoué 1995;Thackeray et al 2004), water temperature (Patalas and Salki 1992;Pinel-Alloul et al 1999), basin morphology (Pothoven et al 2004) or local eutrophication, e.g., by river inflows (Patalas and Salki 1992;Fietz et al 2005). Such factors inducing patchy plankton distributions in lakes may be separated in two different modes of patch generation (George and Heaney 1978); factors inducing spatial variation in the rate of population increase or decrease, e.g., local differences in resource availability, predation pressure or temperature, and factors bringing about a spatial redistribution of the population.…”

Infestation of zooplankton with Triaenophorus and Proteocephalus procercoids (Cestoda) in a deep oligotrophic lake

“…From the literature it is known that infected copepods are not uniformly distributed over the whole lake (Watson and Lawler, 1965). In Lake Achensee, strong winds are frequent, which have the potential to influence the lateral transport of zooplankton as seen in other wind-exposed lakes (Thackeray et al, 2004). Pike (Esox lucius) spawn along the southern shoreline of this lake (A. Kandler, fisheries manager of Lake Achensee, personal communication).…”