Embryonic and larval ecology and biochemistry of offshore decapods

Understanding the biology of offshore species is hardened by the difficulties of sampling in the deep-sea environment. Additionally, due to the vastness of the open ocean, knowledge of early life histories of pelagic larvae is still relatively scarce. In decapod species with bentho-pelagic lifestyle, the transition from life in the seafloor to the water column not only is associated with drastic morphological metamorphosis, but also with changes in behavior and feeding ecology. The purpose of the present thesis was to investigate physiological, biochemical and behavioral adaptation occurring during early development of such species. The Norway lobster, Nephrops norvegicus, and the crab Monodaeus couchi were used as a model as these two species are encountered off the NE Atlantic shelf at depth greater than 300 m. Chapter 1 introduces the challenges faced by both adult and larvae inhabiting such remote habitats, including the effect of food availability on development and oceanographic processes on dispersal and recruitment. The thesis follows early life histories, starting with within-brood variability in the fatty acid (FA) profile displayed by developing N. norvegicus embryos. There were no differences in the FA composition of embryos sampled from both sides of the brooding chamber in most females. However, all females exhibited significant differences in the FA profiles of embryos sampled from different pleopods. Potential causes for the variations recorded may be differential female investment during oocyte production or shifts in FA catabolism during the incubation period promoted by embryo’s location within the brooding chamber. Next, feeding rates and digestive enzymes activity of the early stage larvae was investigated in N. norvegicus. Both stages were able to maximize food intake when larvae were scarce and showed increased feeding rate following periods of starvation. Amylase activity indicated that carbohydrates are not the primary energy reserve and that feeding may be required soon after hatching to trigger amylase activity. Protease activity indicated that protein reserves are catabolized under starvation. These results indicate that larvae may maximize prey ingestion in the presence of plankton patches with higher food abundance and minimize the deleterious effects induced by previous periods of intermittent starvation or unsuitable prey densities/types. Additionally, changes in enzymatic activity may allow newly hatched N. norvegicus larvae to metabolize protein reserves to overcome short-term starvation. Vertical migration behavior and the influence of oceanographic properties were studied next. All zoeal stages of M. couchi displayed reverse diel vertical migration. Abundance of early stages was correlated with chlorophyll a levels. An ontogenic shift in vertical distribution explained the results; earlier zoeal stages remain in the food-rich upper water column while later stages migrate to the bottom for settlement. This vertical migration behavior is likely to affect horizontal distribution of larvae. Indeed, global current patterns will result in low inter-annual variations in decapod larvae recruitment, but short term variations such as upwelling events will cause deviation from the expected dispersal pattern. Throughout development, from the embryo to metamorphosis into benthic juvenile, offshore decapods face many challenges. For the developing individual survivorship will depend heavily on food availability but also on the reserves passed on by the mother. Even though vertical migration behavior can allow the larvae to take advantage of depth varying currents for transport, the effect of general circulation pattern will superimpose local current and influence feeding conditions and affect dispersal and recruitment.

Analysis of annuli in otoliths, age distribution and growth rates of the Namibian hake (Merluccius capensis)

Dissertação mest., Gestão da Água e da Costa, Universidade do Algarve, 2007

Caracterização endócrina da PTH-L e calcitonina no transporte de cálcio e na secreção de bicarbonato no intestino da dourada (Sparus auratus)

Dissertação de Mestrado, Biologia Marinha, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2009

Estimation of unemployment rates in small areas of Portugal: a best linear unbiased prediction approach versus a hierarchical Bayes approach

The high level of unemployment is one of the major problems in most European countries nowadays. Hence, the demand for small area labor market statistics has rapidly increased over the past few years. The Labour Force Survey (LFS) conducted by the Portuguese Statistical Office is the main source of official statistics on the labour market at the macro level (e.g. NUTS2 and national level). However, the LFS was not designed to produce reliable statistics at the micro level (e.g. NUTS3, municipalities or further disaggregate level) due to small sample sizes. Consequently, traditional design-based estimators are not appropriate. A solution to this problem is to consider model-based estimators that "borrow information" from related areas or past samples by using auxiliary information. This paper reviews, under the model-based approach, Best Linear Unbiased Predictors and an estimator based on the posterior predictive distribution of a Hierarchical Bayesian model. The goal of this paper is to analyze the possibility to produce accurate unemployment rate statistics at micro level from the Portuguese LFS using these kinds of stimators. This paper discusses the advantages of using each approach and the viability of its implementation.

Effects of environmental conditions on planktonic abundances, benthic recruitment and growth rates of the bivalve mollusc Ruditapes decussatus in a Portuguese coastal lagoon

Controlling environmental parameters for the early stages of marine invertebrates have received little attention, particularly in field studies. This study involves measurement of abundances and growth rates of the bivalve Ruditapes decussatus Linnaeus 1758 during its planktonic larval and early benthic life stages in a coastal lagoon: Ria Formosa, Portugal. Measured abundances were compared with tidal amplitude, water temperature, salinity, wind velocity and direction, and a food availability indicator 2chlorophyll a). Data were obtained on abundance and prodissoconch length of the larvae, measured two tothreetimes perweek,and ofpost-larval stagesindividuals thathadsettled inartificial collectors over10months.Larval and juvenile cohorts were identified using size-frequency distributions and larval ages estimated by larval shell growth lines.

