Where Rivers Meet the Ocean
This type of coastal body of water forms where fresh river water mixes with salty ocean water.
What is an estuary?
The amount of dissolved salt in water
What is salinity?
This term describes water cloudiness caused by suspended particles such as silt, mud, or algae.
What is turbidity?
These organisms are carried by currents and cannot swim strongly enough to overcome them.
What are plankton?
Fish and many other aquatic organisms need this gas dissolved in water.
What is oxygen?
This is a condition that can differ, such as depth, salinity, or water clarity.
What is a variable?
This area of land drains into the same river or body of water.
What is a watershed?
At the same temperature, this is why salt water tends to sit below fresh water.
What is salt water being denser than fresh water?
This upper part of the water has enough sunlight for photosynthesis.
What is the euphotic zone?
These microscopic algae use sunlight to make food and form the base of the harbor food web.
What are phytoplankton?
These two nutrients named in the reading help phytoplankton grow.
What are nitrogen and phosphorus?
Which question is more focused: "Is Boston Harbor healthy?" or "How does salinity differ between surface and bottom water at our sites?"
What is "How does salinity differ between surface and bottom water at our sites?"
Name one of the three rivers in the reading that bring fresh water into Boston Harbor.
What is the Charles, Mystic, or Neponset River? (Accept any one.)
This term means water forms layers with different densities.
What is stratification?
As water becomes cloudier, this happens to the depth of the euphotic zone.
What is it becomes shallower because less light reaches deeper water?
This animal group includes copepods and the young stages of some crabs, mussels, and oysters.
What are zooplankton?
This term describes a rapid increase in algae.
What is an algal bloom?
Name two things to keep consistent when comparing plankton samples fairly.
What are the sampling tool, amount of water sampled, depth, time, units, or collection method? (Accept any two appropriate examples.)
This water flowing over land can carry soil and nutrients into the harbor.
What is runoff?
In a well mixed estuary, describe the salinity pattern from surface to bottom at one location.
What is similar salinity from top to bottom?
This material comes from decaying living things and absorbs sunlight.
What is colored dissolved organic matter, or CDOM?
Put these in food-web order, starting with the original energy source: fish, phytoplankton, sunlight, zooplankton.
What is sunlight → phytoplankton → zooplankton → fish?
Explain why dissolved oxygen can decrease after large amounts of algae die.
What is decomposers using dissolved oxygen as they break down the dead algae?
A single cruise describes conditions at its sampling places and times. What additional sampling would help us investigate seasonal patterns?
What is repeating comparable measurements at the same sites across different seasons?
Explain one way that activity on land could reduce water clarity in the harbor.
What is runoff carrying soil or other particles into the harbor? (Also accept extra nutrients encouraging algae growth.)
A sample has much lower salinity at the surface than at the bottom. Is this more consistent with well mixed or partially mixed water, and why?
What is partially mixed water, because salinity increases with depth?
Site A is clearer than Site B. Predict which site has a deeper euphotic zone and explain why.
What is Site A, because clearer water allows sunlight to reach deeper?
Explain how a decrease in phytoplankton could affect fish.
What is less food for zooplankton, leaving less food available for fish?
Explain why cloudy water alone does not prove an algal bloom.
What is other materials, such as soil particles or CDOM, can also reduce water clarity?
Two measurements change together. Explain why this does not prove that one caused the other.
another factor could influence both measurements, so other explanations must be checked