The influence of light and nutrients on benthic filamentous algal growth: A case study of Saginaw Bay, Lake Huron

• Benthic algal nutrient content and photosynthesis were measured in Saginaw Bay.
• Light appears to set the benthic algal maximum depth limit in inner Saginaw Bay.
• P is predicted to limit algae at light.

The benthic filamentous green algal (FGA) community of Saginaw Bay, Lake Huron, has not been extensively examined, despite its apparent link to shoreline fouling. The objective of this study was to elucidate factors, including light, nutrients, and substrate, expected to affect growth of FGA. We examined the FGA community in the southwest region of the bay, which started ~ 5 km northwest from the Saginaw River, a known source of nutrients and sediment. Cellular nutrient quotas and photosynthetic parameters were measured in FGA over a range of water column depths and distances from the Saginaw River and then compared to published thresholds of limitation. Our results sugges