Cancer Mortality and West Virginia Coal Miners

Anesetti-Rothermel, A et al. (2010) used geographic information systems to  test the hypotheses that age-adjusted county cancer mortality rates were positively associated with distance-weighted population exposure to coal extraction and processing activities, and distance-weighted exposure measures are more strongly correlated to cancer mortality than exposure based on tons of coal mined in the county. Their results supported their hypothesis in that they found a relationship between population proximity to coal mine features and cancers. All three global spatial autocorrelation tests ran resulted in positive spatial autocorrelation. Other variables, like the tonnage exposure measure, race/ethnicity percentages, education, poverty, primary health care access, etc. contributed significant additional variance and for total cancer and three cancer subgroups, the exposure measure was correlated to higher mortality after controlling for smoking rates. The previous exposure measure, based on tonnage, was not related as strongly to cancer mortality.Rosemary Kulp
Anesetti-Rothermel, A., Fedorko, E. Hendryx, M. 2010 A geographical information system-based analysis of cancer mortality and population exposure to coal mining activities in West Virginia, United States of America. Geospatial Health 4(2), 2010, pp. 243-256

Approximately 50% of West Virginia’s population resides within just 11counties. West Virginia’s counties have an average population density of 94.9 persons, and a median of 51.1 persons, per square land mile. Persons who live in coal mining counties of Appalachia, like the counties of West Virginia have elevated all-cause cancer as well as lung cancer mortality, compared to non-mining counties or the nation, even after controlling for socio-economic, health services and behavioral variables.
The higher cancer mortality in the region has been attributed to behavioral risks such as smoking, poor socio-economic conditions and problematic access to medical care.  This experiment conducted an exploratory spatial data analysis to determine if there was a spatial relationship between the existing data. In this study a distance-based index describing, per county, the proximity of that county’s population to coal mine features was developed and then used in a regression analysis.
The experiment was conducted with the expectation that  distance-weighted population exposure is more highly correlated to cancer mortality rates than the previous measure of tons of county-level coal mining. If cancer mortality is not related to exposure to mining activity, and is only a reflection of socio-economic status or behavior, there would be no improvement in the capacity of the exposure measure to account for mortality rates.
Cancer mortality rates were taken from the Centers for Disease Control and Prevention. The rates were age-adjusted using the 2000 US standard population, and were found for West Virginia counties as the rate per 100,000 person-years for 1979-2004. The person-year approach allowed for aggregation across years to estimate cancer mortality in rural, less populated counties that typify most coal mining locations.
The time period, represented by covariates, was sometimes based on the 2000 Census, and sometimes on more recent estimates when available. These covariates include average poverty rate for 2000-2002, high school and college education rates in 2000, supply of primary care physicians per 1,000 population in 2001, and smoking rate in 2003. Geographic data on activities of the coal mining industry included mining permit boundaries for mining sites, the point locations of surface slurry impoundment dams, the point locations of permitted underground injection sites, and the point locations of coal processing facilities. Most of the data compilation and manipulation was performed using ArcView GIS software,versions 9.2 and 9.3
Within each of the study area’s census block groups the mean distance was calculated in km from the nearest mine boundary, the impoundment dam, the injection site, and the preparation plant. The inverse distance for each mine infrastructure type for each block group was then calculated. The mean inverse distances were multiplied by the population of the block group. This resulted in a value per block group/infrastructure type where closer distances and bigger populations have larger values, and farther distances and smaller populations have smaller values.
The tonnage measured, rather than the distance weighted measure, was used for the spatial analysis because tonnage measures from border counties outside West Virginia could be included. However, the mapping of mining activities was available onlywithin the state.
Anesetti-Rothermel, A et al. (2010) identified two sources of spatial information for coal processing facilities the US environmental Protection Agency and the the West Virginia Department of Environmental Protection (WVDEP) data sets. With the data a basic photo alignment of the point was relocated to a more accurate location. Of 76 entities, 46 were realigned.
The last coal mining data set used in the study was slurry injection sites. These are areas where waste water from mining, drilling or processing has been injected into underground areas for the purpose of storage. Injection sites are permitted by the EPA as National Pollution Discharge Elimination System (NPDES) points. The content of the slurry is monitored at the discharge points as part of the NPDES regulatory process. Mining operations often involve the capture of used water in artificial impoundments, held in place by earthen dams, for the purpose of removing contaminants and non-combustibles. Acid mine drainage (AMD) is also held in surface impoundments. These coal impoundment dams are regulated by WVDEP. Further information involving potential health effects of coal slurry and toxic water will be addressed later in the chapter.
Global measure of spatial autocorrelation was used to measure the level and direction (positive or negative) of association for the entire sample used. The resulting test is similar to a correlation coefficient as it varies between -1.0 and +1.0. This test of global spatial autocorrelation was computed using GeoDa 0.9.5-i software. The variables of interest, county-level age-adjusted combined cancer mortality rates (1979-2004) and tonnage of coal production per county (1986-2005), were joined to a georeferenced spatial county layer file of West Virginia and its neighboring counties from surrounding states.
All three global spatial autocorrelation tests yielded a value of P <0.001, showing that the data was not spatially random. The correlations between cancer mortality and the total distance-weighted exposure were higher than the corresponding correlations between cancer mortality and the tonnage exposure measure for all cancer sites. Respiratory cancer was found to be correlated to the distance-weighted measure but not to the tonnage measured.
The superior performance of the distance-weighted exposure measure is consistent with the possibility of environmental contamination from the mining industry as a causal factor in the etiology of cancer for populations residing in West Virginia. The strong association between respiratory cancer and mining boundaries, controlling for smoking, may reflect air quality problems around the mines, especially at mountaintops and other surface mining operations.
This experiment was done under the assumption that current mining reflects past mining and based off of  the long history of coal mining in the region but there is the possibility of error if there has been significant change in coal mining technology in the area. Another interesting fact is that the population in West Virginia decreased from 1.94 million to 1.79 million before becoming stable from 1990 to 2000 (1.79 to 1.81 million). The population loss to emigration affected coal-mining counties significantly more than non-mining counties: between 1980 and 1990, the average coal mining county lost 5,233 people to migration compared to a loss of 1,175 people for non-mining counties This could make observed mining effects more conservative than they are, because people  exposed in mining areas would develop cancer later in another area later on.

