Thermal conductivity of sand and its effect on the temperature of loggerhead sea turtle (Caretta caretta) nests

J R Speakman, G C Hays, E Lindblad

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13 Citations (Scopus)

Abstract

The conductivity of sand at a depth of 30-50 cm was measured at 15 sites on the beach at Captiva Island in south-west Florida which is used by nesting loggerhead turtles (Caretta caretta). The mean daily temperature of the sand was correlated with conductivity at the same depth measured the same day (r=0.611). When day to day variation was removed the correlation between nest temperature and conductivity increased to 0.694. The sand was highly variable in its grain structure. The dominant variability (80.6%) was redescribed by the first two principal components of a Principal Components Analysis (PCA). These two components were influenced mostly by percentages of large (>1 mm) and small (<500 mu m) grains respectively. Conductivity was strongly correlated with the grain structure of the sand. The first three principal components describing sand grain structure, explained 84.1% of the variation in conductivity. Moisture content of the sand (always <5%) was not an important factor. Sites dominated by larger grains generally had poorer conductivity and were cooler. Comparisons of eight nests to seven adjacent random sites revealed no strong evidence for directional selection in nest placement relative to sand conductivity. The variance in conductivities recorded at nests was also not significantly different from the variance at random sites.

Original languageEnglish
Pages (from-to)1337-1352
Number of pages16
JournalJournal of the Marine Biological Association of the United Kingdom
Volume78
Publication statusPublished - 1998

Keywords

  • SITE SELECTION
  • CHELONIA-MYDAS
  • DERMOCHELYS-CORIACEA
  • SEXUAL-DIFFERENTIATION
  • PIVOTAL TEMPERATURES
  • ASCENSION ISLAND
  • SOUTH-ATLANTIC
  • BEACH
  • RATIO
  • LEATHERBACK

Cite this

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title = "Thermal conductivity of sand and its effect on the temperature of loggerhead sea turtle (Caretta caretta) nests",
abstract = "The conductivity of sand at a depth of 30-50 cm was measured at 15 sites on the beach at Captiva Island in south-west Florida which is used by nesting loggerhead turtles (Caretta caretta). The mean daily temperature of the sand was correlated with conductivity at the same depth measured the same day (r=0.611). When day to day variation was removed the correlation between nest temperature and conductivity increased to 0.694. The sand was highly variable in its grain structure. The dominant variability (80.6{\%}) was redescribed by the first two principal components of a Principal Components Analysis (PCA). These two components were influenced mostly by percentages of large (>1 mm) and small (<500 mu m) grains respectively. Conductivity was strongly correlated with the grain structure of the sand. The first three principal components describing sand grain structure, explained 84.1{\%} of the variation in conductivity. Moisture content of the sand (always <5{\%}) was not an important factor. Sites dominated by larger grains generally had poorer conductivity and were cooler. Comparisons of eight nests to seven adjacent random sites revealed no strong evidence for directional selection in nest placement relative to sand conductivity. The variance in conductivities recorded at nests was also not significantly different from the variance at random sites.",
keywords = "SITE SELECTION, CHELONIA-MYDAS, DERMOCHELYS-CORIACEA, SEXUAL-DIFFERENTIATION, PIVOTAL TEMPERATURES, ASCENSION ISLAND, SOUTH-ATLANTIC, BEACH, RATIO, LEATHERBACK",
author = "Speakman, {J R} and Hays, {G C} and E Lindblad",
year = "1998",
language = "English",
volume = "78",
pages = "1337--1352",
journal = "Journal of the Marine Biological Association of the United Kingdom",
issn = "0025-3154",
publisher = "Cambridge University Press",

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TY - JOUR

T1 - Thermal conductivity of sand and its effect on the temperature of loggerhead sea turtle (Caretta caretta) nests

AU - Speakman, J R

AU - Hays, G C

AU - Lindblad, E

PY - 1998

Y1 - 1998

N2 - The conductivity of sand at a depth of 30-50 cm was measured at 15 sites on the beach at Captiva Island in south-west Florida which is used by nesting loggerhead turtles (Caretta caretta). The mean daily temperature of the sand was correlated with conductivity at the same depth measured the same day (r=0.611). When day to day variation was removed the correlation between nest temperature and conductivity increased to 0.694. The sand was highly variable in its grain structure. The dominant variability (80.6%) was redescribed by the first two principal components of a Principal Components Analysis (PCA). These two components were influenced mostly by percentages of large (>1 mm) and small (<500 mu m) grains respectively. Conductivity was strongly correlated with the grain structure of the sand. The first three principal components describing sand grain structure, explained 84.1% of the variation in conductivity. Moisture content of the sand (always <5%) was not an important factor. Sites dominated by larger grains generally had poorer conductivity and were cooler. Comparisons of eight nests to seven adjacent random sites revealed no strong evidence for directional selection in nest placement relative to sand conductivity. The variance in conductivities recorded at nests was also not significantly different from the variance at random sites.

AB - The conductivity of sand at a depth of 30-50 cm was measured at 15 sites on the beach at Captiva Island in south-west Florida which is used by nesting loggerhead turtles (Caretta caretta). The mean daily temperature of the sand was correlated with conductivity at the same depth measured the same day (r=0.611). When day to day variation was removed the correlation between nest temperature and conductivity increased to 0.694. The sand was highly variable in its grain structure. The dominant variability (80.6%) was redescribed by the first two principal components of a Principal Components Analysis (PCA). These two components were influenced mostly by percentages of large (>1 mm) and small (<500 mu m) grains respectively. Conductivity was strongly correlated with the grain structure of the sand. The first three principal components describing sand grain structure, explained 84.1% of the variation in conductivity. Moisture content of the sand (always <5%) was not an important factor. Sites dominated by larger grains generally had poorer conductivity and were cooler. Comparisons of eight nests to seven adjacent random sites revealed no strong evidence for directional selection in nest placement relative to sand conductivity. The variance in conductivities recorded at nests was also not significantly different from the variance at random sites.

KW - SITE SELECTION

KW - CHELONIA-MYDAS

KW - DERMOCHELYS-CORIACEA

KW - SEXUAL-DIFFERENTIATION

KW - PIVOTAL TEMPERATURES

KW - ASCENSION ISLAND

KW - SOUTH-ATLANTIC

KW - BEACH

KW - RATIO

KW - LEATHERBACK

M3 - Article

VL - 78

SP - 1337

EP - 1352

JO - Journal of the Marine Biological Association of the United Kingdom

JF - Journal of the Marine Biological Association of the United Kingdom

SN - 0025-3154

ER -