Hypothalamic integration of body fluid regulation.

The progression of animal life from the paleozoic ocean to rivers and diverse econiches on the planet's surface, as well as the subsequent reinvasion of the ocean, involved many different stresses on ionic pattern, osmotic pressure, and volume of the extracellular fluid bathing body cells. The relatively constant ionic pattern of vertebrates reflects a genetic "set" of many regulatory mechanisms--particularly renal regulation. Renal regulation of ionic pattern when loss of fluid from the body is disproportionate relative to the extracellular fluid composition (e.g., gastric juice with vomiting and pancreatic secretion with diarrhea) makes manifest that a mechanism to produce a biologically relatively inactive extracellular anion HCO3- exists, whereas no comparable mechanism to produce a biologically inactive cation has evolved. Life in the ocean, which has three times the sodium concentration of extracellular fluid, involves quite different osmoregulatory stress to that in freshwater. Terrestrial life involves risk of desiccation and, in large areas of the planet, salt deficiency. Mechanisms integrated in the hypothalamus (the evolutionary ancient midbrain) control water retention and facilitate excretion of sodium, and also control the secretion of renin by the kidney. Over and above the multifactorial processes of excretion, hypothalamic sensors reacting to sodium concentration, as well as circumventricular organs sensors reacting to osmotic pressure and angiotensin II, subserve genesis of sodium hunger and thirst. These behaviors spectacularly augment the adaptive capacities of animals. Instinct (genotypic memory) and learning (phenotypic memory) are melded to give specific behavior apt to the metabolic status of the animal. The sensations, compelling emotions, and intentions generated by these vegetative systems focus the issue of the phylogenetic emergence of consciousness and whether primal awareness initially came from the interoreceptors and vegetative systems rather than the distance receptors.

cemA homologue essential to CO2 transport in the cyanobacterium Synechocystis PCC6803.

We have isolated mutants of Synechocystis PCC6803 that grew very slowly in a low-sodium medium, which is unfavorable for HCO3(-) transport, and examined two of these mutants (SC1 and SC2) for their ability to take up CO2 and HCO3(-) in the light. The CO2 transport activity of SC1 and SC2 was much lower than that of the wild type (WT), whereas there was no difference between the mutants and the WT in their activity of HCO3(-) transport. A clone containing a 3.9-kilobase-pair insert DNA that transforms both mutants to the WT phenotype was isolated from a genomic library of WT Synechocystis. Sequencing of the insert DNA in the region of mutations in SC1 and SC2 revealed an open reading frame (designated cotA), which showed significant amino-acid sequence homology to cemA encoding a protein found in the inner envelope membrane of chloroplasts. The cotA gene is present in a single copy and was not cotranscribed with any other gene(s). cotA encodes a protein of 247 amino acids containing four transmembrane domains. There was substitution of a single base in SC1 and two bases in SC2 in their cotA genes. A possible role of the cotA gene product in CO2 transport is discussed.

Isolation of small polarized bile duct units.

Fragments of small interlobular bile ducts averaging 20 microns in diameter can be isolated from rat liver. These isolated bile duct units form luminal spaces that are impermeant to dextran-40 and expand in size when cultured in 10 microM forskolin for 24-48 hr. Secretion is Cl- and HCO3- dependent and is stimulated by forskolin > dibutyryl cAMP > secretion but not by dideoxyforskolin, as assessed by video imaging techniques. Secretin stimulates Cl-/HCO3- exchange activity, and intraluminal pH increases after forskolin administration. These studies establish that small polarized physiologically intact interlobular bile ducts can be isolated from rat liver. These isolated bile duct units should be useful preparations for assessing the transport properties of small bile duct segments, which are the primary site of injury in cholestatic liver disorders, known as "vanishing bile duct syndromes."

