Climate Change and Biodiversity
@Anastassiya Yegarmina
@Maria Jose Molina
@Shantan Reddy (shantu21@gmail.com)
@Milton Mealla
@Natalia
Problem and Hypothesis
When corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white (1).
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CORAL BLEACHING
Scope of analysis:
Methods of analysis:
Correlation analysis, exploratory analysis
Our data for analysis:
We see on the map above, that more points with high severity of bleaching appeared for period 2000-2015
The temperature increasing as a main factor affecting the coral bleaching
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Temperatures have risen during the last 30 years, and 2001 to 2010 was the warmest decade ever recorded.
This graph shows the increase of the sea surface temperature of the ocean at the last 36 years and the bleaching effect in Hawaii. The circles represent the number of samples per year analized. The colors represents the bleaching severity in the coral. �
The graph on the left shows how the average surface temperature of the ocean’s has changed. �Warmer oceans put communities at risk, including high level of mortality or loss of breeding grounds. Coral reefs are also affected by increasing temperatures which cause coral bleaching and increase their risk of mortality. For that reason, we represent this data with the bleaching effect in communities of corals in Hawaii (graph on the bottom).
Even, we analyzed all the data available, we have not enough data (5 years) in the dataset to find a robust and direct relation between the increase of the ocean temperature and the bleaching effect in corals in Hawaii.
Ocean acidity as the second factor, affecting the coral bleaching
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Here, we want to know whether the decreasing of pH in ocean correlates with the amount of CO2.
As result as more CO2 accumulates in the ocean lower is the pH (negative correlation).
The Ocean acidification is occurring because too much carbon dioxide ( CO2) is being released into the atmosphere.
The increase of CO2 levels and the decreasing of pH in seawater produce in many marine organisms a negative impact in their calcium carbonate shells or skeletons. The increasing of the ocean acidification has been shown to significantly reduce the ability of reef-building corals to produce their skeletons. Hawaii has a really important Coral reef and more than 500 species live in Hawaii's coral reefs.
Initial data about CO2 and pH
Both graphs show the correlation between rising levels of CO2 and pH in the sea surface at Hawaii.
On the left, the graph shows the amount of CO2 and the pH per year. On the right, the graph shows the mean of CO2 and the Error Standard (Vertical error bars results from analytical error of pH. Horizontal error bars results from analytical error of CO2 per year).
Biodiversity of corals in the US Hawaiian region
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While the rising sea temperatures can be seen having an impact on the coral biodiversity itself it is important to note that with increasing awareness and preventive measures being taken, some of the corals are also slowly recovering. Corals here are referred to by their vernacular names.
Works Cited
Tools Used
© 2017 Udacity. All rights reserved.
https://www.epa.gov/climate-indicators/climate-change-indicators-ocean-acidity
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MS Excel, Python modules: Numpy and Pandas, Data.world Visualisation tool.