Eric Heinen De Carlo - Academia.edu (original) (raw)

Papers by Eric Heinen De Carlo

Rocks & Minerals, 2017

The Hawaiian Islands frequently evoke a vision of “Paradise on Earth,” a mysterious garland of is... more The Hawaiian Islands frequently evoke a vision of “Paradise on Earth,” a mysterious garland of isles in the Pacific Ocean graced with a natural beauty unparalleled throughout the world. What the Ha...

This work describes use of a buoy system to monitor, autonomously, water quality responses to lan... more This work describes use of a buoy system to monitor, autonomously, water quality responses to land-derived nutrient inputs and the physical forcings associated with local storm events. These data represent 2.5 years of near-real time observations at a fixed station, collected concurrently with spatially distributed synoptic sampling over larger sections of Kaneohe Bay. Nutrient loadings from direct rainfall and/or terrestrial runoff produce an immediate increase in the N:P ratio of bay waters up to 48, and drive phytoplankton biomass growth. Rapid uptake of nutrient input subsidies by phytoplankton causes a rapid decline of nitrogen levels, a return to N-limited conditions, and a subsequent decline of phytoplankton biomass over time scales ranging from a few days to several weeks, depending on the conditions and proximity to the sources of runoff. This work exemplifies the utility of combining synoptic sampling and real-time autonomous observations to elucidate the responses of coas...

The IOC 2002 cruise of the R/V Melville tested the Duce et al. (1991) model of atmospheric dust d... more The IOC 2002 cruise of the R/V Melville tested the Duce et al. (1991) model of atmospheric dust deposition to the NW Pacific during the latter half of the peak Asian dust season. The cruise track sampled regions of the ocean where changes in hydrography and large biogeochemical gradients lead to variations in trace element cycling. The cruise sampled from the Kuroshio to the HNLC region at ~50 N, 167 E. A southerly track at 170E traversed from the Western Subarctic Gyre to the Subtropical Gyre. The ship then sailed east ending at the Hawaii Ocean Time-series (HOT) station. Surface water was collected throughout the cruise by a towed surface sampling fish using Teflon lined tubing. We will discuss rare earth element concentrations in surface waters collected along the IOC 2002 cruise track. REE were determined by flow injection analysis-inductively coupled plasma-mass spectrometry (FIA-ICP-MS). Fe and Al concentrations were determined at sea by FIA. REE concentrations vary substantia...

Concentrations of minor and trace elements (Li, Rb, Sr, Ba, Fe, and Mn) in interstitial water (IW... more Concentrations of minor and trace elements (Li, Rb, Sr, Ba, Fe, and Mn) in interstitial water (IW) were found in samples collected during Ocean Drilling Program (ODP) Leg 166 from Sites 1005, 1006, and 1007 on the western flank of the Great Bahama Bank (GBB). Concentrations of Li range from near-seawater values immediately below the sediment/water interface to a maximum of 250 μM deep in Site 1007. Concentrations determined during shore-based studies are substantially lower than the shipboard data presented in the Leg 166 Initial Reports volume (range of 28–439 μM) because of broad-band interferences from high dissolved Sr concentrations in the shipboard analyses. Rubidium concentrations of 1.3–1.7 μM were measured in IW from Site 1006 when salinity was less than 40 psu. A maximum of 2.5 μM is reached downhole at a salinity of 50 psu. Shipboard and shore-based concentrations of Sr2+ are in excellent agreement and vary from 0.15 mM near the sediment water interface to 6.8 mM at depth...

