Joseph Daniel Ortiz

Joseph Daniel Ortiz
  • Ph.D., Oregon State University, 1995
  • Professor at Kent State University

About

236
Publications
45,092
Reads
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8,008
Citations
Introduction
Advances in scientific fields often occur at the interfaces between well established disciplines. I have intentionally directed my research objectives toward interdisciplinary paths. My research background has provided me with a broad and powerful set of tools with which to attack problems using a multi-dimensional, interdisciplinary approach. These skills and experiences enable me to conduct significant research on topics ranging from climate change to water quality.
Current institution
Kent State University
Current position
  • Professor
Additional affiliations
February 1996 - June 1998
Columbia University
Position
  • Lamont Doherty Post-Doctoral Research Scientist
May 1995 - December 1995
Oregon State University
Position
  • NSF-funded Post-Doctoral Research Scientist
August 1988 - April 1995
Oregon State University
Position
  • PhD Student
Education
August 1988 - May 1995
Oregon State University
Field of study
  • Oceanography
August 1984 - May 1988
Brown University
Field of study
  • Aquatic Biology

Publications

Publications (236)
Article
Visible derivative spectroscopy (VDS) analysis of sediment from Cleland Lake, Southeastern British Columbia provides a reconstruction of paleolimnological productivity and hydrologic change during the past 14,000 calibrated 14C years before present (cal yr BP). The first five principal components (PC) of the VDS data explain 97% of the variance in...
Article
Full-text available
The lack of well-preserved carbonate in much of the Arctic marine environment dictates the need for alternative methods of paleoceanographic reconstruction. The broad variety of physical properties measurements makes them well suited for use in a variety of environments, but they provide unique opportunities when employed in the Arctic. Because Arc...
Article
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Lake Erie is part of the Great Lakes systems in North America, which represent the largest continental lake systems in the world. Anthropogenic eutrophication in the Western Basin of Lake Erie, a Case II environment, has an adverse impact on the surrounding ecosystems and the regional economy. The optical complexity found in Lake Erie is a feature...
Article
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The complex composition and distribution of colour producing agents (CPAs) in turbid aquatic environments such as the Western Basin of Lake Erie (WBLE) presents a challenge to the application of remote sensing data for differentiating among in-water constituents and estimating their concentrations independently. In this study, multivariate procedur...
Article
Full-text available
Lake Erie is biologically the most active lake among the Great Lakes of North America, experiencing seasonal harmful algal blooms (HABs). The early detection of HABs in the Western Basin of Lake Erie (WBLE) requires a more efficient and accurate monitoring tool. Remote sensing is an efficient tool with high spatial and temporal coverage that can al...
Article
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The use of stone hammers to produce sharp stone flakes—knapping—is thought to represent a significant stage in hominin technological evolution because it facilitated the exploitation of novel resources, including meat obtained from medium-to-large-sized vertebrates. The invention of knapping may have occurred via an additive (i.e., cumulative) proc...
Article
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Correction for ‘Soil contamination by environmentally persistent free radicals and dioxins following train derailment in East Palestine, OH’ by Myron L. Lard et al. , Environ. Sci.: Processes Impacts , 2025, https://doi.org/10.1039/d4em00609g.
Article
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The Norfolk Southern train derailment on February 3, 2023, in East Palestine, Ohio, prompted concerns about the health impacts from the chemical spills and open-air combustion. We hypothesize that the...
Article
The Society of Sigma Gamma Epsilon (SGE), Kent State University (KSU), and the geoscience community lost a loyal supporter, remarkable student mentor, and world-renowned paleontologist when Dr. Rodney M. “Rod” Feldmann died peacefully at home on May 1, 2024, at the age of 84. He is survived by his wife Dr. Carrie Schweitzer (Kent, OH), his daughter...
Article
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Precipitation variations in the tropical Indian Ocean region result from changes in the Indian Summer Monsoon (ISM), as well as convective and cyclonic rainfall. The relative roles of such forcing can be elucidated by constructing robust paleoclimate records, which help to better predict future variability in precipitation due to rising greenhouse...
Article
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Lithic raw material properties are often invoked to explain the presence, absence, form, or ontogeny of Paleolithic stone tools. Here, we explore whether the frequency of the Middle Paleolithic Nubian core form and core‐reduction systems co‐varies with toolstone quality in two neighboring regions in Oman: the southern region of Nejd, Dhofar, and th...
