Citizen Science Design: Narrowly Focused Mercury Study

This was one outcome/response to what we learned in early work. The connection to the first mercury project was not just pedagogical, but was also scientific, since we found in that project that dragonfly nymphs were particularly useful “sentinels” with regard to mercury in other biota. (Nelson et al., 2011; 2014). The work in the first project suggested conjectures about the spatial pattern of mercury concentration across the New England landscape that Sarah Nelson wanted to explore with help from students.

This project again focused on mercury in biota, but with a much sharper focus on dragonfly nymphs. We supported analysis of other invertebrates that students and teachers collected with the proviso that they focused primarily on collection of dragonfly nymphs.


  • A more narrowly defined focus would lessen the burden of question formation and make it easier for teachers to get started with the work.
  • In addition, we expected that the clear connection to real need by a scientist would add to the authenticity of the work.


Similar in some ways to the first mercury project, but with the following changes:

  • Participation by high school (primarily grade 9 and 10) teachers from a number of Maine communities.
  • More attention to collection protocols.
  • A strict focus on collection of freshwater benthic macro invertebrates with particular attention to dragonfly nymphs.
  • Although the individual dragonfly nymphs that the students collected were essential to Dr. Nelson’s inquiry, investigation of the actual questions about spatial distribution of mercury that were the focus of Dr. Nelson’s work required statistical techniques beyond what the students could do. So, we provided supports to teachers that enabled them to use data about the THG in the samples (including samples macroinvertebrates that were not dragonflies) to explore questions about the relationship between mercury concentrations and trophic levels and comparisons between different freshwater environments (e.g., ponds and streams) and different locations.
  • Use of a revised website that focused more on access to information and less on communications between teachers.
  • Use of video by students to share progress reports between participating school
  • Use of instructional approaches and tools (e.g., the Graph Choice Chart) developed in our Data Literacy work.
  • Culminating poster presentations with structured review/critique by students in a multi-school setting.

What We Learned

  • The narrower focus of the investigation did appear to make it easier for teachers to develop field inquiry units for students.  (But other factors, such as experience with field inquiry and data literacy support were probably also involved.)
  • The interaction between schools, which could take on a usefully competitive flavor, appeared to encourage attention to good, careful work.
  • Collection of samples by students at many locations, assuming that collection protocols are not too demanding, can be useful to a scientist involved in a pilot investigation.
  • However, support for sample analysis, even when at reasonable cost (in this case, about $15 per sample) requires external support.
  • Scientific research (distinguished from monitoring) moves forward. In this case, the forward movement was from pilot work that could use samples collected by students at locations and at times that were convenient to the schools and teachers, forward to samples collected under more tightly controlled conditions by paid technicians within a short time period at locations selected according to a research design (Nelson, 2014). Similarly, the questions of interest to a scientist move forward.  This is, to some degree, at odds with the needs of teachers, who would prefer to have some continuity from one year to another. Building on last year’s work to explore new questions is one thing, but doing something entirely different from year to year is quite another.

Other Outcomes

From the Dr. Nelson’s standpoint, the project was successful in that it provided sufficient confirmation of core conjectures and of the value of dragonfly nymphs as bio-sentinels to enable her to secure funding to expand the project.  The methods and models developed though this work with students are now in use in citizen science programs at more than 70 locations within the National Park System. We are proud that this work got its beginning in work with teachers and students.