Diagrama de temas
The relationship of this page to SDGs
In United Nations Decade of Ocean Science, we hope to contribute to SDGs by the knowledge and technology of ocean science. One of the categories of ocean science defined in the UN Decade of Marine Science is "marine ecosystem functions and processes.” This category includes the marine ecosystem structure, diversity, chemical and physical process, nutrient cycling, energy flow, and others, because these support the richness of the ocean. To study t these, we need to examine the real ocean. On this page, you can learn about tools for quickly and safely collecting water near the shore. We would like to contribute to SDG 14 by spreading the fact that we can use such a tool to study the ocean environment.
Development of MIWA sampler and usage
Why MIWA sampler?
What would you do if you were trying to collect water from the shore?
You would think of collecting water from the shore with a ladle in your hand. There are few situations where this method can be used. The coast is usually covered with tetrapods or rocks. If the weather is bad, you will be swept away by the waves. Your life is at stake.
Would you go into the ocean wearing waders? Even this is dangerous.
Would you rent a fisherman's boat? It's expensive and hard work.
We need to develop a quick, safe way to collect water from the shore!
Lc-MIWA (Long casting style of Marine Instant Water sampling Apparatus)
I named it after the developer, Mr. Miwa (a graduate student).
How to use
1) Swing over a long fishing rod (to cast the water sampler farther)
Miwa's best friend, Nobu (who likes fishing)
2) Wait for the water to enter the water sampler
3) Collect water together
At the beginning of the development, our goal was to collect water at any depth. For this purpose, we prepared a transparent tube equivalent to the length of a third floor of a building, and investigated at what depth the water would enter the bottle. We hoped that by fine-tuning the shape of the water sampling port, we would be able to collect water from deeper depths with a subtle difference in pressure. However, it turned out that water could enter the bottle at a depth of about 1 m, and further adjustment was impossible. (So, it became a limited tool to collect water at a depth of 1 m near the shore.)
Schematic diagram of MIWA sampler and observation of Funka Bay
This is how the MIWA sampler works.
A butyl rubber stopper is attached to a glass bottle, and two stainless steel tubes are inserted into the stopper. When put into water, seawater enters the bottle due to the difference in water pressure. To protect the glass, a protective net (yellow) is wrapped around it. In order to throw the sampler as far as possible, we used a fishing rod that targets big fish. It seems that it is difficult to use this unless you are quite a fishing fanatic.
Reproduced from Fig. 2 of the following reference
Collect seawater from the coast around Funka Bay in Hokkaido
Funka Bay has a radius of about 30 kilometers. To cover the surrounding coast in one day, we leave Hakodate in the morning and take the expressway to each location. If we can complete the sampling at each shore in 30 minutes, we can return to Hakodate in the evening. The MIWA sampler is essential to collect water from the coast in such a short time.
We collected seawater from Sunasaki to Muroran, as shown on the coastline in the figure below.
Reproduced from Fig. 1 in the following reference
This is the result of collecting seawater from the coast and measuring the concentration of bromoform. Bromoform is a type of organic halogen gas released by large algae (kelp) that live on the coast. The concentration was found to be high on the coast of Usu, where kelp thrives.
Reproduced from Fig. 5 in the following reference
We'd like to continue observing the water at the coast, but we are on pause because I can't find a fishing enthusiast (and analysis enthusiast) who can operate the MIWA sampler.
Reference: Ooki et al., Seasonal Variations of Bromoform Distribution in the Funka Bay, BUNSEKI KAGAKU (
62) 12, 1071-1078 (2013)DOI: 10.2116/bunsekikagaku.62.1071
Bromoform is considered to be produced by an enzymatic reaction in macroalgae. Learn more about the functional components of macroalgae at the link above.