A review of interstitial water samples collected from Sites 1003–1007 of the Bahamas Transect alo... more A review of interstitial water samples collected from Sites 1003–1007 of the Bahamas Transect along with a shore-based analysis of oxygen and carbon isotopes, minor and trace elements, and sediment chemistry are presented. Results indicate that the pore-fluid profiles in the upper 100 meters below seafloor (mbsf) are marked by shifts between 20 and 40 mbsf that are thought to be caused by changes in sediment reactivity, sedimentation rates, and the influence of strong bottom currents that have been active since the late Pliocene. Pore-fluid profiles in the lower Pliocene–Miocene sequences are dominated by diffusion and do not show significant evidence of subsurface advective flow. Deeper interstitial waters are believed to be the in situ fluids that have evolved through interaction with sediments and diffusion. Pore-fluid chemistry is strongly influenced by carbonate recrystallization processes. Increases in pore-fluid Cl – and Na + with depth are interpreted to result mainly from c...

Science (New York, N.Y.), Feb 23, 2018

Ocean acidification refers to the lowering of the ocean's pH due to the uptake of anthropogen... more Ocean acidification refers to the lowering of the ocean's pH due to the uptake of anthropogenic COfrom the atmosphere. Coral reef calcification is expected to decrease as the oceans become more acidic. Dissolving calcium carbonate (CaCO) sands could greatly exacerbate reef loss associated with reduced calcification but is presently poorly constrained. Here we show that CaCOdissolution in reef sediments across five globally distributed sites is negatively correlated with the aragonite saturation state (Ω) of overlying seawater and that CaCOsediment dissolution is 10-fold more sensitive to ocean acidification than coral calcification. Consequently, reef sediments globally will transition from net precipitation to net dissolution when seawater Ωreaches 2.92 ± 0.16 (expected circa 2050 CE). Notably, some reefs are already experiencing net sediment dissolution.

Proceedings of the Ocean Drilling Program, 1992

Nannofossil assemblages enriched in Braarudosphaera occur in lower Oligocene to lower Miocene sed... more Nannofossil assemblages enriched in Braarudosphaera occur in lower Oligocene to lower Miocene sediments at Ocean Drilling Program Sites 762 and 763 on the central Exmouth Plateau. Braarudosphaerids appear here rather abruptly in the lower Oligocene (in Zone NP21). They reach their greatest numbers in the lower Oligocene (in Zones NP22 and NP23), where they comprise up to 10% of some samples. Braarudosphaera bigelowii is the overwhelmingly dominant species, occurring together with rare specimens of B. discula and Micrantholithus pinguis. The holococcoliths Peritrachelina joidesa and Lantemithus minutus are also associated with the Braarudosphaera enrichment. There are two populations of B. bigelowii: one of normal size (10-14 µm) and one of large specimens (20-22 µm). The larger braarudosphaerids are more common than the smaller forms. Braarudosphaera-nch sediments are absent at Wombat Plateau sites during the same time interval. We attribute this to latitudinal control, because the Wombat sites are about 4° north of the central Exmouth Plateau sites. We believe that the occurrence of braarudosphaerids is related to an Oligocene to early Miocene oceanographic event on the Exmouth Plateau. We suspect that mid-ocean up welling of cool, low-salinity, nutrient-rich water along a divergent zone created the Braarudosphaera-nch sediments in the South Atlantic and Indian oceans.

Marine Geology, 1991

... Amsterdam Paleoceanographic implications of rare earth element variability within a Fe-Mn cru... more ... Amsterdam Paleoceanographic implications of rare earth element variability within a Fe-Mn crust from the central Pacific Ocean* Eric H. De ... to correlate the composition of crusts to paleoceanographic events (Halbach and Puteanus, 1984; Segl et al., 1984; Von Stackelberg ...

Marine Technology …, 2009

In 2006, the US Department of the Army and Department of the Navy funded a survey of Site HI-06, ... more In 2006, the US Department of the Army and Department of the Navy funded a survey of Site HI-06, locally known as Ordnance Reef, Oahu, Hawaii, an area of shallow fringing nearshore reef that was used as a disposal area for discarded military munitions following World ...

