Temperature effects on body size of freshwater crustacean zooplankton from Greenland to the tropics

Abstract

The body size of zooplankton has substantive effects on the function of aquatic food webs because size affects the ability of zooplankton to: exploit food resources, effectively clear the water of algae, and serve as a food source for fish. A variety of factors may affect size, and earlier studies indicate that water temperature may be a particularly important variable. Here we tested the hypothesis that the body size of cladocerans, calanoids and cyclopoids declines with increasing water temperature, a response documented in an earlier study that considered only cladoceran zooplankton. We tested the hypothesis by comparing body size data that were available from prior studies of lakes ranging from 6 to 74 o latitude and encompassing a temperature range of 2 to 30 o C. Cladoceran body size declined with temperature, however, the trend was just marginally significant (p = 0.01). The decline in size was significant (p = 0.05) for cyclopoids. In both cases, there was considerably more variation around the regression than previously observed suggesting that other variables such as fish predation played an important role in affecting size. Calanoid body size was unrelated to temperature. In contrast with cladocerans and cyclopoids, perhaps calanoid body size is not metabolically constrained by temperature or is differently affected by changes in fish predation occurring with increasing temperature. The unexpected result for calanoids requires further investigation.

A long-term study on crustacean plankton of a shallow tropical lake: the role of invertebrate predation

“…According to these authors, the highest mean sizes were observed between 6°C and 8°C, declining at higher or lower temperatures. Havens et al (2015), comparing 122 lakes located from 6° to 74°N and from 19° to 21°S, showed a relationship between size (as weight) of cladocerans and cyclopoid copepods and temperature. In contrast, Iglesias et al (2011) suggested that predation by fish is the major factor explaining the smaller size of zooplankton in warm lakes.…”

Fish but Not Macroinvertebrates Promote Trophic Cascading Effects in High Density Submersed Plant Experimental Lake Food Webs in Two Contrasting Climate Regions

“…Fish predation is apparently even stronger in warm lakes than in comparable temperate lakes [19][20][21]; the fish communities in warm lakes typically have higher densities, greater taxonomic and trophic diversity (with predominance of omnivores) and smaller body size [22,23]. Experimental studies have elucidated the effect of planktivorous fish predation on zooplankton communities in subtropical and Mediterranean shallow lakes [24][25][26][27].…”

Environmental and zooplankton parameter changes during the drying of a saline shallow temporary lake in central Argentina

“…However, this is common among fishless, saline lakes in Central Argentina. These lakes are inhabited by the crustaceans B. poopoensis and M. eugeniae and by the rotifers Hexarthra fennica and Brachionus plicatilis (Vignatti, 2011;Vignatti et al 2012a;2012b;2016; Echaniz, 2010; Echaniz et al 2006; 2013a; 2013b;2015;2016). Whereas these crustacean species are endemic to Neotropical halophilic lakes, the rotifers are cosmopolitan and are broadly distributed given their wide tolerance to salinity (Fontaneto et al 2006;Echaniz et al 2016).…”

“…Whereas in ectotherm vertebrates, individuals of small size are likely to occur at lower environmental temperatures (Gillooly et al 2002;Ohlberger, 2013), in zooplankton animals, such as cladocerans (Havens et al 2015) and copepods (Anufriieva & Shadrin, 2014), larger body sizes have been registered at lower temperatures. In the present study, the observed increase in body size for B. poopoensis and M. eugeniae is a likely consequence of the stress produced by increased salinity rather than that of low temperatures (Herbst, 2001).…”

“…Most of the studies on Argentine temporary lakes have been conducted in aquatic ecosystems, located in La Pampa Province, and many of them took place during annual cycles characterized by a certain hydrological stability. Therefore, many aspects of their ecology, under relatively limited salinity variation, are now documented (Echaniz et al 2013a;2015). Other studies have also compared the conditions recorded in different periods (annual cycles) for a given lake and showed differences in physical and chemical variables, as well as in zooplankton biological traits (Echaniz & Vignatti, 2011;Echaniz et al 2006;2012;2013a;2016;Vignatti et al 2012a).…”