Ecology and evolution of tolerance in two cruciferous species

Tolerance to herbivory is the ability of plants to maintain fitness in spite of damage. The goal of this thesis is to investigate the genetic variation and expression of tolerance within species, determine whether and in what conditions tolerance has negative side-effects, and how tolerance is affected by different ecological factors. Tolerance is investigated with special focus on the effects of different damage types, competitive regimes, history of herbivory, and polyploidization in plants. Studies are conducted as a literature review and three experiments on two cruciferous species Raphanus raphanistrum and Cardamine pratensis. In the tolerance experiments, plants are subjected to artificial damage solely, or in a combination with natural damage. A literature review was conducted in order to investigate the effects of damage method. We found that traits related to tolerance, such as growth and fitness were not as sensitive in regard to damage method as measures of induced chemical traits, or measures of secondary herbivory. Genetic variation of tolerance was demonstrated within populations of R. raphanistrum and between subspecies of C. pratensis. In R. raphanistrum, traits involved in floral display and male fitness were positively associated with plant tolerance to herbivore damage. A potential cost of tolerance was demonstrated as a negative correlation between levels of tolerance in high and low competitive regimes. I found no evidence of other proposed costs of tolerance in terms of highly tolerant plants suffering of reduced fitness in the absence of herbivores or trade-offs in terms of a negative association between tolerance to apical and leaf damage, or between tolerance and competitive ability. In C. pratensis, higher ploidy level in plants involved higher levels of tolerance measured as clonal reproduction. Furthermore, populations exposed to higher levels of herbivory had better tolerance than populations exposed to lower levels of herbivory. In this thesis, I demonstrate evidence of different components for the evolution of tolerance in plants: genotypic variation, selective factors in terms of costs and ploidization, and selective agents in terms of changing environment or herbivore pressure

Samband mellan skaltillväxt och ålder hos blåmusslan (Mytilus edulis) i Östersjön

Dunca, E. & Boalt, E. 2011. Rapport Nr 6/2011: Relationen mellan skaltillväxt och ålder hos blåmusslan (Mytilus edulis) i Östersjön Blåmusslor från fem lokaler längs svenska kusten (Landskrona, Kullen, Abbekås, Dragviksfjärden och Högby fyr) har åldersbestämts med hjälp av en noggrann metod som utvecklades på 90-talet vid Naturhistoriska riksmuseet i Stockholm. Denna metod jämfördes med den vanliga åldersbestämningen genom att räkna årsringar på utsidan av skalen. Skalens längd har sedan uttryckts som en funktion av musslornas ålder i tillväxtdiagram för varje av de fem studerade populationer. Det finns en stor variation i skalstorlek och tjocklek, samt åldersfördelning mellan de fem olika populationerna. Detta innebär att om man med stor säkerhet vill uppskatta åldern på musslor utifrån deras skallängd så behöver man anpassa en tillväxtkurva för varje population. En allmän tillväxtkurva har räknats fram genom att använda olika matematiska formler. Den mest korrekta åldersuppskattningen ger en kurva byggd på von Bertanlanffy tillväxtekvation.Dunca, E. & Boalt, E. 2011. Rapport Nr 6/2011: Shell length and age relationship in blue mussel (Mytilus edulis) from Baltic Sea. Blue mussels from five Baltic Sea locations (Landskrona, Kullen, Abbekås, Dragviksfjärden och Högby fyr) were age determined employing a special method developed at the Swedish museum of Natural History in Stockholm during late 90s. This method was compared with the most common method of age determination by counting the annual rings on the shell surface of the bivalves. The shell length of the five populations bivalves in this study was then expressed as a function of their age in growth diagrams. Shell size varies between the mussel populations as well as the age distribution. In order to estimate the age of the mussels by their shell length growth curves were constructed for each population. The growth curves were calculated using several formulas but the most reliable was the von Bertanlanffy growth equation

Cadmium, lead, and mercury concentrations in whole-fish, liver, and muscle of herring (Clupea harengus) and perch (Perca fluviatilis)