Efeitos da associação de azaperone e xilazina em veados-mateiros (Mazama americana) mantidos em cativeiro

O presente estudo objetivou determinar um protocolo para sedação de veados-mateiros (Mazama americana) que permitisse procedimentos comumente utilizados no manejo dessa espécie em cativeiro. Foram utilizados seis animais adultos, pesando 38,4 ± 5 Kg, pertencentes ao Núcleo de Pesquisa e Conservação de Cervídeos (UNESP - Jaboticabal). Os animais foram submetidos a dois tratamentos, com um intervalo mínimo de 30 dias entre eles, a saber: AX-0,5 - associação de 1 mg/kg de azaperone e 0,5 mg/kg de xilazina via intramuscular (IM) e AX-1,0 - associação de 1 mg/kg de azaperone e 1 mg/kg de xilazina (IM). A partir da administração do tratamento (0 minuto) foram avaliados os tempos para latência da sedação, para decúbito esternal, para a manipulação segura e para a manipulação sem segurança. Ainda, foram avaliados a qualidade da contenção química por meio da somatória de pontos obtida com a utilização de uma escala descritiva adaptada, a cada 10 minutos, por até 90 minutos, parâmetros fisiológicos (FC, fR, PAM e To) a cada 10 minutos, durante 60 minutos, perfil ácido-base e eletrolítico (pH, PaCO2, PaO2, HCO3-, EB, SaO2, Na+ e K+) aos 10, 30 e 60 minutos e lactato sérico aos 30 e 60 minutos pós-tratamentos. As diferenças foram consideradas significantes quando P < 0,05. O período de latência da sedação e período para os animais apresentarem decúbito esternal foram maiores em AX-0,5 (7 ± 6,6 e 12 ± 9,7 minutos, respectivamente) em relação a AX-1,0 (5 ± 2,0 e 6 ± 3,1 minutos respectivamente), porém não houve diferenças entre os grupos para os demais tempos avaliados. A qualidade da contenção química diferiu entre os grupos a partir de 60 minutos, observando-se possibilidade de manipulação sem segurança a partir de 60 minutos para AX-0,5 e de 90 minutos para AX-1,0. Não houve diferenças entre FC, fR, PAM e To e o lactato sérico entre os momentos nem entre os grupos. Em relação ao perfil ácido-base e eletrólitico, AX-0,5 apresentou diferenças em pH, HCO3-,, EB e K+, com valores aos 60 minutos superiores aos valores em 10 minutos, e AX-1,0 apresentou diferenças apenas para EB também com valores aos 60 minutos superiores aos 10 minutos. Diante dos resultados conclui-se que os dois protocolos promoveram sedação adequada e que a escolha entre eles deve ser pautada pela índole do animal. Embora não tenham ocorrido alterações fisiológicas consideráveis em nenhum dos grupos, sugere-se a suplementação de oxigênio nos primeiros 30 minutos de contenção química.

Caracterização limnológica do rio do Peixe (microrregião geográfica de Botucatu - SP), em duas épocas do ano (períodos de seca e chuva)

O rio do Peixe, um dos principais afluentes do rio Tietê (Reservatório de Barra Bonita/Hidrovia Tietê Paraná), juntamente com seus formadores (microrregião geográfica de Botucatu - SP) constituem os principais mananciais das cidades que se localizam em suas bacias. A maior parte da bacia hidrográfica do rio do Peixe desenvolve-se sob rochas sedimentares arenosas, favoráveis às atividades de extração de areia, fato que aliado ao manejo incorreto do solo favorece a ocorrência de processos erosivos. Foram realizadas amostragens de água durante dez dias consecutivos e de sedimento durante três dias alternados, em dois períodos hidrológicos (seca e chuva), para a determinação de variáveis físicas, químicas e biológicas,com o objetivo principal de caracterizar do ponto de vista limnológico esse rio e sua foz. As análises das diferentes variáveis seguiram os métodos que são utilizados rotineiramente no Laboratório de Limnologia do CRHEA/EESC/USP. As águas do rio do Peixe apresentaram, principalmente altas concentrações de sólidos em suspensão. Os maiores valores de turbidez, condutividade, alcalinidade, HCO3-, CO3-, nitrito, nitrogênio amoniacal, nitrogênio Kjedhal, fosfato inorgânico, carbono orgânico e sólidos em suspensão foram obtidos durante o período de chuvas, influenciados principalmente pelo escoamento superficial que promove o carreamento de materiais da bacia hidrográfica. Foi possível ainda através das características limnológicas, agrupar as estações de amostragem ao longo do contínuo do rio em três regiões (alto, médio e baixo curso), e diferenciar do ponto de vista trófico as estações da foz com o rio Tietê. Um aumento da biomassa fitoplanctônica, no período de seca, no baixo curso do rio do Peixe foi favorecido pela menor vazão na barragem de Barra Bonita.

