Calcium carbonate alters the functional response of coastal sediments to eutrophication-induced acidification

Abstract

Coastal ocean acidification research is dominated by laboratory-based studies that cannot necessarily predict real-world ecosystem response given its complexity. We enriched coastal sediments with increasing quantities of organic matter in the field to identify the effects of eutrophication-induced acidification on benthic structure and function, and assess whether biogenic calcium carbonate (CaCO 3 ) would alter the response. Along the eutrophication gradient we observed declines in macrofauna biodiversity and impaired benthic net primary productivity and sediment nutrient cycling. CaCO 3 addition did not alter the macrofauna community response, but significantly dampened negative effects on function (e.g. net autotrophy occurred at higher levels of organic matter enrichment in +CaCO 3 treatments than −CaCO 3 (1400 vs 950 g dw m −2 )). By identifying the links between eutrophication, sediment biogeochemistry and benthic ecosystem structure and function in situ , our study represents a crucial step forward in understanding the ecological effects of coastal acidification and the role of biogenic CaCO 3 in moderating responses.

An evaluation of the efficacy of shell hash for the mitigation of intertidal sediment acidification

“…Sediments enriched with OM and other nutrients such as ammonium provide an environment for enhanced microbial activity producing high rates of OM remineralization. As noted, this, in turn, leads to increases in CO 2 in porewaters (Drylie et al, 2019) which results in lowering the pH within sediments.…”

Implications of Sediment Properties on Phosphorus Availability to the Selenastrum capricornutum in Urmia Lake Rivers

“…Drylie et al reported that CaCO 3 dampened the effects of eutrophication-induced acidification and OM enrichment in the costal sediments. [46] There is also a positive relationship between OM and the algal growth, which might represent the availability of organic P for the growth of algae, thus decreasing resilience of river systems by creating hypoxic conditions in water. [47] The P extractants were negatively correlated with pH and the correlation was strongest with 0.1 m NaOH.…”

Bioavailability of phosphorus of river sediments and its effect on growth of Selenastrum capricornutum

“…Therefore, Selenastrum capricornutum is not calcium-loving and occurs in calcareous streams with deposits of travertine and tufa. Drylie et al (2019) reported that CaCO 3 dampened the effects of eutrophication-induced acidification and OM enrichment in the costal sediments. There is also a positive relationship between OM and the algae growth, which might represent the availability of organic P for the growth of algae thus decreasing resilience of river system by creating hypoxic condition in water (Kortinger et al, 2001) The P extractants were negatively correlated with pH and the correlation was strongest with 0.1 M NaOH.…”