Search results | Digital Commons of Moss Landing Marine Laboratories

Title: The effects of Cu on the adenylate energy charge of open ocean phytoplankton,
Description: The effects of short-term, acute Cu exposure (6 h) on the adenylate energy charge (EC A) of open-ocean phytoplankton populations (northeastern equatorial Pacific) were investigated. Energy charge remained at ̃0.77 over the range of Cu additions (0.025 - 5.μg l -1), even though 14C uptake and total adenylate levels (ATP + ADP + AMP) were reduced by as much as 60%. These findings suggest that EC A alone is not a sensitive indicator of acute sublethal metal effects on phytoplankton. © 1983 IRL Press Ltd., Cited By (since 1996):1, Oceanography, CODEN: JPLRD, ,
Author: Fitzwater, Knauer, Martin
Date: 1983-01-01T00:00:00Z

Title: Vertex: Phytoplankton/iron studies in the Gulf of Alaska,
Description: VERTEX studies were performed in the Gulf of Alaska in order to test the hypothesis that iron deficiency was responsible for the phytoplankton's failure to remove major plant nutrients from these waters. In view of the observed Fe distributions and the results of phytoplankton Fe enrichment experiments, it was concluded that Gulf of Alaska atmospheric Fe input rates are sufficient to support moderately high rates of primary productivity; however, not enough Fe is available to support the high growth rates that would lead to normal major nutrient depletion. Enhanced Fe input does occur along the Alaska continental margin, where normal NO 3 surface depletion is observed. Coccolithophorids appear to be best able to cope with low Fe conditions; however, they cannot compete with diatoms when Fe is readily available. Iron may be more important than available N in determining global rates of phytoplankton new production. Offshore Pacific Ocean water, replete with major nutrients, appears to be infertile without supplemental iron from the atmosphere or continental margin. © 1989., Cited By (since 1996):399, ,
Author: Martin, Gordon, Fitzwater, Broenkow
Date: 1989-01-01T00:00:00Z

Title: Iron, primary production and carbon-nitrogen flux studies during the JGOFS North Atlantic bloom experiment,
Description: Primary production was measured every other day towards the end (18-31 May) of the 1989 North Atlantic spring bloom. Rates varied with light and averaged 90.4 mmol C m -2 day -1 at the 47°N, 20°W station. Productivities measured south of Iceland (59°30′N, 20°45′W) were somewhat lower, averaging 83.6 mmol C m -2 day -1. Carbon and nitrogen fluxes were estimated using free-floating, VERTEX type particle trap arrays. To obtain mean rates representative of the North Atlantic spring bloom, flux data from three trap deployments were combined and fitted to normalized power functions:. mmol C m -2 day -1 = 14.35 (z/100) -0.946, mmol N m -2 day -1 = 2.34(z/100) -1.02, with depth z in meters. Regeneration rates were:. mmol C m -2 day -1 = 0.136(z/100) -1.946, mmol N m -2 day -1 = 0.0239(z/100) -2.02. The carbon export rate from the upper 35 m for the entire NABE study period (24 April to 1 June) was 39 mmol m -2 day -1. This value divided by the averaged productivity for the entire study (86 mmol N m -2 day -1) gave an F-ratio of 0.45. Concentrations of Cu, Fe, Ni, Pb and Zn were determined in water samples provided by JGOFS NABE scientists involved with primary productivity measurements. Although little contamination was observed for Cu, Ni and Pb, relatively large amounts of Zn (10 nmol kg -1) were found in some cases. In subsequent studies it was learned that this quantity of Zn can depress productivity rates by 25%. North Atlantic dissolved Fe concentrations were similar to those occurring in the Pacific (surface = 0.07; deep = 0.5-0.6 nmol kg -1). Although no evidence of Fe deficiency was found in enrichment experiments, the addition of nmol amounts of Fe did increase CO 2 uptake and POC formation by factors of 1.3-1.7. In this region, most of the phytoplankton's Fe requirement is probably met via the lateral transport of Fe from distant continental margins., Cited By (since 1996):170, CODEN: DSROE, ,
Author: Martin, Fitzwater, Michael Gordon, Hunter, Tanner
Date: 1993-01-01T00:00:00Z

