510 



SCIENCE 



[N. S. Vol. XL. No. 1032 



by Perry ;^ the effects of the eruption as seen 

 in June and July, 1912, by Martin;^ the com- 

 position of the ash that fell at Kodiak by Fry;* 

 and the effects of the eruption on land vegeta- 

 tion by Griggs.^ 



The eruption was a violent one and proved 

 fatal to a considerable amount of life both 

 plant and animal. It also modified, at least 

 temporarily, the conditions of plant life on 

 the eastern portion of the Alaskan Peninsula 

 and on Kodiak, Afognak and Shuyak Islands 

 and the neighboring smaller islands. 



Katmai volcano is situated toward the 

 eastern end of the Alaskan Peninsula. It is 

 about 24 km. north of the nearest point of 

 Shelikof Strait and about 104 km. southwest 

 of Cape Douglas. The wind was westerly at 

 the time of the eruption so that the regions 

 principally affected were those situated imme- 

 diately to the eastward. 



Of the effects of this eruption on marine 

 vegetation as seen in the two months follow- 

 ing its occurrence, Martin says: 



Marine life was affected to a larger degree than 

 would perhaps be expected. . . . Kelp is apparently 

 dead as far as the eastern end of Afognak Island. 



Such injury to marine vegetation as was 

 still apparent when the writer visited this 

 region, over a year after the eruption, had evi- 

 dently resulted from one or more of the fol- 

 lowing causes: (1) the grinding effect of the 

 floating pumice, (2) actual burial of plants 

 by the deposit of ash, (3) the burial by the 

 ash of rocks which had furnished anchorage 

 for marine algte, (4) the effect of poisonous 

 gases on plants growing in the littoral zone 

 or whose distal portions are kept at the sur- 

 face of the water by floats. 



2 Perry, Captain K. W. (U. 8. E. C. S.), extract 

 from report. The National Geographic Magazine, 

 23, 824-832, 1912. 



3 Martin, George C, ' ' The Recent Eruption of 

 Katmai Volcano in Alaska," The National Geo- 

 graphic Magazine, 24: 131-181, 1913. 



«Fry, William H., "The Mineral Content of 

 Volcanic Ashes from Kodiak," Science, N. S., 36: 

 682, 1912. 



5 Griggs, Eobert F., ' ' The Effects of the Kat- 

 mai Eruption on Land Vegetation. ' ' 



Of the masses of floating pumice, as seen in 

 August, 1912, Martin says: 



The pumice is being washed ante the sea by the 

 combined action of streams, waves and tides. 

 There it forms great floating fields which migrate 

 with the winds and tides and greatly impede the 

 navigation of small craft such as ours. An im- 

 mense field of pumice . . . visited our anchorage at 

 Takli Island. . . . This visitor came and went under 

 the influence of tidal currents and winds, and 

 constituted a menace which led us to seek a more 

 sheltered nook for our boat. Even this was in- 

 vaded by the floating rock, which jammed tight 

 around and carried our boat with it when it 

 moved, in spite two anchors and two pieces of pig 

 iron down, and forced us to make fast to a pro- 

 jecting cliff. The floating pumice was twelve 

 inches thick alongside the boat and possibly was 

 much thicker in the center of a large field. Fish- 

 ermen reported a pumice field dense enough to 

 support a man in Shelikof Strait. 



In July, 1913, the schooner from which we 

 were conducting the kelp investigation passed 

 through fields of floating pumice more than 

 241 km. west of Mount Katmai. Some of 

 these fields were as much as 213 m. long and 

 15 m. wide. In several places the fields were 

 so dense that we scooped up quantities of 

 pumice with a dip net as our schooner passed 

 through them. Drifts of pumice 20 cm. or 

 more in depth were found in August over 

 considerable areas on the beach of a lagoon 

 opening from Popof Strait in the Shumagin 

 Islands. In the region principally affected by 

 the volcanic eruption we found considerable 

 quantities of pumice drifted up on the beaches 

 but did not encounter any floating fields of it. 

 Reports from residents agree, however, that 

 there were extensive fields in Shelikof Strait, 

 Kupreanof Strait and other waters of the 

 region in 1912. 



Undoubtedly the grinding effect of the con- 

 tinued movement by tides and waves of the 

 rough pieces of pumice composing these float- 

 ing fields must have caused considerable injury 

 to beds of Nereocystis luetkeana and Alaria 

 fistulosa, both of which species are anchored to 

 the bottom and are provided with floats that 

 keep the distal portion of the plant at the 

 surface of the water. 



