Declines of biomes and biotas and the future of evolution

Although panel discussants disagreed whether the biodiversity crisis constitutes a mass extinction event, all agreed that current extinction rates are 50–500 times background and are increasing and that the consequences for the future evolution of life are serious. In response to the on-going rapid decline of biomes and homogenization of biotas, the panelists predicted changes in species geographic ranges, genetic risks of extinction, genetic assimilation, natural selection, mutation rates, the shortening of food chains, the increase in nutrient-enriched niches permitting the ascendancy of microbes, and the differential survival of ecological generalists. Rates of evolutionary processes will change in different groups, and speciation in the larger vertebrates is essentially over. Action taken over the next few decades will determine how impoverished the biosphere will be in 1,000 years when many species will suffer reduced evolvability and require interventionist genetic and ecological management. Whether the biota will continue to provide the dependable ecological services humans take for granted is less clear. The discussants offered recommendations, including two of paramount importance (concerning human populations and education), seven identifying specific scientific activities to better equip us for stewardship of the processes of evolution, and one suggesting that such stewardship is now our responsibility. The ultimate test of evolutionary biology as a science is not whether it solves the riddles of the past but rather whether it enables us to manage the future of the biosphere. Our inability to make clearer predictions about the future of evolution has serious consequences for both biodiversity and humanity.

Global environmental impacts of agricultural expansion: The need for sustainable and efficient practices

The recent intensification of agriculture, and the prospects of future intensification, will have major detrimental impacts on the nonagricultural terrestrial and aquatic ecosystems of the world. The doubling of agricultural food production during the past 35 years was associated with a 6.87-fold increase in nitrogen fertilization, a 3.48-fold increase in phosphorus fertilization, a 1.68-fold increase in the amount of irrigated cropland, and a 1.1-fold increase in land in cultivation. Based on a simple linear extension of past trends, the anticipated next doubling of global food production would be associated with approximately 3-fold increases in nitrogen and phosphorus fertilization rates, a doubling of the irrigated land area, and an 18% increase in cropland. These projected changes would have dramatic impacts on the diversity, composition, and functioning of the remaining natural ecosystems of the world, and on their ability to provide society with a variety of essential ecosystem services. The largest impacts would be on freshwater and marine ecosystems, which would be greatly eutrophied by high rates of nitrogen and phosphorus release from agricultural fields. Aquatic nutrient eutrophication can lead to loss of biodiversity, outbreaks of nuisance species, shifts in the structure of food chains, and impairment of fisheries. Because of aerial redistribution of various forms of nitrogen, agricultural intensification also would eutrophy many natural terrestrial ecosystems and contribute to atmospheric accumulation of greenhouse gases. These detrimental environmental impacts of agriculture can be minimized only if there is much more efficient use and recycling of nitrogen and phosphorus in agroecosystems.

Physical Health Problems and Environmental Challenges Influence Balancing Behaviour in Laying Hens

With rising public concern for animal welfare, many major food chains and restaurants are changing their policies, strictly buying their eggs from non-cage producers. However, with the additional space in these cage-free systems to perform natural behaviours and movements comes the risk of injury. We evaluated the ability to maintain balance in adult laying hens with health problems (footpad dermatitis, keel damage, poor wing feather cover; n = 15) using a series of environmental challenges and compared such abilities with those of healthy birds (n = 5). Environmental challenges consisted of visual and spatial constraints, created using a head mask, perch obstacles, and static and swaying perch states. We hypothesized that perch movement, environmental challenges, and diminished physical health would negatively impact perching performance demonstrated as balance (as measured by time spent on perch and by number of falls of the perch) and would require more exaggerated correctional movements.We measured perching stability whereby each bird underwent eight 30-second trials on a static and swaying perch: with and without disrupted vision (head mask), with and without space limitations (obstacles) and combinations thereof. Video recordings (600 Hz) and a three-axis accelerometer/gyroscope (100 Hz) were used to measure the number of jumps/falls, latencies to leave the perch, as well as magnitude and direction of both linear and rotational balance-correcting movements. Laying hens with and without physical health problems, in both challenged and unchallenged environments, managed to perch and remain off the ground. We attribute this capacity to our training of the birds. Environmental challenges and physical state had an effect on the use of accelerations and rotations to stabilize themselves on a perch. Birds with physical health problems performed a higher frequency of rotational corrections to keep the body centered over the perch, whereas, for both health categories, environmental challenges required more intense and variable movement corrections. Collectively, these results provide novel empirical support for the effectiveness of training, and highlight that overcrowding, visual constraints, and poor physical health all reduce perching performance.

