Surface sediment diatoms from the western Pacific marginal seas and their correlation to environmental variables

Diatom data of 192 surface sediment samples from the marginal seas in the western Pacific together with modern summer and winter sea surface temperature and salinity data were analyzed. The results of canonical correspondence analysis show that summer sea-surface salinity (SSS) is highly positively correlated with winter SSS and so is summer sea-surface temperature (SST) with winter SST. The correlations between SSSs and SSTs are less positively correlated, which may be due to interactions of regional current pattern and monsoon climate. The correlations between diatom species, sample sites and environmental variables concur with known diatom ecology and regional oceanographic characters. The results of forward selection of the environmental variables and associated Monte Carlo permutation tests of the statistical significance of each variable suggest that summer SSS and winter SST are the main environmental factors affecting the diatom distribution in the area and therefore preserved diatom data from down core could be used for reconstructions of summer SSS and winter SST in the region.

Distribution of calcifying and silicifying phytoplankton in relation to environmental and biogeochemical parameters during the late stages of the 2005 North East Atlantic Spring Bloom

The late stage of the North East Atlantic (NEA) spring bloom was investigated during June 2005 along a transect section from 45 to 66 degrees N between 15 and 20 degrees W in order to characterize the contribution of siliceous and calcareous phytoplankton groups and describe their distribution in relation to environmental factors. We measured several biogeochemical parameters such as nutrients, surface trace metals, algal pigments, biogenic silica (BSi), particulate inorganic carbon (PIC) or calcium carbonate, particulate organic carbon, nitrogen and phosphorus (POC, PON and POP, respectively), as well as transparent exopolymer particles (TEP). Results were compared with other studies undertaken in this area since the JGOFS NABE program. Characteristics of the spring bloom generally agreed well with the accepted scenario for the development of the autotrophic community. The NEA seasonal diatom bloom was in the late stages when we sampled the area and diatoms were constrained to the northern part of our transect, over the Icelandic Basin (IB) and Icelandic Shelf (IS). Coccolithophores dominated the phytoplankton community, with a large distribution over the Rockall-Hatton Plateau (RHP) and IB. The Porcupine Abyssal Plain (PAP) region at the southern end of our transect was the region with the lowest biomass, as demonstrated by very low Chla concentrations and a community dominated by picophytoplankton. Early depletion of dissolved silicic acid (DSi) and increased stratification of the surface layer most likely triggered the end of the diatom bloom, leading to coccolithophore dominance. The chronic Si deficiency observed in the NEA could be linked to moderate Fe limitation, which increases the efficiency of the Si pump. TEP closely mirrored the distribution of both biogenic silica at depth and prymnesiophytes in the surface layer suggesting the sedimentation of the diatom bloom in the form of aggregates, but the relative contribution of diatoms and coccolithophores to carbon export in this area still needs to be resolved.

Distribution characteristics of matrix-bound phosphine along the coast of China and possible environmental controls

Matrix-bound phosphine (MBP) concentrations in surface sediments collected from 37 stations along the coast of China in 2006 are reported. MBP was found in all samples and the average concentration was 6.30 ng kg(-1) dry weight (dw). The distribution of MBP showed certain spatial variation characteristics with high MBP concentrations at stations near to the coast. The average concentrations of MBP in the northern Yellow Sea (NYS), the southern Yellow Sea (SYS), the northern area of East China Sea (NECS), the southern area of East China Sea (SECS), and South China Sea (SCS) were 5.57 +/- 3.78, 3.78 +/- 2.81, 5.27 +/- 3.07, 5.48 +/- 4.05 and 13.52 +/- 7.86 ng kg(-1) dw. respectively. The correlations between MBP and influencing factors, such as the sedimentary environmental characteristics (sediment type, the grain size, contents of phosphorous, organic matters and redox potential) and the aquatic environmental characteristics (temperature, salinity, depth and hydrodynamics) were studied. The results indicated that MBP was strongly influenced by various factors, such as total phosphorus (TP), organic phosphorus (OP), organic carbon (OC), the grain size and hydrodynamics, all of which not only offered reasonable interpretations for the distribution characteristics of MBP but also provided evidence to support the viewpoint that phosphine originated from OP decomposition. This work is the first comprehensive study of the distribution of MBP along the coast of China and its relationships with environmental factors which will lead to a better understanding of the phosphorus (P) biogeochemical cycle in the sea. (C) 2008 Elsevier Ltd. All rights reserved.

