Introduction To Tiny Engineers
Stand on the damp sand on a California beach and chances are you're standing on top of an active earthworks site. Sand hoppers, tiny, shrimp-like creatures commonly found eating away at kelp on the shore, have been found to move massive amounts of sand. These tiny crustaceans, also known as amphipods, excavate up to 50 kg (110 pounds) of sand per meter (3.3 feet) of shoreline per day. This sheer volume of sediment moved by these crustaceans puts them on par with coastal longshore processes and some major Southern California rivers.
According to UC Santa Barbara marine scientist David Hubbard, "They have one of the highest rates of bioturbation of anything on the planet," referring to the process of sediment displacement by living organisms. The findings, published in the Journal of Geophysical Research: Earth Surface, put new perspectives on the roles of these and other sand-dwelling creatures in the physical processes that shape the coast.
Understanding The Role Of Sand Hoppers
Sandy beaches act like rivers of sediment, constantly moving sand transported by waves, winds, and currents along the coast. The beach is but one part of a bigger system called a littoral cell that cycles sediment from its sources, such as cliffs and dunes that back some beaches, rivers, and streams that carry sediment from coastal watersheds, or onshore processes that push sand from nearshore to the beach. Beaches serve as reservoirs for sand as it continues its way along the coast.
While coastal sediment transport processes are well known, the impact of the animals that live in this highly dynamic environment is less understood. It became an intriguing question for Tim Baxter, a physical geographer interested in interactions between wildlife and their physical environment in the coastal zone. Baxter found in marine scientists Hubbard, Kyle Emery, and Jenny Dugan a complementary curiosity about sand hoppers.
Experimental Methodology
These tiny crustaceans burrow 10–30 cm (4–12 inches) into the sand or hide under washed-up seaweed, emerging after dark to feed on kelp wrack. To find out how much they contribute to the sediment system and sediment transport on these beaches, the researchers devised a simple field experiment at Isla Vista Beach, a bluff-backed stretch of shore adjacent to the UCSB campus.
After high tide on a summer night, when the waves had smoothed the sand and the tide had begun to recede, they sectioned off an array of sampling plots with metal frames in the sand hoppers' preferred burrowing zone. The researchers used rectangular metal frames to estimate the mounding rate of burrowing talitrids.
Key Findings And Implications
The study found that sand hoppers have a significant impact on the physical processes that shape the coast. The sheer volume of sediment moved by these crustaceans is substantial, with up to 50 kg (110 pounds) of sand per meter (3.3 feet) of shoreline per day. This puts them on par with coastal longshore processes and some major Southern California rivers.
The findings of this study have important implications for our understanding of coastal sediment transport processes and the role of animals in shaping the coast. The researchers suggest that sand hoppers and other sand-dwelling creatures play a crucial role in the physical processes that shape the coast, and that their activities should be taken into account in coastal management and conservation efforts.
Future Outlook And Research Directions
The study's findings open up new avenues for research into the role of sand hoppers and other sand-dwelling creatures in coastal sediment transport processes. Further research is needed to fully understand the impact of these animals on the coast and to explore the implications of their activities for coastal management and conservation.
The researchers suggest that their study provides a new perspective on the importance of considering the role of animals in shaping the coast. By taking into account the activities of sand hoppers and other sand-dwelling creatures, coastal managers and conservationists can develop more effective strategies for managing and protecting the coast.
Sources
This is an original synthesis by Qivorane based on reporting from the outlets below.
