As a result of these collections there now exists a fair assortment of 

 benthic organisms caught at moderate depths and an assortment of meso- 

 pelagic fish and invertebrates from several depths between the surface and 

 1000 m. In making these latter collections a great effort was made to se- 

 cure the same (or very closely similar) species from a wide range of lati- 

 tudes and, when possible, a wide range of depths. Plankton collections and 

 collections of surface organisms were made over as wide a geographical 

 range as possible. 



This project serves three functions : 1) to determine the absence of or, 

 if present, the concentrations of the pollutants in organisms collected at 

 selected localities in the ocean and in selected components of the marine 

 food chain in the ocean; 2) to establish species and sediment variability, 

 relating this when possible to proximity of sources; and 3) to allow inter- 

 calibration of methods among all participants. 



The following are highlights of the Atlantic Project: 



a) Heavy Metals — Specimens are being analyzed by at least two of 

 the following methods: neutron-activation analysis, atomic absorption 

 spectroscopy, and colorimetry. In the case of mercury, and possibly some 

 others, attempts are being made to distinguish various organically-bound 

 forms. 



b) Chlorinated Hydrocarbons — Oceanic fishes, plankton, and sedi- 

 ments are being analyzed for DDT and PCB. These compounds have been 

 in agricultural and domestic use on a global scale for at least 25 years. 

 DDT has a half life in excess of four years, and has been implicated in 



10 the decline of populations of sea birds and other marine life. 



c) Petroleum-Derived Hyrocarbons — The ratio between hydrocarbon 

 background and the oil-derived hydrocarbons in upper and midwater ma- 

 rine organisms is being studied. A judicious selection of fish and inverte- 

 brates from areas of very different pollutant supply should permit assess- 

 ment of the extent to which petroleum enters the marine food web. The 

 natural hydrocarbons in the less heavily polluted samples will show how 

 relevant existing hydrocarbon baseline data from coastal regions are to 

 open oceanic regions. This exploratory study will both define the severity 

 of the oil pollution problem in the open ocean and give guidelines on 

 which to base a longer and more intense research effort. 



d) Foreign Participation — Samples of benthos, plankton, and sedi- 

 ments are being collected from the North Sea, the Faroe Bank, and posi- 

 tions in deep water to the west and north of Scotland to cover the probable 

 range in concentration of pollutants in the North East Atlantic. Pesticides 

 and heavy metals are being analyzed by the Marine Laboratory, Aber- 

 deen, Scotland, in conjunction with other interested laboratories. 



e) Results — Data accumulated thus far support three tentative con- 

 clusions: 1) While both DDT and PCB increase in concentration along 

 oceanic food chains, there are significant differences in their pathways; 

 2) There is a significant downward pathway out of the euphotic zone in 

 the bodies of mesopelagic organisms undertaking daily vertical migra- 

 tions; and 3) Fishes and Crustacea which feed near the sea surface at 

 night but migrate to considerable depths during the day show DDT and 

 PCB concentrations not greatly different from those of predaceous orga- 

 nisms whose lives are spent mostly in the upper layers. 