Effect of Polycyclic Aromatic Hydrocarbon Compounds (PAH’s) on Missed Abortions in Tianjin, China

Chen et al. (2010) examined the potential impact of PAH exposure on in-utero fetal death during early pregnancy, specifically missed abortions. Missed abortion refers to an intrauterine pregnancy in which the fetus does not develop normally over a prolonged period of time (typically 6 weeks) or the fetus is already known to have died but the products of conception remain in-utero. Missed abortion is a complication of early pregnancy that occurs in up to 15% of all clinically recognized pregnancies. The scientists conducted a case–control study examining the influence of maternal exposure to polycyclic aromatic hydrocarbons (PAHs), specifically BaP, a five-ring PAH whose metabolites are mutagenic and highly carcinogenic, on missed vs. induced abortions in Tianjin, an industrial city in northern China. Maternal blood, but not aborted tissues, tested showed BaP-DNA adduct levels were strongly associated with the risk of missed abortions. The BaP-DNA adduct levels in maternal blood were found to be significantly and positively associated with environmental exposure, including proximity of the residence to the nearest roadway, commuting by walking, traffic congestion near the residence, and daily average time outdoors.  BaP-DNA adduct levels were found to be negatively associated with the consumption of grilled, smoked, or barbecued foods. Rosemary Kulp
Chen, Y. Hou, H. Ritz, B. Wu, J. 2010.  Exposure to polycyclic aromatic hydrocarbons and missed abortion in early pregnancy in a Chinese population. doi:10.1016/j.scitotenv.2010.02.028

 Human exposure to PAHs occurs largely through inhalation and diet. PAHs adversely impact birth outcomes and cognitive development in early childhood; including decreased head circumferences, birth length, and birth weight.  In animal studies transplacental exposure to benzo[a]pyrene (BaP), a specific type of PAH, has been associated with an increase in xenobiotic (a chemical found in an organism but not normally produced or expected to be present in it, or a substances present in much higher concentrations than usual) metabolism in the placental tissues, fetal loss and a decrease in plasma hormone levels of progesterone; a steroid hormone involved in the female menstrual cycle, which supports gestation and embryogenesis of humans and other species. BaP has also been found to negatively affect estrogen levels and prolactin peptides; which control lactation during breastfeeding. It is hypothesized that fetuses may be particularly sensitive to the impact of toxic PAHs during early pregnancy (e.g. the 1st trimester) because of the rapid development of fetal organs and the higher exposure per body weight of the fetus.
The biologic mechanisms through which parental exposures to PAHs might affect early pregnancy loss are not well understood but may involve the induction of apoptosis (the process of programmed cell death that can occur in multicellular organisms) after DNA damage from PAHs, antiestrogenic effects of PAHs, and binding to the human aryl hydrocarbon hydroxylase to induce P450 enzymes or to receptors for placental growth factors, altering trophoblast (cells forming the outer layer of a blastocyst, which provide nutrients to the embryo and develop into a large part of the placenta. They are formed during the first stage of pregnancy and are the first cells to differentiate from the fertilized egg proliferation as well as its endocrine function and decreasing exchange of oxygen and nutrients between the fetus and the mother. The endocrine system is a system of glands, each of which secretes a type of hormone into the bloodstream to regulate the body’s homeostasis.
This study was conducted in Tianjin, the second largest city in northern coastal China. It is an important industrial center and contains a developed sea–land–air transportation network. As one of the fastest growing areas in coastal China, the PAH’s levels are considered much higher than in rural areas. This study was conducted during a relatively warm period (April– November), reducing the potential for high PAH exposures from coal combustion during home heating. Data from the Tianjin Environmental Protection Agency showed BaP concentrations to be as high as 14.5 ng/m3 in January compared to only 1.3 ng/m3 in July of 2006.
All study participants were screened to exclude smokers, women with chronic diseases (e.g. hypertension, heart disease, and diabetes), pregnancy complications, women with potentially high occupational exposures to PAH’s like bus or taxi drivers, traffic police officers, coal plant workers, coke oven workers, cooks, etc, and those who had resided in the city for less than a year. After scrrening, aproximatly 80 control subjects and 90 test cases were used. Cases with missed abortions and controls seeking induced abortion services were gathered and recorded from four hospitals, including the Main Hospital of Tianjin Medical University, the 2nd Hospital of Tianjin Medical University, the Hospital of Chinese People’s Armed Police Forces, and Dongli Hospital. All four hospitals allowed the collection of aborted tissues, but only two of the hospitals gave permission for maternal blood drawings. Thus, maternal blood samples were collected for only a subset of the matched case–control pairs. However the other two hospitals were within a close distance (6 km) of the other two hospitals, and so were not adjusted for in the calculations.
Test cases were pregnant women carrying an in-utero fetus that was confirmed dead by ultrasound measurements before 14 weeks of gestation. Control cases were women with normal pregnancies who requested an induction of an abortion due to an unplanned and unwanted pregnancy. BaP levels were measured via biomarker in maternal blood and aborted tissues.
One hour after the abortion procedure the aborted tissues and maternal blood were collected and a standardized twenty minute interview was administered by trained personnel to the recipient of the procedure. During the interview the demographics and socioeconomic information was collected, as well as the reproductive history (e.g. previous abortion history, and number of previous birth to a fetus with a gestational age of 24 weeks or more); and any factors that may have lead to increased  exposure to PAHs during pregnancy, such as time spent outdoors and intransit (commuting), proximity to nearby industrial facilities, traffic activities near residence, cooking activities and fuels used, dietary PAH exposure via grilled, smoked, or barbecued foods, exposure to environmental tobacco smoke, etc.
Two ml of maternal blood were drawn from consenting women by syringe. The aborted tissue was analyzed in total because it is difficult to separate the villous (gastrointestinal polyps) from the embryo early in pregnancy, so all samples contained both embryo and villous materials together. Two different purification kits were used for the aborted tissue and the maternal blood in order to determine the levels of BaP in the aborted tissue and maternal blood.  BaP-DNA adducts (the places where BaP is taken up into the neurons) in extracted DNA were analyzed using the high-performance liquid chromatography-fluorescence method, a technique that can separate a mixture of compounds out so that certain compounds can be analyzed for concentration. This specific test detects benzo[a] pyrene diol-epoxide (BPDE) tetrols (a type of PAH) in the DNA adducts and from these concentrations BaP-DNA adduct levels were calculated by dividing the BPDE concentrations by the total DNA concentrations.
A set of multivariate conditional logistic regression models was used to examine the influence of the PAH adduct levels in maternal blood and aborted tissue on the risk of missed abortions. BaP-DNA adduct levels were modeled as a continuous exposure, and compared to subjects with higher adduct levels and those with lower adduct levels using the median adduct level in the control group as the cut point.
Approximately ninety percent (90.1%) of the study participants were between 20 and 35 years of age. Missed abortion subjects were less educated, reported lower monthly household income, and were somewhat younger than the control subjects seeking induced abortions. After controlling for maternal education and household income, maternal blood BaP-DNA level (per adduct/108 nucleotides) increased the risk of having experienced a missed abortion, and when the number of BaP-DNA adducts was categorized according to the median in the control group, the risk of a missed abortion was more than four times higher for those exposed above the fifty percent marker. 
BaP-DNA adducts in maternal blood correlated poorly and slightly negatively with the levels measured in aborted tissues (overall r=−0.12, n=102; cases r=−0.02, n=51; controls r=−0.21, n=51). BaP-DNA adduct levels in maternal blood were significantly higher in the case group.  The mean number of BaP-DNA adducts in the aborted tissues was somewhat lower in the case (4.8 adducts/108 nucleotides) than in the control group (6.0 adducts/108 nucleotides), however, this difference was not statistically significant (p=0.29).  Missed abortions were not associated with the BaP-DNA adducts in aborted tissues regardless of whetherthe adduct levels were treated as a continuous variable or not. 
There was an observed risk of increase for missed abortion in women who reported commuting by walking (adjusted OR=3.52; 95% CI, 1.44–8.57), traffic congestion near their residence (adjusted OR=3.07; 95% CI, 1.31–7.16), living near an industrial site (adjusted OR=3.21; 95% CI, 0.98– 10.48), and frequent cooking activities during pregnancy (adjusted OR=3.78; 95% CI, 1.11–12.87). Living close to a roadway and spending more time outdoors was also positively associated with missed abortion. Surprisingly, reporting the consumption of grilled, smoked, or barbecued foods seemed to decrease the risk of missed abortion even after adjustmant for socioeconomic factors (OR=0.22; 95% CI, 0.06–0.86). However, these foods were mostly consumed by women who reported cooking never, or occasionally, rather than routinely.
The lack of an association between missed abortion and PAH adduct levels in aborted tissue, as well as the absence of any correlation between maternal blood and aborted tissues DNA adduct levels in both cases and controls could be due to the more active and complex metabolism taking place in the rapidly developing placental and fetal cells of early pregnancy compared to the fully differentiated lymphocytes of the mother.
Other scientists have proposed that the placenta might act as a protective barrier against some genotoxic components between the circulation of mother and child. PAH-DNA adduct levels in placental tissues have been found to be influenced by the activity of the enzymes cytochrome P450-1A1 and glutathione Stransferases.  The overall average BaP-DNA adduct levels (including cases and controls) were about 26% higher in the aborted tissue than in maternal blood. The higher levels measured in aborted tissues in comparison to the maternal blood in this study might be due to the aborted tissues having been collected early in pregnancy when the fetal/villous tissues exhibit a very high metabolism rate in order to form a fully functional placenta.
This study shows that it cannot be assumed that PAH exposures preferentially effect missed abortions. It is even conceivable that the highest exposures lead to earlier spontaneous abortions that may or may not be clinically recognized by women.
The consumption of grilled, smoked, or barbecued foods seemed to decrease the risk of missed abortions while cooking frequently at home increased risk. However, intake of possibly high PAH food items was found to be associated with a low frequency of cooking at home, i.e. the less a woman reported cooking at home the more she may have eaten outside the home; and while this Chinese population seldom cooks, grills, smokes, or barbecues food at home, such foods are easily available from vendors outside the home. While missed abortions were associated with frequent cooking activities, statistically significant correlation were not found between cooking frequency and maternal blood PAH-DNA adduct levels. 

