Needs, opportunities and strategies for a long-term oceanic sciences satellite program

Several areas of the National Oceanic Satellite System are addressed including Satellite-borne communication systems, subsurface remote sensing, data coordination, color scanners, formatting important historical data sets, and sea surface temperature observations

Dissolved Organic Phosphorus Production during Simulated Phytoplankton Blooms in a Coastal Upwelling System

Dissolved organic phosphorus (DOP) is increasingly recognized as an important phosphorus source to marine primary producers. Despite its importance, the production rate and fate of DOP is poorly understood. In this study, patterns of DOP production were evaluated by tracking the evolution of DOP during simulated phytoplankton blooms initiated with nutrient amended surface waters, relative to controls, from the Oregon (USA) coastal upwelling system. Nitrogen (N) and phosphorus (P) additions were used to decouple DOP production and hydrolysis by inducing or repressing, respectively, community alkaline phosphatase activity. In order to examine the progression of nutrient uptake and DOP production under upwelling versus relaxation conditions, two experiments were initiated with waters collected during upwelling events, and two with waters collected during relaxation events. Maximum [under (+P) conditions] and minimum [under (+N) conditions] DOP production rates were calculated and applied to in situ DOP levels to evaluate which end-member rate most closely approximates the in situ DOP production rate at the four study sites in this coastal system. Increases in DOP concentration occurred by day-5 in control treatments in all experiments. N treatments displayed increased chlorophyll a, increased alkaline phosphatase activity, and yielded lower net DOP production rates relative to controls, suggesting that DOP levels were depressed as a consequence of increased hydrolysis of bioavailable DOP substrates. Phosphorus additions resulted in a significant net production of DOP at all stations, but no increase in chlorophyll a relative to control treatments. The contrasting patterns in DOP production between treatments suggests that changes in the ambient dissolved inorganic nitrogen:dissolved inorganic phosphorus (DIN:DIP) ratio could exert profound control over DOP production rates in this system. Patterns of DOP production across the different experiments also suggest that bathymetry-driven differences in water residence times can influence DOP cycling. Taken together, these factors may impact the potential export of DOP to offshore ecosystems

What Is Philosophy?

The speaker relates philosophy to and distinguishes it from all the arts and sciences in terms of its breadth and depth. Philosophy thinks about things, and thoughts, and words and actions (“words and deeds”, in Cicero’s phrase). There are examples of philosophers who have reduced all three of them to one and of philosophers who have kept them distinct. There have been revolutions in philosophy, responsive to great changes in cultural life, in science and politics, and in reaction against established traditions within philosophy. In modern times, there has been a metaphysical revolution against the Aristotelian schoolmen, an epistemological revolution against that metaphysical tradition, and a revolution of phenomenology, logic, and pragmatism against the psychologism of that epistemological tradition. The last part of the lecture considers important ideas of that last revolution that have become determinant of the ways in which we think about science and life. The goal of the lecture was to show the usefulness of philosophy in the past and to promote liberation of thinking for new gains in the future

Bacterially mediated removal of phosphorus and cycling of nitrate and sulfate in the waste stream of a "zero-discharge" recirculating mariculture system

Simultaneous removal of nitrogen and phosphorus by microbial biofilters has been used in a variety of water treatment systems including treatment systems in aquaculture. In this study, phosphorus, nitrate and sulfate cycling in the anaerobic loop of a zero-discharge, recirculating mariculture system was investigated using detailed geochemical measurements in the sludge layer of the digestion basin. High concentrations of nitrate and sulfate, circulating in the overlying water (~15 mM), were removed by microbial respiration in the sludge resulting in a sulfide accumulation of up to 3 mM. Modelling of the observed S and O isotopic ratios in the surface sludge suggested that, with time, major respiration processes shifted from heterotrophic nitrate and sulfate reduction to autotrophic nitrate reduction. The much higher inorganic P content of the sludge relative to the fish feces is attributed to conversion of organic P to authigenic apatite. This conclusion is supported by: (a) X-ray diffraction analyses, which pointed to an accumulation of a calcium phosphate mineral phase that was different from P phases found in the feces, (b) the calculation that the pore waters of the sludge were highly oversaturated with respect to hydroxyapatite (saturation index = 4.87) and (c) there was a decrease in phosphate (and in the Ca/Na molar ratio) in the pore waters simultaneous with an increase in ammonia showing there had to be an additional P removal process at the same time as the heterotrophic breakdown of organic matter

Importance of Suspended Particulates in Riverine Delivery of Bioavailable Nitrogen to Coastal Zones

Total nitrogen (TN) loadings in riverine sediments and their coastal depocenters were compared for Il river systems worldwide to assess the potential impact of riverine particulates on coastal nitrogen budgets. Strong relationships between sediment specific surface area and TN allow these impacts to be estimated without the intense sampling normally required to achieve such budgets. About half of the systems showed higher nitrogen loadings in the riverine sediments than those from the coastal depocenter. In spite of uncertainties, these comparisons indicate that large, turbid rivers, such as the Amazon, Huanghe, and the Mississippi, deliver sediments that in turn release significant or major fractions of the total riverine nitrogen delivery. Riverine particulates must therefore be considered an essential factor in watershed nutrient loading to coastal ecosystems and may affect delivered nutrient ratios as well as total nutrient loading. The relative importance of particulate versus dissolved delivery has decreased over recent decades in the Mississippi as a result of damming and fertilizer use in the watershed