Treatise on Estuarine and Coastal Science

ACS Earth and Space Chemistry

Frontiers in Marine Science

A statistical evaluation of nearly 10 years of high-resolution surface seawater carbon dioxide pa... more A statistical evaluation of nearly 10 years of high-resolution surface seawater carbon dioxide partial pressure (pCO 2) time-series data collected from coastal moorings around O'ahu, Hawai'i suggest that these coral reef ecosystems were largely a net source of CO 2 to the atmosphere between 2008 and 2016. The largest air-sea flux (1.24 ± 0.33 mol m −2 yr −1) and the largest variability in seawater pCO 2 (950 µatm overall range or 8x the open ocean range) were observed at the CRIMP-2 site, near a shallow barrier coral reef system in Kaneohe Bay O'ahu. Two south shore sites, Kilo Nalu and Ala Wai, also exhibited about twice the surface water pCO 2 variability of the open ocean, but had net fluxes that were much closer to the open ocean than the strongly calcifying system at CRIMP-2. All mooring sites showed the opposite seasonal cycle from the atmosphere, with the highest values in the summer and lower values in the winter. Average coastal diurnal variabilities ranged from a high of 192 µatm/day to a low of 32 µatm/day at the CRIMP-2 and Kilo Nalu sites, respectively, which is one to two orders of magnitude greater than observed at the open ocean site. Here we examine the modes and drivers of variability at the different coastal sites. Although daily to seasonal variations in pCO 2 and air-sea CO 2 fluxes are strongly affected by localized processes, basin-scale climate oscillations also affect the variability on interannual time scales.

Deep Sea Research Part II: Topical Studies in Oceanography

Circum-Pacific Council for Energy and Mineral Resources Earth Science Series

Marine Chemistry, 2016

Porewater was collected from highly permeable, carbonate-rich, sandy sediments at two locations o... more Porewater was collected from highly permeable, carbonate-rich, sandy sediments at two locations on Oahu, Hawai'i, CRIMP-2 on the Kaneohe Bay barrier reef and Ala Wai on a fringing coral reef nearshore to the Ala Wai canal and urban Honolulu. Samples were collected at the sediment–water interface and from porewater wells installed at sediment depths of 2, 4, 6, 8, 12, 16, 20, 30, 40, and 60 cm. Total alkalinity and dissolved inorganic carbon were enriched, relative to the overlying water column, and ratios of TA:DIC at the two sites (0.80 and 0.93) suggest that aerobic respiration and sulfate reduction – both coupled with carbonate mineral dissolution – in the oxic and anoxic layers, respectively , are the major controls on the biogeochemistry of the sediment–porewater system. The porewater was approaching thermodynamic saturation with respect to aragonite with increasing depth (Ω = 1.2–3.5) and was found to be undersaturated with respect to all phases of magnesian calcite (Ω = 0.3–0.9) containing greater than 12 mol% MgCO 3. In addition to microbial controls on porewater diagenesis, transient physical events in the water column, such as swells and changing bottom current speeds, appear to exert a strong influence on the porewater chemistry due to the highly permeable and porous nature of the sediments. Profiles collected before and after swell events at each location show an apparent flushing of the porewater system, replacing low pH, high DIC inter-stitial waters with seawater from the overlying water column. Based partially on the results of our porewater analysis , we hypothesize that future changes in surface water DIC and pH resulting from ocean acidification (OA) could have a very significant impact on the dissolution rates of metastable skeletal and abiotic carbonate phases of varying magnesian calcite compositions (Mg-calcite) and aragonite. This is especially important in sandy reef sediments like those of this study, which are greatly influenced by the overlying water column. As the carbonate mineral saturation state of the overlying water column continues to decrease due to OA, an increase in carbonate mineral dissolution is expected and the high advective rate of water exchange between the porewater of sandy sediments and the over-lying water column, as observed in this study and others, along with increased rates of dissolution of metastable car-bonate phases, could lead to significantly higher future rates of mass transfer of TA and DIC between the sediments and the overlying water column. This may result in a deficit of the CaCO 3 balance in some reef ecosystems and a decrease in accretion rates. Analysis of our porewater work in conjuction with previous studies of the porewater chemistry of Kaneohe Bay, Oahu in both siliciclastic-rich and siliciclastic-poor carbonate sediments leads to the conclusion that the porewaters of the former are more strongly buffered with respect to pH than those of the latter due to reverse weathering reactions. Thus carbonate-rich sandy sediments of reefs with little terrestrial influence and alumi-nosilicate detritus may become more susceptible to calcium carbonate loss due to the enhanced environmental and microbial dissolution of carbonate substrates expected due to OA.

