Statistical Analysis of Ocean Climate and Coral
Bleaching
Kayla
2026-06-07
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Background
Coral bleaching is a stress response in which corals expel the algae
living in their tissues. As a result, the coral loses its color and
turns white, and prolonged bleaching can lead to coral death. Common
stressors associated with bleaching include marine heatwaves, changes in
ocean pH, and increased sea surface temperatures (SSTs).
Using a coral reef dataset obtained from Kaggle, this presentation
investigates the relationship between these environmental stressors and
coral bleaching through statistical analysis and data visualization.
The dataset used includes 500 temperature observations from several
different locations globally between the years 2015 - 2023.
Statistical Model of Bleaching Severity with Environmental
Variables
\[
Y = \beta_0 + \beta_1 SST + \beta_2 pH + \beta_3 HW + \epsilon
\] Where:
- \(Y\) =
Bleaching Severity (Low, Medium, High)
- \(SST\) = Sea Surface Temperature (°C)
-
\(pH\) = Ocean pH Level
- \(HW\) = Marine Heatwave Absence/Presence (0
or 1)
- \(\epsilon\) = Random
Error
Mean Comparison
\[
\mu_{High} > \mu_{Low}
\] Mean comparison to compare the global sea surface temperature
(SST) to coral bleaching severity. Higher temperature is expected to be
associated with high bleaching severity than lower severity.
Sea Surface Temperature Trends Over Time
Sea Surface Temperature (SST) is the measure of the ocean’s
temperature within a few millimeters from the surface. It provides
crucial information on how the atmosphere impacts the ocean system.
## `geom_smooth()` using formula = 'y ~ x'
Based on the plot, between the years 2015 and 2023, the dataset suggests
the global SST has remained consistent.
Geographic Representation of Coral Bleaching
SST vs. Coral Bleaching Severity
## `geom_smooth()` using formula = 'y ~ x'
Based on the plot, there is a slight correlation between higher SST and
increased coral bleaching severity globally.
Marine Heatwaves vs. Bleaching Severity
Based on the plot, there is no suggestion that the presence or
absence of a marine heatwave increased the severity of coral bleaching
globally.
pH Level vs. Bleaching Severity
## `geom_smooth()` using formula = 'y ~ x'
Conclusion
The statistical analysis did not show a strong global relationship
between coral bleaching severity and and any one variable such as SST,
pH level, or marine heatwave presence. This does not necessarily mean
that these variables do not impact coral bleaching, but that the impacts
are likely influenced more locally and by multiple interacting
variables. Future analysis that focuses on a specific location and the
impact of multiple variable may better display the ecological
relationships.