Rapid Enzymatic Response to Compensate UV Radiation in Copepods

Ultraviolet radiation (UVR) causes physical damage to DNA, carboxylation of proteins and peroxidation of lipids in copepod crustaceans, ubiquitous and abundant secondary producers in most aquatic ecosystems. Copepod adaptations for long duration exposures include changes in behaviour, changes in pigmentation and ultimately changes in morphology. Adaptations to short-term exposures are little studied. Here we show that short-duration exposure to UVR causes the freshwater calanoid copepod, Eudiaptomus gracilis, to rapidly activate production of enzymes that prevent widespread collateral peroxidation (glutathione S-transferase, GST), that regulate apoptosis cell death (Caspase-3, Casp-3), and that facilitate neurotransmissions (cholinesterase-ChE). None of these enzyme systems is alone sufficient, but they act in concert to reduce the stress level of the organism. The interplay among enzymatic responses provides useful information on how organisms respond to environmental stressors acting on short time scales

Global data set of long-term summertime vertical temperature profiles in 153 lakes

Climate change and other anthropogenic stressors have led to long-term changes in the thermal structure, including surface temperatures, deepwater temperatures, and vertical thermal gradients, in many lakes around the world. Though many studies highlight warming of surface water temperatures in lakes worldwide, less is known about long-term trends in full vertical thermal structure and deepwater temperatures, which have been changing less consistently in both direction and magnitude. Here, we present a globally-expansive data set of summertime in-situ vertical temperature profiles from 153 lakes, with one time series beginning as early as 1894. We also compiled lake geographic, morphometric, and water quality variables that can influence vertical thermal structure through a variety of potential mechanisms in these lakes. These long-term time series of vertical temperature profiles and corresponding lake characteristics serve as valuable data to help understand changes and drivers of lake thermal structure in a time of rapid global and ecological change

Global data set of long-term summertime vertical temperature profiles in 153 lakes

Measurement(s) : temperature of water, temperature profile Technology Type(s) : digital curation Factor Type(s) : lake location, temporal interval Sample Characteristic - Environment : lake, reservoir Sample Characteristic - Location : global Machine-accessible metadata file describing the reported data: https://doi.org/10.6084/m9.figshare.14619009Climate change and other anthropogenic stressors have led to long-term changes in the thermal structure, including surface temperatures, deepwater temperatures, and vertical thermal gradients, in many lakes around the world. Though many studies highlight warming of surface water temperatures in lakes worldwide, less is known about long-term trends in full vertical thermal structure and deepwater temperatures, which have been changing less consistently in both direction and magnitude. Here, we present a globally-expansive data set of summertime in-situ vertical temperature profiles from 153 lakes, with one time series beginning as early as 1894. We also compiled lake geographic, morphometric, and water quality variables that can influence vertical thermal structure through a variety of potential mechanisms in these lakes. These long-term time series of vertical temperature profiles and corresponding lake characteristics serve as valuable data to help understand changes and drivers of lake thermal structure in a time of rapid global and ecological change

Balance between primary and bacterial production in North Patagonian shallow lakes

Abstract The shallow Andean North Patagonian lakes are suitable environments for the evaluation of autotrophic and heterotrophic production under a scenario of high radiation in high dissolved organic matter (DOM) systems. We aimed to study the balance between primary and bacterial production in three shallow Andean lakes, in a summer sampling (high irradiance condition). Our hypothesis is that two factors would interact: high light and high DOM, affecting bacteria and algae. We carried out experiments of bacterial production (BP) by measuring [ 14 C]-L-leucine incorporation and PP by 14 C uptake in two fractions: picophytoplankton and phytoplankton [2 lm. Cell abundance, chlorophyll a, nutrients, DOM, light, and temperature were also measured. The contribution of picophytoplankton to total primary production (PP) was, in general, very high exceeding 50%. Picophytoplankton was photosynthetically more efficient than the larger autotrophs in all lakes. We observed a decrease in PP at surface levels due the high solar irradiances, while BP was not affected. Changes in the PP:BP ratios were observed in relation to DOM content and light effect. Our data indicate that the amount of available DOM drives the balance between PP and BP. However, solar radiation should be included as an important factor since PP:BP ratio may decrease because of PP photoinhibition