At the National Marine Life Center, one of the interns’ responsibilities is taking care of the “critter tank” in the Discovery Center. The critter tank is a great opportunity for kids to come see some of the common coastal animal and plant species that live in Cape Cod. A couple weeks ago, Brittany and I walked the shores of Onset beach and gathered a number of interesting species to fill the tank with. This was my first beach collection experience, as previously I’ve lived far from the ocean, and it was a blast! You may have read about this experience in Brittany’s blog last week. We caught a large number of different things but had to limit what we actually put into the tank. Why? We had to give the water in the tank the opportunity to build up the nitrogen cycle.
For those familiar with biology, the nitrogen cycle might bring up thoughts of farm fields and rivers, but we’re talking about a different type of nitrogen cycle here. It takes some time for the water quality in a tank to be stable enough to sustain large numbers of different animals.

Figure credit: http://www.aquarticles.com/articles/management/Pearce_Les_Filtration_Nitrogen_Cycle.html

When you feed your fish in the tank, they produce waste and ammonia. This ammonia can also come from the decay of excess food in the tank or dead pieces of plant material. Ammonia is toxic to fish in high levels, but luckily we have a type of good bacteria called Nitrosomonas that exists in your fish’s water that will digest ammonia (NH3) and break it into nitrite (NO2).
Nitrite is slightly better than ammonia for your fish – and can be deadly in high levels, so we need another bacteria friend to take the Nitrite (NO2) and make it into Nitrate (NO3), this bacteria is called Nitrobacter.
Nitrate isn’t good for your fish either, but luckily it takes high levels of it to affect your fish poorly. Nitrate is used by the plants that live in your aquarium, and you can keep toxic levels from developing by doing routine partial water changes to your tank.
Well if my tank contains these good bacteria, why do I have to wait to stock my tank to capacity? Unfortunately, it takes these bacteria awhile to divide and reproduce to a high enough number to be useful. So, putting in a few fish gives the bacteria something to eat and energy to reproduce while not overwhelming your tank and killing your fish.

Brian collecting a water sample from Catch 22's tank for water quality testing.

At the National Marine Life Center, we monitor these levels with weekly water quality tests. We test for nitrite, nitrate, and ammonia as well as pH and salinity (amount of salt in the water). Once we get the numbers from the test, we check to make sure that they are within safe parameters for the animals that live in the water. What happens if the chemical levels are too high or too low? We completely empty out the tank and refill it with new water, and retest before putting the animal(s) back into the tank.
We don’t just check water quality for the critter tank – we do it for all the turtle tanks, the pump house pulls salt water from the canal and the hospital tanks. The interns have been shadowing volunteers doing this task for a couple weeks, but we were able to complete all the tests on our own last week!

Asian shore crab getting friendly.

So, at the moment the critter tank contains a couple Asian Shore Crabs, and invasive species in Massachusetts. Invasive species are species that aren’t native to an area that they inhabit, and so may not have natural predators. They become a problem when they multiply to numbers that compete with native species for food and space. As cute as they are, they’re not a welcome visitor in Cape Cod waters.

The most valuable part of the critter tank to me is that kids can see animals interacting with one another in ways they can’t at the beach. These animals are relatively comfortable in the warm salt water we provide, and the kids can watch them move around, eat, and generally pester each other. The educational value of this is off the charts, not to mention fun! At the end of the summer these animals will be released back into the wild, to live out the rest of their lives in their native waters. Please come see our animals in the critter tank in our Discovery Center – it’s open every day from 10-5, has free admission and once July gets here, we will present daily educational programs for them! Stay tuned for more information!

I realized on my last blog that I did not really talk too much about the daily duties of an intern. Therefore, this blog will just be a broad recap on some of the recent goings-on at NMLC.

Because some very significant donors came this past Thursday to take a look at the animal hospital, our assigned task for a good part of this week was to have the place looking spick and span rather than a haphazard construction site; after hours of heat, sweat, and dirt, the place looks great. I keep looking at the plan and visualizing how grand it’s going to be when it’s all completed. It will really bring so much to the Buzzards’ Bay area in terms of being a site of interest to attract tourists, but it will also be a stately facility to provide great rehabilitative care to sick or injured marine animals.

I also learned this week how to do a full tank change for Patty. It is a multi-step process that sometimes involves manually hauling heavy water-coolers full of salt water to the bin inside, but when I think of all this turtle has been through, it’s so worth it for her. Feeding is, obviously, also part of the daily routine. But it proved particularly challenging that day. Have you ever tried to crack open a frozen clam? It is probably one of the most frustrating experiences you will ever have. For 30 minutes, I tried (in vain) to extract the hearty meat for Patty that was waiting inside… finally, I had to resort to penetrating what I was starting to believe was a concrete shell with a heavy rock. She did not get her typical ‘clams on the half-shell’ that day, but I believe she was fine with this.

Good Ol' Patty... Who can resist that face?!

