N. N. Rabalais

N. N. Rabalais
Louisiana State University | LSU · Department of Oceanography and Coastal Sciences (DOCS)

Ph.D., The University of Texas

About

255
Publications
97,000
Reads
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24,416
Citations
Citations since 2016
48 Research Items
11026 Citations
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Introduction
Biological oceanography-continental shelf ecosystems influenced by large rivers; land ocean interactions Coastal eutrophication; distribution, dynamics and effects of hypoxia Animal/sediment relationships; pelagic-benthic coupling Multiple stressors on ecosystems Integration of science and policy
Additional affiliations
January 2003 - December 2006
Louisiana State University
June 1983 - present
Louisiana Universities Marine Consortium
Description
  • Also, team teach Changing Coastal Oceans via video from LUMCON

Publications

Publications (255)
Article
Dissolved oxygen (DO) and dissolved inorganic carbon (DIC) represent reciprocal sides of aquatic metabolism. In closed systems, absolute DO and DIC changes follow a ~ 1 : 1 ratio, but in open systems coupling depends on mixing, air–sea gas exchange, and anaerobic respiration. To quantify DO–DIC controls in coastal waters, we evaluated their concent...
Article
Full-text available
Ocean acidification (OA) has resulted in global-scale changes in ocean chemistry, which can disturb marine organisms and ecosystems. Despite its extensively populated coastline, many marine-dependent communities, and valuable economies, the Gulf of Mexico (GOM) remains a relatively understudied region with respect to acidification. In general, the...
Article
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In this paper, we outline the need for a coordinated international effort toward the building of an open-access Global Ocean Oxygen Database and ATlas (GO2DAT) complying with the FAIR principles (Findable, Accessible, Interoperable, and Reusable).
Article
Full-text available
Marine oil spills continue to be a global issue, heightened by spill events such as the 2010 Deepwater Horizon spill in the Gulf of Mexico, the largest marine oil spill in US waters and among the largest worldwide, affecting over 1,000 km of sensitive wetland shorelines, primarily salt marshes supporting numerous ecosystem functions. To synthesize...
Article
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Landscape theory for food web architecture (LTFWA) suggests that food webs are hierarchically organized with larger consumers coupling energy from different habitats that would otherwise be functionally isolated. Empirical tests of this theory remain rare and support differs among terrestrial, freshwater, and marine systems. Saltmarshes and their a...
Article
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Anthropogenic nutrient inputs fuel eutrophication and hypoxia ([O2] < 2 mg L−1), threatening coastal and near shore environments across the globe. The world’s second largest anthropogenic coastal hypoxic zone occurs annually along the Louisiana (LA) shelf. Springtime loading of dissolved inorganic nitrogen (DIN) from the Mississippi River, combined...
Article
The epoch of the Anthropocene, a period during which human activity has been the dominant influence on climate and the environment, has witnessed a decline in oxygen concentrations and an expansion of oxygen depleted environments in both coastal and open ocean systems since the middle of the 20th century. This paper provides a review of system-spec...
Article
The epoch of the Anthropocene, a period during which human activity has been the dominant influence on climate and the environment, has witnessed a decline in oxygen concentrations and an expansion of oxygen-depleted environments in both coastal and open ocean systems since the middle of the 20th century. This paper provides a review of system-spec...
Article
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Hypoxia and associated acidification is a growing concern for ecosystems and biogeochemical cycles in the coastal zone. The northern Gulf of Mexico (nGoM) has been experiencing large seasonal hypoxia for decades linked to the eutrophication of the continental shelf by the Mississippi River nutrient discharge. Sediments play a key role in maintainin...
Article
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It is known that surface water eutrophication enhances bottom water ocean acidification via respiration in coastal oceans. However, the role of benthic processes in influencing bottom water acidification has not been sufficiently explored. We examined this issue by analyzing a 10‐year summer carbonate chemistry dataset in bottom water together with...
Article
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Diversion of river waters to adjacent estuaries may occur during wetland restoration, navigation channel development, or storms. We proposed that diversions of nitrogen- and phosphorus-enriched waters from the river to estuarine waters would result in increased phytoplankton biomass and shifts to noxious or harmful algal blooms. We tested this hypo...
