@article{LukasWacker2014,
  author    = {Lukas, Marcus and Wacker, Alexander},
  title     = {Daphnia's dilemma: adjustment of carbon budgets in the face of food and cholesterol limitation},
  series = {The journal of experimental biology},
  volume    = {217},
  journal   = {The journal of experimental biology},
  number    = {7},
  publisher = {Company of Biologists Limited},
  address   = {Cambridge},
  issn      = {0022-0949},
  doi       = {10.1242/jeb.094151},
  pages     = {1079 -- 1086},
  year      = {2014},
  abstract  = {We studied the carbon (C) metabolism in Daphnia when the amount of C (food quantity) and/or the content of biochemical nutrients (food quality) was limiting. Growth performances and C budgets of Daphnia magna (assimilation, faeces egestion, excretion and respiration measured by [C-14]-tracing) were analysed when animals were raised on different food quantities and concentrations of cholesterol, an essential biochemical food compound. Cholesterol is of special interest because it not only acts as limiting nutrient but also contributes to the overall C pool of the animals. As the tissue cholesterol concentration in Daphnia is quite low, we hypothesized the selective exclusion of cholesterol from C budgeting and tested this using radiolabelled cholesterol. Somatic growth rates of D. magna were highest at high quantity and quality and were reduced to a moderate value if either the food quantity or the cholesterol concentration was low. Growth was lowest at low food quantity and quality. The measurements of C budgets revealed high regulative response to low food quality at high food quantity only. Here, low dietary cholesterol caused bulk C assimilation efficiency (AE) to decrease and assimilated (excess) C to be increasingly respired. Additionally, Daphnia enhanced efficient adjustment of C budgets when facing cholesterol limitation by (1) increasing the AE of the cholesterol itself and (2) not changing cholesterol respiration, which was still not detectable. In contrast, at low food quantity, Daphnia is unable to adjust for low food quality, emphasizing that food limitation could overrule food quality effects.},
  language  = {en}
}
@article{BickelTangGrossart2014,
  author    = {Bickel, Samantha L. and Tang, Kam W. and Grossart, Hans-Peter},
  title     = {Structure and function of zooplankton-associated bacterial communities in a temperate estuary change more with time than with zooplankton species},
  series = {Aquatic microbial ecology : international journal},
  volume    = {72},
  journal   = {Aquatic microbial ecology : international journal},
  number    = {1},
  publisher = {Institute of Mathematical Statistics},
  address   = {Oldendorf Luhe},
  issn      = {0948-3055},
  doi       = {10.3354/ame01676},
  pages     = {1 -- 15},
  year      = {2014},
  abstract  = {Zooplankton support distinct bacterial communities in high concentrations relative to the surrounding water, but little is known about how the compositions and functionalities of these bacterial communities change through time in relation to environmental conditions. We conducted a year-long field study of bacterial communities associated with common zooplankton groups as well as free-living bacterial communities in the York River, a tributary of Chesapeake Bay. Bacterial community genetic fingerprints and their carbon substrate usage were examined by denaturing gradient gel electrophoresis (DGGE) of amplified 16S rDNA and by Biolog EcoPlates, respectively. Zooplankton-associated communities were genetically distinct from free-living bacterial communities but utilized a similar array of carbon substrates. On average, bacteria associated with different zooplankton groups were genetically more similar to each other within each month (65.4\% similarity) than to bacterial communities of the same zooplankton group from different months (28 to 30\% similarity), which suggests the importance of ambient environmental conditions in shaping resident zooplankton-associated bacterial communities. Monthly changes in carbon substrate utilization were less variable for zooplankton-associated bacteria than for free-living bacteria, suggesting that the zooplankton microhabitat is more stable than the surrounding water and supports specific bacterial groups in the otherwise unfavorable conditions in the water column.},
  language  = {en}
}