Desempenho, mortalidade e escore fecal de bezerros aleitados com diferentes dietas líquidas e terapias de reidratação quando acometidos por diarreias

O objetivo deste trabalho foi avaliar o efeito da utilização de sucedâneo lácteo com alto conteúdo proteico de origem vegetal no desempenho e saúde de bezerros, e avaliar métodos de reidratação para o tratamento de diarreias. No primeiro estudo foram utilizados 33 bezerros da raça Holandês distribuídos nos tratamentos: 1) Alto volume e baixa proteína (AV/BP): 8 litros, 21,4% PB; 2) Alto volume e alta proteína (AV/AP): 8 litros, 23,7% PB e 3) Baixo volume e alta proteína (BV/AP): 6 litros, 23,7% PB. Os bezerros foram alojados em abrigos individuais, com livre acesso a água e concentrado. Não houve efeito dos tratamentos para o desempenho animal (P>0,05). Os tratamentos AV/BP e AV/AP resultaram em maior consumo de sucedâneo (P<0,05), mas não afetaram o consumo de concentrado nem o consumo total (P>0,05). O escore fecal foi maior (P>0,05) para animais nos tratamentos AV/AP e BV/AP. Os animais nos tratamentos AV/BP permaneceram maior número de dias em diarreia (P<0,05), em comparação aqueles aleitados com BV/AP, os quais tiveram menos dias com vida (P<0,05). A concentração de lactato foi maior (P<0,05) para animais nos tratamentos AV/BP e AV/AP enquanto a concentração de proteína total foi maior (P<0,05) nos tratamentos AV/BP e BV/AP. Sucedâneos com elevado conteúdo de proteína de origem vegetal afetam negativamente o desempenho de bezerros podendo levar o animal a morte. No segundo estudo foram comparados três soluções de hidratação oral quanto a sua eficiência em repor eletrólitos e água, além de manter o desempenho de bezerros. Foram utilizados 42 bezerros mestiços Holandês-Jersey, distribuídos nos tratamentos: 1) Soro comum, 2) Glutellac® e 3) Soro comum + Aminogut®. Os animais foram aleitados com 4 L/d de sucedâneo lácteo até a oitava semana de vida quando foram desaleitados de forma abrupta. As terapias de reidratação foram oferecidas quando os animais apresentavam escore fecal >= 3 na escala de 1 a 5. Não houve efeito das terapias de reidratação no desempenho nem em metabólitos sanguíneos (P>0,05). O consumo voluntário de água foi maior para os animais reidratados com Glutellac®, mas o consumo total maior para os animais reidratados com Soro comum. As concentrações de HCO3 e Na+ foram maiores para os animais no tratamento Glutellac® (P=0,088 e P=0,073 respectivamente), sendo a concentração de glicose também afetada pelo protocolo de hidratação (P<0,05). A concentração de HCO3 aumentou do primeiro para o segundo dia, a de K+ e glicose diminuíram do primeiro para o segundo dia, enquanto que o Beecf teve um comportamento variável segundo a terapia de reidratação utilizada. Houve efeito da interação tratamento x dia de avaliação apenas para a concentração de BUN (P<0,05). O pH, a concentração de Na+ e Beecf foram maiores em animais mais velhos, enquanto K+, hematócrito e hemoglobina, foram menores (P<0,05). O consumo voluntário de água foi maior em animais reidratados com Glutellac®, o que junto com a simplicidade de uso, representam as principais vantagens deste método de reidratação.

