Planktonic foraminifera of sediment trap samples

Biweekly sediment trap samples and concurrent hydrographic measurements collected between March 2005 and October 2008 from the Cariaco Basin, Venezuela, are used to assess the relationship between [CO3]2- and the area densities (ho A) of two species of planktonic foraminifera (Globigerinoides ruber (pink) and Globigerinoides sacculifer). Calcification temperatures were calculated for each sample using species-appropriate oxygen isotope (d18O) temperature equations that were then compared to monthly temperature profiles taken at the study site in order to determine calcification depth. Ambient [CO3]2- was determined for these calcification depths using alkalinity, pH, temperature, salinity, and nutrient concentration measurements taken during monthly hydrographic cruises. The rho A, which is representative of calcification efficiency, is determined by dividing individual foraminiferal shell weights (±0.43 µg) by their associated silhouette areas and taking the sample average. The results of this study show a strong correlation between rho A and ambient [CO3]2- for both G. ruber and G. sacculifer (R**2 = 0.89 and 0.86, respectively), confirming that [CO3]2- has a pronounced effect on the calcification of these species. Though the rho A for both species reveal a highly significant (p < 0.001) relationship with ambient [CO3]2-, linear regression reveals that the extent to which [CO3]2- influences foraminiferal calcification is species specific. Hierarchical regression analyses indicate that other environmental parameters (temperature and [PO4]3-) do not confound the use of G. ruber and G. sacculifer rho A as a predictor for [CO3]2-. This study suggests that G. ruber and G. sacculifer rho A can be used as reliable proxies for past surface ocean [CO3]2?-

(Table 2) Dinoflagellate cysts in surface sediment samples of METEOR cruises M20/2, M23/1, M34/2 and M34/2

The organic walled cyst content of 41 surface sediment samples from the south-eastern South Atlantic Ocean have been studied to create a dataset that can be used for palaeoceanographic reconstructions. In order to obtain insight into which environmental factors influence the distribution of individual cyst species, the cyst associations have been compared with oceanographic characteristics of the overlying water masses, i.e. temperature, salinity, density and stratification gradients. The associations and relationships have been established by visual examination of the dataset and the multivariate ordination techniques, Detrended Correspondence Analysis and Canonical Correspondence Analysis. Special attention has been given to the factors of transport and preservation of the cysts. Five associations have been recognised as being characteristic of (1) areas influenced by coastal upwelling and/or river outflow, (2) open ocean, (3) Agulhas Current and southern Benguela Current, (4) Benguela Current and (5) Walvis Bay, shelf break area. The factors dominant in influencing either directly or indirectly the cyst distributions appear to be the stratification in the upper 50 m of the water column, nutrient concentration and seasonality. Variations in sea surface temperatures and salinities have only minor effect on cyst distribution.

Modelling the effects of inflow parameters on lake water quality

A one-dimensional lake water quality model which includes water temperature, phytoplankton, phosphorus as phosphate, nitrogen as ammonia, nitrogen as nitrate and dissolved oxygen concentrations, previously calibrated for Lake Calhoun (USA) is applied to Uokiri Lake (Japan) for the year 1994. The model simulated phytoplankton and nutrient concentrations in the lake from July to November. Most of the water quality parameters are found to be the same as for Lake Calhoun. To predict probable lake water quality deterioration from algal blooming due to increased nutrient influx from river inflow, the model was run for several inflow water conditions. Effects of inflow nutrient concentration, inflow volume, inflow water temperatures are presented separately. The effect of each factor is considered in isolation although in reality more than one factor can change simultaneously. From the results it is clear that inflow nutrient concentration, inflow volume and inflow water temperature show very regular and reasonable impacts on lake water quality.

