11th ICRS Abstract book - Nova Southeastern University

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The Effects Of Geology, Oceanography And Anthropogenic Activities On The Coral
Reef Ecosystems Of The Pacific Remote Island Areas
Joyce MILLER* 1,2 , Jamison GOVE 1,2
1 NOAA PIFSC Coral Reef Ecosystem Division, Honolulu, HI, 2 Joint Institute for Marine
and Atmospheric Research -- Research Corp. Univ. of Hawaii, Honolulu
A wealth of geologic, oceanographic, and biological data collected since 2000 provides a
unique opportunity to understand the coral reef ecosystems of the Pacific Remote Island
Areas (PRIA). These data were collected by the National Oceanic and Atmospheric
Administration and the U.S. Fish and Wildlife Service (FWS) during biennial cruises to
seven PRIA: Howland, Baker, and Jarvis Islands, Kingman Reef, and Palmyra, Johnston
and Wake Atolls. Detailed bathymetric maps show seven tiny, isolated peaks on
anomalously shallow seafloor ranging in age from 120 to 83 Ma, but the four islands that
have been dated were all formed about 70 Ma. Small submerged terraces from previous
sea level stands can also be detected, providing insight into how sea level change may
affect the PRIA in the future. From an oceanographic perspective, these islands and
atolls are located in three distinct current regimes, providing an understanding of how
current patterns affect the distribution and types of organisms found at each location.
Oceanographic data also provide baseline information for understanding the effects of
climate change, storms, and bleaching events. Although most of the islands are FWS
National Wildlife Refuges and are currently uninhabited, anthropogenic effects from
previous guano mining, military and construction activities, fishing, and shipwrecks also
have recognizable impacts. Combining this information with biological data on the
corals, algae, fish, and macroinvertebrates of the PRIA shows complex interactions that
all influence the health of what are thought to be some of the least disturbed coral reef
ecosystems in the world.
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Long-Term Records Of Reef Growth Under Terrigenoclastic Sediment Influence:
Paluma Shoals, Central Great Barrier Reef, Australia
Suzanne E PALMER* 1 , Chris T PERRY 2 , Scott G SMITHERS 3
1 Environmental & Geographical Sciences, Manchester Metorpolitan University,
Manchester, United Kingdom, 2 Environmental & Geographical Sciences, Manchester
Metropolitan University, Manchester, United Kingdom, 3 Earth and Environmental
Sciences, James Cook University, Townsville, Australia
Nearshore, turbid-zone reefs on the Great Barrier Reef (GBR) grow on the
terrigenoclastic inner shelf and represent important analogues for understanding earlymid
Holocene reef initiation on the GBR. They are recognised as ecologically and
geologically significant, but knowledge of their development remains limited. The
growth history of Paluma Shoals (Halifax Bay, north of Townsville) has been studied in
detail to improve our understanding of inshore reef development. Paluma Shoals
comprises two areas of active reef development. The reef structure displays distinct
phases of reef initiation, reef accretion and reef ‘turn-off’, and the depositional sequence
suggests 1) evidence for long-term reef accretion in association with terrigenoclastic
sediment accumulation, and 2) phases of reef initiation, growth and burial influenced by
nearshore sediment dynamics.
Reef growth began ~1200 cal years BP over coarse-grained, terrigenoclastic-dominated
subtidal sands and/or Pleistocene clays. The reef sequence is up to 2.0-2.5m thick,
comprising an unconsolidated framework of coral rubble within a terrigenoclasticcarbonate
matrix. In situ massive corals (Goniopora stokesi, Favites halicora) within
basal units are interpreted as shallow pioneer coral communities (the ‘reef initiation’
phase), now enveloped in mainly terrigenoclastic silts. Later reef growth was dominated
by framework builders Acropora pulchra, Turbinaria frondens and Montipora mollis,
infilled with fine- to medium-grained sands. Reef growth has been characterised by
vertical accretion and then seaward progradation, followed by accumulation landward.
Since ~250 years BP reef growth of the South Shoal exhibits little variation in framework
builders and is characterised by well-established intertidal coral communities and
carbonate-rich sands. In contrast, the Northern Shoal exhibits an increase of terrigenous
sands, interpreted as a ‘turn-off’ phase in reef development driven by natural shoreline
dynamics.
