Evolution and Climate Change in the Oceans
In evolutionary biology, species can respond to changes in their environment in four distinct (but not mutually exclusive) ways.
They can:
As species face multiple effects of climate change (such as changes in temperature, salinity, acidity, etc.) they may respond differently to different factors. For example, sea turtles may respond to rising sea levels by moving but respond to changes in acidity by adapting. Each additional environmental pressure provides a unique challenge for a species to overcome. In this class, we will mostly be concerned with the first two responses - movement and adaptation.How do marine ectotherms move and adapt in response to climate change compared to terrestrial ectotherms?
The latitudinal shifts of marine ectotherms in response to climate warming can be more accurately predicted than the latitudinal shifts of terrestrial ectotherms. This is because marine ectotherms inhabit a range very close to their thermal limitations. They expand and contrast at both poleward and equatorward ends of their range in response to temperature change, whereas the movement of terrestrial ectotherms are more complex. (Sunday et al, Thermal tolerance).
[JPW: In an earlier meeting there was discussion about why it is important to understand the rate of larval growth given particular genotypes in particular environments (reaction norms). Here are links to some references showing that rapid larval growth leads to greater larval survival.]
There seems to be an increase in the amount of highly damaging natural disasters both inside and outside of the US. These natural disasters impact the climate and habitat of many organisms. Climate change might be the cause of the increase in horrifying natural disasters. On this page you can find more information on the relationship between climate change and many different forms of natural disasters.
Gene flow refers to the movement of alleles due to migration of individuals between two populations. This topic is closely related to the topic of movement.
Movement refers to the change in an organism's typical habitat as it "searches" for a more hospitable environment in which to eat, live, and reproduce. Movement is one of the four ways that an organism or an entire species can respond to a change in their environment and it is heavily affected by climate change. Generally, marine organisms move towards the poles and away from the equator.
In modern times, climate change often refers to the increase in the Earth's average temperature. Since the 20th century, the Earth's average temperature has increased by about 0.7° Celsius and is expected to continue to increase by about 0.2° Celsius per decade. This increase in temperature is expected to affect many things from fetal development and reproduction to species range and survivability often in a negative manner.
As the temperature of the ocean increases, the amount of dissolved oxygen in it decreases. This has many implications for marine wildlife. Without sufficient oxygen, organisms struggle to survive. Many organisms' habitats are very close to their thermal limitations and if temperature rises rapidly, lack of oxygen and other effects will limit the options these organisms have.
Marine salinity levels are influenced by a number of factors including rainfall, evaporation, inflow of river water, wind, and melting of glaciers. Salinity can have a great impact on the type of organisms that live in a body of water. Additionally, salinity plays a critical role in the water cycle and ocean circulation.
Ocean carbon dioxide levels directly correlate to ocean acidity levels. About 30-40% (Feely, R. A.; et al.) of the carbon dioxide humans emit into the atmosphere dissolves into the Earth's waters. From 1751-1994, the ocean's acidity has decreased from 8.25 to 8.14 (Jacobson, M. Z). This decrease in acidity affects marine organisms in a variety of detrimental ways.
The rise in sea level is due to thermal expansion and the melting of land-based ice. Changes in sea level have a variety of effects ranging from the submerging of islands and its terrestrial inhabitants to coral reefs not receiving sufficient light due to a change in depth.
Ocean currents are the directed movements of water in the ocean and can be caused by wind (for currents closer to the surface) and temperature, salinity, or density differences (currents deeper in the ocean). Climate change can have a vast effect on ocean currents because of the change in temperature it causes, which results in change in ocean water temperatures and a subsequent distortion in current flow.
Often the egg or larval stage of marine ectotherms are the most susceptible to changes in the marine environment. Because of this, reproduction will likely be greatly affected by climate change.
Depletion of the ozone layer is the main reason that global temperature is steadily increasing and is predicted to continue to do so. As such, this topic goes hand-in-hand with the topic of temperature change.
Global Evidence of Climate Change
Although some consider climate change ( or "Global Warming") to be debatable or at least exaggerated, there is good evidence to show that climate change is indeed occuring at an alarming rate and that it will greatly impact both marine and terrestrial environments.
Economic Effects of Climate Change
Climate change threatens many marine-dependent sectors of the economy such as fisheries, transportation, and tourism. As climate change continues, its negative effects on the economy will worsen. Many countries, however, continue to implement practices that result in short-term economic boosts but long-term environmental decay.
Climate Change in Popular Culture
As the world learns about the reality and possible consequences of climate change, this daunting phenomenon is becoming the topic of more and more movies, documentaries, and even television shows.
In light of the current election and the class discussion during the week of November 5th, a new "beat" topic has been added that organizes the current thoughts of climate change in politics. NOTE, this is not a place to debate politics, but rather a place to outline the different views that are present in the political system today and the ideas for solutions that have been implemented.
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Here is where you (the class) can start to flesh out this project. Give it some structure, pictures, graphs, links to datasets. But make it organized, so that any given page does one part of the narrative and links to other components. In other words, this won't be a single, linear document, but a complex arrangement of pages that link to one another so that complicated material can be concisely organized.
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