Diatom abundance in surface sediments of the northern North Pacific

In order to map the modern distribution of diatoms and to establish a reliable reference data set for paleoenvironmental reconstruction in the northern North Pacific, a new data set including the relative abundance of diatom species preserved in a total of 422 surface sediments was generated, which covers a broad range of environmental variables characteristic of the subarctic North Pacific, the Sea of Okhotsk and the Bering Sea between 30° and 70°N. The biogeographic distribution patterns as well as the preferences in sea surface temperature of 38 diatom species and species groups are documented. A Q-mode factor analysis yields a three-factor model representing assemblages associated with the Arctic, Subarctic and Subtropical water mass, indicating a close relationship between the diatom composition and the sea surface temperatures. The relative abundance pattern of 38 diatom species and species groups was statistically compared with nine environmental variables, i.e. the summer sea surface temperature and salinity, annual surface nutrient concentration (nitrate, phosphate, silicate), summer and winter mixed layer depth and summer and winter sea ice concentrations. Canonical Correspondence Analysis (CCA) indicates 32 species and species groups have strong correspondence with the pattern of summer sea surface temperature. In addition, the total diatom flux data compiled from ten sediment traps reveal that the seasonal signals preserved in the surface sediments are mostly from spring through autumn. This close relationship between diatom composition and the summer sea surface temperature will be useful in deriving a transfer function in the subarctic North Pacific for the quantitative paleoceanographic and paleoenvironmental studies. The relative abundance of the sea-ice indicator diatoms Fragilariopsis cylindrus and F. oceanica of >20% in the diatom composition is used to represent the winter sea ice edge in the Bering Sea. The northern boundary of the distribution of F. doliolus in the open ocean is suggested to be an indicator of the Subarctic Front, while the abundance of Chaetoceros resting spores may indicate iron input from nearby continents and shelves and induced productivity events in the study area.

(Table T1) Initial water quality conditions for bioassay experiments during Nathaniel B. Palmer cruise NBP09-01 in the Amundsen Sea

Nutrient addition experiments were performed during the austral summer in the Amundsen Sea (Southern Ocean) to investigate the availability of organically bound iron (Fe) to the phytoplankton communities, as well as assess their response to Fe amendment. Changes in autotrophic biomass, pigment concentration, maximum photochemical efficiency of photosystem II, and nutrient concentration were recorded in response to the addition of dissolved free Fe (DFe) and Fe bound to different model ligands. Analysis of pigment concentrations indicated that the autotrophic community was dominated by the prymnesiophyte Phaeocystis antarctica throughout most of the Amundsen Sea, although diatoms dominated in two experiments conducted in the marginal ice zone. Few significant differences in bulk community biomass (particulate organic carbon, nitrogen, and chlorophyll a) were observed, relative to the controls, in treatments with Fe added alone or bound to the ligand phytic acid. In contrast, when Fe was bound to the ligand desferrioxamine B (DFB), decreases in the bulk biomass indices were observed. The concentration of the diatom accessory pigment fucoxanthin showed little response to Fe additions, while the concentration of the P. antarctica-specific pigment, 19'-hexanoyloxyfucoxanthin (19'-hex), decreased when Fe was added alone or bound to the model ligands. Lastly, differences in the nitrate:phosphate (NO3- :PO4**3-) utilization ratio were observed between the Fe-amended treatments, with Fe bound to DFB resulting in the lowest NO3- :PO4**3- uptake ratios (~ 10) and the remaining Fe treatments having higher NO3- :PO4**3- uptake ratios (~ 17). The data are discussed with respect to glacial inputs of Fe in the Amundsen Sea and the bioavailability of Fe. We suggest that the previously observed high NO3- :PO4**3- utilization ratio of P. antarctica is a consequence of its production of dissolved organic matter that acts as ligands and increases the bioavailability of Fe, thereby stimulating the uptake of NO3-.

Seawater carbonate chemistry and growth rate during experiments with coral Acropora cervicornis, 2005

The growth rate of Acropora cervicornis branch tips maintained in the laboratory was measured before, during, and after exposure to elevated nitrate (5 and 10 µM NO3-), phosphate (2 and 4 µM P-PO43) and/or pCO2 (CO2 ~700 to 800 µatm). The effect of increased pCO2 was greater than that of nutrient enrichment alone. High concentrations of nitrate or phosphate resulted in significant decreases in growth rate, in both the presence and absence of increased pCO2. The effect of nitrate and phosphate enrichment combined was additive or antagonistic relative to nutrient concentration and pCO2 level. Growth rate recovery was greater after exposure to increased nutrients or CO2 compared to increased nutrients and CO2. If these results accurately predict coral response in the natural environment, it is reasonable to speculate that the survival and reef-building potential of this species will be significantly negatively impacted by continued coastal nutrification and projected pCO2 increases.