Temporal changes in plankton of the North Sea: community shifts and environmental drivers

This paper analyses long-term and seasonal changes in the North Sea plankton community during the period 1970 to 2008. Based on Continuous Plankton Recorder (CPR) data covering 38 yr, major changes in both phytoplankton and zooplankton abundance and community structure were identified. Regime changes were detected around 1978, 1989 and 1998. The first 2 changes have been discussed in the literature and are defined as a cold episodic event (1978) and a regime shift towards a warm dynamic regime (1989). The effect of these 2 regime changes on plankton indicators was assessed and checked against previous studies. The 1998 change represents a shift in the abundance and seasonal patterns of dinoflagellates and the dominant zooplankton group, the neritic copepods. Furthermore, environmental factors such as air temperature, wind speed and the North Atlantic water inflow were identified as potential drivers of change in seasonal patterns, and the most-likely environmental causes for detected changes were assessed. We suggest that a change in the balance of dissolved nutrients driven by these environmental factors was the cause of the latest change in plankton community structure, which in turn could have affected the North Sea fish community.

Effects of environmental conditions on the seasonal distribution of phytoplankton biomass in the North Sea

We study the spatial and seasonal variability of phytoplankton biomass (as phytoplankton color) in relation to the environmental conditions in the North Sea using data from the Continuous Plankton Recorder survey. By using only environmental fields and location as predictor variables we developed a nonparametric model (generalized additive model) to empirically explore how key environmental factors modulate the spatio-temporal patterns of the seasonal cycle of algal biomass as well as how these relate to the ,1988 North Sea regime shift. Solar radiation, as manifest through changes of sea surface temperature (SST), was a key factor not only in the seasonal cycle but also as a driver of the shift. The pronounced increase in SST and in wind speed after the 1980s resulted in an extension of the season favorable for phytoplankton growth. Nutrients appeared to be unimportant as explanatory variables for the observed spatio-temporal pattern, implying that they were not generally limiting factors. Under the new climatic regime the carrying capacity of the whole system has been increased and the southern North Sea, where the environmental changes have been more pronounced, reached a new maximum.

Macroscale factors affecting diatom abundance: a synergistic use of Continuous Plankton Recorder and satellite remote sensing data

Diatoms exist in almost every aquatic regime; they are responsible for 20% of global carbon fixation and 25% of global primary production, and are regarded as a key food for copepods, which are subsequently consumed by larger predators such as fish and marine mammals. A decreasing abundance and a vulnerability to climatic change in the North Atlantic Ocean have been reported in the literature. In the present work, a data matrix composed of concurrent satellite remote sensing and Continuous Plankton Recorder (CPR) in situ measurements was collated for the same spatial and temporal coverage in the Northeast Atlantic. Artificial neural networks (ANNs) were applied to recognize and learn the complex non-monotonic and non-linear relationships between diatom abundance and spatiotemporal environmental factors. Because of their ability to mimic non-linear systems, ANNs proved far more effective in modelling the diatom distribution in the marine ecosystem. The results of this study reveal that diatoms have a regular seasonal cycle, with their abundance most strongly influenced by sea surface temperature (SST) and light intensity. The models indicate that extreme positive SSTs decrease diatom abundances regardless of other climatic conditions. These results provide information on the ecology of diatoms that may advance our understanding of the potential response of diatoms to climatic change.

The `Chicken and Egg' of Subjective and Social Factors in Desistance from Crime

It is now widely acknowledged that progression from persistent offending to desistance from crime is the outcome of a complex interaction between subjective/ agency factors and social/environmental factors. A methodological challenge for desistance researchers is to unravel the differential impacts of these internal and external factors and the sequence in which they come into play. Towards this, the present investigation draws on a prospective study of 130 male property offenders, interviewed in the 1990s (the Oxford Recidivism Study), and followed up 10 years later. The analysis supports a `subjective—social model' in which subjective states measured before release have a direct effect on recidivism as well as indirect effects through their impact on social circumstances experienced after release from prison.

Are richness patterns of common and rare species equally well explained by environmental variables?

We investigated relationships between richness patterns of rare and common grassland species and environmental factors, focussing on comparing the degree to which the richness patterns of rare and common species are determined by simple environmental variables. Using data collected in the Machair grassland of the Outer Hebrides of Scotland, we fitted spatial regression models using a suite of grazing, soil physicochemical and microtopographic covariates, to nested sub-assemblages of vascular and non-vascular species ranked according to rarity. As expected, we found that common species drive richness patterns, but rare vascular species had significantly stronger affinity for high richness areas. After correcting for the prevalence of individual species distributions, we found differences between common and rare species in 1) the amount of variation explained: richness patterns of common species were better summarised by simple environmental variables, 2) the associations of environmental variables with richness showed systematic trends between common and rare species with coefficient sign reversal for several factors, and 3) richness associations with rare environments: richness patterns of rare vascular species significantly matched rare environments but those of non-vascular species did not. Richness patterns of rare species, at least in this system, may be intrinsically less predictable than those of common species.

