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characteristic for the eastern part of the Limfjord and for the inner reaches (e. g. 
Louns Bredning). This brownish Limfjord water can be followed a good distance 
out into the Kattegat off the mouth of the Limfjord. 
Pitter (1909 pp. 108 and 127) has put forward the view, that the dis- 
solved matter in sea water comes from the plankton algae, which he regards as 
»sugar manufactories«. Without entering upon a criticism of Pitter's evidence, 
which seems to me not specially convincing, I may remark that my data rather 
indicate, that the dissolved organic matter, like the organic matter in the sea- 
bottom, mainly comes from the benthos formations, at any rate in our 
fjords. In the Limfjord there is more dissolved organic matter in Hjarbæk 
Fjord than in Thisted Bredning, and in Roskilde Bredning there is almost double 
as much dissolved organic matter as in the mouth of Isefjord. This agrees fully 
with the occurrence of the organic matter in the sea-bottom, and we may therefore 
conclude, for the reasons shown in the preceding section, that the dissolved organic 
matter also mainly comes from the benthos formations. 
The quantity of the organic matter suspended in the sea-water is, 
as can be seen from the tables, of very variable proportions. On the whole it is 
fairly small; in two cases, in Louns Bredning and Thisted Bredning, no suspended 
organic matter at all could be found in the sea-water by the permanganate 
method, most was found in Hjarbæk Fjord and in Isefjord, where half as much 
suspended as dissolved organic matter was tound. 
It seems as if the winds play a very great part in the occurrence of 
suspended organic matter in the sea. In the beginning of July, when a series of 
water-samples was taken (Nos. 1, 2, 3, 6), the weather was calm, and we see that 
extremely little suspended organic matter occurs in these water-samples. Sample 
10 was also taken in calm weather. On the other hand, samples 11 and 12 were 
taken after a heavy storm; in both we find a fairly considerable amount of suspended 
organic matter. I shall return later to this point; first of all we may enquire as 
to the nature of the suspended matter. 
4. Microscopic examination of the material suspended in the water. In 
the foregoing we have investigated the quantity of the suspended matter; we may 
now investigate, of what it consists. Å microscopic examination of material centri- 
fuged from the sea-water gives the following results. The larger part consists of 
detritus, a mixture of dust-fine, organic and inorganic materials in such a finely 
divided condition, that we can no longer determine what it originally came from. 
Here and there we find pieces a little larger, which can be seen to consist of the 
tissues of higher plants, as also shells of diatoms, Peridineae, bristles of Annelids, 
bits of Copepoda, rarely a whole copepod, starch grains, strands of cotton, in fact, 
with sufficiently careful search we can find everything which might possibly end 
in the sea in sufficiently finely divided condition. 
But what is of special interest and what I wish to emphasize especially, 
is the inappreciable part played by the plankton organisms in relation 
to the quantity of detritus. In July, when the water in the Limfjord, as the 
plankton nets showed, contained large quautities of Chætoceros, a series of centri- 
fuging experiments was made; only in quite a few cases did we find a single 
Chætoceros among the centrifuged material. That the reason for this was not that 
