Note 11 — Chapter VII · The Spring and Summer of 1894

“Blessing collected several specimens on the upper surface of the ice earlier in the summer, and came to the same conclusions. I must look further into this, in order to see whether all this brown dust is of a mineral nature, and consequently originates from the land.11 We found in the lanes quantities of algæ like those we had often found previously. There were large accumulations of them in nearly every little channel. We could also see that a brown surface layer spread itself on the sides of the floes far down into the water. This is due to an alga that grows on the ice. There were also floating in the water a number of small viscid lumps, some white, some of a yellowish red color; and of these I collected several. Under the microscope they all appeared to consist of accumulations of diatoms, among which, moreover, were a number of larger cellular organisms of a very characteristic appearance.12 All of these diatomous accumulations kept at a certain depth, about a yard below the surface of the water; in some of the small lanes they appeared in large masses. At the same depth the above-named alga seemed especially to flourish, while parts of it rose up to the surface. It was evident that these accumulations of diatoms and alga remained floating exactly at the depth where the upper stratum of fresh water rests on the sea-water. The water on the surface was entirely fresh, and the masses of diatoms sank in it, but floated on reaching the salt-water below.