The rise of animal biotelemetry and genetics research data integration.

The advancement and availability of innovative animal biotelemetry and genomic technologies are improving our understanding of how the movements of individuals influence gene flow within and between populations and ultimately drive evolutionary and ecological processes. There is a growing body of work that is integrating what were once disparate fields of biology, and here, we reviewed the published literature up until January 2023 (139 papers) to better understand the drivers of this research and how it is improving our knowledge of animal biology. The review showed that the predominant drivers for this research were as follows: (1) understanding how individual-based movements affect animal populations, (2) analyzing the relationship between genetic relatedness and social structuring, and (3) studying how the landscape affects the flow of genes, and how this is impacted by environmental change. However, there was a divergence between taxa as to the most prevalent research aim and the methodologies applied. We also found that after 2010 there was an increase in studies that integrated the two data types using innovative statistical techniques instead of analyzing the data independently using traditional statistics from the respective fields. This new approach greatly improved our understanding of the link between the individual, the population, and the environment and is being used to better conserve and manage species. We discuss the challenges and limitations, as well as the potential for growth and diversification of this research approach. The paper provides a guide for researchers who wish to consider applying these disparate disciplines and advance the field.

Optimal light conditions for Daphnia filtration.

Daphnia populations are present in lakes and ponds. They are known to experience diurnal vertical migrations according to their feeding needs. During the day they migrate downwards to avoid predation in light-receiving layers and at night they migrate upwards, searching for food in the shallow productive layers. The light photoperiod and light intensity vary depending on the latitude and, therefore, the precise location of lakes and ponds will be an additional and crucial parameter in determining the development of Daphnia. Here we will focus on a population of Daphnia magna (a genus of the Cladocera order). The effect of both light intensity and photoperiod on Daphnia filtration was studied in laboratory experiments. An increase in the light intensity resulted in two D. magna responses depending on the exposure time of individuals to light. Short time exposures to a decrease in the light intensity of less than one day produced an increase in the D. magna filtration. However, exposures of longer than one day resulted in a decrease in the D. magna filtration along with a decrease in the light intensity. Photoperiod exposures of 8, 12 and 16 h produced greater D. magna filtrations than photoperiods of 0, 4 and 24 h. In this study, regulation of the light intensity and the period of exposure were used in laboratory experiments to establish D. magna development thresholds by latitudinal variation in the photoperiod.

Mediated food and hydrodynamics on the ingestion of microplastics by Daphnia magna.

There is consensus on the need to study the potential impact microplastics (MP) have on freshwater planktonic organisms. It is not yet fully understood how MP enter the aquatic food web or the effect they have on all the trophic levels. As a result of the potential for MP to accumulate throughout food webs, there is increasing interest in evaluating their fate in a variety of environmental conditions. This study investigated the variability in the ingestion of MP to food ratios and the exposed time of MP to Daphnia magna in non-sheared and sheared conditions. The sheared environment provided Daphnia magna with the conditions for optimal filtering capacity. Regardless of the ratios of MP concentration to food concentration (MP:Food), the filtration capacity of the Daphnia magna was enhanced in the sheared experiments. In both the sheared and non-sheared experiments, filtration capacity decreased when the ratios of MP to food concentration and the exposure times to MP were increased. Mortality was mainly enhanced in the non-sheared conditions at higher MP concentrations and exposure times to MP. No mortality was found in the sheared conditions for the exposure times studied. Therefore, in aquatic systems that undergo constant low sheared conditions, Daphnia magna can survive longer when exposed to MP than in calm conditions, provided food concentrations do not limit their capacity to filter.

Functional responses of Daphnia magna to zero-mean flow turbulence.

Daphnia are important to understanding the biogeochemistry of aquatic ecosystems, mainly because of their ability to filter bacteria, algae and inorganic particles as well. Although there are many studies on the general effects that biotic and abiotic stressors, increased temperature and hypoxia, salinity, metals, pharmaceuticals, pesticides, etc., have on Daphnia populations, little is known about the impact elevated turbulence has. Here, we show that turbulence affects Daphnia magna survival, swimming behaviour and filtering capacity. Our data demonstrate that altering their habitat by induced mixing from turbulence, induces an increased filtering capacity of the Daphnia magna individuals, provided the level of background turbulence (defined by the dissipation of turbulent kinetic energy) is lower than ε = 0.04 cm2 s-3. The filtering capacity reduced exponentially with increasing ε, and at ε > 1 cm2 s-3 both mobility and filtration were suppressed and eventually led to the death of all the Daphnia magna individuals.

Temperature-driven response reversibility and short-term quasi-acclimation of Daphnia magna.

Analysing the effect water temperature has on Daphnia magna is essential in anticipating the impact climate change will have on this freshwater zooplanktonic keystone species. While many authors have followed this line of research, few have covered an extensive temperature range or complex temperature change scenarios. Global warming is mostly associated with increased extreme temperature events, such as heat waves, as well as earlier and more intense thermal stratification. Both of these events may directly influence D. magna fitness, especially in those populations performing diel vertical migration (DVM). We analysed the effect water temperatures, ranging from 11 to 29°C, have on the filtration capacity (FC) of D. magna, to anticipate the effects of acclimation, temperature change rate (TCR) and potential reversibility of responses to such conditions. Results show that sudden temperature changes have an immediate negative impact on the FC of D. magna and is more severe at higher temperatures and higher TCRs. However, D. magna individuals have shown themselves to be capable of quasi-acclimating to temperatures ranging from 11 to 25°C in around a week and achieving much higher FCs; albeit never reaching the optimal FC achieved at 20°C. That said, 29°C is lethal for D. magna individuals within approximately five days. Finally, non-optimal temperature acclimated individuals can recover maximal FC within 2-4 days of the optimal long-term acclimation temperature (20°C) being re-established, thus proving temperature responses to be reversible.