174 Productivity and Benthic Organisms
Fig. 6.14 a, b. Tracks and burrows in deepsea clay. a Furrow-like feeding trails of holothurians (deposit feeders). Note range of
states of preservation, fresh trail at lower
Ie/i. Also meander-like fecal strings extruded onto sediment surface. Small compact structures probably are agglutinating
foraminifera. Tracks and trails are not
preserved in the record , unless burial is by
sudden influx of sediment (such as turbidites). Northern Solomon Trench, water
depth 8500 m, field of view in upper photo
1.5 x 3 m. [Photo courtesy R. L. Fisher.)
b X-ray radiograph , positive, of deep-sea
Red Clay. Dense areas are dark. Network
of burrows (mainly deep-reaching burrows
are preserved) illustrates intensity of bioturbation. Typical burrow diameter, 0.5 to
I cm. Left Small manganese nodule. Core
taken about 1000 km SE of Hawaii , water
depth 5000 m, 49-{j0 cm below sediment
surface. [Photo F. C. Kogler)