(Press-News.org) Nearly 100 percent of the red snapper sampled in the Gulf of Mexico over a six-year period by University of South Florida (USF) marine scientists showed evidence of liver damage, according to a study reported in Aquatic Toxicology.
The study is the first to correlate the concentration of crude oil found in the workhorses of the digestive system -- the liver, gall bladder, and bile - with microscopic indicators of disease, such as inflammation, degenerative lesions, and the presence of parasites. The team sampled nearly 570 fish from 72 Gulf locations between 2011 to 2017 in the wake of the historic 2010 Deepwater Horizon oil spill.
"The results add to the list of other species we've analyzed indicating early warning signs of a compromised ecosystem," said Erin Pulster, PhD, first author of the study and researcher at the USF College of Marine Science.
Pulster and the team of researchers studying oil pollution in Gulf of Mexico fishes have previously reported high levels of oil exposure in yellowfin tuna, golden tilefish, and red drum as well.
The Gulf of Mexico not only experiences hundreds of annual oil spills with long-lasting effects such as the historic Deepwater Horizon spill in 2010 but is routinely subject to intense shipping traffic and collects pollutants from faraway places that flow in from coastlines and rivers like the Mighty Mississippi and the Rio Grande.
In this study Pulster and the team looked specifically at the most toxic component of crude oil called polycyclic aromatic compounds, or PAHs. PAH sources include old oil and gas rigs, fuel from boats and airplanes, and natural oil seeps, which are fractures on the seafloor that can add millions of barrels of oil to the Gulf every year.
The presence of PAHs in the bile, which is produced by the liver to aid in digestion, indicates relatively recent oil exposure (days to weeks). The team found that the PAH concentration in the bile declined and remained relatively stable after 2011 but they noted a sharp increase in 2017.
Overall, the bile PAH "hot spots" were on the West Florida Shelf (WFS) and in the vicinity of the Deepwater Horizon spill, off the mouth of the Mississippi River. This is the site of the 2004 Taylor oil platform collapse off Louisiana, the longest oil spill in history, which continues to leak oil today. The hotspot west of Tampa on the WFS could be due to shipping traffic or submarine groundwater discharge, Pulster said.
PAH found in the liver indicates the fish has been chronically exposed to oil (months to years). The team found the liver PAH "hot spots" in the northwest Gulf of Mexico, where a considerable number inactive oil and gas platforms exist.
While the PAH concentrations in the liver remained relatively stable throughout the study, indicating that the red snapper are physically managing the oil exposure, there is a tipping point, Pulster said. Red snapper can live upwards of 40 years but fish manage oil toxins, similar to the way humans manage exposure to greasy burgers and alcohol.
Repeated exposure to oil in fish can lead to cancer and eventually to death, but it can also result in sublethal impacts. Virtually all (99 percent) of the red snapper sampled had an average of five physical signs of liver damage. The observed changes can result from natural causes but are also well documented secondary responses to stress which, could potentially signal disease progression.
"We just don't know when we will tip the scale," said Pulster. There was literally one red snapper in the bunch with PAHs but no physical signs of damage when viewed under the microscope, said Pulster.
It's a good thing that humans only eat the muscle of the fish, not the liver. Red snapper remain safe to eat but Pulster stressed the need for continued monitoring. Only then can scientists keep their finger on the pulse of fish health and know what the impacts of additional oil spills may be - especially in species like snapper that are so critical to the Gulf economy, she said.
"This is a unique study. Most investigations of oil spill effects only last a year or two, and this study gives us both a wide scale of reference across the Gulf and also long-term monitoring, which we lacked prior to Deepwater Horizon," said Steve Murawski, PhD, senior author on the study. Murawski, a professor and the St. Petersburg Downtown Partnership Peter R. Betzer Endowed Chair at the USF College of Marine Science, led the 10-year research effort in response to the Deepwater Horizon oil spill (C-IMAGE (usf.edu).
"There is a story we can tease out of the data," Murawski said. "The observed decline in oil exposure in red snapper in the few years following the Deepwater Horizon accident suggests the high levels measured in earlier years were a direct impact from the spill. Its legacy continues, and we'd be wise to continue the critical research ironically made possible by long-term monitoring post-disaster."
INFORMATION:
The study was supported by The Gulf of Mexico Research Initiative, and The Center for the Integrated Modeling and Analysis of the Gulf Ecosystem (C-IMAGE I, II, and II).
In a breakthrough for quantum computing, University of Chicago researchers have sent entangled qubit states through a communication cable linking one quantum network node to a second node.
The researchers, based in the Pritzker School of Molecular Engineering (PME) at the University of Chicago, also amplified an entangled state via the same cable first by using the cable to entangle two qubits in each of two nodes, then entangling these qubits further with other qubits in the nodes.
