The effects of copper on the development of Crassostrea gigas embryos were determined with a 48-hr static bioassay. In filtered, sterilized seawater from Bodega Bay, California, the LC100 was 20 microgram Cu/L, and the LC50 was 12 microgram Cu/L. Destruction of the naturally occurring dissolved organic material in the culture water by UV oxidation decreased embryo survival at 10 microgram Cu/L. The addition to seawater of five organic chelators (ethylenediaminetetraacetic acid (EDTA), sodium citrate, glycine, and oxalate at 1 x 10(-6) M, and humic matter at 2 mg/L) increased embryo survival. EDTA and humic matter were the most effective chelators; EDTA significantly increased survival at 100 microgram Cu/L and humic matter did so at 40 microgram Cu/L. The ability of a chelator to increase survival was related to the stability constant of the copper-chelator complex.

No abstract

In February, 1957, a hydrographic team 3 from the Hopkins Marine Station accidentally discovered a bed of Allocentrotus fragilis (Swann, 1953) at a depth of 68 to 98 fathoms in Monterey Bay, California. This discovery was made during a routine hydrographic run. At the time a mid-water plankton haul with a standard one-meter net was in progress. The Hopkins Marine Station research vessel, the "Tage," had apparently drifted with the onshore current. When the net was surfaced, to their surprise and delight, the team found approximately two dozen specimens of the deep sea urchin, Allocentrotus. This was the first time that the animal had been obtained alive and intact in large numbers. At this spot the fathometer indicated 80 fathoms and a radio "fix" recorded the position of the boat to be 3637'54" N and 12201'12" W. All subsequent hauls were started from this station.Since a project on the biology of the shore sea urchins, Strongyloccntrotus pur pit rat its and S. francisannts, was in progress at the Hopkins Marine Station, the chance finding of a bed of the deep sea urchins was of immediate comparative interest. Consequently, whenever possible, studies were made on the biology of Al-

No abstract

No abstract