Where do sand fleas live? - briefly
Sand fleas are typically found in the upper layers of moist sand along beaches, estuaries, and coastal dunes, often near the high‑tide line. They also occupy shallow, brackish pools and tidal flats where they can burrow and hunt for organic debris.
Where do sand fleas live? - in detail
Sand fleas occupy the supralittoral zone of marine coastlines, where the sand remains damp but is not regularly submerged. They are most abundant in the upper intertidal region, often beneath wrack, dead seaweed, and decaying organic material that retains moisture. Typical micro‑habitats include:
- Shallow burrows in fine‑grained, well‑sorted sand that stays moist after tidal retreat.
- Crevices among sand grains beneath accumulations of drift algae, shells, and detritus.
- Sandy patches of salt‑marsh edges and estuarine banks where freshwater mixing creates brackish conditions.
- Dune fore‑dunes with a thin layer of humus or leaf litter that provides shelter from desiccation.
Geographically, sand fleas are found on temperate and tropical coasts worldwide, from the Atlantic seaboard of North America to the Pacific shores of Australia and New Zealand. Their distribution correlates with stable, sandy substrates and a reliable source of organic debris. Species that inhabit colder regions tolerate temperatures near 0 °C, while tropical representatives thrive in waters up to 30 °C. Salinity tolerance ranges from full marine strength (≈35 ppt) to reduced levels (≈5 ppt) in brackish habitats.
Environmental parameters governing their presence include:
- Moisture content – sand must retain at least 10 % water by weight to prevent lethal desiccation.
- Organic enrichment – presence of decaying plant material supplies food and microbial communities essential for growth.
- Grain size – particles between 0.1 mm and 1 mm allow easy burrowing while maintaining structural stability.
- Temperature stability – extreme fluctuations reduce survivorship; optimal ranges lie between 10 °C and 25 °C for most species.
Population density peaks during the night, when individuals emerge from burrows to feed on detritus and microorganisms. Daytime activity retreats to deeper sand layers, providing protection from predators and solar drying. Human activities that alter shoreline composition—such as beach nourishment, heavy foot traffic, or pollution—can diminish suitable habitats, leading to local declines.