Article
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Severe and persistent bottom-water hypoxia (≤2 mg O2 L−1) occurs on the Louisiana/Texas continental shelf from mid-May through mid-September over a large area (up to 23,000 km2 in mid-summer). Benthic infauna are less mobile than demersal organisms and become stressed by the low dissolved oxygen; benthic community composition, abundance, diversity,...
Article
Full-text available
One of the largest human‐caused areas of bottom‐water oxygen deficiency in the coastal ocean is on the northern Gulf of Mexico continental shelf adjacent to the Mississippi River, which discharges nitrogen and phosphorus loads into its surface waters. The beginnings of seasonal hypoxia (≤2 mg l−1 dissolved oxygen) in this area was in the 1950s with...
Article
Van Meter et al . (Reports, 27 April 2018, p. 427) warn that achieving nitrogen reduction goals in the Gulf of Mexico will take decades as a result of legacy nitrogen effects. We discuss limitations of the modeling approach and demonstrate that legacy effects ranging from a few years to decades are equally consistent with observations. The presente...
Article
Full-text available
We examined the sub-lethal effect of Macondo oil from the Deepwater Horizon oil spill on predator-prey interactions using blue crabs (Callinectes sapidus) and periwinkle snails (Littoraria irrorata). A 2 × 2 factorial mesocosm design determined the effect of oil (no oil vs. oil) and blue crabs (no blue crab predator vs. one blue crab predator) on p...
Article
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A 3-D unstructured-grid hydrodynamic model for the northern Gulf of Mexico was developed, with a hybrid s–z vertical grid and high-resolution horizontal grid for the main estuarine systems along the Texas–Louisiana coast. This model, based on the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM), is driven by the observed rive...
Article
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We measured the temporal and spatial trajectory of oiling from the April, 2010, Deepwater Horizon oil spill in water from Louisiana's continental shelf, the estuarine waters of Barataria Bay, and in coastal marsh sediments. The concentrations of 28 target alkanes and 43 target polycyclic aromatic hydrocarbons were determined in water samples collec...
Article
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Rich geochemical datasets generated over the past 30 years have provided fine-scale resolution on the northern Gulf of Mexico (nGOM) coastal hypoxic (≤ 2 mg of O2 L⁻¹) zone. In contrast, little is known about microbial community structure and activity in the hypoxic zone despite the implication that microbial respiration is responsible for forming...
Data
Supplementary tables. Table A. 2014 nGOM hypoxic zone sample metadata and in situ chemistry. Table B. Wilcoxon B-H corrected p-values for diversity statistics and environmental variables for all datasets. Table C. Operational taxonomic unit (OTU) table for all samples collected in 2014. Table D. P-values (B-H corrected) for Spearman's correlation c...
Article
Full-text available
We present a 3D unstructured-grid hydrodynamic model for the northwestern Gulf of Mexico that utilizes a high-resolution grid for the main estuarine systems along the Texas-Louisiana coast. This model, based on the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM) with hybrid horizontal and vertical grids, is driven by the obs...
Preprint
Full-text available
Rich geochemical datasets generated over the past 30 years have provided fine-scale resolution on the northern Gulf of Mexico (nGOM) coastal hypoxic (≤ 2 mg of O2 L-1) zone. In contrast, little is known about microbial community structure and activity in the hypoxic zone despite the implication that microbial respiration is responsible for forming...
Article
Nearly every summer, a large hypoxic zone forms in the northern Gulf of Mexico. Research on the causes and consequences of hypoxia requires reliable estimates of hypoxic extent, which can vary at sub-monthly time scales due to hydro-meteorological variability. Here, we use an innovative space-time geostatistical model and data collected by multiple...
Article
We examined the stable carbon isotopic composition of remineralized organic carbon (δ13COCx) in the northern Gulf of Mexico (nGoM) using incubations (sediment and water) and a three end‐member mixing model. δ13COCx in incubating sediments was ‐18.1±1.3‰, and δ13COCx in incubating near‐surface and near‐bottom waters varied with salinity, ranging fro...