Title: Notes on the JGOFS North Atlantic Bloom Experiment-dissolved organic carbon intercomparison,
Description: Using high temperature catalytic oxidation (HTCO), personnel from four laboratories analyzed water samples collected during the JGOFS North Atlantic Bloom study for their dissolved organic carbon (DOC) content. In general, good agreement was obtained. Values obtained on samples filtered and frozen compared well with those analyzed immediately after collection. DON analyses of the same frozen samples did not co-vary with DOC; thus far, DON results have only been reported by Moss Landing Marine Laboratories. © 1993., Cited By (since 1996):7, CODEN: MRCHB, ,
Author: Fitzwater, Martin
Date: 1993-01-01T00:00:00Z

Title: Iron deficiency limits phytoplankton growth in Antarctic waters,
Description: Enrichment experiments were performed in the Ross Sea to test the hypothesis that iron deficiency is responsible for the phytoplankton's failure to use up the luxuriant major nutrient supplies found in these and all other offshore Antarctic ocean waters. The results suggest that Fe deficiency is the primary reason that the present-day southern ocean biological pump is shut off. In contrast, iron was 50 times more abundant during the last glacial maximum; greater Fe availability may have stimulated the biological pump and contributed to the ice age drawdown of atmospheric CO 2. These results also imply that large-scale southern ocean Fe fertilization is feasible, at least in terms of the total amounts of Fe required; i.e., 100 000 to 500 000 tons yr -1., Cited By (since 1996):277, , , Downloaded from: http://onlinelibrary.wiley.com/doi/10.1029/GB004i001p00005/pdf (9 June 2014).
Author: Martin, Fitzwater, Gordon
Date: 1990-01-01T00:00:00Z

Title: The case for iron,
Description: Excess major nutrients occur in offshore areas ranging from the tropical equatorial Pacific to the polar Antarctic. In spite of the great ecological differences in these environments, they share a common trait: iron deficiency. All of these areas are far from Fe-rich terrestrial sources and atmospheric dust loads in these regions are amongst the lowest in the world. Experiments were performed in three nutrient-rich areas: The Gulf of Alaska, the Ross Sea, and the equatorial Pacific. In general, populations without added Fe doubled at rates 11-40% of the expected maxima at various temperatures. The addition of nanomole quantities of Fe increased these doubling rates by factors of 2-3. In spite of the lack of Fe, tightly coupled phytoplankton/zooplankton communities seem to inhabit these major nutrient-rich areas. -from Authors, Cited By (since 1996):341, Oceanography, , , Downloaded from: aslo.org/lo/toc/vol_36/issue_8/1793.pdf (16 June 2014).
Author: Martin, Gordon, Fitzwater
Date: 1991-01-01T00:00:00Z

Title: Iron deficiency limits phytoplankton growth in the north-east Pacific subarctic,
Description: An interesting oceanographic problem concerns the excess major plant nutrients (PO 4, NO 3, SiO 3) occurring in offshore surface waters of the Antarctic 1-3 and north-east Pacific subarctic Oceans 4. In a previous study 5, we presented indirect evidence suggesting that inadequate Fe input was responsible for this limitation of growth; recently we had the opportunity to seek direct evidence for this hypothesis in the north-east Pacific subarctic. We report here that the addition of nmol amounts of dissolved iron resulted in the nearly complete utilization of excess NO 3, whereas in the controls-without added Fe-only 25% of the available NO 3 was used. We also observed that the amounts of chlorophyll in the phytoplankton increased in proportion to the Fe added. We conclude that Fe deficiency is limiting phytoplankton growth in these major-nutrient-rich waters., Cited By (since 1996):854, ,
Author: Martin, Fitzwater
Date: 1988-01-01T00:00:00Z

Title: Iron in Antarctic waters,
Description: WE are testing the hypothesis that Antarctic phytoplankton suffer from iron deficiency 1-3 which prevents them from blooming and using up the luxuriant supplies of major nutrients found in vast areas of the southern ocean. Here we report that highly productive 4 (∼3 g Cm -2 day -1), neritic Gerlache Strait waters have an abundance of Fe (7.4 nmol kg -1) which facilitates phytoplankton blooming and major nutrient removal, while in low-productivity 4 (∼0.1 g Cm -2 day -1), offshore Drake Passage waters, the dissolved Fe levels are so low (0.16 nmol kg -1) that the phytoplankton are able to use less than 10% of the major nutrients available to them. The verification of present-day Fe deficiency is of interest as iron-stimulated phytoplankton growth may have contributed to the drawing down of atmospheric CO 2 during glacial maxima 2,3; it is also important because oceanic iron fertilization aimed at the enhancement of phytoplankton production may turn out to be the most feasible method of stimulating the active removal of greenhouse gas CO 2 from the atmosphere, if the need arises (J.H.M., manuscript in preparation)., Cited By (since 1996):449, CODEN: NATUA, ,
Author: Martin, Gordon, Fitzwater
Date: 1990-01-01T00:00:00Z