Trophic Level Asynchrony in Rates of Phenological Change For Marine, Freshwater and Terrestrial Environments

Recent changes in the seasonal timing (phenology) of familiar biological events have been one of the most conspicuous signs of climate change. However, the lack of a standardised approach to analysing change has hampered assessment of consistency in such changes among different taxa and trophic levels and across freshwater, terrestrial and marine environments. We present a standardised assessment of 25 532 rates of phenological change for 726 UK terrestrial, freshwater and marine taxa. The majority of spring and summer events have advanced, and more rapidly than previously documented. Such consistency is indicative of shared large-scale drivers. Furthermore, average rates of change have accelerated in a way that is consistent with observed warming trends. Less coherent patterns in some groups of organisms point to the agency of more local scale processes and multiple drivers. For the first time we show a broad scale signal of differential phenological change among trophic levels; across environments advances in timing were slowest for secondary consumers, thus heightening the potential risk of temporal mismatch in key trophic interactions. If current patterns and rates of phenological change are indicative of future trends, future climate warming may exacerbate trophic mismatching, further disrupting the functioning, persistence and resilience of many ecosystems and having a major impact on ecosystem services

Comparing growth rates of natural phytoplankton communities to laboratory culturing experiments

Senior thesis written for Oceanography 445

Preterm nutritional intake and MRI phenotype at term age: a prospective observational study

Objective: To describe (1) the relationship between nutrition and the preterm-at-term infant phenotype, (2) phenotypic differences between preterm-at-term infants and healthy term born infants and (3) relationships between somatic and brain MRI outcomes. Design: Prospective observational study. Setting: UK tertiary neonatal unit. Participants: Preterm infants (<32 weeks gestation) (n=22) and healthy term infants (n=39) Main outcome measures: Preterm nutrient intake; total and regional adipose tissue (AT) depot volumes; brain volume and proximal cerebral arterial vessel tortuosity (CAVT) in preterm infants and in term infants. Results: Preterm nutrition was deficient in protein and high in carbohydrate and fat. Preterm nutrition was not related to AT volumes, brain volume or proximal CAVT score; a positive association was noted between human milk intake and proximal CAVT score (r=0.44, p=0.05). In comparison to term infants, preterm infants had increased total adiposity, comparable brain volumes and reduced proximal CAVT scores. There was a significant negative correlation between deep subcutaneous abdominal AT volume and brain volume in preterm infants (r=−0.58, p=0.01). Conclusions: Though there are significant phenotypic differences between preterm infants at term and term infants, preterm macronutrient intake does not appear to be a determinant. Our preliminary data suggest that (1) human milk may exert a beneficial effect on cerebral arterial vessel tortuosity and (2) there is a negative correlation between adiposity and brain volume in preterm infants at term. Further work is warranted to see if our findings can be replicated and to understand the causal mechanisms.

Monetary policy, exchange rates and stock prices in the Middle East region

A structural vector autoregressive model is employed to investigate the impact of monetary policy and real exchange rate shocks on the stock market performance of Kuwait, Oman, Saudi Arabia, Egypt and Jordan. In order to identify the structural shocks both short run and long run restrictions are applied. Unlike previous literature the contemporaneous interdependence between the financial variables are left unrestricted to give a more accurate depiction of the relationships. The heterogeneity of the results reflect the different monetary policy frameworks and stock market characteristics of these countries. Mainly, monetary policy and the real exchange rate shocks have a significant short run impact on the stock prices of the countries that apply a relatively more independent monetary policy and flexible exchange rates.

Investigating the rates and impacts of near misses and related incidents among UK cyclists

The paper investigates the occurrence of non-injury incidents among cyclists in the UK, seeking to (i) generate a rate that can be compared with injury rates, (ii) analyse factors affecting incident rates, and (iii) analyse factors affecting the impact of incidents on cyclists. We collected data on non-injury cycling ‘incidents’ (near misses and other frightening and/or annoying incidents) from 1692 online diaries of cycle trip stages1 and incidents, participants having signed up in advance for a specific day. Following data cleaning and coding, a dataset was created covering 1532 diary days and 3994 records of incidents occurring within the UK. Incident rates were calculated and compared to injury risks for cyclists. Cross-tabulation and regression were used to identify factors affecting incident rates and the effect an incident has on the cyclist. Frightening or annoying non-injury incidents, unlike slight injuries, are an everyday experience for most people cycling in the UK. For regular cyclists ‘very scary’ incidents (rated as 3 on a 0–3 scale) are on average a weekly experience, with deliberate aggression experienced monthly. Per mile, non-injury incidents were more frequent for people making shorter and slower trips. People aged over 55 were at lower risk, as were those cycling at the weekend and outside the morning peak. Incidents that involved motor vehicles, especially those involving larger vehicles, were more frightening than those that did not. Near miss and other non-injury incidents are widespread in the UK and may have a substantial impact on cycling experience and uptake. Policy and research should initially target the most frightening types of incident, such as very close passes and incidents involving large vehicles. Further attention needs to be paid to the experiences of groups under-represented among cyclists, such as women making shorter trips.