Correlation Found Between Low Birth Weight and Open-Coal Mining Areas in West Virginia, USA.

Ahem et al. (2010) conducted a cross-sectional analysis to determine if there was significant presence of low birth weight in mothers living near coal mining areas in West Virginia. After adjusting the findings so that mothers who reported smoking or drinking were accounted for, they found that areas with high levels of coal mining elevated the odds of a low-birth-weight infant by 16- 14% (with the lower percentage adjusted for mothers who drank) in areas with lower mining levels, relative to counties with no coal mining.
—Rosemary Kulp
Ahem, M. Hamilton, C. Mackay, K. Mullett, M. 2010. Residence in coal-mining areas and low-birth-weight outcomes. DOI 10.1007/s10995-009-0555-1


Coal mining releases toxic chemicals including arsenic, mercury, lead, cadmium, selenium, nickel, and copper into local environments, and the processing of coal involves the use of other toxic chemicals like acryamilides, complex polymers used to separate the coal from the sludge. These compounds are called “trade secrets” by many coal companies and given nicknames like “Comax 1000”. This is in addition to the diesel fueled equipment that moves and processes coal. Materials rejected by a cleaning plant tend to be enriched in iron sulfides which oxidize into sulfates, causing the acidification of water that comes into contact with refuse piles. Contaminated water is held in impoundment ponds, or injected underground so as to not accidently become a potable water source.
In West Virginia, mountaintop removal mining has become an increasingly dominant form of coal mining. This form relies on surface explosives and removal of up to 1,000 feet of rock and soil above the coal. While this is an easier and less cost intensive method of reaching coal beds compared to underground mining methods which tunnel into mountains via the sides, levels of airborne particulates are higher in surface mining vs. underground mining operations and result in community level exposure. This is an important point because recent studies have documented significant transplacental transfer of contaminants, including polycyclic aromatic hydrocarbons (PAHs) and environmental tobacco. In addition, the fetus may be vulnerable to pollution stored inside the mother’s body; further research on it will be covered later in this chapter.
Birth data were obtained from the West Virginia Birthscore Dataset, 2005–2007 (n = 42,770) while data on coal mining were taken from the Department of Energy, Energy Information Administration (EIA). Covariates regarding mothers’ demographics, behaviors, and insurance coverage were included.  Mothers who were older, unmarried, less educated, smoked, did not receive prenatal care, were on Medicaid, and had recorded medical risks had a greater risk of low birth weight were not included in the study, reducing the data set from about 45,000 to 42,770.
          Birth weight was converted to a yes/no score based on whether birth weight was less than 2,500 g. The independent variables were counties with zero, moderate, or high levels of coal mining. Counties with coal mining were divided into levels of coal tonnage, and the mother’s age was converted into younger than 18, 18–39, and 40 and older.  Number of previous pregnancies was recorded, including live births, abortions and stillbirths for mothers residing in mining areas.
The results showed a significant association between receiving late prenatal care and elevated risks for low birth weight outcomes. Mothers in mining areas were also found to be at a significantly higher risk of low birth weight before controlling for covariates. Further, there is evidence of a dose response effect, meaning that there was a higher odds ratio of low birth weight in areas of higher levels of mining compared to areas of moderate mining levels. The risk of low birth weight was found to be related to previously established factors as expected.
Before adjustment, living in a high coal mining area increased the odds of a low birth- weight infant by 19%; after adjustment, the odds were still elevated by 16%. For areas with lower mining levels, the odds of a low-birth-weight infant were increased by 13% before adjustment and 14% after adjustment.
Future research needs to refine categories of medical risks to understand the contribution of each of these risks on low birth weight outcomes. In addition, the level of coal mining served as an environmental proxy for air and water contamination, because no direct environmental data related to levels of air particulates or types of water contamination were available.  Recent studies have examined the impact of polycyclic aromatic hydrocarbons (PAH’s) and fine particles on pregnancy outcomes, finding support for the idea that adverse pregnancy outcome is the result of maternal exposures to airborne particulates themselves, vs. the impact of co-pollutants carried by the particles. 

