Drought and pollution

By: Dana Sackett

As an environmental scientist I can honestly say that I am very concerned for the future of our planet and ourselves.  I cannot emphasize enough the reality of climate change, that it is human-caused (and therefore that we can do something about it), and that we definitely need to do something about it, lest we end up with a planet that is largely uninhabitable for our great-grandkids (think of a less intense version of our sister planet Venus).  Also, while there are a large number of environmental issues that will come about as a result of climate change in our lifetimes the ones I would like to focus on today are drought and pollution.  While these are typically separate topics, they can interact in important ways.

A composite image of Venus and Earth. Venus and Earth are often called twins because they are similar in size, mass, density, composition, and gravity. In addition, Venus is thought to have had a similar atmosphere to Earth’s billions of years ago. However, despite not being the closest planet to the sun, Venus is currently the hottest planet in our solar system. This is because of the dense carbon dioxide rich atmosphere, which traps heat in a runaway greenhouse effect (see here). Image credit: Arie Wilson Passwaters/Rice University. Source: http://www.forbes.com/sites/startswithabang/2016/07/06/venus-not-earth-may-have-been-our-solar-systems-best-chance-at-life/#443967ed764d.


First off, drought (caused by decreased precipitation and/or increased evaporation) all by itself can be a daunting problem; just ask California which has been enduring severe drought conditions for several years (see here and here), the southeastern United States which is currently experiencing a serious wildfire (see here), or the western Untied States which has resorted to draining groundwater aquifers to meet water needs, a source that is not renewable at the rate it is being used, is causing the ground to sink, and is running out at an alarming rate (see here).  Wildfires, decreased air quality (rain cleans the air), running out of water for agriculture, recreation or even drinking have become serious concerns for a number of states in the US.  And if you think that is bad imagine how it is for the plants and animals that live in that dwindling water.  Studies have shown that the stress of drought can have major impacts on the health of aquatic life (besides simply having no water to live in). 


Some of the potential future effects of global climate change include more frequent wildfires, longer periods of drought in some regions and an increase in the number, duration and intensity of tropical storms. Credit: Left – Mellimage/Shutterstock.com, center – Montree Hanlue/Shutterstock.com. Source: http://climate.nasa.gov/effects/


Fish health, in particular, can be measured in a number of ways, one of which is ‘condition’ or how fat or skinny a fish is.  The reason this measure is so useful to identify health is because of bioenergetics.  That is a fancy way to say the study of energy flow and energy budgets.  Think of balancing a check book, you have to balance what comes in with what goes out.  Energy is similar: fish eat food and gain energy to grow, avoid being eaten, find a mate, and to reproduce.  So when a stressful drought situation occurs (shallower, warmer, and less oxygen rich water), energy is now required to deal with those stressors.  This stress response takes energy away from those other measures, particularly growth, making for skinny fish.  This also means that these stressed-out fish have less energy to use for immune response and defense to disease and contaminants, making these animals more susceptible to illness and death from waterborne pollutants.   


An empty boat marina at Folsom Lake, at 17% of capacity, in Folsom, California, on January 22, 2014. Credit: Reuters/Robert Galbraith. Source: http://www.theatlantic.com/photo/2014/03/californias-historic-drought/100706


Pollutants can compound drought stress because the little bit of water that is available may have unsafe levels of contaminants as a result of the drought.  Water quality, an issue near and dear to any fish (and all of us that like to trust that our water supply is safe) can become a serious problem during severe droughts.  The trouble is that water dilutes those contaminants in aquatic environments and groundwater.  When that water starts to disappear during a drought, concentrations of those pollutants increase, degrading water quality.  For aquatic life this can be a serious problem as they would already be under stress from drought conditions and susceptible to normal concentrations of pollutants. 

Refuge pools for fish during a severe drought in Australia. Source: http://ewater.org.au/science/where-do-fish-go-in-a-drought/

When looking to the future, consider the world you would like your grandkids and great-grandkids to live in.  If it includes a largely habitable planet, clean drinking water, clean air to breath, and healthy aquatic ecosystems, make sure our leaders know that combatting climate change is a priority. 


Some excellent resources, reading material, and references for this article are below:



Dai A. 2013. Increasing drought under global warming in observations and models. Nature Climate Change. 3, 52-58. http://www.nature.com/nclimate/journal/v3/n1/full/nclimate1633.html

Barnett, T., R. Malone, W. Pennell, D. Stammer, B. Semtner, and W. Washington. 2004. The effects of climate change on water resources in the West: Introduction and overview. Clim. Change 62(1–3):1–11.

 Bennotti MJ, Stanford BD, Snyder SA. Impact of drought on wastewater contaminants in an urban water supply. J Environ Qual 39, 1196-1200.

 Bonga SE W. 1997. The stress response of fish. Physiol Rev. 77, 591-625.

 Kjellstrom T and Weaver HJ. 2009. Climate change and health: impacts, vulnerability, adaptation and mitigation. NSW Public Health Bulletin 20, 5-9.

 Matthews WJ, Marsh-Matthews E. 2003. Effects of drought on fish across axes of space, time and ecological complexity. Freshwater Biology 48, 1232-1253.

 Tibbetts JH. 2015. Air quality and climate change: a delicate balance. Environmental Health Perspectives 123:A148-A153.











3 Comments Add yours

  1. Saseun Antonio says:

    It’s our prayer also in Nigeria to have the government and oil companies put a stop to the perennial oil spillage taking place in the Niger-delta which apparently is decimating the population of aquatic organisms in the creeks and freshwater environments.

  2. Jake says:

    Yes this concerning knowing that we need to do more to help our planet. There is so much we need to do

  3. Sarah says:

    I wonder Jake how we can do more. I wonder if there is more blogs as this with the information like above

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