The end of the experiment

We returned to the hotel and analyzed our samples for nitrogen. We were done around 4:00 in the afternoon and decided to drive down to the beach. Alex opted to stay behind. He needed to teach a lecture to his class the morning after he got home. His notes for it were on the disappeared laptop. He borrowed one of our computers, planted himself with two pillows propped behind his back on his bed and got to work re-writing his lecture.

Not 15 minutes after we left, he heard a sound at the window. One of the maintenance men from the hotel was climbing up a stepladder to the window. Looking quite startled to see Alex in his room, he continued climbing and did something right above the window.

He left rather quickly and a short time later another hotel worker came and took the ladder. Alex went out to look at what the maintenance man was doing but saw nothing other than a concrete sill and the top of the window. Nothing looked changed or worked on; there was essentially nothing to work on there.
It all seemed very suspicious given that Alex’s laptop had disappeared from two rooms down, and the thief hand entered through the same window. We decided Edgardo was probably correct about who had taken the computer earlier, but had no way to do anything about it.

The next day was our last field day and we needed to collect samples of all the organisms in the stream so that we could determine where the nitrogen tracer had ended up. We collected algae from rocks, rotting leaves (filled with fungi and bacteria), and fine sediments both at the water surface and from the stream bottom. These are the primary food sources for the few remaining tadpoles, and many of the invertebrate larvae, freshwater crabs and few freshwater shrimp in the stream.

The other animals still in the stream are predators, such as the large (half inch long) vicious dragonfly larvae with extendable jaws that flip out and jab prey, and the dark brown hellgrammites as long a pinky finger with massive pinching jaws. A little caution is necessary with the hellgrammites because their jaws can draw blood. Amanda collected the animals because she had the collection permits from the Panamanian government, such permits are not necessary for leaves, sediment, and algae.

We pulled all our electronic probes out of the stream and attempted to download the data. I went to get the light meters from a clearing on the hill and walked down the new road carved over the last few days into the hillside above our research site. It went to an area along the hill about half way up our experimental reach.

The new road had broad areas of dirt that had been exposed. At the top of the cut, it was easy to see that the jungle soil has a thin black layer that sits on a very poor mineral soil beneath. In the US, this type of construction would require that materials be placed over the open sediments to stop erosion from allowing the sediments to pollute the nearby streams. No such requirements are in place in Panama, or if they were, they were not being enforced. Luckily, sediments from the construction had a hundreds of feet to go through the forest and densely vegetated side channels before reaching our stream. The rapid regrowth might cover the open sediments before the rainy season came and erosion began in earnest.

The sediments would not influence our results from this week. However, once all the houses were built in the marked lots, it looked very likely to me that the portion of Rio Maria we were studying would become severely degraded. This was sad, but being a researcher, thoughts of coming back to document the effects also occurred to me. Just recently ecologists have started studying urban and suburban streams in the US, but little work has been done elsewhere in the world. With our extensive background data, we would be able to detect any changes that occurred in the stream. This seems to be the way than many scientists deal with bad things, they study them.

Upon my return to the stream with the light meters, I learned that one of the instruments had malfunctioned, but we had a duplicate, so this was not a problem. The pump that had been used to release the tracer was turned off. As we carried the last of the sampling gear and electronics it started pouring rain. The group joke was “Dry season? This is a heck of a way to run a rain forest”. Not a great joke, but it had rained every day and this was an unusually wet dry season .