Nutrient Pollution and Coastal Health
One of the most common forms of nutrient pollution is excess nitrogen. Nitrogen is a nutrient that is naturally found in the environment, and is very important for plant growth as well as development of proteins and DNA in organisms. It's also a larger percentage of the air we breathe than oxygen (21% oxygen, 78% nitrogen)!
Nitrogen v.s. Excess Nitrogen
Nitrogen can come from fertilizers we use, plant material, lighting, and even our own waste as part of the natural cycle of nitrogen. There can be indirect seepage from the coastline (also known as Non-Point Source), or more direct sources (also known as Point Source) from freshwater streamlets, rivers, and underwater freshwater springs (submarine ground water).
If there are excess levels of nitrogen, it allows more invasive or competitive algae species to readily take up that nitrogen and overgrow the surrounding reef. These algae can choke out native species (including native algae), not only by overgrowing them, but also by using up all the available oxygen in the water. Some of these invasive algae species are microscopic and can have toxins that cause things like swimmers itch, and their die off can cause increased bacterial growth, including pathogenic bacterial (bacteria that can get you sick!).
The Source...
As part of a Master's project and community interest, through the University of Hawai'i, we have been collecting water and limu (seaweed) samples along the coast of Kauaʻi, more specifically, along the beaches and river mouths of ʻAnini, Kalihiwai, and Moloaʻa.
Stable Isotope Analysis
Nitrogen naturally has two isotopes, and stable isotope analysis allows us to determine what source the nitrogen is from (Sewage, Fertilizer, or Natural Sources). Please see the Stable Isotope Analysis page for more information on this analysis. Higher ratios indicate sewage or waste sources (such as cesspools). The results are expected to show us where the areas of higher nitrogen isotope ratios, and therefore sewage signatures, along these coast lines.
Water is typically used in past research for stable isotope analysis. However, a newer sampling method using algae (or limu) has recently been used, and is the method we are also following in this research. We are also concerned about the communities of limu and the ways in which the increased nutrients available are changing what species are still found in these areas.
This website is a way for us as student researchers to communicate our findings to you, the community, and continue the conversation about what to do next.
Nitrogen v.s. Excess Nitrogen
Nitrogen can come from fertilizers we use, plant material, lighting, and even our own waste as part of the natural cycle of nitrogen. There can be indirect seepage from the coastline (also known as Non-Point Source), or more direct sources (also known as Point Source) from freshwater streamlets, rivers, and underwater freshwater springs (submarine ground water).
If there are excess levels of nitrogen, it allows more invasive or competitive algae species to readily take up that nitrogen and overgrow the surrounding reef. These algae can choke out native species (including native algae), not only by overgrowing them, but also by using up all the available oxygen in the water. Some of these invasive algae species are microscopic and can have toxins that cause things like swimmers itch, and their die off can cause increased bacterial growth, including pathogenic bacterial (bacteria that can get you sick!).
The Source...
As part of a Master's project and community interest, through the University of Hawai'i, we have been collecting water and limu (seaweed) samples along the coast of Kauaʻi, more specifically, along the beaches and river mouths of ʻAnini, Kalihiwai, and Moloaʻa.
Stable Isotope Analysis
Nitrogen naturally has two isotopes, and stable isotope analysis allows us to determine what source the nitrogen is from (Sewage, Fertilizer, or Natural Sources). Please see the Stable Isotope Analysis page for more information on this analysis. Higher ratios indicate sewage or waste sources (such as cesspools). The results are expected to show us where the areas of higher nitrogen isotope ratios, and therefore sewage signatures, along these coast lines.
Water is typically used in past research for stable isotope analysis. However, a newer sampling method using algae (or limu) has recently been used, and is the method we are also following in this research. We are also concerned about the communities of limu and the ways in which the increased nutrients available are changing what species are still found in these areas.
This website is a way for us as student researchers to communicate our findings to you, the community, and continue the conversation about what to do next.
The PurposeWe are concerned about the health of our nearshore reefs, the loss of native limu species, and changes in the water quality from upstream and nearshore sources. The purpose behind this research is to learn more about the types of sources affecting our reefs at different areas along the north shore on the island of Kauaʻi. Learn more about us by clicking below.
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