Using elemental ratios of calcium and strontium to track calcium availability in the freshwater zooplankton <i>Daphnia pulicaria</i>

Peters, Stephen C.; Lockwood, Ryan S.; Williamson, Craig E.; Saros, Jasmine E.

doi:10.1029/2008jg000782

Cited by 5 publications

(4 citation statements)

References 55 publications

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“…For example, daphnids contain up to 8% calcium by dry mass and uptake this element directly from water, but its availability and assimilation could be deregulated by the presence of similar ions like Sr 2+ due to their relatively poor discrimination between these ions (e.g. Peters et al ., 2008). Thus, there may be additional eco(toxico)logical effects that accompany the intrusion of paleoseawaters, and the measures that aim to protect these ecosystems must take this into account.…”

Section: Discussionmentioning

confidence: 99%

Seawater intrusion: an appraisal of taxa at most risk and safe salinity levels

2021

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Seawater intrusion into low‐lying coastal ecosystems carries environmental risks. Salinity levels at these coastal ecosystems may vary substantially, causing ecological effects from mortality to several sublethal endpoints, such as depression of rates of feeding, somatic growth, or reproduction. This review attempts to establish safe salinity levels for both terrestrial and freshwater temperate ecosystems by integrating data available in the literature. We have four specific objectives: (i) to identify the most sensitive ecological taxa to seawater intrusion; (ii) to establish maximum acceptable concentrations–environmental quality standards (MAC‐EQSs) for sea water (SW) from species sensitivity distributions (SSDs); (iii) to compile from the literature examples of saline intrusion [to be used as predicted environmental concentrations (PECs)] and to compute risk quotients for the temperate zone; and (iv) to assess whether sodium chloride (NaCl) is an appropriate surrogate for SW in ecological risk assessments by comparing SSD‐derived values for NaCl and SW and by comparing these with field data. Zooplankton, early life stages of amphibians and freshwater mussels were the most sensitive ecological receptors for the freshwater compartment, while soil invertebrates were the most sensitive ecological receptors for the terrestrial compartment. Hazard concentration 5% (HC5) values, defined as the concentration (herein measured as conductivity) that affects (causes lethal or sublethal effects) 5% of the species in a distribution, computed for SW were over 22 and 40 times lower than the conductivity of natural SW (≈ 52 mS/cm) for the freshwater and soil compartment, respectively. This sensitivity of both compartments means that small increments in salinity levels or small SW intrusions might represent severe risks for low‐lying coastal ecosystems. Furthermore, the proximity between HC5 values for the soil and freshwater compartments suggests that salinized soils might represent an additional risk for nearby freshwater systems. This sensitivity was corroborated by the derivation of risk quotients using real saline intrusion examples (PECs) collected from the literature: risk was >1 in 34 out of 37 examples. By contrast, comparisons of HC5 values obtained from SSDs in field surveys or mesocosm studies suggest that natural communities are more resilient to salinization than expected. Finally, NaCl was found to be slightly more toxic than SW, at both lethal and sublethal levels, and, thus, is suggested to be an acceptable surrogate for use in risk assessment.

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Section: Discussionmentioning

confidence: 99%

Seawater intrusion: an appraisal of taxa at most risk and safe salinity levels

2021

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“…Adequate Ca is essential for proper carapace development; however, as the moulting rate is independent of both Ca and food concentrations, the impacts of low Ca are greatest during the juvenile stages of development due to their rapid growth Rukke 2002a), and in low Ca environments mothers must provide Ca to developing young at the expense of their own growth (Giardini et al 2015; Pérez-Fuentetaja and Goodberry 2016). At low Ca concentrations, the Ca uptake mechanisms of D. pulicaria become less efficient at discriminating between Ca and elemental analogues such as strontium (Peters et al 2008), while Ca concentrations <1.5 mg L -1 negatively impact the growth, reproduction and survival of D. pulex (a daphniid common in ponds on the Precambrian Shield) under laboratory conditions (Ashforth and Yan 2008). Outside of the laboratory, the negative impacts of low Ca availability are likely to be more pronounced due to the impacts on anti-predator defences, reducing body size and carapace strength, while also impeding the production of neck spines (Riessen et al 2012).…”

Section: Ca Decline and The Cladoceramentioning

confidence: 99%

The ecological impacts of lakewater calcium decline on softwater boreal ecosystems

Jeziorski

Smol

2017

Environ. Rev.

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In recent decades, marked declines in calcium (Ca) concentrations have been noted in many softwater boreal lakes, and are believed to be a long-term consequence of acid deposition as well as other stressors (such as timber harvesting). Reduced Ca availability may act as a potent environmental stressor. Investigations of the direct ecological impacts of lower Ca concentrations in freshwater systems have largely focused on Ca-rich members of the Cladocera; however, a growing body of work, spanning several scientific fields, suggests Ca decline will have profound direct and indirect consequences for aquatic ecosystems. Here, we synthesize recent laboratory analyses and field surveys to provide an overview of these consequences, while highlighting paleolimnological investigations that provide some long-term perspective on the phenomenon. However, considerable questions remain regarding ‘baseline’ or pre-impact conditions, due to the accelerated leaching of Ca from watershed soils during the period of anthropogenic influence. Furthermore, catchment-specific differences in both leaching rates and the initial size of the Ca pool in watershed soils complicate determination of the eventual endpoints of the declines. Despite these uncertainties, persistent low Ca concentrations are anticipated to impede biological recovery from lake acidification, and that ongoing declines will have cascading effects throughout aquatic ecosystems due to the loss of vulnerable taxa. To better understand how reduced Ca availability will continue to change affected surface waters and how these changes will interact with other environmental stressors will require continued investigation of the declines from multiple scientific perspectives.

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“…29 The Sr to Ca ratios in corals, carbonate minerals and rocks were used as indicators of the sea surface temperature by several researchers. [30][31][32][33] The rm relationship between the Sr to Ca ratio in the diet and that absorbed in the bones of consumers was established previously. 34 The incorporation of Sr in bone is reported to vary, not with dietary Sr levels, but with the ratio of Ca to Sr. 35 Although both elements are amenable to XRF, none of the above-mentioned studies utilized this technique for quantication.…”

Section: Introductionmentioning

confidence: 99%