To my friends in Finland, why the sea is black?

Question

I was in Helsinki last month. And I noticed that the sea is black, unlike my country where the sea is clear and blue color.

Do you have any idea why it's black or dark brown?

Answer 1

Finland has known environmental issues and probably why the sea is black is due to air pollution from manufacturing and power plants contributing to acid rain which runs to the sea. Of course, the pollution in the air gives the illusion of black color on the clouds which is then reflected in the sea.

Also, water pollution from industrial wastes and agricultural chemicals can also contribute to why their seas appears to be dark.

Answer 2

Maybe the seabed is dirty.......

Answer 3

You don't say where your country is, but I assume it's quite a bit further south. In my experience traveling, water closer to the equator generally appears much lighter than water in the colder parts of the earth (an exception would be near the poles where frozen water can appear white). I'm not sure what the exact influence of Latitude is on perceived color, but since some of the warm light colored water closer to the equator is also terribly polluted, I would have to strongly disagree with the person who claimed that darker water indicated pollution. I have fished and gathered edible seaweed on isolated areas of the US Pacific Northwest coast which had been tested as low in pollution, but had very dark greenish brown appearing water. From what I have read, the ocean appears to be different colors at different places (and at different times) based on a number of factors. 1. The depth of the water (deeper water appears darker) 2. The amount of light reflecting off of the water from the sun (so water looks darker further away from the equator, in winter, in the evening, or on cloudy days) 3. The color of the ocean floor (dark colored sand, rocks, or seaweed forests as opposed to light colored sand or rocks) 4. The amount and type of particles suspended in the water, which would include pollution, and pollution triggered abnormal algae blooms (which can create what is called a "red tide') but apparently, even in this polluted time period, much of the particulates in the ocean that are responsible for causing different parts of the ocean to appear different colors (also visible from outer space) are normal dissolved minerals and seaweed and micro algae, which differ from place to place naturally. Also, ancient Nordic poetry and stories (from the region including part of what is now Finland) have referred to the ocean as being dark in color, and although pollution has certainly had a terrible effect on the health of the ocean in the meantime, I doubt that it has had such a dramatic effect on it's color.

Answer 4

nope

Answer 5

Strictly speaking the Finnish seawater is not 100% "genuine", mainly because of so many rivers streaming towards the sea. So, in short, the darker-coloured river water is the thing making the colour of the water so dark (and the salt percentage is therefore quite low). This is known as the brackish water or "mixed" water.