Bird diversity and environmental gradients in Britain:a test of the species-energy hypothesis

1. We tested the species diversity-energy hypothesis using the British bird fauna. This predicts that temperature patterns should match diversity patterns. We also tested the hypothesis that the mechanism operates directly through effects of temperature on thermoregulatory loads; this further predicts that seasonal changes in temperature cause matching changes in patterns of diversity, and that species' body mass is influential.

2. We defined four assemblages using migration status (residents or visitors) and season (summer or winter distribution). Records of species' presence/absence in a total of 2362, 10 x 10-km, quadrats covering most of Britain were used, together with a wide selection of habitat, topographic and seasonal climatic data.

3. We fitted a logistic regression model to each species' distribution using the environmental data. We then combined these individual species models mathematically to form a diversity model. Analysis of this composite model revealed that summer temperature was the factor most strongly associated with diversity.

4. Although the species-energy hypothesis was supported, the direct mechanism, predicting an important role for body mass and matching seasonal patterns of change between diversity and temperature, was not supported.

5. However, summer temperature is the best overall explanation for bird diversity patterns in Britain. It is a better predictor of winter diversity than winter temperature. Winter diversity is predicted more precisely from environmental factors than summer diversity.

6. Climate change is likely to influence the diversity of different areas to different extents; for resident species, low diversity areas may respond more strongly as climate change progresses. For winter visitors, higher diversity areas may respond more strongly, while summer visitors are approximately neutral.

Ecological genetics in the North Atlantic: environmental gradients and adaptation at specific loci

The North Atlantic intertidal community provides a rich set of organismal and environmental material for the study of ecological genetics. Clearly defined environmental gradients exist at multiple spatial scales: there are broad latitudinal trends in temperature, meso-scale changes in salinity along estuaries, and smaller scale gradients in desiccation and temperature spanning the intertidal range. The geology and geography of the American and European coasts provide natural replication of these gradients, allowing for population genetic analyses of parallel adaptation to environmental stress and heterogeneity. Statistical methods have been developed that provide genomic neutrality tests of population differentiation and aid in the process of candidate gene identification. In this paper, we review studies of marine organisms that illustrate associations between an environmental gradient and specific genetic markers. Such highly differentiated markers become candidate genes for adaptation to the environmental factors in question, but the functional significance of genetic variants must be comprehensively evaluated. We present a set of predictions about locus-specific selection across latitudinal, estuarine, and intertidal gradients that are likely to exist in the North Atlantic. We further present new data and analyses that support and contradict these simple selection models. Some taxa show pronounced clinal variation at certain loci against a background of mild clinal variation at many loci. These cases illustrate the procedures necessary for distinguishing selection driven by internal genomic vs. external environmental factors. We suggest that the North Atlantic intertidal community provides a model system for identifying genes that matter in ecology due to the clarity of the environmental stresses and an extensive experimental literature on ecological function. While these organisms are typically poor genetic and genomic models, advances in comparative genomics have provided access to molecular tools that can now be applied to taxa with well-defined ecologies. As many of the organisms we discuss have tight physiological limits driven by climatic factors, this synthesis of molecular population genetics with marine ecology could provide a sensitive means of assessing evolutionary responses to climate change.

Spatial variability of macroinvertebrate assemblages and the influence of hydrological and environmental variables along the Sigi River, Tanzania-East Africa

The study of investigating the spatial and temporal variability of macroinvertebrate and their relation to hydrology, hydraulic and environmental factors was done along the Sigi River during two sampling periods in the dry (March) and wet (May) periods of 2012. The river was demarcated based on slope ranges and five river zones were identified as mountains streams (MS), upper foothills (UF), lower foothills (LF), rejuvenated foothills (REJ) and mature lower river (MR). Samples of macroinvertebrate were collected from the five river zones and measurements of hydrological (discharge), hydraulics (Depth, velocity and Froude number) and Environmental (pH, Temperature, substrate, conductivity) parameters were done in each zone. In characterizing the macroinvertebrate assemblages along the Sigi River diversity indices (number of taxa, total abundances, Margalef richness index and ShannonWiener index) were calculated and the most representative species for the spatial and temporal variation were identified. Melanoides and Afronurous showed differences in abundance in two samplings periods while Cleopatra, Potamonautes, Ephemerythus, Neoperla, Caenis, Ceratogomphus and Cheumatopsyche showed significant difference among the river zones. Spearman rank correlation and Distance Linear Model (DistLM) used to revealed physical factors governing the macroinvertebrate assemblages distribution. The study demonstrated that the variation of physical factors like discharge, temperature, conductivity and pH have an important role in the spatial distribution of macroinvertebrate assemblages along the river and the life cycle of macroinvertebrate (Afronurus) is important in determining the temporal variability.