Distribution of diatoms, coccolithophores and planktic foraminifera in the Arabian Sea

The distribution of diatoms, coccolithophores and planktic foraminifers mirrored the hydrographic and trophic conditions of the surface ocean (0-100 m) across the upwelling area off the Oman coast to the central Arabian Sea during May/June 1997 and July/August 1995. The number of diatoms was increased in waters with local temperature minimum and enhanced nutrient concentration (nitrate, phosphate, silicate) caused by upwelling. Vegetative cells of Chaetoceros dominated the diatom assemblage in the coastal upwelling area. Towards the more nutrient depleted and stratified surface waters to the southeast, the number of diatoms decreased, coccolithophore and planktic foraminiferal numbers increased, and floral and faunal composition changed. In particular, the transition between the eutrophic upwelling region off Oman and the oligotrophic central Arabian Sea was marked by moderate nutrient concentration, and high coccolithophore and foraminifer numbers. Florisphaera profunda, previously often referred as a 'lower-photic-zone-species', was frequent in water depths as shallow as 20 m, and at high nutrient concentration up to 14 µmol NO3/l and 1.2 µmol PO4/. To the oligotrophic southeast of the divergence, cell densities of coccolithophores declined and Umbellosphaera irregularis prevailed throughout the water column down to 100 m depth. In general, total coccolithophore numbers were limited by nutrient threshold concentration, with low numbers (<10*10**3 cells/l) at high [NO3] and [PO4], and high numbers (>70*10**3 cells/l) at low [NO3] and [PO4]. The components of the complex microplankton succession, diatoms, coccoliths and planktic foraminifers (and possibly others), should ideally be used as a combined paleoceanographic proxy. Consequently, models on plankton ecology should be resolved at least for the seasonality, to account for the bias of paleoceanographic transfer calculations.

Bioremediation of piggery effluents using Scenedesmus Obliquus microalga [Resumo]

Effluents from intensive pig farms present high nutrient concentration, mainly ammonium, contributing to water eutrophication and pollution. Microalgae ability to deplete inorganic nutrients makes them an efficient effluent bioremediation tool. Scenedesmus obliquus was grown in piggery effluent (without any pretreatment) diluted with tap water at 5%v/v (187±25mg/L N-NH4+) and compared with growth in synthetic Bristol media. A 21-days trial was performed in 1L bubble-column reactors illuminated by fluorescent and LED lamps(3klux). Microalgae growth was monitored through OD540nm, dry weight and Chlorophyll content and also by flow cytometry in terms of autofluorescence read in FL3 channel (>670 nm), cell size (FSC), internal complexity (SSC) and cell membrane integrity (PI). S. obliquus cells have grown slower in pig effluent (mmax=0.13-19d-1) than in Bristol media (mmax=0.46-0.50d-1) although after 15 days the biomass productivity observed for the pig waste cultivation, operated under LED (0.127gL-1d-1) was similar to those attained for the Bristol media after 8 and 12 days (0.130 and 0.129 gL-1d-1 using Fluorescent and LED lights, respectively). The Chlorophyll content was correlated to FL3 autofluorescence, with R2>0.97 for Bristol and R2>0.92 for pig waste cultures. Regarding cell size and complexity, Bristol cultures did not show significant differences along time, while cells grown on pig waste increased, attaining FSC and SSC values similar to those observed for Bristol cultures. However, pig waste led to higher percentage of cells with permeabilised membrane (up to 18%) than Bristol cultures (7%). For pig waste experiments, ammonium removal rates were 95% with final values within legal limits. S. obliquus cultivations proved to be an efficient system for direct piggery effluent bioremediation, attaining biomass productivities similar to those obtained in synthetic media. Using LED lighting enables to reduce the energy consumption while maintaining microalgae growth and bioremediation performance. Scale-up to an outdoor 150L photobioreactor is underway.

CRESCIMENTO INICIAL DE ACÁCIA-NEGRA COM VERMICOMPOSTOS DE DIFERENTES RESÍDUOS AGROINDUSTRIAIS

A utilização de vermicompostos de diferentes resíduos agroindustriais na produção de mudas de acácianegra pode ser uma alternativa de reutilização de resíduos e aumentar a produção de mudas. Assim, os objetivos deste trabalho foram avaliar o crescimento e a concentração de nutrientes em mudas de acácianegra, cultivadas em substratos com diferentes vermicompostos de resíduos orgânicos agroindustriais. Instalou-se em casa de vegetação 11 diferentes tratamentos: T1) vermicomposto de esterco bovino (EB); T2) vermicomposto de esterco ovino (EO); T3) vermicomposto de lodo de parbolização de arroz (LP); T4) tratamento controle (sem adubação); T5) tratamento controle com adução mineral (NPK); T6) mistura de EB e LP; T7) mistura de EO e LP; T8) mistura de EB e vermicomposto de resíduos de alimentos (RA); T9) mistura de EO e RA; T10) mistura de EB e vermicomposto de resíduos de frutas (RF); T11) mistura de EO e RF. Após 180 dias de cultivo em recipiente com capacidade de cinco litros, foram analisadas a massa seca e a concentração de nutrientes na parte aérea da acácia-negra, e a concentração de nutrientes no solo, após o cultivo. A adição do esterco bovino, bem como a mistura de esterco bovino e resíduos alimentícios favoreceram o incremento de matéria seca das plantas de acácia-negra. Os resultados mostraram que as concentrações de nutrientes nas plantas, com exceção de Fe e Mn, variaram com adição de vermicompostos no solo. Os tratamentos T3 e T6 elevaram as concentrações em P, N, Zn de Cu nas folhas de acácia-negra. Além disso, a adição dos vermicompostos ao solo aumentou a disponibilidade de nutrientes para as plantas, mesmo após o cultivo, especialmente com relação ao fósforo, potássio e magnésio, sendo uma alternativa viável e eficaz na produção de mudas, podendo substituir a utilização de adubação mineral.