Monitoring of metal concentrations in fish is commonly conducted using samples of fish liver or muscle. This becomes problematic when these values are used for environmental status evaluations regarding chemical pollution, as many of the thresholds evaluating environmental status are designed to evaluate concentrations in whole-fish. In this study, concentrations of cadmium, lead, and mercury in herring and perch are compared between liver, muscle, and whole-fish. The aim is to create conversion factors that can be used to convert metal concentrations between tissues and organs. Mercury and cadmium were detected in all analyzed organs and tissues, whereas lead concentrations were below the level of quantification for most muscle and liver samples. In general, there was a strong relationship between liver and muscle concentrations and concentrations in whole-fish, indicating that creation of conversion factors between tissues and organs is suitable. The resulting conversion factor between whole-fish and liver concentrations for cadmium was 0.1 and 0.16 for herring and perch, respectively. The conversion factor between whole-fish and liver concentrations for mercury was 0.52 and 1.66 for herring and perch, respectively, while for whole-fish and muscle concentrations for mercury, the conversion factor was 0.86 and 0.74 for herring and perch. As there was no significant relationship between liver and whole-fish concentrations for lead, a conversion is not appropriate. Conversion factors levels differed significantly between herring and perch, indicating that species-specific conversion factors are necessary

A retrospective study of metals and stable isotopes in seals from Swedish waters

Concentrations of Hg in Swedish marine systems are generally lower than in fresh water systems, but still often exceed environmental target levels. As top predators in many marine food webs, seals are exposed to heavy metals, like Hg and Cd, which are known to biomagnify with increasing trophic level in the food web. Therefore, studies of Hg concentrations over time are preferably conducted in relation to seal diet during the same period. By analysis of naturally occurring stable nitrogen and carbon isotopes it is possible to determine on which trophic level a certain organism is located and where it feeds. The aim of the present study was to try to establish background concentrations of Hg and some other metals in Swedish marine waters by analyses of seal bones from the 1840s and forward. Stable isotopes were analyzed in order to discover possible correlations between metal concentrations and trophic level, and changes over time in dietary intake of metals. No significant change in metal concentrations was seen over time, except for a significant decrease in Zn concentrations in Baltic Grey seal. A significant difference in δ 15N and δ13C values between species and between Baltic and Skagerrak areas was discovered. No significant correlation between δ 15N or δ13C values and metals was found, however, the seal with the highest δ 15N value (Harbor seal) also had the highest Hg concentration. Even though the δ 15N values suggested an increase over time the increase was not statistically significant. No statistically significant change over time was found in δ 13C values. It is important to keep in mind that this study was based on 44 individual seals spread over 126 years. Data on sex and age was lacking for almost half of the seals, which made statistical analysis on these parameters difficult to perform. Even though no obvious trends or differences in metal concentrations between areas and species were seen, the results from this study can serve as a base for further studies and provide valuable information for interpreting the actual contamination load in Swedish marine systems

The relationship between mercury and selenium in Baltic herring - a retrospective study

Hg is known to affect productivity, reproduction and survival of coastal and marine animals and when deposited in aquatic ecosystems the metal can be bioaccumulated in the food web. Se is a naturally occurring essential nonmetal that is present in all cells. It has many important functions in the cell and it also stimulates the immune system. The relationship between Hg and Se has been subject to numerous studies and the majority point to a negative relationship between the two elements, showing mitigating effects of Se on Hg toxicity. However, some studies have shown no relationship between Hg and Se concentrations and others demonstrate a positive relationship between the two. Generally a large excess of Se in relation to Hg has been observed in fish. The tissue concentrations of and the relationship between Hg and Se are suggested to be dependent on a number of factors, such as the relative concentrations of the elements and their bioavailabilities. The aim of this study was to investigate the temporal trends and the relationship between Hg and Se concentrations in herring muscle at three different locations along the Swedish east coast. Further, the aim was to give recommendations to whether Se concentrations in fish in Swedish waters should be included in the SCMPMB. Concentrations of Hg in herring muscle were generally higher than concentrations of Se. The highest Hg concentrations were found in herring muscle from Ängskärsklubb, while Landsort had the highest Se concentrations. Se concentrations in herring muscle were decreasing at Utlängan and Ängskärsklubb. The results from this study indicate a complex relationship between Hg and Se concentrations in herring muscle, depending on the magnitude of the Hg concentration. At Hg concentrations below 40 ng/g, a negative correlation between Hg and Se was seen, while at concentrations of Hg above 40 ng/g w.w the correlation to Se was positive. The conclusion of this study is that concentrations of Se in herring from Swedish waters should be included in the SCMPMB.