Influence of environmental variables on the predatory sucess of the iberian wolf in the north of Portugal

Tese de mestrado em Biologia da Conservação, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2016

Resilience in environmental educators

Contemporary environmental issues (such as global warming) can present psychological stress, the effects of which are under-examined. The ability to "bounce back" from stress associated with increasing environmental adversity can be understood as resilience, and can be found in some environmental educators. The following paper examines how veteran environmental educators respond to psychological stress to increasing environmental adversity and describes the experience of resilience. Through in-depth interviews, this hermeneutical study sheds light on the environmental factors and internal competencies that contribute to resilience in seven environmental educators. Additionally, the interaction (known as the person/environment transactional process) between these factors and competencies is explored, providing insight into how the participants construct resilience. Kumpfer's (1999) Resilience Framework provided the organizational framework for the results of this study. Findings suggest ways in which resilience in environmental educators can be supported and offers directions for future research.

Haematology of Fenneropenaeus indicus in response to environmental alterations and microbial infections

Aquaculture has developed to become one of the fastest growing food producing sectors in the world.Today India is one among the major shrimp producing countries in the world.There are extensive and intensive shrimp culture practices. In extensive shrimp culture, shrimps are stocked at low densities (< 25 PLs m'2)in large ponds or tidal enclosures in which little or no management is exercised or possible. Farmers depend almost entirely on natural conditions in extensive cultures. Intensive shrimp culture is carried out in high densities (>200 PLs m'2). Much of the world shrimp production still comes from extensive culture.There is a growing demand for fish and marine products for human and animal consumption. This demand has led to rapid growth of aquaculture, which some times has been accompanied by ecological impacts and economic loss due to diseases. The expansion of shrimp culture always accompanies local environmental degradation and occurrence of diseases.Disease out breaks is recognised as a significant constraint to aquaculture production. Environmental factors, water quality, pollution due to effluent discharge and pathogenic invasion due to vertical and horizontal transmission are the main causes of shrimp disease out breaks. Nutritional imbalance, toxicant and other pollutants also account for the onset of diseases. pathogens include viruses, bacteria, fungi and parasites.Viruses are the most economically significant pathogens of the cultured shrimps world wide. Disease control in shrimp aquaculture should focus first on preventive measures for eliminating disease promoting factors.ln order to design prophylactic and proactive measures against shrimp diseases, it is mandatory to understand the immune make up of the cultivable species, its optimum culture conditions and the physico chemical parameters of the rearing environment. It has been proven beyond doubt that disease is an end result of complex interaction of environment, pathogen and the host animal. The aquatic environment is abounded with infectious microbes.The transmission of disease in this environment is extremely easy, especially under dense, culture conditions. Therefore, a better understanding of the immune responses of the cultured animal in relation to its environmental alterations and microbial invasions is essential indevising strategic measures against aquaculture loss due to diseases. This study accentuate the importance of proper and regular health monitoring in shrimps employing the most appropriate haematological biomarkers for application of suitable prophylactic measures in order to avoid serious health hazards in shrimp culture systems.

Environmental Influences on the Frequency and Intensity of North Indian Ocean Tropical Cyclones

Tropical cyclones genesis, movement and intensification are highly dependent on its environment both oceanic and atmospheric. This thesis has made a detailed study on the environmental factors related to tropical cyclones of North Indian Ocean basin. This ocean basin has produced only 6% of the global tropical cyclones annually but it has caused maximum loss of human life associated with the strong winds, heavy rain and particularly storm surges that accompany severe cyclones as they strike the heavily populated coastal areas. Atmospheric factors studied in the thesis are the moisture content of the atmosphere, instability of the atmosphere that produces thunderstorms which are the main source of energy for the tropical cyclone, vertical wind shear to which cyclones are highly sensitive and the Sub-Tropical westerly Jetsteram and its Asian high speed center. The oceanic parameters studied are sea surface temperature and heat storage in the top layer of the ocean. A major portion of the thesis has dealt with the three temporal variabilities of tropical cyclone frequency namely intra-seasonal (mainly the influence of Madden Julian Oscillation), inter- annual (the relation with El Nino Southern Oscillation) and decadal variabilities. Regarding decadal variability, a prominent four decade oscillation in the frequency of both tropical cyclones and monsoon depressions unique to the Indian Ocean basin has been brought out. The thesis consists of 9 chapters.