The role of Ulva spp. as a temporary nutrient sink in a coastal lagoon with oyster cultivation and upwelling influence

Abstract

Bahía San Quintín is a coastal lagoon with large Ulva biomass and upwelling influence. Previous observations suggest that Ulva has increased recently as a result of oyster cultivation. To evaluate the possible role of Ulva as a temporary nutrient sink, biomass and tissue C, N, and P were determined seasonally. Maximum biomass was present during spring and early summer (1,413-1,160 t (dry)) covering about 400 ha. However, the biomass decreased to 35 t (dry) by winter. The mean annual percentage of Ulva C, N, and P was 28%, 2%, and 0.14%, respectively. This study shows that Ulva can store up to 28 t of N and 2 t of P in Bahía San Quintín during spring-summer. Ulva may be displacing the seagrass Zostera marina subtidal beds. A partial removal of the seaweed would reduce the risk of eutrophication and the displacement of eelgrass beds.

Allelopathic interactions between the HAB dinoflagellate Ostreopsis cf. ovata and macroalgae

“…Nevertheless, it has been observed in field studies that microalgae are sometimes suppressed by macroalgae at high nutrient availability (Smith and Horne, 1988; Sfriso et al, 1989;Sfriso and Pavoni, 1994). Although a high rate of nutrient uptake has been reported particularly for Ulva species (see e.g., Zertuche-Gonzá lez et al, 2009;Luo et al, 2012), we excluded the hypothesis that the inhibitory effect observed in the co-culture experiments was due to nutrient competition, as nutrient levels in both D. dichotoma and U. rigida co-cultures showed values comparable to those of the control and even higher than those in co-cultures of R. pseudopalmata where no inhibition was observed. Changing in pH in surrounding medium due to macroalgae growth is a common event, as high rates of photosynthesis may drawdown CO 2 , increasing pH levels and making the environment unsuitable for microalgal growth (Goldman et al, 1982;Taraldsvik and Myklestad, 2000).…”

Harmful algal blooms along the North American west coast region: History, trends, causes, and impacts

“…; Jousson et al, 2000;Walters et al, 2006), and Baja California (Ulva spp. ; Jorgensen et al, 2010;Zertuche-Gonzá lez et al, 2009) that have displaced native algal species and modified habitat, leading to losses in living resources and economic costs for eradication.…”

The green macroalga, Ulva lactuca, inhibits the growth of seven common harmful algal bloom species via allelopathy

“…Macroalgae are known to display an enormous capacity for the assimilation of nutrients (Valiela et al, 1997;Neori et al, 2004;Zertuche-Gonzá lez et al, 2009) and are purposefully used in many parts of the world to reduce nutrients levels in coastal waters (Neori et al, 2004;Carmona et al, 2006;Chopin et al, 2001Chopin et al, , 2008. Given that many HABs are directly or indirectly promoted by nutrients (Heisler et al, 2008;Anderson et al, 2008), macroalgae may reduce the occurrence of HABs by reducing the levels of nutrients available in the water column.…”

“…Another group of autotrophs promoted by eutrophication in coastal ecosystems is macroalgae (Valiela et al, 1997;Valiela and Cole, 2002;Valiela, 2006). Many species of macroalgae are capable of rapid growth in the presence of high nutrient concentration and have a high assimilative capacity for nutrients thus act as nutrient sinks (Valiela et al, 1997;Neori et al, 2004;Zertuche-Gonzá lez et al, 2009). Like HABs, the overgrowth of macroalgae can be also considered harmful, as they can outcompete and replace seagrass beds, cover other critical benthic habitats, and promote diel hypoxia in estuaries (Valiela et al, 1997;Valiela and Cole, 2002;Valiela, 2006;Liu et al, 2009).…”