Proceedings of the Ocean Drilling Program, 2000

ABSTRACT

Rocks & Minerals, 2017

The Hawaiian Islands frequently evoke a vision of “Paradise on Earth,” a mysterious garland of is... more The Hawaiian Islands frequently evoke a vision of “Paradise on Earth,” a mysterious garland of isles in the Pacific Ocean graced with a natural beauty unparalleled throughout the world. What the Ha...

This work describes use of a buoy system to monitor, autonomously, water quality responses to lan... more This work describes use of a buoy system to monitor, autonomously, water quality responses to land-derived nutrient inputs and the physical forcings associated with local storm events. These data represent 2.5 years of near-real time observations at a fixed station, collected concurrently with spatially distributed synoptic sampling over larger sections of Kaneohe Bay. Nutrient loadings from direct rainfall and/or terrestrial runoff produce an immediate increase in the N:P ratio of bay waters up to 48, and drive phytoplankton biomass growth. Rapid uptake of nutrient input subsidies by phytoplankton causes a rapid decline of nitrogen levels, a return to N-limited conditions, and a subsequent decline of phytoplankton biomass over time scales ranging from a few days to several weeks, depending on the conditions and proximity to the sources of runoff. This work exemplifies the utility of combining synoptic sampling and real-time autonomous observations to elucidate the responses of coas...

The IOC 2002 cruise of the R/V Melville tested the Duce et al. (1991) model of atmospheric dust d... more The IOC 2002 cruise of the R/V Melville tested the Duce et al. (1991) model of atmospheric dust deposition to the NW Pacific during the latter half of the peak Asian dust season. The cruise track sampled regions of the ocean where changes in hydrography and large biogeochemical gradients lead to variations in trace element cycling. The cruise sampled from the Kuroshio to the HNLC region at ~50 N, 167 E. A southerly track at 170E traversed from the Western Subarctic Gyre to the Subtropical Gyre. The ship then sailed east ending at the Hawaii Ocean Time-series (HOT) station. Surface water was collected throughout the cruise by a towed surface sampling fish using Teflon lined tubing. We will discuss rare earth element concentrations in surface waters collected along the IOC 2002 cruise track. REE were determined by flow injection analysis-inductively coupled plasma-mass spectrometry (FIA-ICP-MS). Fe and Al concentrations were determined at sea by FIA. REE concentrations vary substantia...

Concentrations of minor and trace elements (Li, Rb, Sr, Ba, Fe, and Mn) in interstitial water (IW... more Concentrations of minor and trace elements (Li, Rb, Sr, Ba, Fe, and Mn) in interstitial water (IW) were found in samples collected during Ocean Drilling Program (ODP) Leg 166 from Sites 1005, 1006, and 1007 on the western flank of the Great Bahama Bank (GBB). Concentrations of Li range from near-seawater values immediately below the sediment/water interface to a maximum of 250 μM deep in Site 1007. Concentrations determined during shore-based studies are substantially lower than the shipboard data presented in the Leg 166 Initial Reports volume (range of 28–439 μM) because of broad-band interferences from high dissolved Sr concentrations in the shipboard analyses. Rubidium concentrations of 1.3–1.7 μM were measured in IW from Site 1006 when salinity was less than 40 psu. A maximum of 2.5 μM is reached downhole at a salinity of 50 psu. Shipboard and shore-based concentrations of Sr2+ are in excellent agreement and vary from 0.15 mM near the sediment water interface to 6.8 mM at depth...

