Fróðskaparrit - 01.01.2009, Blaðsíða 165

EVNAFRØÐIUGAR BLEYTBOTNSDÁTUR Á FØROYSKUM HAVØKI:
LÍVRUNNIÐ TILFAR, NITROGEN, FOSFOR, SINK OG KOPAR
163
Sediment type was always estimated on
the spot by the person responsible for the
sampling.
In Table 1, mean values, range and stan-
dard deviation (std. dev.) on LOI, total nitro-
gen, total phosphorus, zinc and copper are
given according to depth intervals and in
Table 2 according to sediment types.
Mean LOI value for all samples was 5.4 %
in the range 0.5-13.0 % with a std. dev. of 2.0
%. There seems to be a slight increase in shal-
low water LOI values when going from
seashore to deeper waters. Mean LOI values
were from 4.8 % in the depth range 0-19 m
to 6.3 % at depth range 60-82 m (Fig. 2.a).
Clay and mixed clay had slightly higher LOI
values, compared to the more sandy sedi-
ment types (Fig. 2.b). Clay and mixed clay
have mean LOI values of 6.2 % and 5.7 %,
while sand, gravelly sand and mixed sand
have values of 4.6,4.6 and 5.6 %, respectively.
Total nitrogen has a mean value of 1.49
g/kg dry matter with a minimum value of
0.14 g/kg and a maximum value of 4.01 g/kg.
There was a small increase in nitrogen con-
tent from shallow to deeper waters (Fig. 3.a).
When total nitrogen is calculated against LOI
and compared to depth, essentially no dif-
ference is observed (Fig. 3.b). Mean value of
total nitrogen calculated against LOI is 0.031
g/g. Minimum value is 0.007 g/g and maxi-
mum value is 0.324 g/g. Compared to sedi-
ment types, there is slightly less nitrogen in
sand and gravelly sand (0.51 and 1.27 g/kg),
compared to clay and mixed clay (1.64 and
1.47 g/kg) (Fig.4.a). The same tendency can
be seen when compared to LOI values, but
less distinct (Fig. 4.b).
Total phosphorus has a mean value of
0.92 g/kg dry matter with a minimum value
Figure 1. The localitiesof samplescollected by KMBL
(data in Table 1 and 2). Each dot may represent several
samples from the same sampling area.
of 0.43 g/kg and a maximum value of 2.02
g/kg. There was a small decrease from the
shallower to the deeper parts of the fjords
(Fig. 3.c). When total phosphorus is calcu-
lated against LOI and compared to depth no
difference can be noted (Fig. 3.d). Mean
value of total phosphorus calculated against
LOI is 0.021 g/g. Minimum is 0.007 and max-
imum is 0.170 g/g LOI. Compared to sedi-
ment types, there were minor differences in
values, but without any clear tendency (Fig.
4.c and 4.d).
Total mean value for zinc in the sedi-
ment is 53 mg/kg dry matter. Highest value