Assessment of DNA Damage on Columbian Coal Miners

Da Silvia et al. (2010) evaluated genotoxic effects in a population exposed to coal residues from the open-cast mine in “El Cerrejón” Columbia using a cytokinesis-blocked micronucleus test and a comet assay. The 200 individuals tested had no known exposure to previous toxins like coal, radiation, chemicals or cigarettes. One hundred of the individuals were workers exposed to and working in four different mining activities and one hundred individuals were non-exposed control individuals were which acted as controls. Blood samples were taken to investigate biomarkers of genotoxicity; specifically, primary DNA damage, tail length, and percent of tail. Both biomarkers showed statistically significantly higher values in the exposed group compared to the non-exposed control group. No difference was observed between the exposed groups executing different mining activities. These results indicate that exposure to coal mining residues may result in an increased genotoxic exposure in coal mining workers. The study did not find a correlation between age, alcohol consumption and service time with the biomarkers of genotoxicity.—Rosemary Kulp
          Da Silva, J.  Espitia-Pérez , L. Hartmann, A. Henriques, J. Hoyos-Giraldo, L. León-Mejía, G. Quintana, M. 2010.  Assessment of DNA damage in coal open-cast mining workers using the cytokinesis-blocked micronucleus test and the comet assay. doi:10.1016/j.scitotenv.2010.10.049 2010

Coal is one of the most abundant minerals in nature and is one of the largest fossil fuel sources of energy. Colombia, a country in South America, has large natural coal reserves and “El Cerrejón” located in northern Guajira, is the world’s largest open-cast mine.  Coal residues consist of a mixture of substances, containing carbon, hydrogen, nitrogen, oxygen and sulfur. Some basic parameters of coal from “El Cerrejón” are: total moisture (~10%), volatiles (~30%), ash (~8%), sulfur (~1%), carbon (~70%), hydrogen (~6%), oxygen (~5%), and nitrogen (~1%). The main operations carried out in “ El Cerrejón “ are extraction of coal, and mincing coal for transportation.  During coal extraction large quantities of particles of coal dust are emitted and when it is exposed to oxygen and sunlight a spontaneous combustion can occur sending large clouds of polycyclic aromatic hydrocarbons (PAHs) into the environment.
Chronic inhalation of complex mixtures, containing substances such as heavy metals, ash, iron, PAHs and sulfur, can result in lung disorders including pneumoconiosis, progressive massive fibrosis, bronchitis, loss of lung function, emphysema. In addition to direct cellular damage, compounds like PAHs have mutagenic properties that have been associated with an increased risk for cancer development. However, coal dust still remains classified as a non carcinogen for humans according to the International Agency for Research on Cancer.
The primary target cells of inhaled coal dust particles are macrophages and epithelial cells. Activated macrophages (phagocytosis toxicity) produce excessive amounts of reactive oxygen species (ROS) and cytokines.  Epithelial cells and fibroblasts which are the main producers of components of the extracellular matrix including collagens, proteoglycans and elastic fibres, are also known to produce cytokines and ROS upon stimulation. Additional phagocytotic cell may be recruited by chemokines produced by the alveolar macrophages as well as epithelial cells, and may amplify local production of ROS and cytokines. Both ROS and cytokines may cause damage or proliferation of local epithelial and mesenchymal tissue and may as such have consequences to lung tissue morphology, and cell turnover. When there is excessive production of ROS, or when there are insufficient defense mechanisms, oxidative stress may result in DNA damage, lipid peroxidation, protein modification, membrane disruption, and mitochondrial damage, all of which capable of affecting cytogenetic damage levels.
These types of DNA damages are usually induced by most of the genotoxic agents which induce DNA breaks at the phosphodiester skeleton or between bases and sugars resulting in abasic sites identifiable under microscopic inspection.
Coal dust has been evaluated in real world field tests in wild rodents in coal mining areas in Brazil and in Colombia however this is the first field test on human exposure to coal ash in Columbia thus far. The exposed group was divided into four groups: Extracted coal transport (n=50) in which the workers are involved in coal transport up to the arrival in the storing centers; equipment field maintenance (n=18) the drivers that spread water on the roads where large quantities of coal dust are generated,  coal stripping (n=17) where workers accumulate the coal material after it’s been stripped for transportation (and put out the fires caused by coal spontaneous combustion), and coal embarking (n=15) where the workers ship coal in containers to be exported to other countries.
All the individuals included in the study were non-smokers. The exposed group was composed of volunteers between the ages of 24 and 60, medically evaluated and deemed healthy for at least five years at the time of the assessment, with no previous recorded of prescriptions that are known or suspected to have mutagenetic properties.  Peripheral blood samples from all 200 individuals were collected by venipuncture with 20 mL of blood being drawn.  Thirty micro-liters of isolated lymphocytes were mixed with 270 μL 0.5% of LMA-Invitrogen at 37 °C. This mixture was placed into a slide previously coated with 1.5% of agarose(NMA-Cambrex Bioscience Rockland) and processed at 60 °C. The slides were immersed overnight in lysis solution (2.5 M NaCl, 100 mM EDTA and 10 mM Tris, pH 10.0–10.5, 1% with freshly added 1% Triton X-100 and 10% DMSO) at 4 °C in the dark. Afterwards, the slides were placed for 30 minutes in an alkaline buffer at 4 °C (300 mM NaOH and 1 mM EDTA, pHN13) in order to unwind the DNA. The alkaline electrophoresis was carried out for 30 min at 25 V and 300 mA. This standard alkaline procedure allows single-strand DNA breaks to be detected and lesions are converted to strand breaks under these conditions as well. The gels were neutralized with 0.4 M Tris (pH 7.5) with 3 washes of 5 min each. Finally, the slides were stained with 50 μL ethidium bromide (2 μL/mL) and examined at 40× magnification under a fluorescence microscope.
For each individual 50 cells from each of two replicate slides were analyzed. The cells were classified according to tail size into five classes ranging from undamaged (0) to maximally damaged (4). The damage index (DI) calculation was carried out according to a pre-existing visual classification system. The values for the damage index could range from 0 (100 cells all at class 0) up to 400 (100 cells all at class 4).
The second test, the MN test using the cytokinesis-block technique was chosen because it allows reliable data scoring because only the MN of those cells that have completed one nuclear division are analyzed. Cultures were prepared with whole blood in duplicate. Cultures were incubated at 37 °C in the dark for 46 hours, under 5% CO2 in a humidified atmosphere. Two parallel cultures were then set in tubes for each sample. The cells were harvested after 72 hours before being treated with a hypotonic solution (0.075 M KCl) and were immediately centrifuged and fixed three times with methanol/acetic acid. The fixed cells were then dropped onto humidified slides and MN registration was performed on coded slides in a double blind test.
The mean values of both biomarkers parameters in the exposed group demonstrated significant differences when compared to the values of the non-exposed control group (p > 0.001) using the non-parametric Mann Whitney U-test. The Spearman correlation coefficients for MN frequency with age, and DNA damage (tail length, % of tail DNA, DI) for non-exposed control and exposed groups were not significant (p>0.05). The correlations between MN frequency with time of service, and DNA damage with respect to tail length, % of tail DNA and DI, for the subdivided exposed groups, were not significant (p>0.05). The effect of alcohol consumption on MN frequencies and DNA damage in all groups using Mann Whitney U-test and was not found to be statistically significant in any of the groups (p>0.05). There was also no statistically significant difference between the DNA damage between the four different coal mining activities (pN0.05) using a t-test.

