Quaternary EnvironmentsQuaternary EnvironmentsMarine Sediments and CoralsMarine Sediments and Corals

Marine EnvironmentsMarine Environments

Cover more than 70% of the Earth’s Cover more than 70% of the Earth’s surfacesurface

Between 6-11 billion metric tons of Between 6-11 billion metric tons of sediment accumulate in the ocean basins sediment accumulate in the ocean basins annuallyannually

DefinitionsDefinitions

Planktic – Passively floating organisms Planktic – Passively floating organisms living near the surface (0-200m depth)living near the surface (0-200m depth)

Benthic – Bottom-dwelling organismsBenthic – Bottom-dwelling organismsTest – Protective coveringTest – Protective covering

CLIMAPCLIMAP

The CLIMAP Research GroupThe CLIMAP Research Group Climate: Long-range Investigation, Mapping, and Climate: Long-range Investigation, Mapping, and

prediction (CLIMAP)prediction (CLIMAP) SST and Ocean Surface ConditionsSST and Ocean Surface Conditions From 635 ocean sediment coresFrom 635 ocean sediment cores Data from faunal counts of diatoms, planktonic Data from faunal counts of diatoms, planktonic

foraminifera, coccoliths, and radiolariaforaminifera, coccoliths, and radiolaria Stratigraphy - percent fine, coarse, total carbonate, Stratigraphy - percent fine, coarse, total carbonate,

1818O and O and 1313CC Geochemistry - percent opal, quartz, and organic Geochemistry - percent opal, quartz, and organic

carboncarbon

SPECMAPSPECMAP

Spectral Mapping ProjectSpectral Mapping Project Determining the spectral characteristics of ocean Determining the spectral characteristics of ocean

sediment-based paleoclimatic recordssediment-based paleoclimatic records Establishing a basic timeframe for past climatic Establishing a basic timeframe for past climatic

eventsevents Climate times series of the past 400,000 yearsClimate times series of the past 400,000 years Based on 17 sediment cores from the Atlantic Ocean. Based on 17 sediment cores from the Atlantic Ocean. Quantitative data on planktonic species and Quantitative data on planktonic species and

assemblages which reflect conditions in the surface assemblages which reflect conditions in the surface waters of the Atlantic Oceanwaters of the Atlantic Ocean

1818O, O, 1313C difference (planktic and benthic), and Cd/Ca. C difference (planktic and benthic), and Cd/Ca.

Sedimentation in the OceanSedimentation in the Ocean

Problems With Marine SedimentsProblems With Marine Sediments

Selective dissolution of thin-walled Selective dissolution of thin-walled specimensspecimens

Transportation by ocean currentsTransportation by ocean currents Removal of easily transported speciesRemoval of easily transported species Introduction of exoticsIntroduction of exotics

These problems may make some ocean These problems may make some ocean floor sediments unsuitable for paleoclimatic floor sediments unsuitable for paleoclimatic reconstructionsreconstructions

Regions Usable for Foram StudiesRegions Usable for Foram Studies

Important OrganismsImportant Organisms

Foraminifera - ZooplanktonForaminifera - Zooplankton Coccolithophores (coccoliths) – Unicellular Coccolithophores (coccoliths) – Unicellular

algaealgae Dinoflagellate – Organic walledDinoflagellate – Organic walled Radiolarians – Siliceous zooplankton Radiolarians – Siliceous zooplankton Silicoflagallates – Siliceous Silicoflagallates – Siliceous Diatoms – Siliceous algae Diatoms – Siliceous algae

Foraminifera – Neogloboquadrina pachyderma from the North Atlantic

Foraminifera – Globigerina bulloides from the Labrador Sea

Coccolith Dinoflagellate

Centric Diatom Pennate Diatom

Paleoclimatic Inferences Paleoclimatic Inferences

Oxygen isotopic composition of CaCOOxygen isotopic composition of CaCO3 3 in foram in foram

teststests Quantitative interpretations of species Quantitative interpretations of species

assemblages and their spatial variations through assemblages and their spatial variations through timetime

Morphological variations in particular species Morphological variations in particular species resulting from environmental factorsresulting from environmental factors

Benthic Benthic 1818O record for equatorial O record for equatorial Atlantic for the past 3.2 MyaAtlantic for the past 3.2 Mya

SST Reconstructions for 18,000 yrs BPSST Reconstructions for 18,000 yrs BP

Coral Records of Past ClimateCoral Records of Past Climate

Reef-Building Massive Corals that have a Reef-Building Massive Corals that have a symbiotic relationship with algaesymbiotic relationship with algae The algae produce carbohydrates through The algae produce carbohydrates through

photosynthesis and are therefore dependent photosynthesis and are therefore dependent upon water depth, turbidity, and cloudinessupon water depth, turbidity, and cloudiness

Sectioned and x-rayed Sectioned and x-rayed High and low density bands can be High and low density bands can be

distinguished with high-density bands relating distinguished with high-density bands relating to high SSTto high SST

http://www.noaanews.noaa.gov/magazine/stories/mag95.htm

Drilling corals for paleoclimatic reconstruction.

http://www-ocean.tamu.edu/Quarterdeck/QD6.2/giese.html

Growth bands in Coral. Arrows indicate "stress bands" revealed in an x-ray of coral skeletal material caused by cold, unfavorable temperatures.

Benefits of Coral AnalysisBenefits of Coral Analysis

Tropical records that fill gaps left by other Tropical records that fill gaps left by other marine paleorecordsmarine paleorecords

Annual resolutionAnnual resolution Dating is checked with Dating is checked with 230230ThTh Possible extent back to 130,000 years BPPossible extent back to 130,000 years BP

Problems with Coral AnalysisProblems with Coral Analysis

Few records that extend past one centuryFew records that extend past one century Real extreme events may go unrecorded Real extreme events may go unrecorded

do to death of the coral colony for some do to death of the coral colony for some period of timeperiod of time

Long Coral Based Records of Past Long Coral Based Records of Past ClimateClimate