CRESCIMENTO INICIAL E CONCENTRAÇÃO DE NUTRIENTES EM CLONES DE Eucalyptus urophylla x Eucalyptus grandis SOB INTERFERÊNCIA DE PLANTAS DANINHAS

A presença de plantas daninhas em plantios de eucalipto, especialmente nos dois primeiros anos, pode acarretar grandes prejuízos à produtividade, pois reduz a eficiência de aproveitamento dos recursos de crescimento pela cultura. Assim, objetivou-se com este trabalho avaliar os efeitos da interferência de plantas daninhas sobre o crescimento inicial de dois clones de Eucalyptus urophylla x Eucalyptus grandis e a concentração foliar de nutrientes na cultura e nas plantas daninhas. O experimento foi instalado em esquema fatorial 2 x 5 + 7, sendo dois clones de híbridos de Eucalyptus urophylla x Eucalyptus grandis, identificados como CNB001 e CNB016, em competição com cinco plantas daninhas Urochloa decumbens (capim-braquiária), Ipomoea nil (corda-de-viola), Commelina diffusa (trapoeraba), Spermacoce latifolia (erva-quente) e Panicum maximum (capim-colonião). Adicionalmente, foram cultivados os dois clones de eucalipto e as cinco plantas daninhas em monocultivo como padrão de comparação, no delineamento inteiramente casualizado, com quatro repetições. Foram avaliados eucalipto através da altura de plantas, o diâmetro do coleto, o número de ramos, a área foliar, a matéria seca e, o teor foliar de nutrientes do eucalipto, bem como o teor de nutrientes nas folhas das plantas daninhas. O clone CNB001 apresentou crescimento inicial superior ao clone CNB016, no entanto, livre da interferência de plantas daninhas, verificaram-se teores foliares semelhantes para a maioria dos nutrientes em ambos os genótipos. O clone CNB016 mostrou maior sensibilidade à interferência negativa das plantas daninhas que o clone CNB001, sendo seu crescimento inicial mais afetado por Ipomoea nil e a concentração de nutrientes reduzida pelas espécies Panicum maximum, Urochloa decumbens e Commelina diffusa. Panicum maximum apresentou maior interferência com o clone CNB001, enquanto Ipomoea nil pouco influenciou o crescimento e o teor de nutrientes deste híbrido. As plantas daninhas apresentaram elevada capacidade de extrair nutrientes do solo, mesmo em convivência com os clones de Eucalyptus urophylla x Eucalyptus grandis. A interferência imposta à cultura é dependente da espécie infestante e do genótipo de eucalipto.

EFFECT OF TEMPORARY DROUGHT AT DIFFERENT GROWTH STAGES ON SNAP BEAN POD QUALITY AND YIELD

High quality snap bean ( Phaseolus vulgaris L. ) can be produced under rain-fed conditions, provided that adequate moisture is available. However, drought may occur at any stage of growth of snap bean. The objective of this study was to evaluate the effect of drought stress at different growth stages on pod physical quality and nutrient concentrations. An experiment was conducted at the Horticulture Greenhouse, Hawassa University in Ethiopia. Drought stress (50% of field capacity [FC]) was applied at the unfolding of the fourth trifoliate leaf, flowering and pod formation, against a control with no drought stress. The drought stress treatments and eight cultivars were arranged as a factorial experiment in a completely randomised design, with three replications. Drought stress (50% FC) during reproductive stages significantly (P<0.05) reduced pod texture, appearance, and pod curvature. Drought stress increased protein and zinc concentrations by 41 and 15%, respectively; but reduced iron concentration by 15% in snap bean pods. All the tested cultivars had relatively similar responses to drought stress.

