476 



DiDomenico, Dante A., and Richard L. Iverson. 1977 . 



Uptake of glycolic acid by a marine bivalve. J. Exp. Mar. Biol. Ecol. 

 28(3): 243-254. 



Glycolic acid probably is the most important metabolite released by 

 phytoplankton. Marine invertebrates, including Mercenaria mercenaria, can 

 remove dissolved organic matter, such as amino acids, from solution. This 

 can provide an important nutritional supplement. It was of interest to 

 determine the capability of M. mercenaria to absorb glycolic acid from 

 solution and to study the mechanism by which this was accomplished. It 

 was found that the amino acid was accumulated by in vitro preparations of 

 gill tissue from M. mercenaria, M. eampeehiensis and hybrids, probably by 

 diffusion kinetics. Carbon-14 from labelled glycolic acid was found in the 

 lipid fraction of gill tissue. Evolution of labelled CO2 suggested that 

 glycolic acid was metabolized in gill tissue. - J.L.M. 



477 



Dillaman, R. M. , S. E. Ford, and K. M. Wilbur. 1980. 



Measurement of small growth increments in molluscan shell. Natl. Shellf. 

 Assn., Abstracts, Technical Sessions: 17 (abstract) . 



Measurement of small increments in Mercenaria mercenaria and Avgoyecten 

 irradians shell under natural conditions is limited by the relative insensi- 

 tivity of mechanical measuring devices. Radioisotope incorporation must be 

 done under laboratory conditions where growth may be atypical . The authors 

 have devised a method for measuring small growth increments which circum- 

 vents both problems. Animals are placed in 45^ a medium for several hours 

 where they deposit an isotopically labeled shell layer. They are then re- 

 turned to natural growing areas or to any experimental situation. After a 

 desired period, small pieces of shell are removed, painted on all but the 

 inner surface and placed in a chamber where an etching solution flows over 

 the surface at a constant rate and is collected by a fraction collector. 

 Fractions are counted for 45c a and/or total calcium. Preliminary tests show 

 that total calcium removed from the shell surface is constant from fraction 

 to fraction. The peak of radioactivity falls into progressively later 

 fractions as the animal grows for longer times in unlabeled seawater and 

 deposits non-radioactive calcium over the 45ca-containing layer. The tech- 

 nique may be used to measure shell deposition in very slowly growing ani- 

 mals, or during short time periods in faster growing molluscs. - J.L.M. 



478 



Dimick, R. E., and W. P. Breese. 1965. 



Bay mussel embryo bioassay. Proc . 12th Pac . NW Ind . Waste Conf., Univ. 

 Washington, p. 165-175. 



Mercenaria mercenaria is not mentioned. - J.L.M. 



479 



Dirnberger, Thomas, and Albert P. Kline. 1972. 



A quantitative study of heavy metals in Venus mercenaria: Part II. Concen- 

 trations of zinc, cobolt (sic) , mercury, lead, copper, and cadmium in the 

 clam, Venus mercenaira (sic). Proc. Pa. Acad. Sci . 46:17 (abstract). 



Research substantiated previous conclusions that Venus mercenaria can con- 

 centrate heavy metals from ambient water. Details are not given. - J.L.M. 



480 



Dodgson, K. S., J. I. M. Lewis, and B. Spencer. 1953. 



Studies on sulphatases. 3. The arylsulphatase and 6-glucuronidase of 

 marine molluscs. Biochem. J. 55(2): 253-259. 



Mercenaria (Venus) mercenaria is not mentioned. M.W.S. 



133 



