server.R

# This is the server logic for a Shiny web application.
# You can find out more about building applications with Shiny here:
#
# http://shiny.rstudio.com
#

library(plotrix)
library(seacarb)
library(shiny)

shinyServer(function(input, output) {
  DIC <- reactive({
    carb(21, input$pco2, input$pH, S = input$salinity, T = input$temp, k1k2 = input$k1k2)
  })
  output$DIC.forms <- renderUI({
    HTML(paste0(
      "Dissolved <b>CO<sub>2</sub></b> concentration is <b>",
      round(DIC()$CO2 * 1e6, digits = 1),
      " &mu;mol/kg</b> [",
      round(DIC()$CO2 / DIC()$DIC * 100, digits = 1),
      "%, ",
      round(DIC()$CO2 * 12.01 * 1000, digits = 1), # 44.01 g/mol
      " mg(C)/kg(H<sub>2</sub>O)] <br/>",
      "<i>Bicarbonate</i> (<b>HCO<sub>3</sub><sup>-</sup></b>) concentration is <b>",
      round(DIC()$HCO3 * 1e6, digits = 1),
      " &mu;mol/kg</b> [",
      round(DIC()$HCO3 / DIC()$DIC * 100, digits = 1),
      "%, ",
      round(DIC()$HCO3 * 12.01 * 1000, digits = 1), # 61.02 g/mol
      " mg(C)/kg(H<sub>2</sub>O)] <br/>",
      "<i>Carbonate</i> (<b>CO<sub>3</sub><sup>2-</sup></b>) concentration is <b>",
      round(DIC()$CO3 * 1e6, digits = 1),
      " &mu;mol/kg</b> [",
      round(DIC()$CO3 / DIC()$DIC * 100, digits = 1),
      "%, ",
      round(DIC()$CO3 * 12.01 * 1000, digits = 1), # 60.01 g/mol
      " mg(C)/kg(H<sub>2</sub>O)] <br/>",
      "Total dissolved inorganic carbon (<b>DIC</b>) concentration is <b>",
      round(DIC()$DIC * 1e6, digits = 1),
      " &mu;mol/kg</b>"
    ))
  })
  output$DIC.plot <- renderPlot({
    carb.data <- data.frame(dCO2 = 0, HCO3 = 0, CO3 = 0, DIC = 0)
    pH <- seq(2, 12, 1/3)
    carb.data <- carb(21, input$pco2, pH, S = input$salinity, T = input$temp, k1k2 = input$k1k2)[c("CO2","HCO3","CO3","DIC")]
    y <- log10(carb.data$DIC)
    twoord.plot(
      lx = pH,
      ly = carb.data$CO2 / carb.data$DIC,
      rx = pH,
      ry = y,
      xlab = "pH",
      ylab = "Relative distribution of DIC forms, -",
      rylab = expression("log"[10]*"(Total DIC), "*mu*"mol/kg"),
      rpch = 1
    )
    lines(pH, carb.data$HCO3 / carb.data$DIC, lty = 2)
    lines(pH, carb.data$CO3 / carb.data$DIC, lty = 3)
    legend(2, 0.6, c(expression("dCO"[2]), expression("HCO"[3]^"-"), expression("CO"[3]^"2-")), lty = c(1, 2, 3))
  })
})