Oral Mini-Symposium 1: Lessons From the Past
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Persistent Organic Pollutants And Trace Metals Associated With African Dust – Is There
A Threat To Coral Reefs?
Virginia GARRISON* 1 , Susan GENUALDI 2 , William FOREMAN 3 , Michael MAJEWSKI 4 ,
Azad MOHAMMED 5 , Staci SIMONICH 2
1 US Geological Survey, St. Petersburg, FL, 2 Oregon State University, Corvallis, OR, 3 US
Geological Survey, Denver, CO, 4 US Geological Survey, Sacramento, CA, 5 University of the
West Indies, St. Augustine, Trinidad and Tobago
Increasing quantities of African dust transit the Atlantic and impact the Caribbean and
Americas. As part of an investigation into the effects of African dust on coral reef organisms
and human health, we analyzed African dust for contaminants and compared levels of persistent
organic pollutants (POPs) and metals between the source and downwind regions. Air samples
from Africa (Mali) were found to contain a greater variety and a higher concentration of
pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs)
than downwind sites in the Caribbean (Trinidad and the U.S. Virgin Islands). To date, nine
pesticides, 17 PAHs, and nine PCB congeners have been identified in air samples from the
African Sahara/Sahel (Mali) and the Caribbean. One pesticide and four PAHs were detected
only in samples from Africa. Of the more than 100 priority pollutant and common-use
pesticides screened for in the samples, five pesticides (chlorpyrifos, dacthal, endosulfan I,
hexachlorobenzene, and components of chlordane) were detected in samples from all sites.
DDE (a breakdown product of DDT) was identified in Mali, USVI, and Trinidad samples. To
date, DDT and chlorinated dioxins and furans have been detected only in samples from Mali.
Eight and five PCB congeners were detected in Mali and Caribbean samples, respectively; of
those, four congeners were detected in samples from both regions. Similarly, greater numbers of
PAHs were detected in Mali than at downwind sites. Trace-metal concentrations in both regions
were similar to crustal composition with slight enrichment of lead in Mali. Many of the
identified POPs and metals are toxic to corals and other marine organisms and can interfere
with reproduction, fertilization, and/or immune function. POP and metal contaminants
commonly occur as mixtures that are likely to exhibit synergistic effects. Contaminant
concentrations are sufficiently high to be of concern – for both marine organisms and humans.
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Bioturbation, Taphonomic Bias And Time-Averaging in Tropical Molluscan Death
Assemblages: Differential Shell Half-Lives in Great Barrier Reef Sediment
Matthew A. KOSNIK* 1 , Quan HUA 2,3 , Darrell S. KAUFMAN 4 , Raphael A. WÜST 5
1 Department of Paleobiology, Smithsonian Institution, Washington, DC, 2 Australian Nuclear
Science and Technology Organization, Menai, NSW, Australia, 3 Australian Nuclear Science
and Technology Organization, Menai, Australia, 4 Department of Geology, Northern Arizona
University, Flagstaff, AZ, 5 School of Earth and Environmental Sciences, James Cook
University, Townsville, Australia
Radiocarbon-calibrated amino acid racemization ages of 481 individually dated shells
representing four molluscan taxa are used to quantify time-averaging and shell half-lives with
increasing burial depth in the shallow-water carbonate lagoon of Rib reef, central Great Barrier
Reef, Australia. The top 20 cm of sediment contain a distinct, essentially modern assemblage.
Shells recovered at depths form 25 to 125 cm range in age from modern to 4,000 yrs old. They
are age-homogeneous and significantly older than the surface layer. Taxon age distributions
within layers indicate that the top 125 cm of lagoonal sediment is thoroughly mixed on a subcentury
scale. The age distributions and shell half-lives of four taxa: Ethalia, Natica, Tellina
and Turbo are found to be largely distinct. Shell half-lives do not coincide with any single
morphological characteristic thought to infer greater durability, but they are related to a
combined taphonomic score. These results illustrate the importance of bioturbation in tropical
sedimentary environments, indicate that age estimates in this depositional setting are sensitive
to specimen choice, and quantify a taxon-dependent bias in shell longevity and death
assemblage formation.
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