Oceanography and Atmospheric Sciences and Meteorology Commons^™

Role Of Gulf Stream Frontal Eddies In Forming Phytoplankton Patches On The Outer Southeastern Shelf, James A. Yoder, Larry P. Atkinson, Thomas N. Lee, Hongsuk H. Kim, Charles R. Mcclain

CCPO Publications

Continuous surface mapping of temperature, salinity, and chlorophyll along a 300-km segment of the Gulf Stream cyclonic front defined the spatial scales of a large diatom patch that persisted throughout a 10-day study. The patch was localized in the upwelled cold core of a Gulf Stream frontal eddy centered over the 200-m isobaths off Jacksonville, Florida, in April 1979. The µ g liter^-1 surface chlorophyll isopleth enclosed an area >1,000km² with an alongshore dimension of 130km. Surface chlorophyll exceeded 5µg liter^-1 within the upwelled cold core of the eddy, 10-100X higher than concentrations in Gulf Stream or …

Hydrographic Observations In The Georgia Bight (April 1979), S. R. Lansey, L. P. Atkinson

CCPO Publications

During a cruise in the Georgia Bight in April 1979, an onshore-offshore hydrographic section of thirteen stations was repeated thirteen times. Four additional onshore-offshore hydrographic sections were completed north and south of the main section. Temperature, salinity, dissolved oxygen, and nutrient (N0₃, PO₄, and Si0₂) data were collected.

Two spin off eddies were observed at the Gulf Stream front at the shelfbreak. These eddies resulted in the upwelling of nutrient-enriched North Atlantic Central Water. A period of downwelling was observed between the two upwelling events. The cycling between upwelling and downwelling was relatively rapid. …

First Preliminary Report Of The Gabex-1 Cruises: Station Logs, Standard Sections And Maps And Time Series Transects, Larry P. Atkinson, James J. Singer, William S. Chandler

CCPO Publications

Research progress is reported in studies of the oceanography of the South Atlantic Bight during the spring transition period. Volume II contains the preliminary cruise report.

Ocean Chlorophyll Studies From A U-2 Aircraft Platform, Hongsuk H. Kim, Charles R. Mcclain, Lamdin R. Blaine, William D. Hart, Larry P. Atkinson, James A. Yoder

CCPO Publications

Chlorophyll gradient maps of large ocean areas were generated from U-2/OCS data obtained over test sites in the Pacific and the Atlantic Oceans. The delineation of oceanic features using the upward radiant intensity relies on an analysis method which presupposes that radiation backscattered from the atmosphere and the ocean surface can be properly modeled by using a measurement made at 778 nm. The calculation of atmospheric radiance was performed by using a method developed by J.V. Dave. An estimation of the chlorophyll concentration is performed by properly ratioing radiances measured at 472 and 548 nm after removing the atmospheric effects. …

The Chemical And Biological Effect Of A Gulf Stream Intrusion Off St. Augustine, Florida, Larry P. Atkinson, Gustav-Adolf Paffenhöfer, William M. Dunstan

CCPO Publications

During a 3-day anchor station in shelf waters off St. Augustine, Florida we observed the effect of an intruding mass of deeper Gulf Stream water. The shelf waters were relatively low in nutrients and salinity while the Gulf Stream waters were high in salinity and nutrients. Onshore currents correlated with increases in nitrate and chlorophyll concentrations.

The advection of higher nutrient Gulf Stream water coincided with high chlorophyll (∼ mg chl a m⁻³) concentrations and dense populations of Phaeocystis pouchetii (up to 3.12 × 10°1⁻¹). Zooplankton sampling was impossible in the bottom layer because of the …

The Results Of Four Oceanographic Cruises In The Georgia Bight, L. P. Atkinson

CCPO Publications

During 1973 and 1974 we conducted four oceanographic cruises in the Georgia Bight with the purpose of gaining background seasonal data with which to plan more scientific experiments. In this technical report the data are presented in graphical form with interpretation. The data itself was published in two technical reports (Atkinson, 1975 and 1976). Some of the interpretations in this report will be given in more detail in published journal articles.

Modes Of Gulf Stream Intrusion Into The South Atlantic Bight Shelf Waters, Larry P. Atkinson

CCPO Publications

Consideration is given to the intrusion of Gulf Stream waters into the shelf waters of the South Atlantic Bight. It is observed that three modes of intrusion may occur, depending on particular ambient shelf water density. They are override, interleave, and bottom intrusion. It is noted that: (1) except in January, when the shelf water densities are relatively higher, 20°C Gulf Stream water can form a bottom intrusion anywhere along the coast, (2) Gulf Stream waters of 24°C can only form bottom intrusions from April to November, and (3) the rest of the year, 24°C waters interleave or override.