Behavior analysis of oithona in hypoxic/anoxic conditions

Senior thesis written for Oceanography 445

The fate of Lyngbya majuscula toxins in three potential consumers

Blooms of Lyngbya majuscula have been reported with increasing frequency and severity in the last decade in Moreton Bay, Australia. A number of grazers have been observed feeding upon this toxic cyanobacterium. Differences in sequestration of toxic compounds from L. majuscula were investigated in two anaspideans, Stylocheilus striatus, Bursatella leachii, and the cephalaspidean Diniatys dentifer. Species fed a monospecific diet of L. majuscula had different toxin distribution in their tissues and excretions. A high concentration of lyngbyatoxin-a was observed in the body of S. striatus (3.94 mg/kg(-1)) compared to bodily secretions (ink 0.12 mg/kg- 1; fecal matter 0.56 mg/kg(-1); eggs 0.05 mg/kg(-1)). In contrast, B. leachii secreted greater concentrations of lyngbyatoxin-a (ink 5.41 mg/kg(-1); fecal matter 6.71 mg/kg(-1)) than that stored in the body (2.24 mg/kg(-1)). The major internal repository of lyngbyatoxin-a and debromoaplysiatoxin was the digestive gland for both S. striatus (6.31 +/- 0.31 mg/kg(-1)) and B. leachii (156.39 +/- 46.92 mg/kg(-1)). D. dentifer showed high variability in the distribution of sequestered compounds. Lyngbyatoxin-a was detected in the digestive gland (3.56 +/- 3.56 mg/kg(-1)) but not in the head and foot, while debromoaplysiatoxin was detected in the head and foot (133.73 +/- 129.82 mg/kg(-1)) but not in the digestive gland. The concentrations of sequestered secondary metabolites in these animals did not correspond to the concentrations found in L. majuscula used as food for these experiments, suggesting it may have been from previous dietary exposure. Trophic transfer of debromoaplysiatoxin from L. majuscula into S. striatus is well established; however, a lack of knowledge exists for other grazers. The high levels of secondary metabolites observed in both the anaspidean and the cephalapsidean species suggest that these toxins may bioaccumulate through marine food chains.