Natural production of brominated aromatic compounds in the red alga Ceramium tenuicorne

      Summary High levels of the toxic, brominated substances; hydroxylated polybrominated diphenyl ethers (OH-PBDEs), methoxylated polybrominated diphenyl ethers (MeO-PBDEs), and 2,4,6-tribromophenol (2,4,6-TBP) have been found in Baltic biota with levels fluctuating over seasons. A growing body of evidence is pointing towards filamentous algae as a natural producer of these chemicals. However, conclusive scientific evidence supporting this hypothesis is lacking and why such production occurs has not comprehensively been addressed. This pilot study, carried out with a limited set of replicates reveals a production of 6-OH-BDE47, 6-OH-BDE137, and 2,4,6-TBP in the filamentous alga, Ceramium tenuicorne, a common red alga both in the Baltic Sea and in temperate waters. When exposed to grazing or strong light, monocultures of the female marine clone of C. tenuicorne tended to produce elevated levels of 2,4,6-TBP compared to undamaged controls. When exposed to increased levels of salinity, monocultures of the female brackish clone of C. tenuicorne tended to produce elevated levels of 2,4,6-TBP compared to undamaged controls. Algae collected from the Swedish east coast also tended to produce higher levels of 2,4,6-TBP than algae collected from the west coast. From field collected material, a seasonal variation with a peak of OH-PBDEs, MeO-PBDE, and TBP concentrations in July- August could also be detected. The results of this study open up for further studies regarding natural production of brominated aromatic compounds by filamentous algae as a response to environmental stress. Increased understanding regarding sources and possible variations in production of brominated aromatic compounds is crucial for successful monitoring and assessment of environmental status

Comments Concerning the National Swedish Contaminant Monitoring Programme in Fresh Water Biota 2009

This report gives a summary of the monitoring activities within the national Swedish contaminant programme in freshwater biota. It is the result from the joint efforts of: the Department of Applied Environmental Science at Stockholm University (analyses of organochlorines, flame retardants and perfluorinated compounds), Department of Chemistry at Umeå University (analyses of PCDD/PCDF) and the Department of Contaminant Research at the Swedish Museum of Natural History (co-ordination, sample collection administration, sample preparation, recording of biological variables, storage of frozen biological tissues in the Environmental Specimen Bank for retrospective studies, data preparation and statistical evaluation). The monitoring programme is financed by the Environmental Protection Agency (EPA) in Sweden. The data of concern in this report represent the bioavailable part of the investigated contaminants i.e. the part that has virtually passed through the biological membranes and may cause toxic effects. The objectives of the monitoring program in freshwater biota could be summarised as follows:Chemical analysis:Organochlorines/bromines and perfluorinated substancesDepartment of Applied Environmental Science, Stockholm UniversityPCDD/PCDFDepartment of Chemistry, Umeå University</p

Comments Concerning the National Swedish Contaminant Monitoring Programme in Marine Biota, 2011