Article
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Reservoir ¹⁴C age offsets track past changes in atmospheric carbon content, air–water gas exchange, and freshwater circulation in water bodies. Determination of a freshwater reservoir correction (FWRC) is a crucial step in age-model development to provide accurate climate-proxy records. We employ published, recent water column ¹⁴C measurements from...
Article
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Planktonic Foraminifera are unique paleo-environmental indicators through their excellent fossil record in ocean sediments. Their distribution and diversity are affected by different environmental factors including anthropogenically forced ocean and climate change. Until now, historical changes in their distribution have not been fully assessed at...
Article
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Coral reef health in the U.S. Virgin Islands (USVI) is in decline due to land-based sources of pollution associated with watershed development and global climate change. Water quality is a good indicator of stress in these nearshore environments as it plays a key role in determining the health and distribution of coral reef communities. Conventiona...
Conference Paper
An analysis of a 10 m long sediment core (84a) collected from Lake Erie’s Central basin was conducted to understand the climate and hydrological controls on the development of summer bottom water hypoxia (low oxygen) over thousands of years. This analysis was done by generating new data on the presence and species abundance of ostracod (seed shrimp...
Article
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The biogenic contents of marine sediments, such as carbonate (CaCO3) and organic carbon (TOC), provide important information about past climatic and environmental changes. For sediment cores, such as those found in the marginal seas of the western Pacific, intensive laboratory study takes considerable time and effort. The previous drilling and cori...
Article
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Linking the stone raw material of a lithic artifact to its original outcrop is an important endeavor that facilitates archaeologists' understanding of prehistoric mobility, trade, economics, and land use. Based on macroscopic identification, archaeologists' presume that prehistoric Holocene occupants of the Welling Site, Ohio, made use of the local...
Article
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The effect of agricultural practices on water quality of Old Woman Creek (OWC) watershed was evaluated in a hydrological model using the Parameter-elevation Regressions on Independent Slopes Model (PRISM) climate data and 20 different global circulation models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5). A hydrological mod...
Article
Full-text available
The separate and synergistic effects of land use and climate change on water quality variables in Old Woman Creek (OWC) watershed were evaluated using a hydrological model set up in Soil and Water Assessment Tool (SWAT) for the OWC watershed. Model calibration was done using a multi-objective evolutionary algorithm and pareto optimization. The Para...
Article
Full-text available
The effect of the projected 21st century climate change on water quality in Old Woman Creek (OWC) watershed was evaluated using the Soil and Water Assessment Tool (SWAT) and the precipitation and temperature projections from three best Global Climate Circulation Model (GCM)l ensemble downloaded from the Coupled Model Intercomparison Project Phase 5...
Article
Full-text available
National Academies' Decadal Survey, Thriving on Our Changing Planet, recommended Surface Biology and Geology (SBG) as a "Designated Targeted Observable" (DO). The SBG DO is based on the need for capabilities to acquire global, high spatial resolution, visible to shortwave infrared (VSWIR; 380-2500 nm; ~30 m pixel resolution) hyperspectral (imaging...
Article
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The contribution of Eunice Foote (1819–1888) to early understanding of the relationship between atmospheric gases and climate change has become a focus of interest in the scholarly community and more widely on social media. In this article we offer a detailed interpretation of both of her known published papers, focusing particularly on her first a...
Article
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Frequent Aureoumbra lagunensis blooms in the Indian River Lagoon (IRL), Florida, have devastated populations of seagrass and marine life and threaten public health. To substantiate a more reliable remote sensing early-warning system for harmful algal blooms, we apply varimax-rotated principal component analysis (VPCA) to 12 images spanning ~1.5 yea...
Article
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The December 2004 Sumatra-Andaman tsunami prompted an unprecedented research effort to find ancient precursors and quantify the recurrence time of such a deadly natural disaster. This effort, however, has focused primarily along the northern and eastern Indian Ocean coastlines, in proximal areas hardest hit by the tsunami. No studies have been made...
Article
A revised age reconstruction suggests marine-based regions of the Eurasian Ice Sheet melted rapidly, contributing to a major sea-level rise some 14,600 years ago. Such a rapid collapse of massive ice hints at the vulnerability of Earth’s remaining ice sheets.
