Our Celebration of Learning on June 13th, 2019 was a rewarding experience!  We had many guests visit our classroom, including representatives from the Natural Resources Council of Maine who supported our project with grant money. Students greeted, guided visitors to numerous stations around the room to see the different facets of our work investigating the salinity effects to alewife reproduction in the marsh.  On display were our aquariums with varying salinities and demonstrations of daily observations, data gathering and feeding methods.

A clever zooplankton viewer was rigged up by Jayden to make it very easy to see the natural food of alewife fry.

How we measure salinity with a refractometer and how we monitor our aquarium salinities with our digital hand-held probe was demonstrated; our data from May as well as graphs and data analysis and claims were on display…Bryson had his Maker Space probe to talk to people about, as well as a display of June’s temperature, salinity and tide height data.

We had a live demonstration of how we identify alewives and their gender as well as otolith removal.  Otoliths are the earbones of fish and can give researchers an amazingly detailed analysis of the age of the fish and the waters in which it has lived.  Scale sampling and aging techniques via our classroom microscope were also on hand.

Our life cycle informational graphic displays were there to see and rounding out our displays were our Nature Notes, soon to be published by the Gulf of Maine Natural Resources Institute and their Vital Signs program.

We’d like to thank our visitors and our community for supporting our learning efforts!

Note:  Here is a link to our published Nature Notes in the middle level science journal “Findings From the Field” (Vol. 2).

One our big goals this spring was to collect salinity data during the spring tides of May and June.  We met that goal with the deployment of the Maker Space digital salinity probe.  The data card yielded the following analysis, which is promising for the alewives.  

Here are two student claims about our data.

The Salinity Claims about our Marsh (Ella)

We were able to collect data from our Maker Space probe, here is what we got: 

During the May spring tides there was salt brought into our marsh. Our evidence is the data collected from salinity probe. We made a graph to show what the salinity was day to day from May 8th to May 23rd. On the day of the spring tide, May 18th the salinity shot up from 0.3 PPT to 1.6PPT. On this day the height of the tide was 11.3 feet. 

On our graph we saw that the height of the tide is the independent variable and the salinity is the dependent variable. That means that the salinity depends on the height of the tide. For an example, when the height of the tide is increasing then than the salinity would also be  increasing. For an example on May 17th we had an 11 ft tide and the salinity was 0.3 PPT. Then as the tide increased on May 19th to an 11.3 ft tide with a salinity of 1.3.     

The salinity of the marsh changed quickly, in small amounts. Our evidence is, in the days between May 17th – May 2oth. There was a range of  0.1 PPT over 3 different samples in a 40 minute period. This proves that our salinity probe can measure small amounts of salt at short period of time.  

 

Salinity Data (Brooke)

The May 2019 spring tides brought salt in to our marsh. We gathered all of our data in the marsh from the salinity probe built in the Maker Space by a classmate. The highest spring tide was 11.3 ft on the 18th with a salinity of 1.6 parts per thousand (ppt). 

There is a positive relationship between the height of the tide and the salinity in the marsh. When the height of the tide gets bigger, the salinity increases. When the height of the tide is decreasing, the salinity decreases. For example, on May 19th the tide was 10.6 ft and the salinity was 1.2 ppt. The next day on the 20th, the height of the tide was 10.4 ft and the salinity was 0.8 ppt.     

The salinity changed by small amounts in short amounts of time. From May 17th-20th, for the first forty minutes of each day the salinity changed by 0.1 ppt.

If we had eggs in our marsh they should be able to survive the 1.6 ppt salinity that was measured in May, based on two professional science studies that found eggs can survive in salinities under 2.0 ppt. We read about these studies before setting up our tanks in our classroom.

 

 

 

We are now in LAB mode!  The alewives are spawning in North Pond, where we have a collection permit, and we have some eggs in a bucket (with the cool spring, the eggs have not concentrated in the waters making collection challenging). Now we need to set up our aquariums with the different amounts of salt we have decided for each tank.  Our question is:  Will a salinity greater than 2.0 ppt affect the survival of alewife eggs or fry?  Most classmates think that salinities greater than 2.0 ppt will decrease the survival of eggs and fry.(Substitute student hypothesis here?)  The question and our hypothesis was framed and informed by published results of the few previous salinity studies (a peer review process!) that we found.

 

We have to figure out how to create salinities of 2 ppt, 4 ppt, 6 ppt, and 8 ppt for the aquariums we’ll compare to our control aquarium.  Salinity is the one variable we are testing.  Our constants will be to use the same size tank, the same water level in the aquariums, the same temperature, and the same number of eggs.  To figure out our salinities, we used our math skills.

We started by putting a gallon of distilled water into a clean (large) aquarium.  We added 1/8 of a teaspoon of “Instant Ocean” salts, which we massed and determined was 1.14 grams, to the gallon of distilled water.  Interestingly, the gallon container was marked 3.78 L (3,780 ml), but we measured its contents and found the gallon to contain 3,880 ml of distilled water.  We mixed the solution thoroughly, then let it sit for about 5 minutes, then measured its salinity.  The salinity was 0.26 PPT.  Both our classes did these steps, and we both measured a salinity of 0.26 PPT.  From here, the rest was math to get a basic salinity “recipe” to make whatever we needed.  We had to use math to solve for how many grams of Instant Ocean would make 1 PPT.  Once we knew this, we could double our amount of Instant Ocean to make 2 PPT, for example.

 

The tanks are now all set up and ready for eggs!!