The environmental toxicants examined in this report can be classified into five groups – heavy metals, chlorinated compounds, brominated flame retardants, polyaromatic hydrocarbons and perfluorinated compounds. Each of these contaminants has been examined from various sites for up to six different fish species, in blue mussels, and in guillemot eggs, for varying lengths of time. The following summary examines overall trends, spatial and temporal, for the five groups. Condition and Fat Content Condition and fat content in different species tended to follow the same pattern at the same sites, with a few exceptions. Most of the fish species generally displayed a decreasing trend in both condition and fat content at most sites examined. Exceptions to this were increases in fat content seen in herring (the last ten years) and cod at Fladen; an increase in condition for herring at Ängskärsklubb in spring; and in perch, a decrease in fat content at Kvädöfjärden but no trend in condition for the same site. Heavy Metals Due to a change in methods for metal analysis (not Hg) in 2004, values between 2003 and 2007 should be interpreted with care. From 2009 metals are analyzed at ITM, Stockholm university. The longer time series in guillemot egg and spring-caught herring from the southern Bothnian Sea and southern Baltic Proper show significant decreases of mercury. The herring site in the southern Bothnain Sea indicates a local Hg-source. The rest of the time series show varying concentrations over the study period, and even increasing trends in e.g. cod muscle and blue mussels, but the concentrations are fairly low compared to measured concentrations in perch from fresh water and coastal sites. However, in most cases, these concentrations are above the newly suggested EU-target level of 20 ng/g wet weight. Lead is generally decreasing over the study period (in time series of sufficient length), supposedly due to the elimination of lead in gasoline. Elevated lead concentrations between 2003 and 2007 (e.g. Harufjärden) should be viewed with caution (see above regarding change in analysis methods). Cadmium concentrations show varying non-linear trends over the monitored period. It is worth noting that despite several measures taken to reduce discharges of cadmium, generally the most recent concentrations are similar to concentrations measured 30 years ago in the longer time series. The reported nickel concentrations show no consistent decreasing trends. Some series begin with two elevated values that exert a strong leverage effect on the regression line and may give a false impression of decreasing trends. Chromium generally shows decreasing trends, possibly explained by a shift in analytical method. The essential trace metals, copper and zinc, show no consistent trends during the monitored period

Comments Concerning the National Swedish Contaminant Monitoring Programme in Marine Biota, 2011

The environmental toxicants examined in this report can be classified into five groups – heavy metals, chlorinated compounds, brominated flame retardants, polyaromatic hydrocarbons and perfluorinated compounds. Each of these contaminants has been examined from various sites for up to six different fish species, in blue mussels, and in guillemot eggs, for varying lengths of time. The following summary examines overall trends, spatial and temporal, for the five groups. Condition and Fat Content Condition and fat content in different species tended to follow the same pattern at the same sites, with a few exceptions. Most of the fish species generally displayed a decreasing trend in both condition and fat content at most sites examined. Exceptions to this were increases in fat content seen in herring (the last ten years) and cod at Fladen; an increase in condition for herring at Ängskärsklubb in spring; and in perch, a decrease in fat content at Kvädöfjärden but no trend in condition for the same site. Heavy Metals Due to a change in methods for metal analysis (not Hg) in 2004, values between 2003 and 2007 should be interpreted with care. From 2009 metals are analyzed at ITM, Stockholm university. The longer time series in guillemot egg and spring-caught herring from the southern Bothnian Sea and southern Baltic Proper show significant decreases of mercury. The herring site in the southern Bothnain Sea indicates a local Hg-source. The rest of the time series show varying concentrations over the study period, and even increasing trends in e.g. cod muscle and blue mussels, but the concentrations are fairly low compared to measured concentrations in perch from fresh water and coastal sites. However, in most cases, these concentrations are above the newly suggested EU-target level of 20 ng/g wet weight. Lead is generally decreasing over the study period (in time series of sufficient length), supposedly due to the elimination of lead in gasoline. Elevated lead concentrations between 2003 and 2007 (e.g. Harufjärden) should be viewed with caution (see above regarding change in analysis methods). Cadmium concentrations show varying non-linear trends over the monitored period. It is worth noting that despite several measures taken to reduce discharges of cadmium, generally the most recent concentrations are similar to concentrations measured 30 years ago in the longer time series. The reported nickel concentrations show no consistent decreasing trends. Some series begin with two elevated values that exert a strong leverage effect on the regression line and may give a false impression of decreasing trends. Chromium generally shows decreasing trends, possibly explained by a shift in analytical method. The essential trace metals, copper and zinc, show no consistent trends during the monitored period