The results obtained in Micronucleus frequency show that the values in the exposed to coal mining residuals group (8.6±4.8) are higher compared with the non-exposed control group (2.9±4.0). This clearly demonstrates higher levels of DNA damage in the exposed group (mean tail length=23.4±6.5; mean% of tail DNA=13.1±7.9; mean DI=60.0±39.5) compared to the nonexposed control group (mean tail length=14.3±2.5; mean% of tail DNA=2.9±1.5; mean DI=9.0±6.4). These differences were all statistically significant in the evaluation using a Mann Whitney U-test (p<0.001).

The Effect of Climate Change on the Mediterranean Sea

The Mediterranean Sea is a sea with specific identifiable water masses in each sub-basin and at different depths that have been well recorded. The Mediterranean sea was chosen as the final analysis of ecosystems in this paper because of its wide biodiversity and scientific opinion of being a “miniature ocean” by physical oceanographers (Myers et al. 2000). The circulation of water through the Mediterranean is determined by incoming water from the Gibraltar straights (Atlantic water) and the sinking of waters caused by influx from the three coldest areas of the sea; the northern Adriatic, the Gulf of Lions, and the North Aegean sea. A study performed by Lejeusne et al. (2009) examined the past thirty years and discovered that the traditional flow of water in the Mediterranean Sea has been disrupted due to climate change. Deep-water temperatures from the northwestern Mediterranean have been experiencing a general warming of 0.0048 °C per year since the 1980s. The Eastern Mediterranean transient has encountered temperature and salinity increase as well as increased stratification in the water column. Further research has shown that the Eastern Mediterranean Transient has begun to affect the water circulation and species ecosystems there as well. At shallow depths two types of climate-driven effects have been observed: a warming trend and an increase in the frequency of anomalous events like storms and anomalous annual temperature spikes. Rosemary Kulp
Myers, P.G., Mittermeier, R., Mittermeier, C., Fonseca, G., Kent, J., 2000. Biodiversity hotspots for conservation priorities. Nature 403, 853–858
Lejeusne, C., Chevaldonne, P., Pergent-Martini, C., Boudouresque, C., Pe´rez, T., 2009. Climate change effects on a miniature ocean: the highly diverse, highly impacted Mediterranean Sea. doi:10.1016/j.tree.2009.10.009.

