MaRNiD – 90 thousand marine ammonium data points and counting #OSM2014

In my Ocean Sciences talk yesterday I presented a first look at the ~30k surface ammonium observations from the MaRNiD database. This is mostly data from data centres, but our aim is to capture a similar amount of data direct from the community that might not find its way into data centres. We plan to publish a publicly available dataset as a data paper with all data originators as named authors, some time in the next year. If you’d like to be part of it, please submit data by 31st May. Submission details here.

Here’s a first look at the surface concentration data (<15m), sorted as follows:

  • COASTAL – all data from water column < 20m deep
  • SHELF – all data from water column 20-200m deep
  • Deep ocean (water column >200m deep) is then subdivided:
  • POLAR (>65 degrees latitude)
  • WESTERLIES (between 40 and 65 degrees)
  • OLIGOTROPHIC (between 10 and 40 degrees)
  • EQUATORIAL (<10 degrees)


Things to note:

1) the y axis is logarithmic – the data is highly skewed towards lower concentrations

2) other than any pre-sumbission quality control, this is not quality controlled data. One of the first things we would like to do with the dataset is investigate the possible differences between fresh / stored samples and between different methods as we suspect that both of these may significantly affect the measured concentrations.

One interesting thing, however, is that we do not see a decreasing concentration trend when the data is sorted by decade, which is something we expected on the basis that measurement techniques have improved. This requires further investigation.


Please spread the word about this initiative – tell your friends with ammonium and dissolved organic nitrogen data from estuaries to the deep ocean!


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