Trace element profiles of the sea anemoneAnemonia viridisliving nearby a natural CO₂vent

Abstract

Ocean acidification (OA) is not an isolated threat, but acts in concert with other impacts on ecosystems and species. Coastal marine invertebrates will have to face the synergistic interactions of OA with other global and local stressors. One local factor, common in coastal environments, is trace element contamination. CO2 vent sites are extensively studied in the context of OA and are often considered analogous to the oceans in the next few decades. The CO2 vent found at Levante Bay (Vulcano, NE Sicily, Italy) also releases high concentrations of trace elements to its surrounding seawater, and is therefore a unique site to examine the effects of long-term exposure of nearby organisms to high pCO2 and trace element enrichment in situ. The sea anemone Anemonia viridis is prevalent next to the Vulcano vent and does not show signs of trace element poisoning/stress. The aim of our study was to compare A. viridis trace element profiles and compartmentalization between high pCO2 and control environments. Rather than examining whole anemone tissue, we analyzed two different body compartments—the pedal disc and the tentacles, and also examined the distribution of trace elements in the tentacles between the animal and the symbiotic algae. We found dramatic changes in trace element tissue concentrations between the high pCO2/high trace element and control sites, with strong accumulation of iron, lead, copper and cobalt, but decreased concentrations of cadmium, zinc and arsenic proximate to the vent. The pedal disc contained substantially more trace elements than the anemone’s tentacles, suggesting the pedal disc may serve as a detoxification/storage site for excess trace elements. Within the tentacles, the various trace elements displayed different partitioning patterns between animal tissue and algal symbionts. At both sites iron was found primarily in the algae, whereas cadmium, zinc and arsenic were primarily found in the animal tissue. Our data suggests that A. viridis regulates its internal trace element concentrations by compartmentalization and excretion and that these features contribute to its resilience and potential success at the trace element-rich high pCO2 vent.

Natural high pCO2 increases autotrophy in Anemonia viridis (Anthozoa) as revealed from stable isotope (C, N) analysis

“…Here, the high MIs but same algal densities, relative to algal densities at the control site, suggest that the anemones were unable to regulate algal reproduction under the elevated p CO 2 conditions and therefore densities were likely maintained through Symbiodinium expulsion. Considering that in addition iron (Fe) is the most important trace element for algal growth 30 , Fe enrichment in the seawater near the vent site 13 31 may have also affected algal proliferation to some extent.…”

The stable microbiome of inter and sub-tidal anemone species under increasing pCO2

“…Alternatively, the presence of elevated trace elements may have influenced the bacterial community of the anemones at the vent site. Horwitz et al 26. showed there were differences in trace elements associated with the environment near the vent with higher levels of trace metals such as Fe, Mn, and Cr.…”

“…showed there were differences in trace elements associated with the environment near the vent with higher levels of trace metals such as Fe, Mn, and Cr. Additionally, Fe, Cu, Pb, Co, and Sr increased in both the pedal disk and tentacles of A. viridis when trace elements were high26. Mn, Fe, Co, Ni, Zn, Cu, and Cd are considered trace elements essential for the proper function of marine microorganisms54.…”

“…However, nitrite and silicate have shown significant differences between site 3 and the reference site location25. The vent site, in addition to having extremely low pH conditions (6.05), also contains elevated levels of trace elements, iron, and hydrogen sulfide compared with other sites further from the CO 2 vent2326. Anemone samples for the present study included ~300 μg of tentacles from three randomly selected individuals of A. viridis at each site, and ~300 μg of both tentacles and the body column from three randomly selected A. equina .…”

The Potential Use of Invasive Ascidians for Biomonitoring Heavy Metal Pollution

“…Essential trace elements, such as iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn), are vital components of enzymes and play an important role in electron transport reactions. In contrast, aluminum (Al), nickel (Ni), vanadium (V), cadmium (Cd), lead (Pb), and arsenic (As), lack any known biological role in marine invertebrates and exhibit high toxicity if allowed to accumulate in metabolically active sites (Tchounwou et al, 2012;Horwitz et al, 2014). Different invertebrates accumulate trace metals at different concentrations in their tissues, organs, and bodies.…”