The organisms of the Mediterranean Sea are divided into three biogeographical provinces, the western basin, the eastern basin, and the Adriatic Sea, with each province subdivided along latitudinal patterns (east-west, north-south). Subtropical species are more abundant in the southern parts of these provinces while more temperate species dominate the northern parts. Increasing sea surface temperature and higher frequency of storms has lead directly to an increasing abundance of thermotolerant species and the disappearance of stenothermal species acclimated to colder temperatures. Not surprisingly the major shifts in stenothermal populations have occurred in the colder climate of the Northwestern Mediterranean, the coldest area of the Mediterranean Sea. An example of the changing biodiversity occurring in the Northwestern Mediterranean sea involves the Hemimysis speluncola, a cave-dwelling species which collapsed and re-distributed Northward under the temperature anomalies of the 1990’s. Subsequent studies confirmed a higher thermotolerance for the newly dominant H. margalefi compared to the cold stenothermal H. speluncola, unable to move north and now restricted to the cold regions of the Gulf of Lions and the northern Adriatic. An important note to consider is that current geographical context of the Mediterranean Sea makes it impossible for shallow-water temperate species already trapped in the northernmost, coldest parts of the different basins to migrate or disperse northwards to mitigate temperature changes which will lead to large scale extinction of these trapped species as the waters continue to warm. Significant range expansion is also occurring with two-thirds of the mobile species recorded, as warm loving species, like the ornate wrasse Thalassoma pavo andorange coral Astroides calycularis, found usually along the eastern and southern shores of the Mediterranean Sea, have been recently recorded distributed more north and westward over the decades (Lejeusne et al. 2009).
 The expansion of thermophiliac species from the eastern Mediterranean into the northwestern Mediterranean is important because of the additional organisms introduced through the Suez Canal from the Red Sea. Most of the species introduced into the Mediterranean are of tropical origin, and have been traditionally confined to the easternmost Levantine shores, but the warming of the Mediterranean allows them to progress westwards and northwards, through the whole eastern basin, with some now reaching the Adriatic and the western basin (Galil and Zenetos 2002). It is expected that the southern parts if the Mediterranean Sea will become more colonized by sub-tropical species from the Southern Atlantic and Red Sea, while the Northern parts of the Mediterranean will be populated by current southern and eastern native species of the Mediterranean (Lejeusne et al. 2009).
Climate change and subsequent increases in the severity and frequencies of storms and anomalous temperature spikes can exceed organisms range of thermal tolerance, which leads to diseases and mass mortality. Mediterranean temperate sessile invertebrates such as sponges and corals experienced unprecedented disease outbreaks and mass mortalities within the past decade. After being initially affected, bare skeletons become exposed and are then colonized by microorganisms and eventually macroscopic organisms. Colonized skeletons can remain attached for years, unless detached by storms, and the slow regeneration rate of corals and sponges cannot counterbalance immediate and delayed effects of disease outbreaks, dramatically altering benthic and coastal seascapes within the Mediterranean Sea (Lejeusne et al. 2009).
Since the Mediterranean operates under low levels of nutrients, the benthic ecosystems are under strong nutritional forcing with the summer season traditionally carrying the lowest levels of nutrients. With increased temperatures, the combination of thermal stress and food shortage results in mass mortality events will likely disrupt summer season benthic–pelagic coupling. Cascading effects will likely contain planktonic communities, especially copepod assemblages, which have a strong influence on pelagic ecosystem fluxes due to their role of a biological carbon pump to deeper waters. Plankton populations impact fish recruitment in Mediterranean marine ecosystems and will certainly be influenced by the arrival of new species in these ecosystems, possibly disrupting or completely altering current ecosystem functioning (Lejeusne et al. 2009).
It is important to note that marine invertebrates and fish are not the only species concerned by such expansions. The last decade has seen increasing reports of toxic dinobionts in coastal areas, with possible consequences on human pathology. These dinoflagellants are thermophiliac, exotic species like Gambierdiscus toxicus, and the main causative agent of ciguatera poisoning[1], normally has a tropical or subtropical distribution but have been recently reported from Crete (Lejeusne et al. 2009). Range expansion of the palytoxin-producing dinobiont Ostreopsis ovata in the Mediterranean have also been documented, with definite consequences on human health documented (Kermarec et al. 2008) For both cases increases in water temperature are believed to be the direct result of these species proliferation in the Mediterranean.

In all four ecosystems climate change has resulted in species endangerment with the understanding that barring genetic adaptation the biofood web range-extension northward of current mobile species will occur as stenothermal species that cannot migrate into colder water will die out and ecosystems are reconstructed with invasive themroresiliant species. Increasing sea levels are expected to invade on current real estate properties as primary plant producers and nursery grounds for many commercially valued fish and shrimp flood with sea-water. Further research is required to adequately prove these theories, but based on these analyses a clear north-south gradients is revealed with the impact of invasive species being a key factor to future ecosystem predictions. Another clear issue to consider is the implications of warmer water on the proliferation of potentially harmful bacteria pathogens and microbial ecosystems in relation to human health and commercial consumption of tropical and subtropical fish.


[1] Ciguaterra poisoning is a nonbacterial food poisoning that results from eating fish contaminated with the ciguatoxin, produced by dinoflagellates such as Gambierdiscus toxicus which live in tropical and sub-tropical waters. The toxin is believed to block acetylcholinesterase activity and characteristics of poisoning include vomiting, diarrhea, tingling or numbness of extremities and the skin around the mouth, itching, muscle weakness, pain, and respiratory paralysis. No specific treatment has been developed.

Increasing Sea Levels Negatively Impact Biodiversity of Coastal Lagoons and Increase Susceptibility to Eutrophication

Anthony et al. (2009) studied four separate coastal lagoons and determined the following effects of rising sea levels and temperature increase on these ecosystems. In Barataria Bay Louisiana, they predicted that an increase in air temperature would be 1.1–2.2ºC by 2105 and found that the rate of sea level increase is faster than marsh accretion rates; the effect of climate change in the ecosystem would be increased salinity from rising sea levels resulting in the loss of nursery and mating habitats that the commercially important juvenile penaeid shrimp and blue crabs which thrive in brackish waters close to their tolerance limit. Theyalso found that the air temperature around the Rhode Island salt ponds would increase by 1.9–6.9ºC by 2100, and rising sea levels would increase erosion of barrier beaches, as well as severely decreasing the current land. The increasing temperature and water depth (and accompanying salinity increase due to ocean water exchange) are predicted to shift sea grass species distribution, negatively affecting the current populations of juvenile flounders dependent of the underwater vegetation during the beginning stages of their development. They found that predicted rising sea levels in the Outer Banks along North and South Carolina would have a negative impact on migratory birds that depend on current barrier beaches for breeding, nesting, and shelter. Low oxygen conditions due to eutrophication in the lagoon were also predicted to have negative effects on fish species like the striped bass. Lastly, increasing storm frequency in Jamican Bay NY was found to increase the rate of erosion along the shoreline, decreasing the available breeding grounds for horseshoe crabs and negatively affecting migrating shorebirds (Anthony et al. 2009). — Rosemary Kulp
Anthony, A., Atwood, J., August, P., Byron, C., Cobb, S., Foster, C., Fry, C., Gold, A., Hagos, K., Heffner, K., Kellogg, D., Lellis-Dibble, K., Opaluch, J., Oviatt, C., Pfeiffer-Herbert, A., Rohr, N., Smith, L., Smythe,T., Swift, J., Vinhateiro, N.2009. Coastal lagoons and climate change: ecological and social ramifications in U.S. atlantic and gulf coast ecosystems. Ecology and Society 14, 8.
A coastal lagoon is a “shallow coastal water body separated from the ocean by a barrier, connected in some way to the ocean by one or more restricted inlets. They are formed and maintained through sediment carried by rivers, waves, currents, wind, and tides, that accumulate in river and tidal deltas. Lagoons support a variety of habitats like salt marshes, seagrasses, and mangroves. Seagrass beds influence the stability of the shoreline, and regulate dissolved oxygen. Seagrass beds are also habitats for fish and shellfish species, as they provide physical refuge from predators and serve as a nursery for a variety of organisms that live in the open ocean in later life like for example shrimp.
Because of their relatively low water exchange rates and high transportation of nutrients through surface and groundwater runoff, coastal lagoons are favorable habitats for primary producers, and is able to support higher rates of secondary production in comparison to other ecosystems like open oceans. Eutrophication can occur due to excessive phytoplankton and microalgal blooms, which leads to reduced light penetration and hypoxia, severely affecting the biodiversity of the ecosystem, especially among benthic organisms.
Sea level increase will vary regionally because of differences in sediment loading, groundwater withdrawal, oil extraction, tectonic movement, and the compaction of muddy soils. Barrier-lagoon systems respond naturally to sea level increase by migrating landward along undeveloped shorelines with gentle slopes. However, as lagoon barriers retreat landward, accelerated sea level increase will lead to steeper and narrower barrier profiles, leading to more water exchange with the ocean, increasing lagoon salinity. An increase in sea level will also reduce light penetration to benthic organisms reducing the photosynthetic potential in submerged vegetation and leading to increased probability of eutrophication.
Changes in air temperature strongly influence the water temperature of slow-moving, shallow water bodies like lagoons. Water temperature in turn influences dissolved oxygen concentrations. Many marine species live near their threshold of thermal tolerance meaning small increases in temperature can impact species populations. With increasing temperatures lagoons will also be more susceptible to increases of thermophilian invasive species. Along with warmer waters there is also decreasing in dissolved oxygen concentrations, which will be amplified with seasonal water column stratification, leading to highly oxygenated surface water and depleted oxygen at lower levels, which will negatively impact species diversity. Anthony et al. (2009)

