Carbonate mineralogy of a tropical bryozoan biota and its vulnerability to ocean acidification

Abstract

Decreasing pH levels in the world's oceans are widely recognized as a threat to marine life. Bryozoans are among several phyla that produce calcium carbonate skeletons potentially affected by ocean acidification (OA). Depending on species, bryozoan skeletons can consist of calcite, aragonite or have a bimineralic combination of these two minerals. Aragonite is generally more soluble in seawater than calcite, making aragonitic species more vulnerable to OA. Here, for the first time we use Raman spectroscopy to determine the mineral composition of a tropical bryozoan biota. Compared with bryozoan biotas from higher latitudes in which calcite predominates, aragonite was found to occur in a much higher proportion of the 22 cheilostome bryozoan species collected from the shorelines of Penang and Langkawi in Malaysia, where 46% of species are calcitic, 41% aragonitic and 13% bimineralic. All but one of the aragonitic or bimineralic species belong to the ascophorans, whereas calcitic skeletons characterized most of the anascans, many of which are primitive 'weedy' malacostegines. These results suggest a relatively high vulnerability of tropical bryozoan faunas to OA, with the weedier taxa likely to be least impacted. ARTICLE HISTORY

Skeletal carbonate mineralogy of Scottish bryozoans

“…The main environmental control usually discussed is temperature [ 14 , 15 , 20 , 29 , 80 , 90 ], with higher temperatures reported to drive higher Mg-calcite and aragonite deposition. Other environmental factors which have also been shown to influence mineralogy include salinity [ 47 ], depth [ 40 , 61 ], aragonite compensation depth (ACD) [ 91 ], Mg/Ca ratio in seawater [ 80 , 81 , 88 , 90 , 92 ] and general seawater chemistry [ 29 , 87 ]. Many of these environmental factors, such as temperature, salinity, Mg/Ca ratio and ACD vary with latitude and have resulted in reported correlations between latitude and skeleton mineralogy [ 20 , 43 , 93 ].…”

“…The majority are of limited use due to the very low specimen numbers analysed (e.g. South Africa [ 36 ], Hawaii [ 37 ], Talbot Shoal [ 38 ], Naples [ 39 ], Malaysia [ 40 ]). There have, however, also been a handful of studies where the coverage of regional bryozoans has been great enough to draw meaningful conclusions.…”

Temperature as a likely driver shaping global patterns in mineralogical composition in bryozoans: Implications for marine calcifiers under Global Change

“…In recent years significant efforts have been put into increasing data on skeletal mineralogy in a wide range of bryozoan species from Arctic (Iglikowska et al, 2020;Krzemińska et al, 2022;Piwoni-Piórewicz et al, 2019), temperate (e.g., Loxton et al, 2014b;Smith and Clark, 2010;Steger and Smith, 2005), tropical (Taylor et al, 2016;Taylor & Di Martino, 2014), and Antarctic (Figuerola et al, 2015(Figuerola et al, , 2019Krzeminska et al, 2016;Loxton et al, 2013;Loxton, Kuklinski, Barnes, et al, 2014) regions. However, several reviews have pointed out that mineralogy is known only for a small proportion of living species at all latitudes (Smith et al, 2006;Taylor et al, 2009).…”

“…The mineralogical studies have persisted and proliferated even to today (e.g., Bone and James, 1993; Borisenko and Gontar, 1991; Smith et al, 1998). In recent years significant efforts have been put into increasing data on skeletal mineralogy in a wide range of bryozoan species from Arctic (Iglikowska et al, 2020; Krzemińska et al, 2022; Kuklinski & Taylor, 2009; Piwoni-Piórewicz et al, 2019), temperate (e.g., Loxton et al, 2014b; Smith and Clark, 2010; Steger and Smith, 2005), tropical (Taylor et al, 2016; Taylor & Di Martino, 2014), and Antarctic (Figuerola et al, 2015, 2019; Krzeminska et al, 2016; Loxton et al, 2013; Loxton, Kuklinski, Barnes, et al, 2014) regions. However, several reviews have pointed out that mineralogy is known only for a small proportion of living species at all latitudes (Smith et al, 2006; Taylor et al, 2009).…”

Polymorphism ofCaCO3and the variability of elemental composition of the calcareous skeletons secreted by invertebrates along the salinity gradient of the Baltic Sea

“…Extended periods of aragonite undersaturation in the Baltic Sea do not eliminate aragonite production, which means that structural properties of skeletons are affected to a greater extent by biological rather than environmental parameters, and biological factors can affect the way in which environmental parameters are influencing the formation of the calcareous skeletons(Ballesta-Artero et al, 2018;Vander Putten et al, 2000). Instead, the mineralogical composition of the studied taxa is in line with their mineralogy recorded in different regions of the ocean, regardless of the prevailing environmental conditions(Krzeminska et al, 2016;Kuklinski & Taylor, 2009;Lombardi et al, 2008;Taylor et al, 2016). For example, the studied bryozoans Einhornia crustulenta, CryptosulaF I G U R E 6 Partition coefficients (D) of Mg, Na, and Sr along the salinity gradient.…”