The primary productivity of benthic and planktonic algae in a prairie wetland under controlled water-level regimes

Abstract

There have been few measurements of primary productivity by benthic (periphytic) and planktonic algae in prairie wetlands so their quantitative importance relative to other primary producers is largely unknown. We measured the daily productivity (inorganic carbon assimilation per m 2 of wetland area) of phytoplankton, epipelon, epiphyton, and metaphyton in ten wetland cells in Delta Marsh, Manitoba over a five-year period. Water levels in the cells were manipulated so that some cells had normal water levels for the wetland, while water depths increased 30 cm or 60 cm in other treatments. With increasing water depth, phytoplankton productivity increased while that of epipelon, epiphyton, and metaphyton decreased. Metaphyton was the largest contributor to total algal productivity (70%), followed by epiphyton (23%), phytoplankton (6%), and epipelon (1%). Phytoplankton had the highest photosynthetic efficiency (C assimilated per unit chlorophyll), despite being a minor contributor to total productivity. Variations in P-I parameters (a, I~, Ik, and P,,=) were considerable, possibly due to temporal and spatial fluctuation in the abiotic environment. Alga/ productivity was comparable to that of submersed and emergent macrophytes, suggesting that algae axe probably important resources in supporting food webs in prairie wetlands.

Corrigendum: Does mosquito control by Bti spraying affect the phytoplankton community? A 5-year study in Camargue temporary wetlands (France)

“…Phytoplanktonic algae make a significant contribution to primary production and nutrient cycling in wetlands (Goldsborough and Robinson, 1996;Robinson et al, 1997;Wu and Mitsch, 1998;Weilhoefer and Pan, 2007;Hagen, 2009). Phytoplankton cells are also a significant dietary resource for larvae of many species mosquito that feed opportunistically on microorganisms (i.e., bacteria, fungal, protozoa, algae) (Merritt et al, 1992).…”

Evaluating the influence of macrophytes on algal and bacterial production in multiple habitats of a freshwater wetland

“…Algae can account for approximately half of aboveground primary production in newly constructed and experimental wetlands (Cronk and Mitsch 1994;Robinson et al 1997) as well as salt marshes (e.g., Pinckney and Zingmark 1993), suggesting that they may also make a substantial contribution to primary production in natural freshwater wetlands. The diverse physical structure of these ecosystems-in large part a result of the presence of macrophytes-means that surface area available for microbial growth may be far greater than total water surface area.…”

“…The diverse physical structure of these ecosystems-in large part a result of the presence of macrophytes-means that surface area available for microbial growth may be far greater than total water surface area. Unfortunately, there are little empirical data available to assess the significance of algae to net ecosystem production (NEP) (Robinson et al 1997;Wetzel 2001). Thus, our second objective was to ask the following question: How important are algae versus macrophytes to NEP in a southeastern U.S. wetland?…”

The importance of phytoplankton production for carbon budgets in a semiarid floodplain wetland

“…Few studies (Robarts & al., 1995;Robinson & al., 1997) have focused on shallow, clear-water wetlands, but studies in highly turbid wetlands, where high amounts of dissolved organic matter and/or particulate suspended matter can influence irradiance attenuation, and consequently PP, are almost lacking. This is unfortunate because phytoplankton can play a major role in the carbon metabolism of some wetlands (Robinson & al., 1997;, thereby influencing nutrient cycling. The hydrological regime of wetlands imposes a high spatio-temporal variability on wetland communities and ecosystem processes that are by far more variable than in lakes (Mitsch & Gosselink, 2001;Wetzel, 2001).…”

“…This could translate in an even higher spatiotemporal variability of PP in fluctuating floodplains. Nonetheless, in efforts to make PP measurements cost effective, experiments in wetlands are usually limited to one sampling area (Robinson & al., 1997), thereby missing out much environmental variability of the process.…”