A review of interstitial water samples collected from Sites 1003–1007 of the Bahamas Transect alo... more A review of interstitial water samples collected from Sites 1003–1007 of the Bahamas Transect along with a shore-based analysis of oxygen and carbon isotopes, minor and trace elements, and sediment chemistry are presented. Results indicate that the pore-fluid profiles in the upper 100 meters below seafloor (mbsf) are marked by shifts between 20 and 40 mbsf that are thought to be caused by changes in sediment reactivity, sedimentation rates, and the influence of strong bottom currents that have been active since the late Pliocene. Pore-fluid profiles in the lower Pliocene–Miocene sequences are dominated by diffusion and do not show significant evidence of subsurface advective flow. Deeper interstitial waters are believed to be the in situ fluids that have evolved through interaction with sediments and diffusion. Pore-fluid chemistry is strongly influenced by carbonate recrystallization processes. Increases in pore-fluid Cl – and Na + with depth are interpreted to result mainly from c...

Science (New York, N.Y.), Feb 23, 2018

Ocean acidification refers to the lowering of the ocean's pH due to the uptake of anthropogen... more Ocean acidification refers to the lowering of the ocean's pH due to the uptake of anthropogenic COfrom the atmosphere. Coral reef calcification is expected to decrease as the oceans become more acidic. Dissolving calcium carbonate (CaCO) sands could greatly exacerbate reef loss associated with reduced calcification but is presently poorly constrained. Here we show that CaCOdissolution in reef sediments across five globally distributed sites is negatively correlated with the aragonite saturation state (Ω) of overlying seawater and that CaCOsediment dissolution is 10-fold more sensitive to ocean acidification than coral calcification. Consequently, reef sediments globally will transition from net precipitation to net dissolution when seawater Ωreaches 2.92 ± 0.16 (expected circa 2050 CE). Notably, some reefs are already experiencing net sediment dissolution.

Proceedings of the Ocean Drilling Program, 1992

Nannofossil assemblages enriched in Braarudosphaera occur in lower Oligocene to lower Miocene sed... more Nannofossil assemblages enriched in Braarudosphaera occur in lower Oligocene to lower Miocene sediments at Ocean Drilling Program Sites 762 and 763 on the central Exmouth Plateau. Braarudosphaerids appear here rather abruptly in the lower Oligocene (in Zone NP21). They reach their greatest numbers in the lower Oligocene (in Zones NP22 and NP23), where they comprise up to 10% of some samples. Braarudosphaera bigelowii is the overwhelmingly dominant species, occurring together with rare specimens of B. discula and Micrantholithus pinguis. The holococcoliths Peritrachelina joidesa and Lantemithus minutus are also associated with the Braarudosphaera enrichment. There are two populations of B. bigelowii: one of normal size (10-14 µm) and one of large specimens (20-22 µm). The larger braarudosphaerids are more common than the smaller forms. Braarudosphaera-nch sediments are absent at Wombat Plateau sites during the same time interval. We attribute this to latitudinal control, because the Wombat sites are about 4° north of the central Exmouth Plateau sites. We believe that the occurrence of braarudosphaerids is related to an Oligocene to early Miocene oceanographic event on the Exmouth Plateau. We suspect that mid-ocean up welling of cool, low-salinity, nutrient-rich water along a divergent zone created the Braarudosphaera-nch sediments in the South Atlantic and Indian oceans.

Marine Geology, 1991

... Amsterdam Paleoceanographic implications of rare earth element variability within a Fe-Mn cru... more ... Amsterdam Paleoceanographic implications of rare earth element variability within a Fe-Mn crust from the central Pacific Ocean* Eric H. De ... to correlate the composition of crusts to paleoceanographic events (Halbach and Puteanus, 1984; Segl et al., 1984; Von Stackelberg ...

