Standing stock variations, growth and CaCO₃ production by the calcareous green alga Halimeda opuntia

Abstract

The present paper investigates standing stock variations of Halimeda opuntia on a sandstone reef of the South-west Atlantic Ocean, in order to better understand the role of this seaweed as a CaCO3 producer. The study was conducted over two 3-month periods, using photo quadrats to analyse the coverage area, and destructive sampling to quantify area-specific biomass and CaCO3 percentage. The alga occupied 2.4% of the substrate (4464 m2), growing as clumps with an average biomass of 1.59 kg m−2, resulting in a standing stock of 7097.8 kg of alga. This standing stock varied with environmental conditions, particularly wind speed. Assuming an exponential model for these variations, H. opuntia produced at least 13,050.14 kg (54.37 g m−2 day−1) of carbonate sediments. There was a positive correlation between changes in standing stock and coverage, but not with area-specific biomass. This suggests that net algal growth results in the occupation of new spaces, with minimal increases in height or segment density. Therefore monitoring coverage should complement traditional individual-based methods for estimating Halimeda growth and production. Combined, these approaches should result in more accurate models of the role of this alga on marine carbonate budgets.

Calcium carbonate productivity by Halimeda macroloba in the tropical intertidal ecosystem: The significant contributor to global carbonate budgets

“…Recently, Carneiro et al . () showed that Halimeda opuntia can produce at least 13 050.14 kg or 54.37 g m −2 day −1 . Halimeda can also contribute to carbonate sediments with a wide range of sediment grain‐size fractions from coarse sand to silt and clay size (Drew ; Drew & Abel ; Perry et al .…”

“…), H. opuntia in the tropical South‐west Atlantic Ocean (Carneiro et al . ) and H. macroloba in Thai waters (Sinutok et al . ; Mayakun ; Mayakun et al .…”

Lipid, fatty acid composition and molecular species of betaine lipid in the green algae Halimeda incrassata Lamx. collected from Truong Sa archipelago

“…[1] This is a rare marine plants that CaCO3 is synthesized in the tissues (around 35-45 %) at the speed as same as reefs'one. [2] Halimeda incrassata is a potential resource of compounds with a number of valuable bioactivities such as antibacterial, antiinflammation. [3,4] Along with natural products from marine organism, lipid is increasingly recognized because of its positive effects on bones, cardiovascular and nervous system.…”

The standing stock and CaCO3 contribution of Halimeda macroloba in the tropical seagrass-dominated ecosystem in Dongsha Island, the main island of Dongsha Atoll, South China Sea

“…It can utilize bicarbonate (HCO 3 − ) for calcification and precipitates aragonite crystals in its intercellular spaces (Borowitzka & Larkum, 1976). It is one of the main calcium carbonate (CaCO 3 ) producers that contribute to the marine carbonate budget in tropical reefs and lagoons (Ree et al ., 2007; Mayakun et al ., 2014; Carneiro & Morais, 2016; Kaewsrikhaw et al ., 2016; McNeil et al ., 2016; Perry et al ., 2016; Carneiro et al ., 2018; Prathep et al ., 2018; Mayakun & Prathep, 2019). For instance, global estimates showed that Halimeda species contributed around 2 kg CaCO 3 m −2 year −1 (Drew & Abel, 1985; van Tussenbroek & van Dijk, 2007; Perry et al ., 2016) or accumulated around 0.15 Gt CaCO 3 year −1 (Milliman, 1993), resulting in ~8% of total world carbonate production (Hillis, 1997).…”

“…For instance, global estimates showed that Halimeda species contributed around 2 kg CaCO 3 m −2 year −1 (Drew & Abel, 1985; van Tussenbroek & van Dijk, 2007; Perry et al ., 2016) or accumulated around 0.15 Gt CaCO 3 year −1 (Milliman, 1993), resulting in ~8% of total world carbonate production (Hillis, 1997). When only tropical reefs are considered, Halimeda can produce ~54.37 g m −2 year −1 of carbonate sediments (Carneiro et al ., 2018), equivalent to at least 13,050.14 kg year −1 or around 42% of total sedimentary organic carbon (Tuntiprapas et al ., 2019). Studies have shown that the carbonate production of Halimeda can vary due to abiotic and biotic factors.…”