Effects of ocean acidification on growth and physiology of Ulva lactuca (Chlorophyta) in a rockpool-scenario, link to supplementary data

Rising atmospheric CO2-concentrations will have severe consequences for a variety of biological processes. We investigated the responses of the green alga Ulva lactuca (Linnaeus) to rising CO2-concentrations in a rockpool scenario. U. lactuca was cultured under aeraton with air containing either preindustrial pCO2 (280µatm) or for the end of the 21st century predicted (700µatm) pCO2 for 31 days. We addressed the following question: Will elevated CO2-concentrations affect photosynthesis (net photosynthesis, rETR(max), Fv/Fm, pigment composition) and growth of U. lactuca in rockpools with limited water exchange? Two phases of the experiment were distinguished: In the initial phase (day 1-4) the Seawater Carbonate System (SWCS) of the culture medium could be adjusted to the selected atmospheric pCO2 condition by continuous aeration with target pCO2 values. In the second phase (day 4-31) the SWCS was largely determined by the metabolism of the growing U. lactuca biomass. In the initial phase, Fv/Fm and rETR(max) were only slightly elevated at high CO2-concentrations whereas growth was significantly enhanced. After 31 days the Chl a content of the thalli was significantly lower under future conditions and the photosynthesis of thalli grown under preindustrial conditions was not dependent on external carbonic anhydrase. Biomass increased significantly at high CO2-concentrations. At low CO2-concentrations most adult thalli disintegrated between day 14 and 21, whereas at high CO2-concentrations most thalli remained integer until day 31. Thallus disintegration at low CO2-concentrations was mirrored in a drastic decline in seawater DIC and HCO3-. Accordingly, the SWCS differed significantly between the treatments. Our results indicated a slight enhancement of photosynthetic performance and significantly elevated growth of U. lactuca at future CO2-concentrations. The accelerated thallus disintegration at high CO2-concentrations under conditions of limited water exchange indicates additional CO2 effects on the life cycle of U. lactuca when living in rockpools.

Stable oxygen and carbon isotope of foraminifera from DSDP Leg 90 sites

High-resolution oxygen and carbon isotope stratigraphy is presented for Miocene to early Pliocene sequences at three DSDP sites from the Lord Howe Rise, southwest Pacific, at water depths ranging from 1,300 to 2,000 m. Site 588 is located in the warm subtropics (~26°S), whereas Sites 590 and 591 are positioned in transitional (northern temperate) water masses (~31°S). Benthic foraminiferal oxygen and carbon isotope analyses were conducted on all sites; planktonic foraminiferal isotope data were generated for Site 590 only. Sample resolution in these sequences is on the order of 50,000 yr. or better. The chronological framework employed in this study is based largely upon ages assigned to Neogene calcareous nannoplankton boundaries. The benthic oxygen isotope record exhibits several major features during the Neogene. During most of the early Miocene, delta18O values were relatively low, reaching minimum values in the late early Miocene (19.5 to 16.5 Ma), and recording the climax of Neogene warmth. This was followed by a major increase in benthic delta18O values between ~16.5 and 13.5 Ma, which is interpreted as representing major, permanent accumulation of the East Antarctic ice sheet and cooling of bottom waters. During the 3 m.y. 18O enrichment, surface waters at these middle latitudes warmed between 16 and 14.5 Ma. During the remainder of the middle and late Miocene, benthic delta18O values exhibit distinct fluctuations, but the average value remained unchanged. The isotopic data show two distinct episodes of climatic cooling close to the middle/late Miocene boundary. The earliest of these events occurred between 12.5 and 11.5 Ma in the latest middle Miocene. The second cooling event occurred from 11 to 9 Ma, and is marked by some of the highest delta18O values of the entire Miocene. This was followed by relative warmth during the middle part of the late Miocene. The latest Miocene and earliest Pliocene (6.2 to 4.5 Ma) were marked by relatively high delta18O values, indicating increased cooling and glaciation. During the middle Pliocene, at about 3.4 Ma, a 0.4 per mil increase in benthic delta18O documents a net increase in average global ice volume and cooling of bottom waters. During this interval of increased glaciation, surface waters warmed by 2-3°C in southern middle-latitude regions. During the late Pliocene, between 2.6 and 2.4 Ma, a further increase in delta18O occurred; this has been interpreted by previous workers as heralding the onset of Northern Hemisphere glaciation. Surface-water warming in the middle latitudes occurred in association with major high-latitude glacial increases in the early middle Miocene (16-14 Ma), middle Pliocene (-3.5 Ma), and late Pliocene (~2.4 Ma). These intervals were also marked by increases in the vertical temperature gradient in the open ocean. Intersite correlation is enhanced by using carbon isotope stratigraphy. The great similarity of the delta13C time-series records within and between ocean basins and with water depth clearly indicates that changes in oceanwide average delta13C of [HCO3]- in seawater dominated the records, rather than local effects. Broad changes in the Neogene delta13C record were caused largely by transfer of organic carbon between continental and oceanic reservoirs. These transfers were caused by marine transgressions and regressions on the continental margins. The dominant feature of Neogene delta13C stratigraphy is a broad late early to early middle Miocene increase of about lâ between ~19 and 14.5 Ma. This trend occurred contemporaneously with a period of maximum coastal onlap (transgression) and maximum Neogene climatic warmth. The delta13C trend terminated during the expansion of the Antarctic ice sheet and associated marine regression. The latest Miocene carbon isotope shift (of up to - 0.75 per mil) at 6.2 Ma is clearly recorded in all sites examined and was followed by relatively low values during the remainder of the Neogene. This shift was caused by a glacioeustatic sealevel lowering that exposed continental margins via regression and ultimately increased the flux of organic carbon to the deep sea. An increase in delta13C values during the early Pliocene (~5 to 4 Ma) resulted from marine transgression during a time of global warmth.

