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: 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: A Lagrangian analysis of particles sinking through a velocity field observed by Eulerian frame measurements was used to evaluate the effects of horizontal advection and particle sinking speed on particle fluxes as measured by moored sediment traps. Characteristics of the statistical funnel above moored deep-ocean sediment traps at the German JGOFS quasi-time series station at 47N, 20W (Biotrans site) were determined. The analysis suggests that the distance and direction between a given sediment trap and the region at the surface where the particles were produced depends on the mean sinking velocity of the particles, the horizontal velocity field above the trap and the deployment depth of the trap. Traps moored at different depths at a given mooring site can collect particles originating from different, separated regions at the surface ocean. Catchment areas for a given trap vary between different years. Typical distances between catchment areas of traps from different water depth but for a given time period (e.g., the spring season) are similar or even larger compared to typical length scales of mesoscale variability of phytoplankton biomass observed in the temperate northeast Atlantic. This implies that particles sampled at a certain time at different depth horizons may originate from completely independent epipelagic systems. Furthermore catchment areas move with time according to changes in the horizontal flow field which jeopardizes the common treatment of interpreting a series of particle flux measurements as a simple time series. The results presented in this work demonstrate that the knowledge of the temporal and spatial variability of the velocity field above deep-ocean sediment traps is of great importance to the interpretation of particle flux measurements. Therefore, the one-dimensional interpretation of particle flux observations should be taken with care.

Description: Birds are the most conspicuous, wide-ranging, and easily studied organisms in the marine environment. They can be both predators and scavengers, and they can be harmed by and can benefit from fishing activities. The effects of fishing on birds may be direct or indirect. Most direct effects involve killing by fishing gear, although on a lesser scale some fishing activities also disturb birds. Net fisheries and hook fisheries have both had serious negative effects at the population level. Currently, a major negative impact comes from the by-catch of albatrosses and petrels in long-lines in the North Pacific and in the Southern Ocean. High seas drift nets have had, prior to the banning of their use, a considerable impact on seabirds in the northern Pacific, as have gillnets in south-west Greenland, eastern Canada, and elsewhere. Indirect effects mostly work through the alteration in food supplies. Many activities increase the food supply by providing large quantities of discarded fish and wastes, particularly those from large, demersal species that are inaccessible to seabirds, from fishing vessels to scavengers. Also, fishing has changed the structure of marine communities. Fishing activities have led to depletion of some fish species fed upon by seabirds, but may also lead to an increase in small fish prey by reducing numbers of larger fish that may compete with birds. Both direct and indirect effects are likely to have operated at the global population level on some species. Proving the scale of fisheries effects can be difficult because of confounding and interacting combinations with other anthropogenic effects (pollution, hunting, disturbance) and oceanographic factors. Effects of aquaculture have not been included in the review

Description: New seismic and geodetic data from Costa Rica provide insight into seismogenic zone processes in Central America, where the Cocos and Caribbean plates converge. Seismic data are from combined land and ocean bottom deployments in the Nicoya peninsula in northern Costa Rica and near the Osa peninsula in southern Costa Rica. In Nicoya, inversion of GPS data suggests two locked patches centered at 14 ± 2 and 39 ± 6 km depth. Interplate microseismicity is concentrated in the more freely slipping intermediate zone, suggesting that small interseismic earthquakes may not accurately outline the updip limit of the seismogenic zone, the rupture zone for future large earthquakes, at least over the short (∼1 year) observation period. We also estimate northwest motion of a coastal “sliver block” at 8 ± 3 mm/yr, probably related to oblique convergence. In the Osa region to the south, convergence is orthogonal to the trench. Cocos-Caribbean relative motion is partitioned here, with ∼8 cm/yr on the Cocos-Panama block boundary (including a component of permanent shortening across the Fila Costeña fold and thrust belt) and ∼1 cm/yr on the Panama block–Caribbean boundary. The GPS data suggest that the Cocos plate–Panama block boundary is completely locked from ∼10–50 km depth. This large locked zone, as well as associated forearc and back-arc deformation, may be related to subduction of the shallow Cocos Ridge and/or younger lithosphere compared to Nicoya, with consequent higher coupling and compressive stress in the direction of plate convergence.