Pigment specific growth and grazing rates of phytoplankton in the central equatorial Pacific

Latasa, Mikel; Landry, Michael R.; Schlüter, Louise; Bidigare, Robert R.

doi:10.4319/lo.1997.42.2.0289

Cited by 105 publications

(101 citation statements)

References 46 publications

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“…While the relationship between silicate and nitrate is identical in the eastern and central Pacific (Figure 8a Iron control may be exerted through a shift in the size spectrum of phytoplankton rather than through a shift in phytoplankton specific growth rate. While diatom community specific growth rates did not change significantly between surveys I and II [Latasa et al, 1997], the species composition and size distributions changed dramatically between these time periods [Iriarte and Fryxell, 1995]. Landry et al [1997] provide the convincing argument that differences observed between the two EqPac surveys were due to the combination of selective increase in growth rates of large phytoplankton (including diatoms) through selective grazing control of smaller phytoplankton (including diatoms).…”

Section: Role Of Iron and A Non-steady State Food Webmentioning

confidence: 94%

Silicon‐nitrogen coupling in the equatorial Pacific upwelling zone

Dunne¹,

Murray²,

Aufdenkampe³

et al. 1999

Global Biogeochemical Cycles

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Section: Role Of Iron and A Non-steady State Food Webmentioning

confidence: 94%

Silicon‐nitrogen coupling in the equatorial Pacific upwelling zone

Dunne¹,

Murray²,

Aufdenkampe³

et al. 1999

Global Biogeochemical Cycles

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“…Samples (200 p1) of a mixture of 0.3 m1 H20 and 1 m1 extract were injected into a Varian 9012 HPLC system equipped with a Varian 9300 autosampler, a Timberh e column heater (26"C), and a Spherisorb 5 mm ODS2 analytical (4.6 X 250 mm) column and corresponding guard column. Pigments were detected with a Thermoseparation UV2000 detector (h = 436 and 450 nm) and analyzed after Wright et al (1991) and Latasa et al (1997). The HPLC method used cannot separate monovinyl chl a from divinyl chl a.…”

Section: Methodsmentioning

confidence: 99%

Lake Kauhako-, Moloka'i, Hawai'i: biological and chemical aspects of a morpho-ectogenic meromictic lake

Donachie¹,

Kinzie²,

Bidigare³

et al. 1999

Aquat. Microb. Ecol.

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We undertook the first combined microbiological and hydrochemical study of the 248 m deep meromichc Lake KauhakG. Situated at sea level 1.6 km from the sea in the crater of an extinct volcano on the island of Moloka'i, Hawai'i, USA, Lake KauhakB has the highest relative depth (ratio of depth to surface area, z, = 374 %) of any lake in the world. The upper 4.5 m were stratified (T= 23 to 26'C, salinity = 6 to 24.5), but below a pycnocline at -4.5 m temperature and salinity were uniform (T = -26.25"C; salinity = 32). Seawater hkely intrudes by horizontal hydraulic conductivity through rock separating the lake and the Pacific Ocean. Anoxia commenced below 2 m. Hydrogen sulfide was undetectable at 4 m. but averaged -130 PM between 5 and 28 m. Dissolved inorganic carbon concentrations ranged from -1.50 mM at the surface to -3.3 mM below 5 m. Total organic carbon peaked at 0.94 mM above the pycnocline hut rernaiced about 0.30 mM be!ow 5 m. Soluble reactive phosphorus and ammunium concentrations, nanomolar above the pycnocline, increased to -28 and l75 PM, respectively, at greater depth. Nitrate attained 3.7 PM in shallow water, but was -0.2 pM from the pycnocline to 100 m. Leucine aminopeptidase (LAPase) activity at the surface exceeded 1100 nmol of substrate hydrolyzed I-' h-' Activities of a-and P-glucosidase were lower, but showed depth distributions similar to that of LAPase. Surface waters hosted large and diverse picoplankton populations; chlorophyll a (chl a) exceeded 150 1-19 I-'. and heterotrophic bacteria and autofluorescent bacteria attained 2 X log and 9 X 109 1-l, respectively. Filamentous cyanobacteria and 'Proch1orococcus'-like autotrophs occurred only in the upper 2 m. Chl a was the dominant pigment above 2 m, but pigment diversity increased markedly in anoxic waters between 3 and 5 m. Lake Kauhako is a unique habitat for further studies, particularly of interactions among flora and fauna restricted to a shallow water column within a single basin.

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“…In these studies, size-fractionated rates for different groups were not reported, so primary production by, for example, picoplanktonic prymnesiophytes versus larger size fractions remains uncharacterized. Latasa et al (1997) showed that prymnesiophytes growth was balanced by grazing mortality Brown et al (2002) found that picophytoeukaryote growth was often, but not always, balanced by grazing in the Arabian Sea. This is important, because it indicates that large proportions of picoeukaryotic primary production are transferred to higher trophic levels (e.g., heterotrophic protists).…”

Section: Distribution Abundance and Activitiesmentioning

confidence: 99%