Intake of dairy products in relation to periodontitis in older Danish adults

This cross-sectional study investigates whether calcium intakes from dairy and non-dairy sources, and absolute intakes of various dairy products, are associated with periodontitis. The calcium intake (mg/day) of 135 older Danish adults was estimated by a diet history interview and divided into dairy and non-dairy calcium. Dairy food intake (g/day) was classified into four groups: milk, cheese, fermented foods and other foods. Periodontitis was defined as the number of teeth with attachment loss ≥3 mm. Intakes of total dairy calcium (Incidence-rate ratio (IRR) = 0.97; p = 0.021), calcium from milk (IRR = 0.97; p = 0.025) and fermented foods (IRR = 0.96; p = 0.03) were inversely and significantly associated with periodontitis after adjustment for age, gender, education, sucrose intake, alcohol consumption, smoking, physical activity, vitamin D intake, heart disease, visits to the dentist, use of dental floss and bleeding on probing, but non-dairy calcium, calcium from cheese and other types of dairy food intakes were not. Total dairy foods (IRR = 0.96; p = 0.003), milk (IRR = 0.96; p = 0.028) and fermented foods intakes (IRR = 0.97; p = 0.029) were associated with reduced risk of periodontitis, but cheese and other dairy foods intakes were not. These results suggest that dairy calcium, particularly from milk and fermented products, may protect against periodontitis. Prospective studies are required to confirm these findings.

Anthropometric evaluation and micronutrients intake in patients submitted to laparoscopic Roux-en-Y gastric bypass with a postoperative period of ≥1 year

Backgroung - Bariatric surgery is indicated as the most effective treatment for morbid obesity; the Roux-en-Y gastric bypass (RYGB) is considered the procedure of choice. However, nutritional deficiency may occur in the postoperative period as a result of reduced gastric capacity and change in nutrients absorption in the gastrointestinal tract. The prescription of vitamin and mineral supplementation is a common practice after RYGB; however, it may not be sufficient to prevent micronutrient deficiencies. The aim of this study was to quantify the micronutrient intake in patients undergoing RYGB and verify if the intake of supplementation would be enough to prevent nutritional deficiencies. Methods - The study was conducted on 60 patients submitted to RYGB. Anthropometric, analytical, and nutritional intake data were assessed preoperatively and 1 and 2 years postoperatively. The dietary intake was assessed using 24-h food recall; the values of micronutrients evaluated (vitamin B12, folic acid, iron, and calcium) were compared to the dietary reference intakes (DRI). Results - There were significant differences (p < 0.05) between excess weight loss at the first and second year (69.9 ± 15.3 vs 9.6 ± 62.9 %). In the first and second year after surgery, 93.3 and 94.1 % of the patients, respectively, took the supplements as prescribed. Micronutrient deficiencies were detected in the three evaluation periods. At the first year, there was a significant reduction (p < 0.05) of B12, folic acid, and iron intake. Conclusions - Despite taking vitamin and mineral supplementation, micronutrient deficiencies are common after RYGB. In the second year after surgery, micronutrient intake remains below the DRI.

Otimização e validação de um método de cromatografia líquida de alta resolução (HPLC) para a determinação do edulcorante ciclamato: ocorrência em adoçantes de mesa

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Química e Biológica

The effect of long-chain polyunsaturated fatty acids intake during pregnancy on adiposity of healthy full-term offspring at birth

Objective - The adjusted effect of long-chain polyunsaturated fatty acid (LCPUFA) intake during pregnancy on adiposity at birth of healthy full-term appropriate-for-gestational age neonates was evaluated. Study Design - In a cross-sectional convenience sample of 100 mother and infant dyads, LCPUFA intake during pregnancy was assessed by food frequency questionnaire with nutrient intake calculated using Food Processor Plus. Linear regression models for neonatal body composition measurements, assessed by air displacement plethysmography and anthropometry, were adjusted for maternal LCPUFA intakes, energy and macronutrient intakes, prepregnancy body mass index and gestational weight gain. Result - Positive associations between maternal docosahexaenoic acid intake and ponderal index in male offspring (β=0.165; 95% confidence interval (CI): 0.031–0.299; P=0.017), and between n-6:n-3 LCPUFA ratio intake and fat mass (β=0.021; 95% CI: 0.002–0.041; P=0.034) and percentage of fat mass (β=0.636; 95% CI: 0.125–1.147; P=0.016) in female offspring were found. Conclusion - Using a reliable validated method to assess body composition, adjusted positive associations between maternal docosahexaenoic acid intake and birth size in male offspring and between n-6:n-3 LCPUFA ratio intake and adiposity in female offspring were found, suggesting that maternal LCPUFA intake strongly influences fetal body composition.