Water Filtration by the Oyster and a New Hormone Effect upon the Rate of Flow

Abstract

Estimates of water passing through an oyster based on: (1) amount of sediment deposited; (2) number of food organisms collected; and, (3) direct measurement of flow through a tube in the cloacal chamber, vary from 333 cc. per hour to 200 quarts per day. Galtsoff 1 with method (3) obtains maximum pumpage of 7 liters per hour. This method is defective since tube in the cloacal chamber prevents normal operation of the first and second zones of control; the shell and the reflected mantle borders, and interferes with blood supply to the gills from the accessory hearts, Hopkins. 2 In Ostrea virginica much of the water entering the right gill anterior to the adductor muscle leaves through an asymmetric excurrent aperture on the right side hence never enters the cloacal chamber. The small tube, 6 mm. creates high ratio of friction to hydraulic head developed.

A superior method, Nelson, 3 measuring all water passed while the oyster functions normally, is attachment of the rubber apron of Moore 4 to a large (23 mm.) tube into the exhaust chamber of the constant level tank of Galtsoff. 1 Using this method a head of 7 mm. of water was developed by an oyster 11.8 x 7.8 cm. at 25.5°C., as compared with 4 mm. previously obtained. Little water passes below 10°C. but above this temperature pumpage rises rapidly to maximum of 26 liters per hour in an O. virginica 11.5 x 8.9 cm. A total of 111 liters was filtered in 7 hours at 24-27°C. Above 30° flow decreases sharply from partial closure of shell and reflected mantle borders. Hopkins'shows similar effects in O. gigas above 20.°