Variação sazonal da concentração de nutrientes em folhas de bananeiras, no Vale do Ribeira-SP

The Vale do Ribeira, SP, main agricultural activity is the banana crop, which accounts for most of this fruit production in the State of São Paulo. The nutritional balance of the plant is one of the most important factors for the banana plant can complete the cycle and achieve high productivity. Aiming to evaluate the seasonal variation of leaf nutrient concentration in banana plants in Vale do Ribeira-SP, we used the results of 252 chemical analyses of plant tissue, collected from August 2009 to September 2010, in the 18 representative properties for the region, ten cultivated with subgroup Cavendish banana plant and eight of subgroup Prata banana plant. The largest variation between the macronutrient occurred for K and S, and among the micronutrients, especially for Fe and B. In some dates of evaluation, there was a higher leaf concentration of P, K, Ca and Zn, in subgroup Cavendish banana plants, while the subgroup Prata banana plants showed higher leaf concentration, especially of Mn, B and N. Climatic conditions, especially rain, influenced the leaf nutrient content, especially for K, N, S, B and Fe.

THE ROLE OF ECTOMYCORRHIZAL FUNGI ON FERTILIZED AND UNFERTILIZED NURSERY GROWN WHITE SPRUCE

Nursery grown seedlings are an essential part of the forestry industry. These seedlings are grown under high nutrient conditions caused by fertilization. Though grown in a controlled environment, symbionts such as ectomycorrhizal fungi (EcMF) are often found in these conditions. To examine the effects of EcMF in these conditions, colonized Picea glauca seedlings were collected from Toumey Nursery in Watersmeet, MI. After collection, the EcMF present were morphotyped, and seedlings with different morphotypes were divided equally into two treatment types- fertilized and unfertilized. Seedlings received treatment for one growing season. After that time, seedlings were collected, ectomycorrhizas identified using morphotyping and DNA sequencing, and seedlings were analyzed for differences in leaf nutrient concentration, content, root to shoot ratio, total biomass, and EcMF community structure. DNA sequencing identified 5 unique species groups- Amphinema sp. 1, Amphinema sp. 5, Thelephora terrestris, Sphaerosporella brunnea, and Boletus variipes. In the unfertilized treatment it was found that Amphinema sp. 1 strongly negatively impacted foliar N concentration. In fertilized seedlings, Thelephora terrestris had a strong negative impact on foliar phosphorus concentration, while Amphinema sp. 1 positively impacted foliar boron, magnesium, manganese, and phosphorus concentration. In terms of content, Amphinema sp. 1 led to significantly higher content of manganese and boron in fertilized treatments, as well as elevated phosphorus in unfertilized seedlings. Amphinema sp. 5 had a significant negative effect on phosphorus content. When examining root to shoot ratio and biomass, those seedlings with more non-mycorrhizal tips had a higher root to shoot ratio. Findings from the study shed light on the interactions of the species. Amphinema sp. 5 shows very different functionality than Amphinema sp. 1. Amphinema sp. 1 appears to have the highest positive effect on seedling nutrition when in both fertilized and unfertilized environments. Amphinema sp. 5 and T. terrestris appear to behave parasitically in both fertilized and unfertilized conditions.

Effects of increased CO2 concentration on nutrient limited coastal summer plankton depend on temperature

Increasing seawater temperature and CO2 concentrations both are expected to increase coastal phytoplankton biomass and carbon to nutrient ratios in nutrient limited seasonally stratified summer conditions. This is because temperature enhances phytoplankton growth while grazing is suggested to be reduced during such bottom-up controlled situations. In addition, enhanced CO2 concentrations potentially favor phytoplankton species, that otherwise depend on costly carbon concentrating mechanisms (CCM). The trophic consequences for consumers under such conditions, however, remain little understood. We set out to experimentally explore the combined effects of increasing temperature and CO2 concentration for phytoplankton biomass and stoichiometry and the consequences for trophic transfer (here for copepods) on a natural nutrient limited Baltic Sea summer plankton community. The results show, that warming effects were translated to the next trophic level by switching the system from a bottom-up controlled to a mainly top-down controlled one. This was reflected in significantly down-grazed phytoplankton and increased zooplankton abundance in the warm temperature treatment (22.5°C). Additionally, at low temperature (16.5°C) rising CO2 concentrations significantly increased phytoplankton biomass. The latter effect however, was due to direct negative impact of CO2 on copepod nauplii which released phytoplankton from grazing in the cold but not in the warm treatments. Our results suggest that future seawater warming has the potential to switch trophic relations between phytoplankton and their grazers under nutrient limited conditions with the consequence of potentially disguising CO2 effects on coastal phytoplankton biomass.