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The table below shows salinity tests from coastal Louisiana following a salt water influx during hurricanes Katrina and Rita. If efforts are not made to reduce the salinity in these areas, what is the most likely long-term effect?

\begin{tabular}{|lcc|}
\hline
\begin{tabular}{c}
Vegetation \\
type
\end{tabular} & \begin{tabular}{c}
Typical salinity \\
range
\end{tabular} & \begin{tabular}{c}
Maximum salinity \\
measured
\end{tabular} \\
\hline
Swamp & [tex]$0-0.5$[/tex] & 8 \\
\hline
Fresh marsh & [tex]$0-3$[/tex] & 26 \\
\hline
Intermediate marsh & [tex]$2-8$[/tex] & 26 \\
\hline
Brackish marsh & [tex]$4-10$[/tex] & 34 \\
\hline
Saline Marsh & [tex]$8-29$[/tex] & 30 \\
\hline
\end{tabular}

Source: U.S. Geological Survey

A. A growth in the population of salt-intolerant types of plants
B. A shift in species composition to less salt-tolerant plants
C. A shift in species composition to more salt-tolerant plants
D. An increase in the diversity of salt-intolerant plants



Answer :

GinnyAnswer
To determine the most likely long-term effect of increased salinity in the coastal Louisiana areas, we need to analyze the relationship between the typical salinity ranges and the maximum salinity measured for each vegetation type. Let's review the provided salinity values for various vegetation types:

[tex]\[ \begin{array}{|lcc|} \hline \begin{tabular}{c} Vegetation \\ type \end{tabular} & \begin{tabular}{c} Typical salinity \\ range (\text{ppt}) \end{tabular} & \begin{tabular}{c} Maximum salinity \\ measured (\text{ppt}) \end{tabular} \\ \hline Swamp & 0-0.5 & 8 \\ \hline Fresh marsh & 0-3 & 26 \\ \hline Intermediate marsh & 2-8 & 26 \\ \hline Brackish marsh & 4-10 & 34 \\ \hline Saline Marsh & 8-29 & 30 \\ \hline \end{array} \][/tex]

Now let's analyze each case:

1. Swamp:
- Typical salinity range: 0-0.5 ppt.
- Maximum salinity measured: 8 ppt.
- The measured salinity (8 ppt) is far above the typical range (0-0.5 ppt).

2. Fresh marsh:
- Typical salinity range: 0-3 ppt.
- Maximum salinity measured: 26 ppt.
- The measured salinity (26 ppt) is significantly higher than the typical range (0-3 ppt).

3. Intermediate marsh:
- Typical salinity range: 2-8 ppt.
- Maximum salinity measured: 26 ppt.
- The measured salinity (26 ppt) is much higher than the typical range (2-8 ppt).

4. Brackish marsh:
- Typical salinity range: 4-10 ppt.
- Maximum salinity measured: 34 ppt.
- The measured salinity (34 ppt) exceeds the typical range (4-10 ppt).

5. Saline Marsh:
- Typical salinity range: 8-29 ppt.
- Maximum salinity measured: 30 ppt.
- The measured salinity (30 ppt) is slightly above the higher end of the typical range (8-29 ppt).

Given that the maximum salinity measured in each type of vegetation significantly exceeds their typical salinity ranges, salt-intolerant plants that thrive under lower salinity levels will likely be unable to survive under these new conditions. On the other hand, plants that are more tolerant of higher salinity levels will have a competitive advantage.

### Most likely long-term effect:

Considering that the salinity levels are well above the typical ranges for all vegetation types, the species composition is expected to change. Non-tolerant plants will die off, whereas salt-tolerant plants will become more prevalent. Therefore, the most likely long-term effect is:

A shift in species composition to more salt-tolerant plants.

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