Biological Effects Within No-Take Marine Reserves: A global Synthesis

The study and implementation of no-take marine reserves have increased rapidly over the past decade, providing ample data on the biological effects of reserve protection for a wide range of geographic locations and organisms. The plethora of new studies affords the opportunity to reevaluate previous findings and address formerly unanswered questions with extensive data syntheses. Our results show, on average, positive effects of reserve protection on the biomass, numerical density, species richness, and size of organisms within their boundaries which are remarkably similar to those of past syntheses despite a near doubling of data. New analyses indicate that (1) these results do not appear to be an artifact of reserves being sited in better locations; (2) results do not appear to be driven by displaced fishing effort outside of reserves; (3) contrary to often-made assertions, reserves have similar if not greater positive effects in temperate settings, at least for reef ecosystems; (4) even small reserves can produce significant biological responses irrespective of latitude, although more data are needed to test whether reserve effects scale with reserve size; and (5) effects of reserves vary for different taxonomic groups and for taxa with various characteristics, and not all species increase in response to reserve protection. There is considerable variation in the responses documented across all the reserves in our data set—variability which cannot be entirely explained by which species were studied. We suggest that reserve characteristics and context, particularly the intensity of fishing outside the reserve and inside the reserve before implementation, play key roles in determining the direction and magnitude of the reserve response. However, despite considerable variability, positive responses are far more common than no differences or negative responses, validating the potential for well designed and enforced reserves to serve as globally important conservation and management tools

Rapid Invasion of Indo-Pacific Lionfishes (\u3cem\u3ePterois Volitans\u3c/em\u3e and \u3cem\u3ePterois Miles\u3c/em\u3e) in the Florida Keys, USA: Evidence from Multiple Pre- and Post-Invasion Data Sets

Over the past decade, Indo-Pacific lionfishes, Pterois volitans (Linnaeus, 1758) and Pterois miles (Bennett, 1828), venomous members of the scorpionfish family (Scorpaenidae), have invaded and spread throughout much of the tropical and subtropical northwestern Atlantic Ocean and Caribbean Sea. These species are generalist predators of fishes and invertebrates with the potential to disrupt the ecology of the invaded range. Lionfishes have been present in low numbers along the east coast of Florida since the 1980s, but were not reported in the Florida Keys until 2009. We document the appearance and rapid spread of lionfishes in the Florida Keys using multiple long-term data sets that include both pre- and post-invasion sampling. Our results are the first to quantify the invasion of lionfishes in a new area using multiple independent, ongoing monitoring data sets, two of which have explicit estimates of sampling effort. Between 2009 and 2011, lionfish frequency of occurrence, abundance, and biomass increased rapidly, increasing three- to six-fold between 2010 and 2011 alone. In addition, individuals were detected on a variety of reef and non-reef habitats throughout the Florida Keys. Because lionfish occurrence, abundance, and impacts are expected to continue to increase throughout the region, monitoring programs like those used in this study will be essential to document ecosystem changes that may result from this invasion

Elevated Levels of Trace Elements in Cores of Otoliths and Their Potential for Use as Natural Tags

Variation in the chemical composition of fish otoliths has been used in recent years to address a range of ecological questions, including levels of stock mixing, variation in habitat use, and rates of larval exchange. While some of these questions have been answered with varying success, the degree to which discrete populations are connected via larval exchange remains unknown. To identify larval sources using natural variation in otolith chemistry, we must distinguish and measure the chemical composition of the otolith core, the portion of the otolith formed at the spawning site. Using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), we found that the core regions of otoliths from 6 different species of fishes were highly enriched in manganese (Mn), and elevated in magnesium (Mg) and barium (Ba), relative to adjacent regions of the otolith. These patterns were consistent for species drawn from different taxonomic groups, which inhabit temperate and tropical regions, are found in marine and freshwater, and utilize a variety of spawning modes. Variation among species in Mn concentration in the core also corresponds to maternal investment, measured by egg size. These data suggest that core enrichment may be a general characteristic of otoliths, and that the chemical composition of the otolith core is fundamentally different from other regions of the otolith. The localized elemental enrichment of the core underscores the importance of methods that analyze the core region in small, discrete samples if otolith chemistry is used to address questions of larval exchange among populations

Understanding the nature of atmospheric acid processing of mineral dusts in supplying bioavailable phosphorus to the oceans

Acidification of airborne dust particles can dramatically increase the amount of bioavailable phosphorus (P) deposited on the surface ocean. Experiments were conducted to simulate atmospheric processes and determine the dissolution behaviour of phosphorus compounds in dust and dust precursors oils. Acid dissolution occurs rapidly (seconds to minutes) and is controlled by the amount of H + ions present. For H + 10-4 mol per gram of dust, the amount of phosphorus (and Ca) released follows a power law dependent on the amount of H + consumed until all inorganic phosphorus minerals are exhausted and the final pH remains acidic. Once dissolved, phosphorus will stay in solution due to slow precipitation kinetics. Dissolution of apatite-P, the major mineral phase in dust (79-96%), occurs whether CaCO 3 is present or not, though the increase in dissolved phosphorus is greater if CaCO 3 is absent or if the particles are externally mixed. The system was modelled adequately as a simple mixture of apatite-P and calcite. Phosphorus dissolves readily by acid processes in the atmosphere in contrast to iron, which dissolves slower and is subject to re-precipitation at cloud water pH. We show that acidification can increase bioavailable phosphorus deposition over large areas of the globe, and may explain much of the previously observed patterns of variability in leachable phosphorus in oceanic areas where primary productivity is limited by this nutrient (e.g. Mediterranean)