Effects of ocean warming with stable and fluctuating ocean acidification on seawater transition in Chinook salmon smolts.

Anadromous salmon populations are declining in the Pacific Northwest, with high mortality during the transition from fresh- to seawater as smolts, a stage particularly vulnerable to adverse environmental conditions. This study seeks to explore the impacts of warming and ocean acidification on the transition of life in freshwater to life at sea in Chinook salmon smolts. In a fully factorial experiment, we transitioned Chinook salmon from fresh- to seawater at current and future conditions of temperature (13 °C and 16 °C, respectively) and ocean acidification (400 and 1400 atm CO), including a fluctuating CO treatment (between control and high CO) that may be more representative of natural environmental conditions associated with upwelling and tidal cycling.

Living in flowing water increases resistance to ultraviolet B radiation.

Ultraviolet B radiation (UV-B) is an important environmental driver that can affect locomotor performance negatively by inducing production of reactive oxygen species (ROS). Prolonged regular exercise increases antioxidant activities, which may alleviate the negative effects of UV-B-induced ROS. Animals naturally performing exercise, such as humans performing regular exercise or fish living in flowing water, may therefore be more resilient to the negative effects of UV-B.

Ultraviolet B radiation alters movement and thermal selection of zebrafish (Danio rerio).

Temperature and ultraviolet B (UV-B) interact in causing cellular damage and impairing locomotor performance. Here, we test the hypothesis that movement and thermal selection of zebrafish (Danio rerio) change in the presence of UV-B, and in particular, that fish which were chronically exposed to UV-B avoid high and low temperature extremes to maximize activities of antioxidant enzymes. Fish chronically (two to three weeks) exposed to UV-B had increased reactive oxygen species (ROS)-induced damage to proteins and membranes, and reduced swimming performance at high (more than 26°C) temperatures.

UV-B exposure reduces locomotor performance by impairing muscle function but not mitochondrial ATP production.

Ultraviolet B radiation (UV-B) can reduce swimming performance by increasing reactive oxygen species (ROS) formation. High concentrations of ROS can damage mitochondria, resulting in reduced ATP production. ROS can also damage muscle proteins, thereby leading to impaired muscle contractile function.

Plasticity of protective mechanisms only partially explains interactive effects of temperature and UVR on upper thermal limits.

Temperature and ultraviolet radiation (UVR) are key environmental drivers that are linked in their effects on cellular damage. Exposure to both high temperatures and UVR can cause cellular damage that result in the up-regulation of common protective mechanisms, such as the induction of heat shock proteins (Hsps) and antioxidants. As such, the interactive effects of these stressors at the cellular level may determine physiological limits, such as thermal tolerance.

Ionocyte Immunolocalization and the Effects of Ultraviolet Radiation on Their Abundance and Distribution in the Alenins of Caspian Sea Salmon, Salmo trutta caspius.

Objective: On a global scale, stratospheric ozone depletion has caused an increase in UV-B radiation reaching the earth's surface. Ultraviolet radiation has long been suspected to be harmful to aquatic organisms.

Materials And Methods: In order to study ionocyte localization (by Na(+)/K(+)-ATPase immunolocalization) and the effects of UV radiation on the ionocytes of skin and gills, the alevins of Salmo trutta caspius were exposed to different doses of UV radiation [unit low doses (ULD) of: 60 µw/cm(2) UVC; 100 µw/cm(2) UVB and 40 µw/cm(2) UVA and unit high doses (UHD) of: 90 µw/cm(2) UVC; 130 µw/cm(2) UVB and 50 µw/cm(2) UVA] using two adjustable F8T5 UV-B, 302 nm lamps (Japan) for 15 minutes once a day in laboratory conditions.