Ecosystem structure of Gomishan Wetland

Gomishan Wetland is situated in the extreme southern part of the eastern coast of Caspian Sea. It is connected to the Caspian Sea, so its hydrological features are directly generated from the sea. The whole wetland area (which also consists of the northern part of the wetland that is situated in Turkmenistan republic) is calculated with the aid of the Satellite Images for the years of 1977, 1987 and 1998 respectively 5070, 16320 and 29520 hectares. To have better ideas about food chains in the aquatic ecosystem, five permanent stations was appointed in different parts of the wetland. During one year field study, at the beginning of each month, physical, chemical and biological characteristics of the water and the sediment was surveyed and different specimens were gathered, fixed and took to the laboratories for the relevant analyses. The factors measured in water samples were mainly consist of turbidity, pH, EC, DO, BOD, PO4, NO3, alkalinity, Cl and hardness . The factors measured from sediment samples were the percentage of Sand, Very Fine Sand, Silt, Clay, K, P, N, and Organic Carbon. Biological examinations of the water has been consist of planktonic sample collections, determination, counting and analysis of both phyto and zoo planktons of the wetland. For example the zooplanktons of the Gomishan Wetland are determined in 15 groups, belonging to 5 phyla. The seasonal changes are recognized considerable. The least density of the zooplanktons is occurred in February. The density of most of the groups is seen from the beginning of the summer until the mid autumn. The annual mean density for any 15-zooplankton groups and also the minimum and maximum density with %95 confidences, for each of them, is calculated for the environment of all of the stations and also for the whole wetland. The spatial distribution of the individuals within the population of each of the groups is introduced, according to regular or contagious or random distribution. Diversity indices are calculated for the zooplanktons living in the environment of the stations. Comparison of the wetland, with the southeastern Caspian Sea, from the point of view of zooplankton density and diversity is also obtained. Benthos invertebrates in each station from sediment samples were also extracted. The specimens were colored by Rose Bengal solvent and then were determinate and counted, in separate groups of macro and meio benthos. Among the macro benthos, the highest density was seen in the species of Fyrgula caspia. After that, more density was seen respectively in Apra ovata, Cerastoderma sp., Balanus sp., Nerds divesicolarr, lifytilaster lineatus and Dreissena sp. Among the meio benthos, the most density was seen in Foraminifera and then respectively in Ostracoda, Nernatoda and Bivalve larvae. The indices of diversity and distribution are also calculated. As the birds in this lagoon are of prime importance, all mid winter waterfowl censuses available from recent 13 years are gathered and analysis. Also a whole year (12 times, each at the beginning of one month) waterfowl census was undertaken, throughout the wetland. According to this study, the Eastern Ecosystem of the wetland, is supporting the most population (%75) of the waterfowls, the Middle Open Water Ecosystem and the Western Reed bed Ecosystem, are supporting respectively %14 and %11 of the population. Four of the species are found in the global threatened red list, and the wintering population of the 20 species of the site, in some years, are observed more than %I of the global populations. The Waterfowl Species Diversity and Similarity Indices are given also.

Salt content of processed foods available in the Portuguese market

Evidence suggests that current levels of salt consumption across Europe are linked with several chronic diseases. In recent decades, high blood pressure has increased, together with the consumption of processed foods. World Health Organization (WHO) recommends a salt intake of less than 5 g/day for the prevention of cardiovascular disease. The aim of this study was to evaluate the salt content of processed foods available in the Portuguese market and to compare the determined values with the recommended daily intake established by WHO. Categories of processed foods that contribute to a higher intake of salt were identified: pastry, bakery, fast-food, snacks, ready-to-eat meals, nuts, seeds, soups, cereals, sauces, patties, among others. Between 2013 and 2015, 267 processed food samples were acquired in food chains and restaurants from Lisbon region (Portugal) and the salt content was quantified using Charpentier-Volhard method. High amounts of salt were quantified in the analysed processed foods, namely snacks, fast-food, patties, meals and bakery products. If we consider one portion of a curd cheese pie (193 g), the intake of salt can reach 45% of the recommended value. For snacks, regular portion size is 35 g. One portion of a salty snack can contribute with 31% of the salt recommended daily intake. Up to now food industry has developed efforts to decrease the salt content of some food products, namely bread. However, there still exist foods with high salt content and from a nutritional point of view this should be a priority area of intervention. The obtained results are an effective assessment of current salt content in foods which will be important for further reformulation strategies and to monitor progress in the next years.

Características limnológicas e estrutura trófica das comunidades de peixes de alguns lagos naturais e artificiais do Rio Grande do Norte