Methane Distribution And Production In The Georgia Salt Marsh, Larry P. Atkinson, John R. Hall

CCPO Publications

Bacterial action in the anaerobic sediments of Spartina salt marsh produce large quantities of methane. Water in contact with the marsh has methane concentrations 200-300 times normal oceanic concentrations. The methane content of the water varies from maximum of 1.2 mu l CH sub(4)/ super(l) super(-1) in the summer to a minimum of 0.005 mu l CHl1

77-4 Hydrographic And Biological Observations At An Anchor Station Off St. Augustine, Florida (Eastward Cruise E-1g-75), Larry P. Atkinson, Gustav A. Paffenhofer, William M. Dunstan

CCPO Publications

The intrusion of deep, nutrient-rich Gulf Stream water into the shelf waters off the southeastern United States is probably the major source of nutrients in the shelf waters and consequently intrusions have a major impact on the biota. This particular cruise was one of the first to be designed to find the front that represents the interface between intruding Gulf Stream waters and normal shelf water. Once the front was delineated an anchor station was occupied to observe the time change at a particular location as the front moved back and forth past the station.

The methods used and resultant …

Effect Of Air Bubble Solution On Air-Sea Gas Exchange, Larry P. Atkinson

CCPO Publications

Recent data on ambient wave generated oceanic bubble spectra (Medwin, 1970) permit the calculation of the influence of bubble solution on air-sea gas exchange. Schulkin's formula is used to estimate the depth variation of bubbles, and a square law is used to estimate the increase of bubble volume with wind speed. Calculations indicate that bubble solution can be a very significant factor in gas exchange. Bubble solution enhances gas input and retards degassing of the water column. Preliminary data show a lag time of about 5 hours in the response of the water column to an atmospheric pressure change.

Air Bubbles In An Oceanic Mixed Layer: Effect On Gas Concentrations And Air-Sea Gas Exchange, Larry P. Atkinson

CCPO Publications

This thesis attempts to determine the effect of air bubbles that are entrapped into the surface layers of the ocean by breaking waves on gas concentrations in the ocean and gas exchange across the air-sea interface. N₂ and Ar data gathered during the Hudson-70 expedition produced indications of the magnitude and nature of the effect. A mathematical model is developed that equates the input of gas via bubble solution with the vertical eddy diffusion. Published values for bubble spectra and solution rates are used and assumptions are made concerning the effect of wind on bubble spectra. The model predicts …

Nutrient-Density Relationships In The Western North Atlantic Between Cape Lookout And Bermuda, Unnsteinn Stefánsson, Larry P. Atkinson

CCPO Publications

A study of the nutrient-density relationships of Sargasso Sea water reveals a close correlation; Gulf Stream waters are anomalously higher and more variable in nutrients for a given density. Nutrient anomalies can be used in the same way as oxygen anomalies to map the distribution of Caribbean water in sections across the Gulf Stream. They show that contributions of Caribbean water to the Gulf Stream vary greatly from time to time. Oxidative ratios of ΔO : ΔN : ΔP = (−233) : 16.3 : 1.0 were derived from the correlation between oxygen anomalies and nutrients anomalies of Gulf Stream water …

The Occurrence And Distribution Of Methane In The Marine Environment, Larry P. Atkinson, Francis A. Richards

CCPO Publications

The distributions of methane dissolved in the sulfide-bearing waters of the Black Sea, the Cariaco Trench, and Lake Nitinat are reported. The gas was not detected in the oxygen-deficient water of the eastern tropical Pacific Ocean, in the Santa Barbara Basin, nor in the sulfide-bearing water of Saanich Inlet. Maximum concentrations observed were 70 μmole CH4/l., and the distribution tends to follow that of sulfide. The data indicate that methane is derived from organic compounds not containing nitrogen or phosphorus and that its formation is much slower than that of sulfide. The solubility coefficient in seawater (salinity = 40‰) is …

Some Consequences Of The Decomposition Of Organic Matter In Lake Nitinat, An Anoxic Fjord, Francis A. Richards, Joel D. Cline, William W. Broenkow, Larry P. Atkinson

CCPO Publications

Observations in Lake Nitinat, an anoxic fjord on Vancouver Island, British Columbia, indicate that the large accumulations of ammonia, carbonates, phosphates, silicates, and sulfides in the deep water are the result of oxidative and fermentative decomposition of organic matter of planktonic origin, the reduction of sulfate ions, hydrolytic or other non-oxidative release (in the case of silicates), and the solution of carbonates (which also increases the alkalinity). Ammonia, sulfides, and silicates accumulate in the sulfide zone in direct proportion to each other, but some of the phosphate is probably released from the organic matter earlier than the other components, and …