Article
Full-text available
Coastal regions experiencing declining dissolved oxygen are increasing in number and severity around the world. However, despite the importance of microbial metabolism in coastal hypoxia, few metagenomic surveys exist. Our data set from within the second largest human-caused hypoxic region provides opportunities to more deeply explore the microbiol...
Article
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Beneath the waves, oxygen disappears As plastic waste pollutes the oceans and fish stocks decline, unseen below the surface another problem grows: deoxygenation. Breitburg et al. review the evidence for the downward trajectory of oxygen levels in increasing areas of the open ocean and coastal waters. Rising nutrient loads coupled with climate chang...
Article
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We examined organic-walled dinoflagellate cysts from one ²¹⁰Pb-dated sediment core and 39 surface sediment samples from the northern Gulf of Mexico to determine the relationship between nutrient enrichment and cyst assemblages in this region characterized by oxygen deficiency. The core spans from 1962 to 1997 and its sampling location is directly i...
Article
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The oil/water/dispersant mixture from the 2010 Deepwater Horizon oil spill was juxtaposed on the Louisiana continental shelf with the annual development of oxygen-depleted bottom waters. There was uncertainty whether the oil from the spill might worsen the extent or severity of the seasonal hypoxic area formation in 2010. The surface and bottom wat...
Article
Full-text available
Marine regions that have seasonal to long-term low dissolved oxygen (DO) concentrations, sometimes called “dead zones,” are increasing in number and severity around the globe with deleterious effects on ecology and economics. One of the largest of these coastal dead zones occurs on the continental shelf of the northern Gulf of Mexico (nGOM), which...
Article
Full-text available
We quantified trends in the 1985 to 2015 summer bottom-water temperature on the northern Gulf of Mexico (nGOM) continental shelf for data collected at 88 stations with depths ranging from 3 to 63 m. The analysis was supplemented with monthly data collected from 1963 to 1965 in the same area. The seasonal summer peak in average bottom-water temperat...
Data
Figure A in S1 File. The temperature values for each bottom-water sample for five depth zones from 1985 to 2015 for summertime values. Figure B in S1 File. The change in the average summer salinity values in bottom and surface samples from 1985 to 2015. The trends in the bottom and surface salinities are not statistically significant. Figure C in S...
Preprint
Full-text available
Marine regions that have seasonal to long-term low dissolved oxygen (DO) concentrations, sometimes called ‘dead zones,’ are increasing in number and severity around the globe with deleterious effects on ecology and economics. One of the largest of these coastal dead zones occurs on the continental shelf of the northern Gulf of Mexico (nGOM), which...
Article
The Gulf of Mexico Large Marine Ecosystem (GoM LME) is shared by the United States, Mexico and Cuba and requires collaborative work based on ecosystem science for integrated management scenarios to conserve its natural assets, socioeconomic value and derived benefits to multiple societies, as well as to foster the overall regional economic wealth....
Article
A simple river-ocean mixing approach has been frequently used to examine estuarine and coastal carbonate system speciation. Coastal areas receiving significant nutrient inputs, however, can have the carbonate chemistry greatly deviated from this mixing-only scheme because of disparate, but spatially coupled biogeochemical processes, i.e., intense p...
Article
Full-text available
Oil gushed from the Macondo Mississippi Canyon 252 well into the Gulf of Mexico for 87 days after the Deepwater Horizon drilling rig exploded and sank. A concern, after widespread dispersant use offshore on surface waters and at the wellhead, was that the oil/dispersant mixture would reach valuable, and vulnerable, coastal ecosystems. Standardized...
Article
We show the first conclusive evidence that Melitasphaeridium choanophorum, a dinoflagellate cyst species until recently considered extinct, is still living in the northern Gulf of Mexico. This suggests the Gulf of Mexico may have acted as a refugium for some warm-water dinoflagellates during past glaciations. Melitasphaeridium choanophorum can be c...
Article
Azadinium poporum produces a variety of azaspiracids and consists of several ribotypes, but information on its biogeography is limited. A strain of A. poporum (GM29) was incubated from a Gulf of Mexico sediment sample. Strain GM29 was characterized by a plate pattern of po, cp, x, 4′, 3a, 6″, 6C, 5S, 6‴, 2⁗, a distinct ventral pore at the junction...
