Environmental Engineering Reference
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burrowing crustaceans are isopods, amphipods, and decapods ( Figs. 3 and 5 ).
Isopods typically construct trackways (e.g., Cruziana , Isopodichnus ) and very
shallow burrows as they scavenge for food ( Griffith and Telford, 1985; Hauck
et al., 2008 ). As a result of the shallow burrow depths, the preservation potential
of isopod burrows is low.
Amphipods have adapted to living in a range of marginal-marine and marine
settings, although only a few extant species are known to burrow. Within the
marginal-marine realm, burrowing amphipods are evident from the sandy back-
shore to the seaward end of the intertidal zone. In sandy backshores, Talitrid
amphipods often feed on seaweed and organic detritus washed up by the waves.
These animals excavate unlined, vertical burrows, akin to Skolithos . Talitrid
burrows range up to 25 cm deep ( Figs. 3 and 5 A; Dashtgard and Gingras,
2005 ), but are typically less than 5 cm deep.
In the intertidal zone, two burrowing amphipods are commonly found:
Corophium spp. and Haustorius spp. Corophium volutator ( Fig. 5 C and D) is a
small mud-loving amphipod which occurs in population densities of up to
63,000/m 2 ( Pearson and Gingras, 2006; Thurston, 1990 ). It constructs a
U-shaped tube that promotes water circulation, enabling the amphipod to breathe,
surface-deposit feed, and evacuate waste material within the safety of its burrow
( Ingle, 1966 ). Corophiumarenarium is commonly found in sandy substrates in the
intertidal zone, where it excavates a single vertical shaft that provides access to the
sediment/water interface for surface-deposit feeding, and allows water to flow
freely through the burrow walls ( Bromley, 1990; Ingle, 1966 ). Haustoriid amphi-
pods, commonly referred to as digger amphipods, move through the sediment by
excavating and backfilling their burrow as they move. The smaller species of this
group are only a few millimeters long and tend to contribute to the formation of
cryptobioturbation. Large specimens disrupt the sediment, producing a visible trail
of deformed sediment in their wake ( Howard and Elders, 1970 ).
Of the decapods, thalassinid shrimp are the most well-known burrowers
( Fig. 5 E and F). The common element of most thalassinid shrimp burrows is
a vertical shaft that connects to the sediment/water interface and branches at
depth ( Atkinson and Nash, 1990; Bromley, 1990; Giffis and Chavez, 1988;
Gingras et al., 2000a; Shinn, 1968; Swinbanks and Luternauer, 1987 ). The
upper part of the burrow may split, forming a small Y-shape. Deeper in the bur-
row, it is common to observe tiered and box-work networks ( Atkinson and
Nash, 1990; Bromley and Frey, 1974; Giffis and Chavez, 1988; Gingras
et al., 2008a; Shinn, 1968 ). In general, thalassinid shrimp use the vertical shaft
to maintain a connection to the sediment/water interface and the basal network
for deposit feeding. Some genera, including Upogebia spp. ( Fig. 5 E), maintain a
broader Y-shaped burrow that the animal employs for filter feeding, and where
the descending branch is used as a refuge from predation ( Dworschak, 1982;
Stevens, 1929 ). Thalassinid shrimp are also known to make helical burrows
(i.e., Gyrolithes ; Dworschak and Rodrigues, 1997; Wetzel et al., 2010 ), where
the spiral ramp is either used for the easy maintenance of their domiciles or
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