Oceanus 402 Nutrient data

                                                      First results of data analysis


 1.  Data source:
  GOMnutsummary (client).xls (received from Paul Henderson, 18-Oct-2004): NO3, PO4, Si, NH4 versus Sample ID;
  Oceanus 402 Samples Log Book: Sample ID versus depth.

 2. Datafile with merged data:
  oc402_GOMnutsummary.xls - NO3, PO4, Si, NH4 versus Sample ID and Depth.

  
 3. Results of  merging Nutrient data ID and Depth:

    During this work duplicated samples, duplicated depth and lost samples have been found.

    3.1. DUPLICATED DEPTHS: Depth duplicated  in the datafile without any explanation in the Logbook:

C71N10 (1m) and  C71N11 (1m);
C183N3 (30m) and  C183N4 (30m);
C183N9 (1m) and  C183N10 (1m);
C186N4 (15m), C186N5 (15m), C186N6 (15m) and C186N7 (15m);

    3.2. DUPLICATED SAMPLES: Samples duplicated in the datafile without any explanation in the Logbook:

C92N10;
C117N2;
C186N7;
C186N10;
C208N3;
C208N4;
C208N5;
C208N7;
C208N8;
C208N10.

    3.3. LOST SAMPLES: Shown in the Logbook and not available in the datafile:

C72N11 (1m)
C92N8 (10m);
C118N7 (15m);
C183N8 (5m);
C185N5 (30m);
C194N2 (95m);
C195N2 (80m);
Station 187 all samples -  Niskin##: 4:10;
Station  209 all samples except one -  Niskin##: 3, 4, 5, 7, 8 and 10.

4. Summary of the analysis of LOST and DUPLICATED data.
  Some of the lost samples could be found from duplicated, but every point needs additional verification - handwriting, profiles, sections, etc.

   4.1.  Duplicated C117N2 probably is lost C118N7 ;
          Duplicated depth sample C183N3 probably is lost C183N8;
          Duplicated depth sample C71N11  probably is lost C72N11.

   4.2. Station  186 duplicated samples (Niskin##: 7 and 10) as well as some of duplicated depth samples  (Niskin##: 4, 5, 6 and 9)  probably belong to station 187.  In case of duplicated samples it is not clear who is who - both sets of samples labeled as C186.
 
   4.3. Station  208 duplicated samples (Niskin##: 3, 4, 5, 7, 8 and 10) belong to station 209. It is not clear who is who - both sets of samples labeled as C208;

5. Data profiles analysis.

   Attached figures show Nutrients versus depth for each station.  Profiles look good except a couple of samples that probably we need to rerun:
 
   5.1. Silicates:
         C224N1 Si=0.397761
         Some values are <0 (C109N8, C111N9, C136N10). What does that mean?
   5.2. Nitrates: C224N1 NO3=1.626164
   5.3. Phosphates: C137N1 PO4=0.385345, C224N1 PO4=0.365424
   5.4. Ammonium: C136N3 NH4=103.422627.