Pragmatic values for saving coastal lagoon ecosystem include tourism aquaculture and fisheries recreational fishing boating refuge harbors real estate ecological, geological, historical, anthropological, and sociological studies. 

The Use of Eocene Fossil Records to Predict Effects of Climate Change on Antarctic Bottom Fauna

Aronson et al. (2009) used the Eocene fossil record in the La Meseta Formation at Seymore Island, Antarctic Peninsula, to track the response of suspension feeding echinoderms and brachiopods that lived off the Antarctic coastal shelf at the time of the Eocene cooling event. The patterns of decline in predation on these organisms within the pre-cooling Eocene ecosystem were then used to predict how the current warming of Antarctic coastal water would affect the current organisms living along the shelf. It is predicted that increasing predation by invasive shell breaking species will reduce current populations of suspension feeding echinoderms possibly into extinction. It is also predicted that climate change will not affect the colonies of brachiopods or the current amount of shell drilling predation on modern populations of bivalves. –Rosemary Kulp
Aronson RB, Moody RM, Ivany LC, Blake DB, Werner JE, Linda C. Ivany4, Daniel B. Blake5, John E. Werner5¤a,
Alexander Glass5 (2009) Climate Change and Trophic Response of the Antarctic Bottom Fauna. PLoS ONE 4(2):e4385. doi:10.1371/journal.pone.0004385

The morphology of the Antarctic fauna is a product of climatic cooling that began in the Eocene 33.5 million years ago. At the beginning of the Eocene the Antarctic climate was considered temperate and contained predators like bony fish (telosts), crustaceans, and sharks (neoslachian elasmobranchs). With the cooling of coastal sea temperatures of up to 10°C by the end of the Eocene period, most of the durophageous (boney fish, ray, shark, and crustacean) predators became extinct. Along with the extinction of these predators, crinoids and ophiuroid (suspension feeders that prey on zooplankton) populations were able to increase. In today’s Antarctic coastal waters, the top predators are slow moving invertebrates that cannot break hard-shelled prey. 
Current increases in polar water temperatures allow predators like anomuran crabs to reinvade the western arctic peninsula in deep water only 1–2 degrees warmer than water on the coastal shelf. In order to predict how the current populations will be affected by the possible invasions of shell breaking, shell drilling, and durophageous predators, the Eocene fossil record from Seymore Island, Antarctic Peninsula was used to track the effects of a cooling period on the populations of modern organisms living on the Antarctic shelf and soft substrata.
After comparing the fossil record to modern day data it was found that populations of ophiuroids and crinoids increased after the cooling event but not before. Since both ophiuroids and crinoids are susceptible to predation and unintentional damage by durphageous organisms, their abundance is evidence of low predation after the post cooling Eocene period.
In order to determine whether there was any change in predation by shell breakers on brachiopods across the 41 million year Eocene cooling event, the shell morphologies of Bouchardia antarctica from two different sites in the pre cooling period and two sites in the post cooling period were compared using principle component analysis in order to determine the variance in shell morphology across sites and between the two time intervals. After comparing four shell metrics (i.e. length of brachial valve, and width of brachial valve) that could be measured precisely, it was determined that there was no consistent change in shell shape or size associated with a decrease in temperature or with the decline of predators.
A second examination was done on predation from shell drilling gastropods using a similar method, comparing evidence of shell drilling predation (boreholes) between nests of B. antarctica and between species of bivalve also susceptible to shell drilling predation before and after the cooling event. The data showed that declining temperatures in the Eocene did not significantly affect the frequency of shell drilling predation on the bivalve species while B. antarctica were not affected either before or after the cooling by shell drilling predation.
When running the Eocene cooling event in reverse, it was predicted that increasing predation associated with reinvasion of shell breaking predators would reduce drastically the populations of suspension feeders like epifaunal ophiuroids and crinoids that currently inhabit the area. It was concluded that the epifaunal brachiopods would not decline with the increase of boney fish (durophage) predators. Lastly, it was determined that the intensity of shell drilling predation on infaunal bivalves would not change appreciably. 

The Use of Eocene Fossil Records to Predict Effects of Climate Change on Antarctic Bottom Fauna

Aronson et al. (2009) used the Eocene fossil record in the La Meseta Formation at Seymore Island, Antarctic Peninsula, to track the response of suspension feeding echinoderms and brachiopods that lived off the Antarctic coastal shelf at the time of the Eocene cooling event. The patterns of decline in predation on these organisms within the pre-cooling Eocene ecosystem were then used to predict how the current warming of Antarctic coastal water would affect the current organisms living along the shelf. It is predicted that increasing predation by invasive shell breaking species will reduce current populations of suspension feeding echinoderms possibly into extinction. It is also predicted that climate change will not affect the colonies of brachiopods or the current amount of shell drilling predation on modern populations of bivalves. –Rosemary Kulp
Aronson RB, Moody RM, Ivany LC, Blake DB, Werner JE, Linda C. Ivany4, Daniel B. Blake5, John E. Werner5¤a,
Alexander Glass5 (2009) Climate Change and Trophic Response of the Antarctic Bottom Fauna. PLoS ONE 4(2):e4385. doi:10.1371/journal.pone.0004385

