Linking mean body size of pelagic Cladocera to environmental variables in Precambrian Shield lakes: A paleolimnological approach

Abstract

ABSTRACT

Response of Bosmina size structure to the acidification and recovery of lakes near Sudbury, Canada

“…Moreover, the increases in size of antennules and carapaces (Figs. 2 and 3) with acidification differ with results of studies that report smaller Bosmina size attributes in low-pH lakes (Locke and Sprules, 2000;Korosi et al, 2008). We therefore suggest that direct physiological effects of metal contamination and low pH were not the main drivers of Bosmina size structure in these systems.…”

“…The influence of invertebrate predation on cladoceran cyclomorphosis has been well-studied, with invertebrate predators inducing an increase in body size and the development of defensive structures such as neck teeth in Daphnia (Hebert and Grewe, 1985;Black, 1993) and elongated mucros and antennules in Bosmina (Kerfoot, 1975;Black, 1980). However, other environmental factors also affect cladoceran size structure, including temperature (Coker, 1939;Brooks, 1946;Hebert, 1978;Kappes and Sinsch, 2002), food availability (Hebert, 1978), and pH (Locke and Sprules, 2000;Korosi et al, 2008). Size structure is an important attribute of zooplankton ecology, influencing algal grazing rates (larger-sized animals tend to be more efficient grazers; DeMott, 1982;Tóth and Kato, 1997), fitness, competitive abilities, and energy transfer up the food web (Lynch, 1977;Hart and Bychek, 2011).…”

“…In the presence of visual predators such as planktivorous fish, smaller size attributes may be beneficial to reduce visibility to these predators, which often selectively prey upon larger individuals (Kerfoot, 1975;Nilssen and Sandøy, 1990). Abiotic factors may also impact Bosmina size structure; notably, acidification has been associated with shifts in antennule and carapace length (Locke and Sprules, 2000;Korosi et al, 2008). However, reported changes in size structure associated with lake acidification have not been consistent.…”

“…However, reported changes in size structure associated with lake acidification have not been consistent. In some cases, acidification was associated with decreases in Bosmina body size Sprules, 1993, 2000;Korosi et al, 2008), while others observed increases in body size and appendage length (Nilssen and Sandøy, 1990). Acidification not only impacts organisms through direct physiological mechanisms, but can also alter food webs and predation regimes, which may account for these discrepancies.…”

Anomalous rise in algal production linked to lakewater calcium decline through food web interactions

“…Daphnia were grouped into the Daphnia pulex complex based on the presence of stout spines on the middle comb of the post-abdominal claw, and in Lake George, this complex may consist of Daphnia pulicaria or Daphnia catawba (no remains belonging to the Daphnia longispina complex were identified). A total of 50 Bosmina remains were measured per interval using techniques outlined in Korosi et al [26]. In order to estimate sedimentary chlorophyll a content, selected intervals were freeze-dried and sieved (125 mm), and then analysed for spectral reflectance using a FOSS NIRSystems Model 6500 rapid content analyser [27,28].…”