Marine Technology …, 2009

In 2006, the US Department of the Army and Department of the Navy funded a survey of Site HI-06, ... more In 2006, the US Department of the Army and Department of the Navy funded a survey of Site HI-06, locally known as Ordnance Reef, Oahu, Hawaii, an area of shallow fringing nearshore reef that was used as a disposal area for discarded military munitions following World ...

Treatise on Estuarine and Coastal Science

ACS Earth and Space Chemistry

Frontiers in Marine Science

A statistical evaluation of nearly 10 years of high-resolution surface seawater carbon dioxide pa... more A statistical evaluation of nearly 10 years of high-resolution surface seawater carbon dioxide partial pressure (pCO 2) time-series data collected from coastal moorings around O'ahu, Hawai'i suggest that these coral reef ecosystems were largely a net source of CO 2 to the atmosphere between 2008 and 2016. The largest air-sea flux (1.24 ± 0.33 mol m −2 yr −1) and the largest variability in seawater pCO 2 (950 µatm overall range or 8x the open ocean range) were observed at the CRIMP-2 site, near a shallow barrier coral reef system in Kaneohe Bay O'ahu. Two south shore sites, Kilo Nalu and Ala Wai, also exhibited about twice the surface water pCO 2 variability of the open ocean, but had net fluxes that were much closer to the open ocean than the strongly calcifying system at CRIMP-2. All mooring sites showed the opposite seasonal cycle from the atmosphere, with the highest values in the summer and lower values in the winter. Average coastal diurnal variabilities ranged from a high of 192 µatm/day to a low of 32 µatm/day at the CRIMP-2 and Kilo Nalu sites, respectively, which is one to two orders of magnitude greater than observed at the open ocean site. Here we examine the modes and drivers of variability at the different coastal sites. Although daily to seasonal variations in pCO 2 and air-sea CO 2 fluxes are strongly affected by localized processes, basin-scale climate oscillations also affect the variability on interannual time scales.

Deep Sea Research Part II: Topical Studies in Oceanography

Circum-Pacific Council for Energy and Mineral Resources Earth Science Series

Marine Chemistry, 2016

Porewater was collected from highly permeable, carbonate-rich, sandy sediments at two locations o... more Porewater was collected from highly permeable, carbonate-rich, sandy sediments at two locations on Oahu, Hawai'i, CRIMP-2 on the Kaneohe Bay barrier reef and Ala Wai on a fringing coral reef nearshore to the Ala Wai canal and urban Honolulu. Samples were collected at the sediment–water interface and from porewater wells installed at sediment depths of 2, 4, 6, 8, 12, 16, 20, 30, 40, and 60 cm. Total alkalinity and dissolved inorganic carbon were enriched, relative to the overlying water column, and ratios of TA:DIC at the two sites (0.80 and 0.93) suggest that aerobic respiration and sulfate reduction – both coupled with carbonate mineral dissolution – in the oxic and anoxic layers, respectively , are the major controls on the biogeochemistry of the sediment–porewater system. The porewater was approaching thermodynamic saturation with respect to aragonite with increasing depth (Ω = 1.2–3.5) and was found to be undersaturated with respect to all phases of magnesian calcite (Ω = 0.3–0.9) containing greater than 12 mol% MgCO 3. In addition to microbial controls on porewater diagenesis, transient physical events in the water column, such as swells and changing bottom current speeds, appear to exert a strong influence on the porewater chemistry due to the highly permeable and porous nature of the sediments. Profiles collected before and after swell events at each location show an apparent flushing of the porewater system, replacing low pH, high DIC inter-stitial waters with seawater from the overlying water column. Based partially on the results of our porewater analysis , we hypothesize that future changes in surface water DIC and pH resulting from ocean acidification (OA) could have a very significant impact on the dissolution rates of metastable skeletal and abiotic carbonate phases of varying magnesian calcite compositions (Mg-calcite) and aragonite. This is especially important in sandy reef sediments like those of this study, which are greatly influenced by the overlying water column. As the carbonate mineral saturation state of the overlying water column continues to decrease due to OA, an increase in carbonate mineral dissolution is expected and the high advective rate of water exchange between the porewater of sandy sediments and the over-lying water column, as observed in this study and others, along with increased rates of dissolution of metastable car-bonate phases, could lead to significantly higher future rates of mass transfer of TA and DIC between the sediments and the overlying water column. This may result in a deficit of the CaCO 3 balance in some reef ecosystems and a decrease in accretion rates. Analysis of our porewater work in conjuction with previous studies of the porewater chemistry of Kaneohe Bay, Oahu in both siliciclastic-rich and siliciclastic-poor carbonate sediments leads to the conclusion that the porewaters of the former are more strongly buffered with respect to pH than those of the latter due to reverse weathering reactions. Thus carbonate-rich sandy sediments of reefs with little terrestrial influence and alumi-nosilicate detritus may become more susceptible to calcium carbonate loss due to the enhanced environmental and microbial dissolution of carbonate substrates expected due to OA.