The morphology of the Antarctic fauna is a product of climatic cooling that began in the Eocene 33.5 million years ago. At the beginning of the Eocene the Antarctic climate was considered temperate and contained predators like bony fish (telosts), crustaceans, and sharks (neoslachian elasmobranchs). With the cooling of coastal sea temperatures of up to 10°C by the end of the Eocene period, most of the durophageous (boney fish, ray, shark, and crustacean) predators became extinct. Along with the extinction of these predators, crinoids and ophiuroid (suspension feeders that prey on zooplankton) populations were able to increase. In today’s Antarctic coastal waters, the top predators are slow moving invertebrates that cannot break hard-shelled prey.  
Current increases in polar water temperatures allow predators like anomuran crabs to reinvade the western arctic peninsula in deep water only 1–2 degrees warmer than water on the coastal shelf. In order to predict how the current populations will be affected by the possible invasions of shell breaking, shell drilling, and durophageous predators, the Eocene fossil record from Seymore Island, Antarctic Peninsula was used to track the effects of a cooling period on the populations of modern organisms living on the Antarctic shelf and soft substrata.
After comparing the fossil record to modern day data it was found that populations of ophiuroids and crinoids increased after the cooling event but not before. Since both ophiuroids and crinoids are susceptible to predation and unintentional damage by durphageous organisms, their abundance is evidence of low predation after the post cooling Eocene period.
In order to determine whether there was any change in predation by shell breakers on brachiopods across the 41 million year Eocene cooling event, the shell morphologies of Bouchardia antarctica from two different sites in the pre cooling period and two sites in the post cooling period were compared using principle component analysis in order to determine the variance in shell morphology across sites and between the two time intervals. After comparing four shell metrics (i.e. length of brachial valve, and width of brachial valve) that could be measured precisely, it was determined that there was no consistent change in shell shape or size associated with a decrease in temperature or with the decline of predators.
A second examination was done on predation from shell drilling gastropods using a similar method, comparing evidence of shell drilling predation (boreholes) between nests of B. antarctica and between species of bivalve also susceptible to shell drilling predation before and after the cooling event. The data showed that declining temperatures in the Eocene did not significantly affect the frequency of shell drilling predation on the bivalve species while B. antarctica were not affected either before or after the cooling by shell drilling predation.
When running the Eocene cooling event in reverse, it was predicted that increasing predation associated with reinvasion of shell breaking predators would reduce drastically the populations of suspension feeders like epifaunal ophiuroids and crinoids that currently inhabit the area. It was concluded that the epifaunal brachiopods would not decline with the increase of boney fish (durophage) predators. Lastly, it was determined that the intensity of shell drilling predation on infaunal bivalves would not change appreciably. 
           

Predicting Coral Adaptation to Climate Change in the Western Indian Ocean

Ateweberhan and McClanahan (2010) documented coral coverage in 36 major reef areas in the Western Indian Ocean through the 1998 rise of Sea Surface temperature due to El Niño/Southern Oscillation.  Average coral cover decline was about 37% with a standard deviation of 31% after the 1998 event. As expected there was significant regional variation with a decline of 14% around the Madagascar coast compared to a decline of 96% in the central Maldives region. The data showed a strong positive relationship between loss of coral cover and the level of thermal stress. Reef areas with low kurtosis, weak bimodal sea surface temperature and moderate standard deviation were the most resistant to the warming. The data contradicted previous assumptions that warming would be less severe in the warmest waters in the Western Indian Ocean, illustrating that the warmest waters had the highest thermal anomalies during the 1998 El Niño/Southern Oscillation event. The study also showed that standard deviation does not have a significantly linear relationship with rising levels of sea surface temperature, so that reef areas of both low and high sea surface temperature could be at high or low risk. The study predicts that areas that were protected in the 1998 episode will be more susceptible to future declines due to climate change. Reef populations that survived the worst of the 1998 event and with genetic variation remain the most likely reefs to survive climate change.
Ateweberhan, M., McClanahan, T., 2010. Relationship between historical sea-surface temperature variability and climate change-induced coral mortality in the western Indian ocean Marine Pollution Bulletin 60, 964–970.

 Coral reefs were chosen to study because they have been the first ecosystem to show measurable declines of species diversity, abundance, and distribution due to rising sea surface temperatures. Stress induced by overly warm water causes coral to expel the zooxanthellae organisms that live symbiotically within coral tissue. These organisms use photosynthesis to provide the coral with nutrition and give pigmentation to the coral tissue they reside within. If zooxanthellae populations cannot be rebuilt in the coral, then bleaching induced mortality occurs.
The objective of the study was to determine if coral responses to documented events could be used to predict how current coral populations in the Western Indian Ocean will react to future rises in Sea Surface Temperature. There was also hope that aspects from Sea Surface Temperature properties could be identified as properties used to predict which reefs in the Western Indian Ocean are currently most susceptible to dramatic rises in Sea Surface Temperature. Since Sea Surface Temperature and bleaching can be inconsistent and vary within a reef or reefs, the experiment was conducted in order to seek patterns from within the variable reef data in order to observe possible relationships which could predict how a reef will be impacted. Thirty six reefs were separated into three major sea surface temperature zones with varying coral coverage. Sea Surface parameters were calculated in accordance to a previous study which found that changes in coral populations were related to standard deviation, kurtosis, and skewness (McClanahan et al. (2007).
Change in cover also varied with size of standard deviation in relation to changes in kurtosis, skewness, and degrees of bimodality.   For regions that were not constantly monitored before the 1998 event, data from previous years was used. In addition some areas were protected from the most dramatic thermal rise due to their location.
            The experiment showed that despite differences in local and regional hydrodynamics, response to coral stressors demonstrated by the 1998 El Niño/Southern Oscillation event are related to a few unifying sea surface temperature statistical properties. It is predicted that shifts toward a negative skewness with warming may counteract thermal rise in some areas, but coupled with a decline in standard deviation, may not provide thermal resistance against extreme anomalous events.
As of this study, coral population structure, and acclimation due to sea surface temperature variability remain the foremost factors expected to create resiliency in coral ecosystems in response to climate change.
References:
Ateweberhan, M., McClanahan, T., 2010. Relationship between historical sea-surface temperature variability and climate change-induced coral mortality in the western Indian Ocean Marine Pollution Bulletin 60, 964–970.
McClanahan, T.R., Ateweberhan, M., Graham, N.J., McClanahan, T.R., Ateweberhan,
M., Graham, N.A.J., Wilson, S.K., Sebastian, C.R., Guillaume, M.M.M.,
Bruggemann, J.H., et al., 2007. Western Indian Ocean coral communities,
bleaching responses, and susceptibility to extinction. Marine Ecology Progress
Series 337, 1–13.