Host-influenced geochemical signature in the parasitic foraminifera <i>Hyrrokkin sarcophaga</i>

Abstract

Abstract. Hyrrokkin sarcophaga is a parasitic foraminifera that is commonly found in cold-water coral reefs where it infests the file clam Acesta excavata and the scleractinian coral Desmophyllum pertusum (formerly known as Lophelia pertusa). Here, we present measurements of the trace element and isotopic composition of these parasitic foraminifera, analyzed by inductively coupled optical emission spectrometry (ICP-OES), electron probe microanalysis (EPMA) and mass spectrometry (gas-source MS and inductively-coupled-plasma MS). Our results reveal that the geochemical signature of H. sarcophaga depends on the host organism it infests. Sr / Ca ratios are 1.1 mmol mol−1 higher in H. sarcophaga that infest D. pertusum, which could be an indication that dissolved host carbonate material is utilized in shell calcification, given that the aragonite of D. pertusum has a naturally higher Sr concentration compared to the calcite of A. excavata. Similarly, we measure 3.1 ‰ lower δ13C and 0.25 ‰ lower δ18O values in H. sarcophaga that lived on D. pertusum, which might be caused by the direct uptake of the host's carbonate material with a more negative isotopic composition or different pH regimes in these foraminifera (pH can exert a control on the extent of CO2 hydration/hydroxylation) due to the uptake of body fluids of the host. We also observe higher Mn / Ca ratios in foraminifera that lived on A. excavata but did not penetrate the host shell compared to specimen that penetrated the shell, which could be interpreted as a change in food source, changes in the calcification rate, Rayleigh fractionation or changing oxygen conditions. While our measurements provide an interesting insight into the calcification process of this unusual foraminifera, these data also indicate that the geochemistry of this parasitic foraminifera is unlikely to be a reliable indicator of paleoenvironmental conditions using Sr / Ca, Mn / Ca, δ18O or δ13C unless the host organism is known and its geochemical composition can be accounted for.

Quantifying Sub‐Seasonal Growth Rate Changes in Fossil Giant Clams Using Wavelet Transformation of Daily Mg/Ca Cycles

“…Macroscopically visible darker seasonal bands and thus areas with low growth rates coincide with higher Mg/Ca, as has previously been shown in other mollusks (e.g., Lorens & Bender, 1977;Schleinkofer et al, 2021). Here, we demonstrate one advantage of deriving a continuous growth rate model by testing whether Mg/Ca and other elemental ratios correlate with the growth rates determined (Figure 7).…”

“…This might be due to the impact of reduced growth during the night, characterized by elevated Mg/Ca values, and vice versa (cf., Warter et al., 2018). In bivalves, reduced growth and elevated Mg/Ca values can also be coupled to a relative increase in organic content (Schleinkofer et al., 2021).…”

Interações entre eucariontes unicelulares e Porifera: função fisiológica e aplicações biotecnológicas de Labyrinthulomycetes associados

“…In a survey of the Faroe Islands archipelago, these protists were found in the pinacoderm of all studied sponges of the family Geodiidae (Klitgaard, 1995). The most common species were Cibicides refulgens and Hyrrokkin sarcophaga, the latter described as a parasite of corals and bivalves (Schleinkofer et al 2021). Histological approaches have shown that in the sponges Isops phlegraei (now accepted as Geodia phlegraei) and Stelleta normani, the foraminifera H. sarcophaga can dissolve part of the cortex of the animal (Cedhagen, 1994).…”