Proceedings of the Ocean Drilling Program, 2000

ABSTRACT

The purpose of this project is to assess and report on the biota and sediment composition in the ... more The purpose of this project is to assess and report on the biota and sediment composition in the Ordnance Reef (HI-06) study area, to determine the potential effects of discarded military munitions (DMM) deposited off the leeward coast of Oahu following the Army’s Remotely Operated Underwater Munitions Recovery System (ROUMRS) technology demonstration. The Project Team (which includes the University of Hawaii and Environet) has prepared the attached Assessment Report for the HI-06 study area. This report summarized the activities of the University of Hawaii and Environet in gathering and analyzing biota and sediment samples from HI-06. The Project Team conducted and gathered three separate rounds of sediment samples, two rounds of biota samples, and analyzed them for munitions constituents. The results of their activities are compiled and provided in the attached Assessment Report (Appendix A) for the Ordnance Reef (HI-06) study area. This report also includes an expanded data analysis of the data gathered during this task and compares it with the results of the ROUMRS demonstration to determine if there was any effect as a result of the demonstration.

Shortly after World War II, conventional military munitions were disposed of in relatively shallo... more Shortly after World War II, conventional military munitions were disposed of in relatively shallow (<100 m) waters off the leeward side of O‘ahu, Hawai‘i. The Department of Defense refers to this area as Hawaii Sea Disposal Site 6 (HI-06). Local residents, who refer to the area as Ordnance Reef, expressed concerns regarding the effects of these discarded military munitions (DMM) on the environment. In this presentation we discuss our use of multivariate statistical techniques to analyze sediment and biota data to identify the possible sources of the various analytes (elements and energetics, i.e., propellants and explosives) that were detected in the sediments and selected biota (typical Hawaiian seafood) of Ordnance Reef. We found that the ordination technique nonmetric multidimensional scaling (NMDS) was particularly sensitive to identifying patterns in both the sediment analytes and samples that suggested two distinct sources – the DMM (copper, zinc, lead, magnesium, and various energetics) and terrestrial sources (iron, aluminum, chromium, and arsenic, to name a few). The analytes in the NMDS plot for biota generally did not cluster by source (e.g., DMM) nor did the biota samples cluster by strata but instead clustered by organism type. The only exception was what appeared to be some clustering by strata for limu (seaweed) possibly because it was a plant rather than an animal and limu is sessile. We did, however, notice that crabs and octopus clustered near each other and with zinc and copper. We attributed this to the fact that both organisms have copper-based hemocyanin in their blood and copper- and zinc-based enzymes in their bodies.