Limitations of microbial hydrocarbon degradation at the Amon Mud Volcano (Nile Deep Sea Fan)

The Amon mud volcano (MV), located at 1250 m water depth on the Nile Deep Sea Fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the Amon MV center in the presence of sulphate and hydrocarbons in the seeping subsurface fluids. By comparing spatial and temporal patterns of in situ biogeochemical fluxes, temperature gradients, pore water composition and microbial activities over three years, we investigated why the activity of anaerobic hydrocarbon degraders can be low despite high energy supplies. We found that the central dome of the Amon MV, as well as a lateral mud flow at its base, showed signs of recent exposure of hot subsurface muds lacking active hydrocarbon degrading communities. In these highly disturbed areas, anaerobic degradation of methane was less than 2% of the methane flux. Rather high oxygen consumption rates compared to low sulphide production suggest a faster development of more rapidly growing aerobic hydrocarbon degraders in highly disturbed areas. In contrast, the more stabilized muds surrounding the central gas and fluid conduits hosted active anaerobic hydrocarbon-degrading microbial communities. Furthermore, within three years, cell numbers and hydrocarbon degrading activity increased at the gas-seeping sites. The low microbial activity in the hydrocarbon-vented areas of Amon mud volcano is thus a consequence of kinetic limitations by heat and mud expulsion, whereas most of the outer mud volcano area is limited by hydrocarbon transport.

Maintenance of coelomic fluid pH in sea urchins exposed to elevated CO2: the role of body cavity epithelia and stereom dissolution

Experimental ocean acidification leads to a shift in resource allocation and to an increased [HCO3-] within the perivisceral coelomic fluid (PCF) in the Baltic green sea urchin Strongylocentrotus droebachiensis. We investigated putative mechanisms of this pH compensation reaction by evaluating epithelial barrier function and the magnitude of skeleton (stereom) dissolution. In addition, we measured ossicle growth and skeletal stability. Ussing chamber measurements revealed that the intestine formed a barrier for HCO3- and was selective for cation diffusion. In contrast, the peritoneal epithelium was leaky and only formed a barrier for macromolecules. The ossicles of 6 week high CO2-acclimatised sea urchins revealed minor carbonate dissolution, reduced growth but unchanged stability. On the other hand, spines dissolved more severely and were more fragile following acclimatisation to high CO2. Our results indicate that epithelia lining the PCF space contribute to its acid-base regulation. The intestine prevents HCO3- diffusion and thus buffer leakage. In contrast, the leaky peritoneal epithelium allows buffer generation via carbonate dissolution from the surrounding skeletal ossicles. Long-term extracellular acid-base balance must be mediated by active processes, as sea urchins can maintain relatively high extracellular [HCO3-]. The intestinal epithelia are good candidate tissues for this active net import of HCO3- into the PCF. Spines appear to be more vulnerable to ocean acidification which might significantly impact resistance to predation pressure and thus influence fitness of this keystone species.

