A Heaty Situation: A Feeding Frenzy or Speeding Away From the Hot Ocean?


For as long as I can remember global warming has been on the news every extra hot summer and every time the fall was unexpectedly, yet pleasantly, warm. I always wondered what the big fuss was about, Vancouver, which has the ability to be extremely miserable and cold, was finally achieving weather that you could enjoy. However, as I got older and several ecology classes later I started to understand the implications of increased temperatures on our ecosystems, which often alter community structure and the interactions of organisms that are sharing the world with us. For example, as the temperatures begin to increase globally, owing to factors such as fossil fuel use, the oceans also begin to heat up. We may enjoy a hot day by going to the beach, indulging in ice cream or planting ourselves in front of a fan when the heat becomes unbearable, however organisms in the ocean simply can’t pack up and leave.

Oceans and Global Warming


Herbivores are essential in an oceanic community since it is their consumption of plants that provides energy to entire ecosystems. However, as the heat increases they begin to suffer at a physiological level or begin to excel wonderfully and eat like it’s an all you can eat buffet to unsustainable levels. And that was our focus in lab last week, as we tested the effects of temperature on the feeding and activity levels of a local turban snail and a key oceanic herbivore, Chlorostoma funebralis. We placed the snails in two different conditions, cold and room temperature, with their kelp of preference to see how much these little guys could eat in the two different conditions. Judging by their size I had expected them to be at it for a while, however within 48 hours, due to kelp degradation and apparently the feasting ability of the snails, the experiments need to be taken apart and some good samaritan students and T.A.s gave up a part of their Friday in the name of science!

Experiment Setup

Getting comfortable on a bed of kelp!

 


We discovered that though temperature has an effect on the loss of kelp mass, there was no significant interaction between the snail and temperature, meaning increased temperatures did not cause the snail to feed more. We also conducted trials that attempted to discern any significant relation between our chosen metabolic markers of righting time, biting rate, and speed of the snail and temperature. We found no significant relation between temperature and biting rate or righting time, which is essentially recording the time it takes for a snail to upright itself after being turned on its shell, diabolical I know. However, we did find a significant relation between temperature and the speed with which the snails flee after they upright themselves. I noted however that the snails seemed to be running from a perceived danger due to the stress we placed on them, which may have been a factor in their speedy success, and increased temperatures may have allowed for a heightened response due to increased metabolic rate.

Speedvs.T

Just a graph!

This lab really kindled my intrigue for understanding the interactions between different organismal levels, such as herbivores and plants, known as primary producers, such that I’ve googled some extremely nerdy information that can be found here if I’ve also gotten you thinking about science:

www.nrdc.org/globalwarming/

http://www.ehow.com/info_8170032_herbivores-ecosystem.html

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