Description: The Joint Global Ocean Flux Study (JGOFS) has completed a decade of intensive process and time-series studies on the regional and temporal dynamics of biogeochemical processes in five diverse ocean basins. Its field program also included a global survey of dissolved inorganic carbon (DIC) in the ocean, including estimates of the exchange of carbon dioxide (CO2) between the ocean and the atmosphere, in cooperation with the World Ocean Circulation Experiment (WOCE). This report describes the principal achievements of JGOFS in ocean observations, technology development and modelling. The study has produced a comprehensive and high-quality database of measurements of ocean biogeochemical properties. Data on temporal and spatial changes in primary production and CO2 exchange, the dynamics of of marine food webs, and the availability of micronutrients have yielded new insights into what governs ocean productivity, carbon cycling and export into the deep ocean, the set of processes collectively known as the "biological pump." With large-scale, high-quality data sets for the partial pressure of CO2 in surface waters as well for other DIC parameters in the ocean and trace gases in the atmosphere, reliable estimates, maps and simulations of air-sea gas flux, anthropogenic carbon and inorganic carbon export are now available. JGOFS scientists have also obtained new insights into the export flux of particulate and dissolved organic carbon (POC and DOG), the variations that occur in the ratio of elements in organic matter, and the utilization and remineralization of organic matter as it falls through the ocean interior to the sediments. JGOFS scientists have amassed long-term data on temporal variability in the exchange of CO2 between the ocean and atmosphere, ecosystem dynamics, and carbon export in the oligotrophic subtropical gyres. They have documented strong links between these variables and large-scale climate patterns such as the El Nino-Southern Oscillation (ENSO) or the North Atlantic Oscillation (NAO). An increase in the abundance of organisms that fix free nitrogen (N-2) and a shift in nutrient limitation from nitrogen to phosphorus in the subtropical North Pacific provide evidence of the effects of a decade of strong El Ninos on ecosystem structure and nutrient dynamics. High-quality data sets, including ocean-color observations from satellites, have helped modellers make great strides in their ability to simulate the biogeochemical and physical constraints on the ocean carbon cycle and to extend their results from the local to the regional and global scales. Ocean carbon-cycle models, when coupled to atmospheric and terrestrial models, will make it possible in the future to predict ways in which land and ocean ecosystems might respond to changes in climate.

Description: Annual catches of Todarodes pacificus in Japan have gradually increased since the late 1980s. Paralarval abundances have also been higher since the late 1980s compared to the late 1970s and mid-1980s. Here is proposed a possible scenario for the recent stock increase based on changing environmental conditions. Based on trends in annual variations in stock and in larval abundances, catches are reviewed and potential spawning areas inferred, assuming that egg masses and hatchlings occur over the continental shelf at temperatures between 15 and 23°C. Changes are then inferred in the spawning areas during 1984–1995, based on GIS data. Since the late 1980s, the autumn and winter spawning areas in the Tsushima Strait and near the Goto Islands appear to have overlapped, and winter spawning sites seem to have expanded over the continental shelf and slope in the East China Sea.

Description: Lake Tahoe is an ultra-oligotrophic subalpine lake that is renowned for its clarity. The region experiences little cloud cover and is one of the most UV transparent lakes in the world. As such, it is an ideal environment to study the role of UV radiation in aquatic ecosystems. Long-term trends in Secchi depths showed that water transparency to visible light has decreased in recent decades, but limited data are available on the UV transparency of the lake. Here we examine how ultraviolet radiation varies relative to longer-wavelength photosynthetically active radiation (PAR, 400-700 nm, visible wavelengths) horizontally along inshore-offshore transects in the lake and vertically within the water column as well as temporally throughout 2007. UV transparency was more variable than PAR transparency horizontally across the lake and throughout the year. Seasonal patterns of Secchi transparency differed from both UV and PAR, indicating that different substances may be responsible for controlling transparency to UV, PAR, and Secchi. In surface waters, UVA (380 nm) often attenuated more slowly than PAR, a pattern visible in only exceptionally transparent waters with very low dissolved organic carbon. On many sampling dates, UV transparency decreased progressively with depth suggesting surface photobleaching, reductions in particulate matter, increasing chlorophyll a, or some combination of these increased during summer months. Combining these patterns of UV transparency with data on visible light provides a more comprehensive understanding of ecosystem structure, function, and effects of environmental change in highly transparent alpine and subalpine lakes such as Tahoe.

Description: During the SAMUM field campaign in southern Morocco in May and June 2006 density currents generated by evaporative cooling after convective precipitation were frequently observed at the Sahara side of the Atlas Mountain chain. The associated strong surface cold-air outflow during such events has been observed to lead to dust mobilization in the foothills. Here a regional model system is used to simulate a density current case on 3 June 2006 and the subsequent dust emission. The model studies are performed with different parameterization schemes for convection, and with different horizontal model grid resolutions to examine to which extent the model system can be used for reproducing dust emissions in this region. The effect of increasing the horizontal model grid resolution from 14 km to 2.8 km on the strength on the density currents and thus on dust emission is smaller than the differences due to different convection parameterization schemes in this case study. While the results in reproducing the observed density current at the Atlas Mountain varied with different convection parameterizations, the most realistic representation of the density current is obtained at 2.8 km grid resolution at which no parameterization of deep convection is needed.