Expression of biomineralization-related ion transport genes in Emiliania huxleyi

Biomineralization in the marine phytoplankton Emiliania huxleyi is a stringently controlled intracellular process. The molecular basis of coccolith production is still relatively unknown although its importance in global biogeochemical cycles and varying sensitivity to increased pCO2 levels has been well documented. This study looks into the role of several candidate Ca2+, H+ and inorganic carbon transport genes in E. huxleyi, using quantitative reverse transcriptase PCR. Differential gene expression analysis was investigated in two isogenic pairs of calcifying and non-calcifying strains of E. huxleyi and cultures grown at various Ca2+ concentrations to alter calcite production. We show that calcification correlated to the consistent upregulation of a putative HCO3- transporter belonging to the solute carrier 4 (SLC4) family, a Ca2+/H+ exchanger belonging to the CAX family of exchangers and a vacuolar H+-ATPase. We also show that the coccolith-associated protein, GPA is downregulated in calcifying cells. The data provide strong evidence that these genes play key roles in E. huxleyi biomineralization. Based on the gene expression data and the current literature a working model for biomineralization-related ion transport in coccolithophores is presented.

Radiocarbon ages, dose rates, water isotopic composition and hydrochemistry of samples from Komakuk Beach and Herschel Island

Terrestrial permafrost archives along the Yukon Coastal Plain (northwest Canada) have recorded landscape development and environmental change since the Late Wisconsinan at the interface of unglaciated Beringia (i.e. Komakuk Beach) and the northwestern limit of the Laurentide Ice Sheet (i.e. Herschel Island). The objective of this paper is to compare the late glacial and Holocene landscape development on both sides of the former ice margin based on permafrost sequences and ground ice. Analyses at these sites involved a multi-proxy approach including: sedimentology, cryostratigraphy, palaeoecology of ostracods, stable water isotopes in ground ice, hydrochemistry, and AMS radiocarbon and infrared stimulated luminescence (IRSL) dating. AMS and IRSL age determinations yielded full glacial ages at Komakuk Beach that is the northeastern limit of ice-free Beringia. Herschel Island to the east marks the Late Wisconsinan limit of the northwest Laurentide Ice Sheet and is composed of ice-thrust sediments containing plant detritus as young as 16.2 cal ka BP that might provide a maximum age on ice arrival. Late Wisconsinan ice wedges with sediment-rich fillings on Herschel Island are depleted in heavy oxygen isotopes (mean d18O of -29.1 per mil); this, together with low d-excess values, indicates colder-than-modern winter temperatures and probably reduced snow depths. Grain-size distribution and fossil ostracod assemblages indicate that deglaciation of the Herschel Island ice-thrust moraine was accompanied by alluvial, proluvial, and eolian sedimentation on the adjacent unglaciated Yukon Coastal Plain until ~11 cal ka BP during a period of low glacio-eustatic sea level. The late glacial-Holocene transition was marked by higher-than-modern summer temperatures leading to permafrost degradation that began no later than 11.2 cal ka BP and caused a regional thaw unconformity. Cryostructures and ice wedges were truncated while organic matter was incorporated and soluble ions were leached in the thaw zone. Thermokarst activity led to the formation of ice-wedge casts and deposition of thermokarst lake sediments. These were subsequently covered by rapidly accumulating peat during the early Holocene Thermal Maximum. A rising permafrost table, reduced peat accumulation, and extensive ice-wedge growth resulted from climate cooling starting in the middle Holocene until the late 20th century. The reconstruction of palaeolandscape dynamics on the Yukon Coastal Plain and the eastern Beringian edge contributes to unraveling the linkages between ice sheet, ocean, and permafrost that have existed since the Late Wisconsinan.

