Can MixSIAR handle empty cells (missing values) in source data?

[amulcan]

Hello,

I have been running MixSIAR to assess potential Pb sources in my study area sediments. I have 3 tracers, 4 sources, about 100 samples/mixtures, and no discrimination factors (trophic discrimination factors are not applicable for this study). My 3 tracers are 3 Pb isotope ratios: 206/204Pb, 207/204Pb, and 208/204Pb. One of the 4 sources, let's call it Source "A", does not have 208/204Pb values. Source A does have values for the other two tracers 206/204Pb and 207/204Pb. I have reason to believe that Source A is a significant source of Pb to my study area sediments, therefore I want to include it in the MixSIAR model.

Knowing that Source A is missing one of the three tracer values can I still use Source A in the MixSIAR model?

I appreciate any help, thanks in advance! Mandy

[brianstock]

MixSIAR can't handle missing tracer values. You could still use Source A in the MixSIAR model if you only use the two other tracers.

[amulcan]

Okay, thanks for the feedback!

[lauriyeso]

Hello, I have an error running calc_area and with run_model. "calc_area(source=source,mix=mix,discr=discr) Error in chull(x, y) : finite coordinates are needed" Is this caused by my empty cells in the loaded data? I have two raws containing NAs in mixture data and one NA in consumers data. There is not an error loading the data but calculating the area....I copy my mixture and source data:

head(mix) $data Especie Rep d18O d2H 1 Anabasis_calcarea 1 -1.46 -37.1 2 Anabasis_calcarea 2 -1.54 -44.5 3 Anabasis_calcarea 3 -1.93 -43.9 4 Atraphaxis_suaedifolia 1 1.34 -29.6 5 Atraphaxis_suaedifolia 2 -2.27 -43.9 6 Atraphaxis_suaedifolia 3 -3.42 -45.4 7 Atraphaxis_suaedifolia 4 -2.19 -38.7 8 Atraphaxis_suaedifolia 5 4.33 -42.9 9 Anabasis_eugeniae 1 -3.26 -52.3 10 Anabasis_eugeniae 2 -4.16 -51.9 11 Anabasis_eugeniae 3 -4.62 -53.9 12 Anabasis_eugeniae 4 -5.91 -47.5 13 Anabasis_eugeniae 5 -5.24 -56.6 14 Caroxylon_gemmascens 1 -6.39 NA 15 Caroxylon_gemmascens 2 -1.77 -52.5 16 Caroxylon_gemmascens 3 0.54 -33.5 17 Caroxylon_gemmascens 4 -0.97 -45.3 18 Caroxylon_gemmascens 5 -3.20 -47.9 19 Oreosalsola_montana 1 -6.17 -66.4 20 Oreosalsola_montana 2 -4.11 -48.2 21 Oreosalsola_montana 3 NA NA

head(source) $n.sources [1] 5

$source_names [1] "Crystal_10" "Crystal_20" "Free_10" "Free_20" "river"

$S_MU Meand18O Meand2H Especie 1 12.483333 10.36667 1 2 14.500000 26.70000 2 3 7.695000 5.95000 3 4 11.296000 -5.04000 4 5 NA NA 5 6 5.592500 29.90000 1 7 9.342000 23.30000 2 8 7.422500 5.40000 3 9 9.972000 33.50000 4 10 10.850000 -6.60000 5 11 -6.935000 -70.20000 1 12 -2.648000 -38.52000 2 13 -2.970000 -46.66000 3 14 -1.352000 -51.32000 4 15 -4.053333 -46.73333 5 16 -4.660000 -52.65000 1 17 -7.900000 -70.36000 2 18 -7.400000 -62.20000 3 19 -7.940000 -73.48000 4 20 -4.285000 -54.50000 5 21 -8.512000 -60.44200 1 22 -8.512000 -60.44200 2 23 -8.512000 -60.44200 3 24 -8.512000 -60.44200 4 25 -8.512000 -60.44200 5

$S_SIG SDd18O SDd2H Especie 1 5.188568 7.203703 1 2 9.153699 55.847053 2 3 4.932778 62.937879 3 4 6.004393 62.864640 4 5 NA NA 5 6 11.199081 63.938616 1 7 6.022497 28.004464 2 8 4.200852 49.061322 3 9 6.591189 38.874735 4 10 3.521392 11.737973 5 11 3.189052 26.304372 1 12 2.132679 12.580024 2 13 1.837893 11.344294 3 14 6.300799 13.538353 4 15 3.836200 6.735231 5 16 2.501560 21.431674 1 17 1.643229 12.083998 2 18 1.440301 10.694235 3 19 2.075054 10.927809 4 20 5.876057 1.697056 5 21 0.001000 0.001000 1 22 0.001000 0.001000 2 23 0.001000 0.001000 3 24 0.001000 0.001000 4 25 0.001000 0.001000 5

$S_factor1 [1] Anabasis_calcarea Anabasis_eugeniae Atraphaxis_suaedifolia Caroxylon_gemmascens Oreosalsola_montana
[6] Anabasis_calcarea Anabasis_eugeniae Atraphaxis_suaedifolia Caroxylon_gemmascens Oreosalsola_montana
[11] Anabasis_calcarea Anabasis_eugeniae Atraphaxis_suaedifolia Caroxylon_gemmascens Oreosalsola_montana
[16] Anabasis_calcarea Anabasis_eugeniae Atraphaxis_suaedifolia Caroxylon_gemmascens Oreosalsola_montana
[21] Anabasis_calcarea Anabasis_eugeniae Atraphaxis_suaedifolia Caroxylon_gemmascens Oreosalsola_montana
Levels: Anabasis_calcarea Anabasis_eugeniae Atraphaxis_suaedifolia Caroxylon_gemmascens Oreosalsola_montana

$S_factor_levels [1] 5

Thanks for your help

[lauriyeso]

I have solved the problem, thanks....I have deleted empty values for consumers and calculated a media data for the sources I did not have a concrete value for each consumer.