Article
Full-text available
Although the cyanobacterium Microcystis is colonial during water blooms, isolated Microcystis strains become unicellular in culture. Studies indicate that heterotrophic bacteria can promote Microcystis colonies in culture, but little is known about the underlying mechanism or how widespread it is among bacteria. This study investigated the identity...
Article
Picking foraminifera from sediment samples is an essential, but repetitive and low-reward task that is well-suited for automation. The first step toward building a picking robot is the development of an automated identification system. We use machine learning techniques to train convolutional neural networks (CNNs) to identify six species of extant...
Article
Full-text available
Timely identification of color-producing agents (CPAs) in Lake Erie is a challenging, but vital aspect of monitoring harmful algal blooms (HABs). In particular, HABs that include large amounts of cyanobacteria (CyanoHABs) can be toxic to humans, posing a threat to drinking water, in addition to recreational and economic use of Lake Erie. The optica...
Article
The Kent State University (KSU) spectral decomposition method provides information about the spectral signals present in multispectral and hyperspectral images. Pre-processing steps that enhance signal to noise ratio (SNR) by 7.37–19.04 times, enables extraction of the environmental signals captured by the National Aeronautics and Space Administrat...
Article
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Sediment core HLY0503-03JPC from the top of the Northwind Ridge provides the first confirmed Plio-Pleistocene record from the western Arctic Ocean, with calcareous microfossils uniquely preserved to ca. 5 Ma. Results are compared to nearby core P1-93AR-P23 from the ridge slope, which was previously used to reconstruct early Quaternary sea-ice condi...
Poster
Full-text available
In the Great Lakes region, despite the diversity of toxic cyanobacteria that have been historically present, there has been a recent proliferation and dominance of cyanobacteria blooms by the genus Microcystis. In many cases, these blooms have been associated with high concentrations of the toxin microcystin, which is particularly troubling given t...
Article
Holocene records of lacustrine primary production are commonly used to reconstruct past changes in environmental and climatic conditions. While several methods exist to infer paleoproductivity trends, few studies to date have applied multiple geochemical indices in the same core sequence from Arctic lakes to evaluate their fidelity and sensitivity...
Article
Full-text available
Counts of Growth Layer Groups (GLGs) in the dentin of marine mammal teeth are widely used as indicators of age. In most marine mammals, observations document that GLGs are deposited yearly, but in beluga whales, some studies have supported the view that two GLGs are deposited each year. Our understanding of beluga life-history differs substantially...
Article
Full-text available
Analysis of visible remote sensing data research requires removing atmospheric effects by conversion from radiance to at-surface reflectance. This conversion can be achieved through theoretical radiative transfer models, which yield good results when well-constrained by field observations, although these measurements are often lacking. Additionally...
Article
Previous studies have shown that radiocarbon activities (∆14C) in the low-latitude, mid-depth Pacific and Indian oceans were anomalously low during the Heinrich 1 (HS1, ~17.8-14.6 ka) and Younger Dryas (YD, ~12.8-11.5 ka) stadials, coincident with intervals of rising atmospheric CO2 concentration and declining atmospheric ∆14C. However, a full expl...
Article
Oxygen isotope (δ18O) measurements of authigenic carbonate from Cleland Lake (southeastern British Columbia), Paradise Lake (central British Columbia), and Lime Lake (eastern Washington) provide a ~9000 year Holocene record of precipitation-evaporation balance variations in the Pacific Northwest. Both Cleland Lake and Paradise Lake are small, surfi...
Technical Report
Full-text available
The proposed Quantified Earth Science Objective (QESO) is to inventory and assess coastal and inland aquatic habitats, which are extremely valuable and productive regions that are vulnerable to global anthropogenic pressures and climatic change. Basic information about sessile communities (wetlands, coral reefs, and sea grasses) includes mapping th...
Technical Report
Full-text available
The proposed Quantified Earth Science Objective (QESO) is to inventory and assess coastal and inland aquatic habitats, which are extremely valuable and productive regions that are vulnerable to global anthropogenic pressures and climatic change. Basic information about sessile communities (wetlands, coral reefs, and sea grasses) includes mapping th...
Technical Report
Full-text available
The proposed Quantified Earth Science Objective (QESO) is to inventory and assess coastal and inland aquatic habitats, which are extremely valuable and productive regions that are vulnerable to global anthropogenic pressures and climatic change. Basic information about sessile communities (wetlands, coral reefs, and sea grasses) includes mapping th...