Description: Juvenile and adult Loligo opalescens Berry were video taped in Monterey Bay with the remotely operated vehicle (ROV) Ventana,captured with an otter trawl in Santa Monica Bay, California, and adults were taken from the Monterey Bay fishery. Behavioral observations were made over a 13 h period of video sequences. Allometry measurements were made on 157 squids ranging in size from 12 to 151 mm mantle length (ML). In addition to ML we measured the morphometric characters of fin length(FL), fin width (FW), mantle width (MW), eye diameter (ED), head width (HW), funnel aperture diameter(FA), fourth arm length (AL) and tentacle length(TL). Loligo opalescens changes shape with ontogeny due to negative allometric growth of ED, HW, TL, MW, FA and positive allometric growth of AL, FL and fin area. The allometry measurements were used to determine the size of juvenile squids video-taped in open water. A linear regression can predict dorsal ML in mm from a dimensionless ratio of ML upon ED (r2=0.857, P〈0.001). Sizes and velocities of video-taped animals were estimated from 26 video sequences ranging from 〈1.0 to 8 s. The average velocity for squids ranging from 12–116 mm ML was 0.21 m s–1 and the maximum velocity was 1.60 m s–1(116 mm ML). Allometric measurements can provide scale for 2-dimensional images in order to estimate size, velocity and age of animals.

Description: A colony of Humboldt penguins Spheniscus humboldti in central Chile was monitored from August 1995 to July 2000 to determine patterns of breeding and colony attendance and how these were affected by climatic (rainfall) and oceanographic (El Niño) factors. Nests were periodically checked for contents and roosting birds were counted from vantage points. Two main breeding events were observed: between August and January (spring event) and between April and June (autumn event). Whereas the spring event regularly produced offspring, the autumn event was systematically affected by rains, causing considerable nest desertion. Adults were present in the colony from August to May, abandoning the colony during winter after the nests were flooded. Juveniles occurred only between November and March. Adults moulted mainly in February, while juveniles moulted in January. During the 1997/98 El Niño episode, the number of breeding pairs was 55 to 85% lower than the mean, the onset of nesting was delayed, and abnormally heavy rainfall flooded nests. While the number of breeding pairs was significantly related to sea surface temperature anomalies (SSTA), breeding success was not. The attendance of adults and juveniles at the colony during El Niño was 25 and 73% lower, respectively, than the mean attendance. This 2-peak breeding strategy of Humboldt penguins appears to have evolved in response to the more favourable oceanographic and climatic conditions of Perú, where breeding is continuous and not interrupted by rains. Although less productive, the species probably maintains its autumnal breeding in central Chile because this provides additional offspring to supplement those regularly produced during the spring event.

Description: Jamaica Bay, NY, is a highly urbanized estuary within the boroughs of New York City conspicuously lacking published information on dissolved trace metal concentrations. The current study examines the distribution and cycling of trace metals in that embayment with data gathered during cruises in November 2004, April 2005, and June 2006. Most of the metal distributions (Fe, Zn, Co, Ag, Cu, Pb, Ni) in the water column are explained by the input of substantial volumes of treated wastewater effluent. However, several lines of evidence suggest that submarine groundwater discharge (SGD) is also an important source of dissolved Fe, Zn, Co, Ni, and isotopically distinct stable Pb ratios (206Pb, 207Pb, 208Pb) in the Bay. Conversely, the recirculated seawater component of SGD is an apparent sink for dissolved Mo. This study provides the first measurements of dissolved trace metals in the Jamaica Bay water column and subterranean estuary and provides evidence for trace metal input due to SGD.

Description: The main physical and biological processes that control the seasonal cycle of the plankton dynamics over the Western Black Sea were explored by means of a three‐dimensional, 7‐compartment, on‐line coupled biophysical model that was developed for this study. Adopting high frequency forcing in terms of air‐sea interaction and Danube river inputs, we performed a simulation of the coupled model during the 2002–2003 period. A series of 8‐day Chl‐a SeaWiFS images provided a validation tool that guided us, along with available in situ measurements, to the improvement of model parameterizations and the calibration of the biological parameters. The simulation of the seasonal phytoplankton variability over the entire Western Black Sea, extending from the highly eutrophic river influenced area to the open sea area, was a major challenge that made necessary the representation of both the spatial and time variability of several processes. Despite the model simplicity, the simulated Chl‐a patterns presented a good agreement as compared to the SeaWiFS and in situ data. During winter, phytoplankton in coastal areas was shown to be limited by light availability, primarily due to the increased particulate matter concentrations, as a result of resuspension from the sediment and the increased river loads. During summer, the primary production was mostly sustained by riverine nutrients and regeneration processes and thus was strongly linked to the evolution of the Danube plume. The limiting nutrients showed deviations from the observed concentrations, indicating the necessity for a more realistic phytoplankton growth model.