The results, published February 24, 2021 in Nature, could help make quantum computing more feasible and could lay the groundwork for future quantum communication networks.
"Developing methods that ...
"Phase transitions" are a central phenomenon in physical sciences. Despite being technical-sounding, they are actually something we all experience in everyday life: ice melting into liquid water, or hot water evaporating as steam. Solid, liquid, and gas are three well known "phases" and, when one turns into another, that is a phase transition.
Rare-earth nickelate oxides, also called nickelates, have attracted a lot of interest from researchers because they display an electronic phase transition, which may be exploited in future electronic devices. This particular phase transition consists of turning from a metallic ...
Game theory is known to be a useful tool in the study of Machine Learning (ML) and Artificial Intelligence (AI) Multi-Agent interactions.
One basic component of these ML and AI systems is the exploration-exploitation trade-off, a fundamental dilemma between taking a risk with new actions in the quest for more information about the environment (exploration) and repeatedly selecting actions that result in the current maximum reward or (exploitation).
However, the outcome of the exploration-exploitation process is often unpredictable in practice and ...
The balance of human intestinal microbiota, consisting of hundreds of bacterial species and phages (bacteria viruses), is crucial to good health. A research team, including scientists from the CNRS* and the Institut Pasteur, has characterised the phage-bacterial interaction networks of the microbiota in ten healthy individuals, with unprecedented precision. Scientists detected several hundred bacterial and phage genomes and identified the thousands of interactions that bind them by quantifying the contacts between the DNA molecules of viruses and their hosts. This method has the advantage ...
Researchers have published a study revealing their successful approach to designing much quieter propellers.
The Australian research team used machine learning to design their propellers, then 3D printed several of the most promising prototypes for experimental acoustic testing at the Commonwealth Scientific and Industrial Research Organisation's specialised 'echo-free' chamber.
Results now published in Aerospace Research Central show the prototypes made around 15dB less noise than commercially available propellers, validating the team's design methodology.
RMIT University aerospace engineer and lead researcher Dr Abdulghani Mohamed said the impressive results were enabled by two key innovations - the numerical algorithms ...
Researchers at the University of Alabama at Birmingham have identified a new molecular target that could potentially treat the deadly, aging-related lung disease idiopathic pulmonary fibrosis (IPF). The study, which will be published March 10 in the Journal of Experimental Medicine (JEM), suggests that targeting a protein called MDM4 could prevent respiratory failure by initiating a genetic program that removes scar tissue from the lungs.
IPF is characterized by the accumulation of scar tissue that stiffens the lungs and makes it difficult for patients to breathe and get sufficient oxygen into their blood. Though the causes of IPF remain unclear, age is a significant risk factor: the disease is ...
Blood pressure measurements in children and adolescents should be taken from both arms after new research showed substantial differences could be seen depending on which arm was used.
The study, led by the Murdoch Children's Research Institute (MCRI) and published in the Journal of Hypertension, found even a small difference in blood pressure measurements between arms could lead to a wrong diagnosis.
MCRI PhD candidate and study lead author Melanie Clarke said this was the first study worldwide to determine the size and frequency of inter-arm blood pressure differences in children and adolescents.
The study involved ...
A researcher at the Instituto de Astrofísica de Canarias (IAC) is the lead author of a study with proposals for "technosignatures" -evidence for the use of technology or industrial activity in other parts of the Universe- for future NASA missions. The article, published in the specialized journal Acta Astronautica, contains the initial conclusions of a meeting of experts in the search for intelligent extraterrestrial life, sponsored by the space agency to gather advice about this topic.
In the article, several ideas are presented to search for technosignatures that would indicate the existence of extraterrestrial civilizations, ...
They say a picture is worth a thousand words. However, many women artists - and the stories their works tell - comprise less than 4 per cent of total art sold at auction and fail to attract high selling prices compared to male artists.
A world-first international study by researchers at Monash University, Maastricht University (The Netherlands) and Artnet Worldwide, based in New York City, found that a staggering 96.1 per cent (2,572,346) of all artworks sold at auctions worldwide between 2000 and 2017 are attributed to male artists.
However, work by female artists are on average 4.4 per cent more ...
When the body detects a pathogen, such as bacteria or viruses, it mounts an immune system response to fight this invader. In some people, the immune system overreacts, resulting in an overactive immune response that causes the body to injure itself, which may prove fatal in some cases.
Now, scientists from Nanyang Technological University, Singapore (NTU Singapore) have created a compound that could help to reduce this overactivation without impairing the body's entire immune response.
An overactive immune system leads to many autoimmune disorders - when the immune system mistakenly attacks healthy ...