Technical Report
Full-text available
The proposed Quantified Earth Science Objective (QESO) is to inventory and assess coastal and inland aquatic habitats, which are extremely valuable and productive regions that are vulnerable to global anthropogenic pressures and climatic change. Basic information about sessile communities (wetlands, coral reefs, and sea grasses) includes mapping th...
Article
Full-text available
There is considerable interest in accurately estimating water quality parameters in turbid (Case 2) and eutrophic waters such as the Western Basin of Lake Erie (WBLE). Lake Erie is a large, open freshwater body that supports diverse ecosystem, and over 12 million people in the mid-western part of the United States depend on it for drinking water, f...
Article
Full-text available
The world’s mega-deltas are extremely important from a human perspective and attract considerable effort to reveal their evolution, growth-related driving forces, and human impacts. Here, we report a case study on the Holocene deltaic evolution of the Yellow River, through development of a conceptual model, which is compared with paleo-proxy to ana...
Technical Report
Full-text available
Coastal and inland aquatic ecosystems support biodiversity, buffer human and animal habitats against storms and floods, and play a key role in the cycling of carbon, minerals and nutrients. Coastal wetlands support fisheries that provide food, livelihood, and recreation to roughly half of the global population. Inland waters provide critical freshw...
Article
Full-text available
This activity provides hands-on exploration of the impact of Rayleigh distillation on the isotopic composition of water in different experimental reservoirs. Similar experimental methods have been a primary source of information for understanding isotopic variations in the natural system. Students are exposed to fundamentals of isotope geochemistry...
Article
Full-text available
Stable carbon isotopes of dissolved inorganic carbon (δ13CDIC) in the ocean are generally not well understood as they are governed by a complex interplay of biological processes and air–sea exchange. In the Arctic Ocean, δ13CDIC values are prone to change in the near future with rapidly changing climate conditions. This study provides a baseline to...
Article
Periods of declining atmospheric radiocarbon activity ( C) during the Heinrich 1 (∼17.8–14.6 ka) and Younger Dryas (∼12.8–11.5 ka) stadials of the last deglaciation coincide with intervals of rising atmospheric CO2, as well as evidence of 14C-depleted carbon at intermediate ocean depths near Baja California, Mexico and in the Arabian Sea. The latte...
Article
Full-text available
Visible and near-infrared (VNIR) derivative spectroscopy of diffuse spectral reflectance (DSR) data can be a potent method to extract lithological information from sediment cores. However, synthesis of multiple DSR data sets collected with different instruments from sediment obtained at different times could subject the DSR measurements to errors a...
Article
Visible diffuse spectral reflectance (DSR) has been described by previous workers as an efficient tool for extracting lithological compositions: clay minerals, iron oxyhydroxides, carbonates and diatoms in sedimentary material. The spatial patterns of these components are essential to understanding the processes driving their distribution and accum...
Article
Reconstructing centennial timescale hydroclimate variability during the late Holocene is critically important for understanding large-scale patterns of drought and their relationship with climate dynamics. We present sediment oxygen isotope records spanning the last two millennia from 10 lakes, as well as climate model simulations, indicating that...
Article
Paleoenvironments during the late Younger Dryas through early Holocene retreat of the Greenland Ice Sheet from the outer shelf in the Disko Trough system of central West Greenland were investigated via lithofacies, foraminifera, dinocysts and sediment provenance analyses in radiocarbon-dated sediment cores from the upper slope (JR175-VC35) and oute...
Article
Full-text available
We report on a 4.1 (±0.2) km diameter and 185 m deep circular submarine structure exposed on the seabed in >40 m water depths in the northwestern Gulf of St. Lawrence (Eastern Canada) from the analysis of high-resolution multibeam bathymetric and seismic data. The presence of a circular form characterized by a central uplift and concentric rings re...
Conference Paper
Full-text available
In small closed-basin lakes in semi arid regions, variations in precipitation/evaporation (P/E) balance affect the physical, biological, and chemical composition of the lake water and sediment. This study presents color reflectance, XRF derived elemental concentrations and δ18O values of carbonates (δ18Ocarb) in sediment cores from Cleland Lake, Br...

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