Which do you think is most dense?

Salt water Fresh water

Click to watch video

Slide 14

Now let’s look at another variable…Which do you think is most dense?

Warm water Cold water

Click to watch video

Warm water

Cold water

Now that you have seen the video ~ which is more dense, warm water or cold water?

What happens to the warm water?

So which would be the MOST dense:

click on the one you think is correct

Warm, fresh water

Warm salty water

Cold fresh water

Cold salty water

Rollover: Almost, but not quite: remember warm water is less dense and layers on top of cold water.

Rollover: Really close! Cold water is more dense than warm, but what did you learn about fresh water? It is less dense than salty water.

Rollover: Congratulations! Cold salty water is the most dense!

The Hudson River Plume is chemically and physically very different from the surrounding bay water. Two ways scientists try and distinguish plume water from surrounding ocean water is to look at the salinity and temperature

Because the plume is freshwater, salinity (or the amount of saltiness) in the plume is much less than outside the plume.

Coastal ocean salinity in the Mid-Atlantic region is generally greater than 31 ppt (parts per thousand) and salinity of the plume is generally less than 25 ppt.

Ocean water and river water tend not to mix due to these differences in salinity.

Without getting mixed and diluted the plume can travel far That’s why we can see the impacts of the plume sometimes as far away as southern New Jersey (that’s over 100 miles!)

The surface water temperature of the plume and ocean water can be very different.

In spring for instance, because river and estuary water are much shallower than ocean water it tends to warm up much faster than the nearby ocean water.

But then in the late fall and early winter the opposite occurs. River water tends to cool down somewhat faster than the ocean water, until winter when both become similarly cold

Slide 16

Find the Plume ~ battleship game

Meet Brian Gaas. Brian is a pretty cool guy. He’s from Texas. He is a certified emergency medical technician, likes to

compose classical music, explore caves on land and also is a certified cave diver.

That’s a person who not only explores underground caves, but has to sometimes

dive underwater to get to them!

Brian is also a marine microbiologist and was the marine technician aboard the R/V Cape Hatteras during a recent scientific experiment off the coast of NJ.

Click to watch an interview with Brian

Brian interview.wmv

Picture of the dye in the plume LaTTE 2004

Slide 17

Adirondack Mountains

Slide 18 Google Earth shot of the Hudson River

Or like one of those tourist maps that

Shows the local points of

Interest in an area.

Jersey City, NJ

Staten Island, NY