ing or retarding the processes of de- 
position and/or erosion and altering 
the chemical composition of both con- 
stituent grains and pore waters. In the 
inner East China Sea — where the 
rates of sedimentation appear to be 
high — one might suspect that the role 
of organisms would be somewhat re- 
duced, with the rapidly accumulating 
sediment restricting the activity of 
many species and, in general, masking 
organisms’ biological impact on the 
sediments. 
Finally, to understand completely 
the interaction of the river and the 
sea, we must consider the recent his- 
tory of the area. Two points are of 
particular interest. First, during the 
last glaciation, about 30,000 to 18,000 
years ago, sea level fell as much as 
300 to 400 feet below the present- 
day level — a result of the utilization 
of seawater in the buildup of con- 
tinental glaciers. Although there is lit- 
tle sea-floor evidence to show : the 
former path of the Chang Jiang, we 
believe that during the maximum low- 
ering of the sea level the river’s path 
extended across the emergent conti- 
nental shelf and emptied into the Oki- 
nawa Trough. As the sea transgressed 
over the continental shelf during the 
last glacial melting, 5,000 to 15,000 
years ago, the Chang Jiang River 
channel was probably buried by sedi- 
ment, so that no present-day trace of 
it can be seen on the sea floor. The 
location of this relict channel, and its 
dimensions, are therefore not known. 
The second point of interest is the 
effect of human activities on the sedi- 
ment load carried by Chinese rivers. 
This impact is difficult to gauge. Poor 
agricultural practices over the past 
several thousand years have greatly 
increased erosion of the land. As a 
result, the high sediment loads that 
characterize China’s rivers may be far 
greater than the prehistoric loads. 
To grasp fully the interrelations be- 
tween these various processes and 
problems requires the integration of 
a number of separate but interacting 
disciplines, among them, geology, 
physical oceanography, chemistry, 
and biology. The American group in- 
cluded scientists prepared to study the 
transfer of Chang Jiang water to the 
sea, the movement of Chang Jiang 
w'ater and other water masses in the 
East China Sea, the transfer of dis- 
solved and suspended loads to the sea, 
the movement of sediment on the sur- 
face of the sea floor in response to 
currents and waves, the geotechnical 
properties of sediments and their his- 
tory, the morphology and shallow 
structure of the sea floor, the rates 
of deposition of sediments and their 
chemical alteration, and the effects 
of biological interaction on bottom 
sediments. 
To carry out a program that ad- 
dressed such a diversity of topics, sev- 
eral ships and many well-coordinated 
schedules were required. After con- 
siderable negotiation, a decision was 
reached to undertake a preliminary 
cruise in June of 1980, so that the 
scientists from the United States could 
learn more about the river and its 
adjacent shelf and scientists from each 
country could evaluate the equipment 
and techniques of the other. Three 
ships were to be used, one from the 
United States and two from China, 
and scientists, equipment, and crews 
from the two countries were to be 
exchanged. One of the Chinese ships 
( Shu Guong, or Dawn # 6 ) would work 
in the Chang Jiang estuary, studying 
the transfer of water and sediment 
loads to the sea; the other Chinese 
ship ( Xiang Yang Hong, or Turning 
Red by the Sun #9) would be respon- 
sible for sampling sediment through- 
out the entire area and for making 
oceanographic observations on the in- 
Transfer of sediment from the 
Yangtze River to the East China Sea 
can be seen in this composite picture 
made from two Landsat satellite 
images of the mouth of the river. 
Although both images were made at 
an altitude of 570 miles, the one at 
the right dates from April 1975 and 
the one on the left from August of 
1979. Runoff is greatest during the 
rainy season, from about June 
through August, but as is shown 
here, heavy cloud cover in this period 
interferes with satellite imagery. 
NASA Landsat phctograc^s 
