Does Sargassum Vegetate in the Open Sea?

Abstract

HAVING had many opportunities of observing patches of “living Sargassum in the open sea” from the deck of H.M.S. Challenger during her cruise in the North Atlantic in the early part of the year 1873, I venture to offer a few remarks in reply to the above inquiry of your correspondent in NATURE, vol. xx. p. 552. The track of our ship between Madeira, the Canary Islands, St. Thomas in the West Indies, Bermudas, and the Azores is almost equivalent, as a glance at the map will show, to a complete circumnavigation of the central part of the North Atlantic generally known as the Sargasso Sea. During this cruise Sargassum bacciferum was met with frequently so as to render the appearance of this seaweed a sight quite familiar to all on board the Challenger. It was first seen on March 2 in about lat. 22° 30′ N., long. 42° W., halfway between the Canaries and the West Indies. Again on March 6, lat 21° N., long. 49° W., quantities of gulf-weed drifted past the ship. On more than one occasion large patches of Sargassum were observed extending from the vicinity of the vessel to a great distance. The gulf-weed was also encountered between St. Thomas and the Bermudas group, and was last met by us between the latter islands and the Azores on June 18, lat. 35° N., long. 53° W.