A multivariate analysis of planktonic interactions in the eastern tropical North Pacific

Biological and hydrographic properties were sampled in the eastern tropical North Pacific (DOMES region) in two seasons, late summer (29 August to 13 October) 1975 and winter (18 February to 13 March) 1976. Differences between cruises and spatial patterns were summarized with factor analysis and non-metric multidimensional scaling and then analyzed in detail by other statistical techniques. Significant between-cruise difference were detected in the concentrations of nitrate and suspended particulate matter in the surface mixed layer and in vertically integrated standing stocks of microzooplankton and day macrozooplankton. Integrated chlorophyll a also increased in winter, but the productivity: chlorophyll a ratio decreased. The near-surface phytoplankton community appears to be more shade-adapted in winter. Pronounced differences in correlation patterns were observed in 1975 and 1976. In winter 1976, integrated primary production rates varied inversely with the nitracline depth and positively with mixed-layer nitrate concentration, sea-surface irradiance (PAR), and integrated chlorophyll a, while zooplankton standing stock covaried with mixed-layer nitrate concentration (P ≤ 0.05). In contrast, none of the correlations was significant in summer 1975 (P > 0.10). In 1975, short-term (30 to 60 h) variations in surface chemical properties and in integrated chlorophyll a were greater than in 1976. The weaker correlations observed in 1975 may have been influenced by the apparent increase in variability. The vertical supply of nitrate, phytoplankton growth, and zooplankton grazing appear to have been more closely coupled in winter 1976 than in summer 1975. © 1982

Dispersal and Resedimentation of the Benthic Plume from Deep-Sea Mining Operations: A Model with Calibration

An analytical solution of the time-dependent mass conservation equation is used to describe the passive dispersion of deep-sea particulates resuspended during mining. Data from bottom photographs, deep-sea particulate casts, and moored nephelometers taken during North Pacific manganese nodule test mining have been used to fix model parameters. The settling velocity spectrum of the resuspended particulates and the near-bottom vertical turbulent eddy diffusivity have been estimated by the least-squares method

Water Mass Variability and Levantine Intermediate Water Formation in the Eastern Mediterranean Between 2015 and 2017

The physical characteristics of water masses in the Cilician Basin were analyzed based on recent, comprehensive in-situ data. Nine seasonal cruises from June 2015 to November 2017 were carried out in an area located in the north-eastern Levantine Basin between the coasts of Turkey and Cyprus. In this little studied area, the structure of the water column, its seasonal variability, and water formation events are investigated. The extensive data set reveals that in summer Modified Atlantic Water (MAW) is observed at about 50 m depth. Saltier and warmer Levantine Intermediate Water (LIW) lies below the MAW between similar to 100 and 250 m. During winter, the water column becomes mixed due to surface cooling and vertical convection, and displays uniform properties from the surface to about 200-300 m depths. The yearly cycle of a vertically uniform water column during winter and the appearance of LIW in the following period suggests that LIW is being formed in this region, which is confirmed through heat and buoyancy flux calculations. It is the first time LIW formation is reported in this area of the north-eastern Levantine Basin and adds to the areas of LIW formation outside Rhodes Gyre. In the 2.5 years of the study, LIW salinity increased by 0.11 psu in 2017, while surface water salinity increased by 0.5 psu over the same period. The presence of meso-scale eddies in the study area is observed throughout the year. The eddies are short-lived, having a time span of a few months, during which they either change location or disappear

Review of the circulation and characteristics of intermediate water masses of the Mediterranean--implications for cold-water coral habitats

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