Vertical profiles of environmental parameters measured on discrete water samples collected with Niskin bottles during the Tara Oceans expedition 2009-2013

The present data publication provides permanent links to original and updated versions of validated data files. The data files include properties of seawater, particulate matter and dissolved matter that were measured from discrete water samples collected with Niskin bottles during the 2009-2013 Tara Oceans expedition. Properties include pigment concentrations from HPLC analysis (10 depths per vertical profile, 25 pigments per depth), the carbonate system (Surface and 400m; pH (total scale), CO2, pCO2, fCO2, HCO3, CO3, Total alkalinity, Total carbon, OmegaAragonite, OmegaCalcite, and dosage Flags), nutrients (10 depths per vertical profile; NO2, PO4, N02/NO3, SI, quality Flags), DOC, CDOM, and dissolved oxygen isotopes. The Service National d'Analyse des Paramètres Océaniques du CO2, at the Université Pierre et Marie Curie, determined CT and AT potentiometrically (Edmond 1970; DOE 1994) on samples preserved according to Dickson et al. (2007). More than 250 vertical profiles of these properties were made across the world ocean. DOC, CDOM and dissolved oxygen isotopes are available only for the Arctic Ocean and Arctic Seas (2013).

Seawater carbonate chemistry and photosynthetic response of Emiliania huxleyi (CS-369) to UV radiation and elevated temperature duirng experiments, 2011

Changes in calcification of coccolithophores may affect their photosynthetic responses to both, ultraviolet radiation (UVR, 280-400 nm) and temperature. We operated semi-continuous cultures of Emiliania huxleyi (strain CS-369) at reduced (0.1 mM, LCa) and ambient (10 mM, HCa) Ca2+ concentrations and, after 148 generations, we exposed cells to six radiation treatments (>280, >295, >305, >320, >350 and >395 nm by using Schott filters) and two temperatures (20 and 25 °C) to examine photosynthesis and calcification responses. Overall, our study demonstrated that: (1) decreased calcification resulted in a down regulation of photoprotective mechanisms (i.e., as estimated via non-photochemical quenching, NPQ), pigments contents and photosynthetic carbon fixation; (2) calcification (C) and photosynthesis (P) (as well as their ratio) have different responses related to UVR with cells grown under the high Ca2+ concentration being more resistant to UVR than those grown under the low Ca2+ level; (3) elevated temperature increased photosynthesis and calcification of E. huxleyi grown at high Ca2+concentrations whereas decreased both processes in low Ca2+ grown cells. Therefore, a decrease in calcification rates in E. huxleyi is expected to decrease photosynthesis rates, resulting in a negative feedback that further reduces calcification.

Seawater carbonate chemistry and accumulation of radiotracers in squid, Loligo vulgaris during experiments, 2011

The anthropogenic release of carbon dioxide (CO2) into the atmosphere leads to an increase in the CO2 partial pressure (pCO2) in the ocean, which may reach 950 ?atm by the end of the 21st century. The resulting hypercapnia (high pCO2) and decreasing pH ("ocean acidification") are expected to have appreciable effects on water-breathing organisms, especially on their early-life stages. For organisms like squid that lay their eggs in coastal areas where the embryo and then paralarva are also exposed to metal contamination, there is a need for information on how ocean acidification may influence trace element bioaccumulation during their development. In this study, we investigated the effects of enhanced levels of pCO2 (380, 850 and 1500 ?atm corresponding to pHT of 8.1, 7.85 and 7.60) on the accumulation of dissolved 110mAg, 109Cd, 57Co, 203Hg, 54Mn and 65Zn radiotracers in the whole egg strand and in the different compartments of the egg of Loligo vulgaris during the embryonic development and also in hatchlings during their first days of paralarval life. Retention properties of the eggshell for 110mAg, 203Hg and 65Zn were affected by the pCO2 treatments. In the embryo, increasing seawater pCO2 enhanced the uptake of both 110mAg and 65Zn while 203Hg showed a minimum concentration factor (CF) at the intermediate pCO2. 65Zn incorporation in statoliths also increased with increasing pCO2. Conversely, uptake of 109Cd and 54Mn in the embryo decreased as a function of increasing pCO2. Only the accumulation of 57Co in embryos was not affected by increasing pCO2. In paralarvae, the CF of 110mAg increased with increasing pCO2, whereas the 57Co CF was reduced at the highest pCO2 and 203Hg showed a maximal uptake rate at the intermediate pCO2. 54Mn and 65Zn accumulation in paralarvae were not significantly modified by hypercapnic conditions. Our results suggest a combined effect of pH on the adsorption and protective properties of the eggshell and of hypercapnia on the metabolism of embryo and paralarvae, both causing changes to the accumulation of metals in the tissues of L. vulgaris.