Article
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The presence of domoic acid (DA) toxin from multiple species of Pseudo-nitzschia is a concern in the highly productive food webs of the northern Gulf of Mexico. We documented the Pseudo-nitzschia presence, abundance, blooms, and toxicity over three years along a transect ∼100 km west of the Mississippi River Delta on the continental shelf. Pseudo-n...
Article
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We establish the cyst-theca relationship of the cyst species Trinovantedinium pallidifulvum Matsuoka 1987 based on germination experiments of specimens isolated from the Gulf of Mexico. We show that the motile stage is a new species, designated as Protoperidinium louisianensis. We also determine its phylogenetic position based on single-cell PCR of...
Article
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We hypothesized that the grazing on phytoplankton by the microzooplankton community is size-dependent and, therefore, the top-down control on phytoplankton by microzooplankton community could be one possible mechanism explaining why small phytoplankton become less abundant than large phytoplankton in eutrophic waters. We tested this hypothesis usin...
Article
In the present study we redescribed Gyrodinium resplendens through incubation of process bearing cysts extracted from sediment collected in the northern Gulf of Mexico. The morphology and ultrastructure of the motile stage and cyst stage were examined using light microscopy, scanning electron microscopy and transmission electron microscopy and this...
Article
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A long-held paradigm is that estuaries are important to the welfare of estuarine-dependent coastal fisheries, providing spawning areas, suitable salinity gradients for development, protection from predators, and food. Many publications link the beneficial nature of estuaries with fisheries production and decry human activities that modify habitat,...
Article
We examined Hg biogeochemistry in northern Gulf of Mexico (nGOM) sediments along a ∼400 km east–west transect off the Louisiana coast in order to characterize primary controls on net methylmercury (MeHg) production and accumulation in sediments and evaluate the potential influence of water column hypoxia. Total Hg (THg) and MeHg concentrations rang...
Article
Full-text available
Areas of low oxygen have spread exponentially over the past 40 years, and are cited as a key stressor on coastal ecosystems. The world's second largest coastal hypoxic (≤ 2 mg of O2 L(-1) ) zone occurs annually in the northern Gulf of Mexico (nGOM). The net effect of hypoxia is the diversion of energy flow away from higher trophic levels to microor...
Article
Full-text available
Significance Hypoxic (low-oxygen) zones threaten an increasing number of marine ecosystems. Hypoxia in the Gulf of Mexico is the second largest in the world. The United States has a policy goal of reducing the average zone to 5,000 km ² . Reductions in nutrients from cropland in the Mississippi-Atchafalaya River Basin are needed to achieve this goa...
Article
In this paper, we discuss the importance of developing integrated assessment models to support the design and implementation of policies to address water quality problems associated with agricultural pollution. We describe a new modelling system, LUMINATE, which links land use decisions made at the field scale in the Upper Mississippi, Ohio and Ten...
Article
Full-text available
Large-scale hypoxia regularly develops during the summer on the Louisiana continental shelf. Traditionally, hypoxia has been linked to the vast winter and spring nutrient inputs from the Mississippi River and its distributary, the Atchafalaya River. However, recent studies indicate that much of the shelf ecosystem is heterotrophic. We used data fro...
Article
The Coastal Waters Consortium (CWC) led by Louisiana Universities Marine Consortium is one of eight Gulf of Mexico Research Initiative research consortia. The CWC focuses on: oil transport and fate, chemical evolution and biological degradation, and environmental effects.The following is an overview of a portion of the research conducted within the...
Technical Report
Full-text available
The 2012 revision of the Gulf of Mexico Monitoring Implementation Plan included the need to hold a workshop to determine the optimal glider design and glider monitoring strategy for temporal/spatial coverage that would complement ship surveys and observing systems. On 17-19 April of 2013 the workshop was held as part of the Forum for Gulf of Me...
Article
Full-text available
Abstract This article reviews and analyzes the issues related to worldwide hypoxic zones and the range of economic questions sorely in need of answers. We begin by describing the extent and causes of hypoxic zones worldwide, followed by a review of the evidence concerning ecological effects of hypoxic zones and their impacts on ecosystem services....