Title: Testing the iron hypothesis in ecosystems of the equatorial Pacific Ocean,
Description: The idea that iron might limit phytoplankton growth in large regions of the ocean has been tested by enriching an area of 64 km 2 in the open equatorial Pacific Ocean with iron. This resulted in a doubling of plant biomass, a threefold increase in chlorophyll and a fourfold increase in plant production. Similar increases were found in a chlorophyll-rich plume down-stream of the Galapagos Islands, which was naturaly enriched in iron. These findings indicate that iron limitation can control rates of phytoplankton productivity and biomass in the ocean., Cited By (since 1996):749, Oceanography, CODEN: NATUA, ,
Author: Martin, Coale, Johnson, Fitzwater, Gordon, Tanner, Hunter, Elrod, Nowicki, Coley, Barber, Lindley, Watson, Van Scoy, Law, Liddicoat, Ling, Stanton, Stockel, Collins, Anderson, Bidigare, Ondrusek, Latasa, Millero, Lee, Yao, Zhang, Friederich, Sakamoto, Chavez, Buck, Kolber, Greene, Falkowski, Chisholm, Hoge, Swift, Yungel, Turner, Nightingale, Hatton, Liss, Tindale
Date: 1994-01-01T00:00:00Z

Title: Dissolved organic carbon in the Atlantic, Southern and Pacific oceans,
Description: The amount of dissolved organic carbon (DOC) in sea water is controversial 1,2. Using a high-temperature catalytic oxidation (HTCO) technique, Sugimura and Suzuki 3 reported that surface waters contained 2-4 times as much DOC as that measured previously using wet chemistry and ultraviolet oxidation techniques 4,5. They also observed a relationship between DOC content and apparent oxygen utilization suggesting that the consumption of DOC is responsible for oxygen depletion in the deep sea. How to reconcile the apparent differences between these techniques has not been clear. Here we provide independent confirmation of the findings of Sugimura and Suzuki. We collected surface and deep waters from the equatorial Pacific Ocean, the Drake passage and the Atlantic Ocean south of Iceland, and analysed their DOC content using the HTCO methodology 3. We found DOC concentrations 2-3 times higher than those measured previously. These results imply that the carbon content of the oceans has previously been underestimated by 10 12 (1,000 billion) tonnes, and that the new estimated total of 1,800 billion tonnes represents one of the largest carbon reservoirs on Earth 6. We found no evidence of a cause-and-effect relationship between DOC and apparent oxygen utilization., Cited By (since 1996):35, Oceanography, CODEN: NATUA, ,
Author: Martin, Fitzwater
Date: 1992-01-01T00:00:00Z

Title: Nitrate utilization in surface waters of the Iceland Basin during spring and summer of 1989,
Description: Oceanographic sampling at 59.5°N, 21°W over the spring and summer months of 1989 provided the basis to quantify the amount of new (nitrate) production and to evaluate the effect of selected environmental factors on new production. Surface water nitrate decreased linearly from 14μM in early April to ∼2.5 μM in August, and suggested that new production averaged 5.4 mmol NO 3 m -2 day -1, almost double the rate suggested by a similar analysis at Ocean Weather Sta. P. Equivalent carbon export in the northern Iceland Basin would be 63 g C m -2 over this period. During a week in early July, it appeared that regenerated production compensated for a sharp decrease in new production to maintain carbon productivity at a fairly consistent level despite a decrease in F-ratio from 0.46 to 0.20. New production was predominantly associated with particles over 5 μm, although a subsurface (35m) peak in 15NO 3 uptake may have been due to bacterial uptake. We suggest that light was the single-most dominant factor regulating nitrate uptake during this time. However the relationship between new production and light was non-linear in that the light efficiency of nitrate uptake varied significantly between stations in addition to variations in available light. © 1992., Cited By (since 1996):21, CODEN: DSROE, ,
Author: Sambrotto, Martin, Broenkow, Carlson, Fitzwater
Date: 1993-01-01T00:00:00Z