Artificial lakes must differ from natural lakes in important structural and functional aspects that need to be understood so that these ecosystems can be properly managed. The aim of this work was to test the hypothesis that the artificial lakes (impoundments) in the semi-arid region of the Rio Grande do Norte State are more eutrophic and turbid and have different trophic structure when compared to the natural coastal lakes that occur in the humid eastern coast of the State. To test this hypothesis, 10 natural lakes and 8 artificial lakes with about 100 ha were sampled between September and November 2005 for the determination of some limnological variables and the abundance of the main fish species, which were grouped in three trophic guilds: facultative piscivores, facultative planktivores and omnivores. The results show that the artificial lakes had significantly higher concentrations of total nitrogen, total phosphorus, chlorophyll a , total and volatile suspended solids than the natural lakes. Results also show that the values of pH, total alkalinity, electric conductivity, turbidity as well as the coefficient of vertical attenuation of light were significantly higher in the artificial lakes than in the natural lakes. In the artificial lakes, the abundance of facultative planktivores was significantly higher, while the abundance of facultative piscivores significantly lower than in the natural lakes. There was no significant difference in the abundance of omnivorous fish between the two types of lakes. These results suggest that the increase in turbidity together with the other changes in the water quality of the artificial lakes, modifies the trophic structure of the fish communities reducing the importance of piscivores and the length of the food chains

Características limnológicas e estrutura trófica das comunidades de peixes de alguns lagos naturais e artificiais do Rio Grande do Norte

Artificial lakes must differ from natural lakes in important structural and functional aspects that need to be understood so that these ecosystems can be properly managed. The aim of this work was to test the hypothesis that the artificial lakes (impoundments) in the semi-arid region of the Rio Grande do Norte State are more eutrophic and turbid and have different trophic structure when compared to the natural coastal lakes that occur in the humid eastern coast of the State. To test this hypothesis, 10 natural lakes and 8 artificial lakes with about 100 ha were sampled between September and November 2005 for the determination of some limnological variables and the abundance of the main fish species, which were grouped in three trophic guilds: facultative piscivores, facultative planktivores and omnivores. The results show that the artificial lakes had significantly higher concentrations of total nitrogen, total phosphorus, chlorophyll a , total and volatile suspended solids than the natural lakes. Results also show that the values of pH, total alkalinity, electric conductivity, turbidity as well as the coefficient of vertical attenuation of light were significantly higher in the artificial lakes than in the natural lakes. In the artificial lakes, the abundance of facultative planktivores was significantly higher, while the abundance of facultative piscivores significantly lower than in the natural lakes. There was no significant difference in the abundance of omnivorous fish between the two types of lakes. These results suggest that the increase in turbidity together with the other changes in the water quality of the artificial lakes, modifies the trophic structure of the fish communities reducing the importance of piscivores and the length of the food chains

The red swamp crayfish Procambarus clarkii in Europe: Impacts on aquatic ecosystems and human well-being

Procambarus clarkii is currently recorded from 16 European territories. On top of being a vector of crayfish plague, which is responsible for large-scale disappearance of native crayfish species, it causes severe impacts on diverse aquatic ecosystems, due to its rapid life cycle, dispersal capacities, burrowing activities and high population densities. The species has even been recently discovered in caves. This invasive crayfish is a polytrophic keystone species that can exert multiple pressures on ecosystems. Most studies deal with the decline of macrophytes and predation on several species (amphibians, molluscs, and macroinvertebrates), highlighting how this biodiversity loss leads to unbalanced food chains. At a management level, the species is considered as (a) a devastating digger of the water drainage systems in southern and central Europe, (b) an agricultural pest in Mediterranean territories, consuming, for example, young rice plants, and (c) a threat to the restoration of water bodies in north-western Europe. Indeed, among the high-risk species, P. clarkii consistently attained the highest risk rating. Its negative impacts on ecosystem services were evaluated. These may include the loss of provisioning services such as reductions in valued edible native species of regulatory and supporting services, inducing wide changes in ecological communities and increased costs to agriculture and water management. Finally, cultural services may be lost. The species fulfils the criteria of the Article 4(3) of Regulation (EU) No 1143/2014 of the European Parliament (species widely spread in Europe and impossible to eradicate in a cost-effective manner) and has been included in the “Union List”. Particularly, awareness of the ornamental trade through the internet must be reinforced within the European Community and import and trade regulations should be imposed to reduce the availability of this high-risk species.