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Exoskeletons are central to the physiology and survival of marine invertebrates, but future increases in the temperature and p CO 2 of the marine environment may alter the biomineralization processes involved in their formation. Thus, it is important to consider the impacts of a changing climate on the functionality of invertebrate exoskeletons. In this study, juvenile blue crab, Callinectes sapidus , from the Chesapeake Bay were exposed to increased temperature and p CO 2 in a 2 × 2 factorial design for a period of two molts (approximately 30 days). Treatment levels were chosen to represent current (26 °C and 800 μatm CO 2 ) and predicted future conditions in the year 2100 (32 °C and 8000 μatm CO 2 ) in the Chesapeake Bay. Thickness was determined by light microscopy and carapace calcium (Ca) and magnesium (Mg) content were determined by Inductively Coupled Plasma – Atomic Emission Spectrometry. All Ca and Mg in the carapace were assumed to be present in the form of high‑magnesium calcite (HMC). Increased temperature decreased the thickness of juvenile blue crab carapaces by 8.5% and significantly reduced weight percent HMC by 2.0% ( P < 0.05). Increased p CO 2 significantly increased weight percent HMC by 2.0% but a significant increase in Mg content was also found. The observed counteractive effects of temperature and p CO 2 on weight percent HMC underscore the importance of assessing such interactions in studies that quantify the impacts of multiple environmental stressors. Combined with new data regarding the influence of increased temperature and p CO 2 on blue crab growth, the results of this study indicate tradeoffs between carapace thickness and chemistry with growth in juvenile blue crab exposed to future warming. [ABSTRACT FROM AUTHOR]

Buscou-se, com este estudo, estimar, através do uso da cokrigagem, valores de cálcio e magnésio, utilizando como co-variável valores de pH. Em um Latossolo Vermelho Distroférrico, amostrou-se a camada de 0-0,2 m, utilizando grade de 25 x 25 m, totalizando 60 pontos em 5,02 ha. Realizou-se, inicialmente, análise descritiva e de correlação e, posteriormente, análise geoestatística, para identificar a dependência espacial das variáveis estudadas. Utilizando a técnica da cokrigagem, os valores de pH mostraram-se eficientes na estimativa de teores de Ca e Mg, devido a elevada correlação entre esta co-variável e as variáveis a serem estimadas.Sought, with this study, estimating, through the use of cokriging, values of calcium and magnesium, using as covariate pH. In a Rhodic Hapludox, sampled the layer of 0-0.2 m, using the grid of 25 x 25 m, totaling 60 points from 5.02 ha. Was held, initially, descriptive analysis and correlation, and subsequently, geostatistical analysis to identify the spatial dependence of variables. Using the technique of cokriging pH values were efficient in the estimation of Ca and Mg, due to the high correlation between this covariate and the variables to be estimated.

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