Limpet feeding rate and the consistency of physiological response to temperature

Abstract

9Thermal reaction norms are fundamental relationships for geographic comparisons of organism 10 response to temperature. They are shaped by an organism's environmental history and provide 11 insights into both the global patterns of thermal sensitivity and the physiological mechanisms 12 underlying temperature response. In this study we conducted the first measure of the thermal 13 reaction norm for feeding, comparing the radula rasping rate of two tropical and one polar limpet 14 species. The consistency of thermal response was tested through comparisons with limpet duration 15 tenacity. Feeding and duration tenacity of limpets are ecologically important muscular mechanisms 16 that rely on very different aspects of muscle physiology, repeated concentric (shortening) and 17 isometric (fixed length) contraction of muscles, respectively. In these limpets the thermal reaction 18 norms of feeding limpets were best described by a single break point at a maximum temperature 19 with linear declines at higher (S. atra) or lower temperatures (N. concinna and C. radiata) rather 20 than a bell shaped curve. The thermal reaction norms for duration tenacity were similar in the two 21 tropical limpets. However, the rasping rate in Antarctic Nacella concinna, increased linearly with 22 temperature up to a maximum at 12.3°C (maximal range 8.5 to 12.3°C) when feeding stopped. In 23 contrast duration tenacity in N. concinna, was maximal at 1.0°C (-0.6 to 3.8°C), and linearly 24 decreased with increasing temperature. The thermal reaction norms of muscular activity were 25 therefore inconsistent within and between species, indicating that different mechanisms likely 26 underlie different aspects of species sensitivities to temperature. 27 28

Physiological Performances of Temperate Vegetables with Response to Chronic and Acute Heat Stress

“…LT 50 values of ETR, NPQ and qP were either similar to that of O 2 evolution or significantly higher for both chronic and acute heat stressed plants. Given that F v /F m ratios were only significantly lower than the other treatment groups at 46˚C (~10% drop) for acute stressed plants, it would be logical to predict that LT 50 values of F v /F m ratios will approach that of NPQ and qP if not exceeding.…”

“…All other parameters for all treatment LT 50 For chronic heat stressed plants, shoot FW was significantly lower compared to all the other parameters (Figure 7(A)). LT 50 of TRN for RIL 141 could not be resolved for there was no significant difference between the four treatment groups.…”

“…LT 50 , or temperature at which index performance changed by 50% compared to that of control plants at 26˚C was calculated by probit analysis. Significant difference in LT 50 for each parameter of the six vegetables was scored if there was no overlap in the 95% confidence intervals. As F v /F m only started to show a decrease in observed value at 46˚C probit analysis could not be performed on this parameter.…”

Thermoregulatory behaviour and thermal tolerance of three species of Conidae in the Eastern Pacific and Gulf of California coasts of Baja California, Mexico

“…For Co. perplexus and Co. ximenes, the thermal stress responses were measured by external stimulation of the siphon and foot as per Morley et al (2014a) because they did not respond by losing their attachment to the acrylic plates. The organisms were placed in groups of five in 40 L aquariums that contained a thermostatically controlled 1000 W titanium heater and air stone.…”

Modelling of Hydrobiological Processes in Coastal Waters

“…Such models have been used, for example, to estimate the production of crops, to search for thresholds in coastal mangrove forests and to examine a limpet feeding rate and its response to temperature [22][23][24].…”