Why Is New York Ocean Water So Dark?

I was recently on holiday in the big apple, and I noted that the ocean water was extremely dark. I had never been to New York, and I wondered if this was normal. I found the dark water interesting and decided I would do more research on this and find out what is causing this.

There are several reasons that can cause the ocean water in New York to be so dark. It can be from natural causes or even from pollution. Natural causes are that deeper parts of the ocean have a darker hue to them. Other factors can cause coastal darkening, such as the many forms of pollution.

As a nature lover and a person who cares about the environment, I started to research New York’s oceans and beaches to educate myself more on the dark ocean water in New York and help create awareness of the factors behind these reasons. I will share my findings below.

Why Is The Ocean Water In New York So Dark?

From the information I have found while doing some research, there are a couple of reasons that the ocean water in New York can be so dark. It can be natural reasons causing this, but it can also be pollution-related.

 I will state my findings in the section below, sharing the natural causes for this and the reasons that can be caused by pollution in the ocean water.

Natural Reasons Causing New York’s Ocean Water To Be Dark

When we think about what causes New York’s ocean water to be so dark, one of the main factors has to be several natural phenomena. Here are a few:

The Sun And Sediment

Interestingly, in deep waters, the water itself absorbs the sun’s rays that hit the water during the day. Because that part of the water lacks sediment and has a lower volume of organic matter, it can make the ocean water appear darker.

In other parts of the ocean, floating sediment and sand can also cause the water to appear dirty as waves can cause the sand to float through the water; this causes the water to look darker.

The Reality Of The Color Of Ocean Waters

In general, the ocean’s water isn’t naturally blue; our eyes and our brain interpret water as blue because of the water molecules that absorb all the colors in the ocean water, making the water appear blue.

Upswelling And River Water

Murkier-looking water can be formed by upswelling. This is when warmer water moves out to sea and is replaced by deeper, colder water.

Furthermore, the ocean water can appear darker as the river water flows into the ocean. The flow of water brings leaves and organic waste that can also make the water appear darker.

Pollution Factors For New York’s Ocean Water To Be Darker

  • Each year, the ocean gets filled with billions of pounds of trash that gets washed into the ocean through its waves and tides. This pollution causes the color of the water to change and can cause the water to appear darker.
  • Pollution in the ocean water happens from oil spills or chemical spills in the ocean water. This pollution is known as point source pollution.
  • Runoff pollution happens from septic tanks dumping their waste into the ocean’s water.
  • Another form of pollution is marine debris pollution; it reaches the entire ocean and even through great lakes.

Many factors can lead to ocean pollution, as stated above. The factors mentioned above are only a small part of the big pollution issue. The water changing color is only a small part of how the different types of pollution negatively affect the oceans.

The Effect Of Pollution On The Oceans Water And Color Change

According to marine experts, 5.25 trillion pieces of plastic can be found in our ocean waters. Around 269,000 tons of plastic are to be floating in the water of our oceans, and around 4 billion microfibers per km2 dwell below the surface of our oceans.

It is known that around 70% of our debris will sink into the ecosystem of the ocean, and then 15% floats in the ocean’s water, and another 15% gets washed out again to our beaches. It all affects the ocean and can be a reason for the ocean’s water to change color and appear to be darker.

Small particles floating in the ocean water like phytoplankton, sediments, and pollution change how the light is absorbed and then scattered in the ocean can lead to the color of the ocean water changing near the surface.

Depending on the type of pollution, the darker color can also be from chemicals mixing with the natural salty water causing the water to darken in some areas.

Oil Spills And Chemical Spills Affecting The Oceans Water

Toxic chemicals can affect the ocean water, which can lead to the water changing color and can go from clear or blue to dirty and dark.

When there is an oil spill in a part of the ocean, the oil floats on the ocean’s surface and then can spread rapidly and form an oil slick, then continues to spread on the ocean’s surface. Even after a thorough clean-up, some of the oil’s dark color might remain.

Marine Debris Pollution’s Impact On The Ocean

The earth’s oceans are extremely polluted by debris, and a wide variety of this debris can affect the ocean’s water to change color; this form of pollution also creates an unsightly look for our oceans.

The debris found in our ocean waters ranges from soda cans, plastic bags, and even fishing gear.

These factors can affect the ocean’s water and cause the water to change its color. The isn’t a place on earth that is free from pollution, and the effects that this pollution has on the environment are frightening and the way it causes the ocean to change.

The pollution can reach the ocean’s water through our beaches covered in trash and even through storm drains and sometimes through sewers, and it all negatively affects the ocean and the ocean water.


Different things can cause the ocean in New York. The water appears so dark in color can be from natural causes or even from causes created by the pollution in the ocean’s water. The darker color could be floating sediment or light reflecting off of different things beneath the water.

Most of the pollution in our oceans comes from pollution on land, which gets washed into our oceans. Around 8 million tons of plastic get washed into the ocean every year.


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