Outdoor seating, particularly in coastal or waterfront areas, can have unintended consequences on local harpacticoid populations—tiny crustaceans vital to marine ecosystems. These organisms thrive in interstitial spaces within sediments, where they play key roles in nutrient cycling and food webs.

The installation of permanent or semi-permanent outdoor seating disrupts their habitat by compacting sediments, altering moisture levels, and reducing oxygen flow. Artificial shading from structures may also impact microalgae growth, a primary food source for harpacticoids. Studies suggest that high-traffic seating areas correlate with reduced harpacticoid diversity, favoring only disturbance-tolerant species.

Mitigation strategies include elevated seating designs, permeable materials, and buffer zones to minimize ecological damage. Understanding these impacts helps balance human leisure needs with the preservation of microscopic marine life critical to shoreline health.