Another exciting piece of news from this week was that the water quality for the critter tank had improved enough to allow more fish and some invertebrates to now call it their home. Wednesday we went out with buckets and nets and collected different types of crabs, sea slugs, periwinkles, and sea stars. All will be catalogued, and while we may have our doubts as to what kind of relationship the crabs and sea stars will foster (the crab’s dinner delight?) we’ll just have to wait and see. Regardless, the kids that come into the Discovery Center will probably be very excited to see some new critters on display.

On this same topic, the start of the summer education programs is coming steadily upon us, and as such we interns have been dividing up the work in order to be ready. Since each week represents a marine animal, we have all chose one or two weeks that match up with what we want to do. I have whale week, and will also be assisting with shark week (which, btw, matches up with Shark Week on the Discovery Channel…. So cool! J I am fascinated by whales, for their immense size is enough to be overwhelming! Also, as part of my intern project on Deep-Sea Exploration (more on that in a later blog) I will be researching sunken whales. What is a sunken whale, you ask? Quite simply, a whale that has died and sunk to the ocean floor, something I believe most of us overlook. Far from being morbid, these occurrences actually offer scientists a rare opportunity to witness the deep-sea food chain in action and all those that feed off of the whale’s carcass. In some cases, when the meat has already been polished off, underwater robots may attempt to bring up the skeleton for scientific purposes. It really is quite fascinating, and I will definitely post more when I research it in-depth.

One of the crafts I'm looking at for Whale week (7/26)

Whale week will also include some adorable sock puppet whales for kids, and stories. I am hoping to find some on whale migration, for the distances some species travel are quite unbelievable. Perhaps a kid’s version of Moby Dick would also go along with the craft quite nicely, as well as a mini-lesson on the history of whaling, particularly right here on Cape Cod.

Things should be picking up soon with the programs, and it’s very exciting!

Although my main task was the critter tank, I did more than just get that up and running. I helped volunteers like Bob with the Red Bellied Cooters. Linda taught me how to check the water quality. Wendy taught me a trick to make siphoning the water easier. When Len and Paula were in Alaska, I filled in for them. Sometimes I went out and got clean salt water from the pump house when a volunteer needed to be somewhere.  I even helped Joanne create Patty’s new set up with the trash cans and higher water level.

Catch-22

I’m sad to say my four weeks here is up but I really enjoyed my time here. Working with the turtles was a lot of fun and I met a lot of great people. I wish the interns luck with maintaining the Critter Tank and I hope the Discovery Center has a successful summer. Next year I will be going to college at Georgetown University in Washington, DC but I hope will have time to come by and visit NMLC to see what’s going on.

The end of the week was a bit more relaxing and fun. I set up some tanks incase we recieved more Red Bellied Cooters when we turned ours in and then I got to travel up to Westborough on Thursday with some of our interns and volunteers to turn the Red Bellies in. In Westborough we attened a meeting at which we learned about the headstart program. At the end of the day we returned with #122 (later to be named Catch-22) a turtle with a fungus problem on it’s shell. On Friday we went to Middleborough to realese the Red Bellies. I personally realesed three and one of mine beat Frank’s and Juan’s Red Bellies in a race. An interesting thing I learned there was that when the program started the population of the Northern Red-Bellied Cooter was around 300, now the population is around 2,500.

Me releasing a Red Bellied Cooter

I’m on my last week here but it has been fun. Check back to see my final update.

My Original Post

The critter tank as of 5/14/10

Hi everyone, my name is Robert Anderson and I am a senior at Cape Cod Academy. For the month of May, I will be volunteering at the National Marine Life Center for my senior project. At Cape Cod Academy the senior class is required to complete 80 hours and four weeks of community service in order to graduate. I chose to volunteer here at the National Marine Life Center because during the fall and winter of the past two years I have spent my Wednesday afternoons helping out with the Red-bellied Cooters and the Diamondback terrapins and I really enjoyed doing that. While here for my project, my main task will be getting the critter tank up and running for this summer. So far I have figured out the filtration system wasn’t working on the right side because the pump was broken, checked the tank for leaks, and set up the aeration system. Another thing I discovered is a way to keep rocks and other things from being sucked into the filtration system. I have also been creating new ways to identify the creatures which involves flipping a picture over to see the facts underneath. Once we obtain a new pump I should be able to get everything working and then hopefully we will be seeing some critters in the tank. Over the next four weeks I’ll keep posting updates, so check back for more.

Can there be anything more exciting to children than a Critter Tank?  I think not.  Snails and shrimp and crabs, oh my!  Children become entranced watching lady (calico) crabs dancing around the tank.  Then there are the too proud hermit crabs parading over the rock floor to show off their latest homes, yet coveting everyone else’s shell at the same time.  The sea star clings to the center of the tank, while shrimp pulse through the water, occasionally getting swept away by a towering spray of air bubbles.

Come rain or come shine, the NMLC Discovery Center is open seven days a week from 10 am to 5 pm.  Don’t miss it!  The National Marine Life Center can be found at 120 Main Street, Buzzards Bay on the north (mainland) bank of Cape Cod Canal, right near the Railroad Bridge and Massachusetts Maritime Academy.

Enoy a sneak peak at the NMLC Critter Tank!

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