Impacts of Seagrass on Benthic Microalgae and Phytoplankton Communities in an Experimentally Warmed Coral Reef Mesocosm

Abstract

The effects of seagrass on microalgal assemblages under experimentally elevated temperatures (28°C) and CO2 partial pressures (pCO2; 800 μatm) were examined using coral reef mesocosms. Concentrations of nitrate, ammonium, and benthic microalgal chlorophyll a (chl-a) were significantly higher in seagrass mesocosms, whereas phytoplankton chl-a concentrations were similar between seagrass and seagrass-free control mesocosms. In the seagrass group, fewer parasitic dinoflagellate OTUs (e.g., Syndiniales) were found in the benthic microalgal community though more symbiotic dinoflagellates (e.g., Cladocopium spp.) were quantified in the phytoplankton community. Our results suggest that, under ocean acidification conditions, the presence of seagrass nearby coral reefs may (1) enhance benthic primary productivity, (2) decrease parasitic dinoflagellate abundance, and (3) possibly increase the presence of symbiotic dinoflagellates.

Carbon Transfer Processes of Food Web and Trophic Pathways in a Tropical Eutrophic Seagrass Meadow

“…Seagrass meadows are highly complex and productive marine ecological systems that provide numerous ecological services. They not only provide spawning grounds (Jiang et al, 2020), nursery regions (Madi Moussa et al, 2020), habitat, and predation refuge areas for abundant fish, crabs, and other invertebrates (Barry et al, 2021;Tew et al, 2021), but they also provide nutrients and energy sources for the food web of the ecosystem (Park et al, 2013). Seagrass is not the only carbon source of this food web, which may also include significant contributions from other carbon sources, such as macroalgae, epiphyte, phytoplankton, and sediment microphytobenthos (Ouisse et al, 2012).…”

Data_Sheet_1.docx

“…Seagrass meadows are highly complex and productive marine ecological systems that provide numerous ecological services. They not only provide spawning grounds (Jiang et al, 2020), nursery regions (Madi Moussa et al, 2020), habitat, and predation refuge areas for abundant fish, crabs, and other invertebrates (Barry et al, 2021;Tew et al, 2021), but they also provide nutrients and energy sources for the food web of the ecosystem (Park et al, 2013). Seagrass is not the only carbon source of this food web, which may also include significant contributions from other carbon sources, such as macroalgae, epiphyte, phytoplankton, and sediment microphytobenthos (Ouisse et al, 2012).…”

Table_4.docx

“…Seagrass meadows are highly complex and productive marine ecological systems that provide numerous ecological services. They not only provide spawning grounds (Jiang et al, 2020), nursery regions (Madi Moussa et al, 2020), habitat, and predation refuge areas for abundant fish, crabs, and other invertebrates (Barry et al, 2021;Tew et al, 2021), but they also provide nutrients and energy sources for the food web of the ecosystem (Park et al, 2013). Seagrass is not the only carbon source of this food web, which may also include significant contributions from other carbon sources, such as macroalgae, epiphyte, phytoplankton, and sediment microphytobenthos (Ouisse et al, 2012).…”