Latitudinal Variations in Mesozooplankton Grazing and Metabolism in the Central Tropical Pacific During the Us Jgofs Eqpac Study

Zhang X, Dam HG, White JR, and Roman MR ·
1995

Pigment ingestion rates by three size classes of mesozooplankton (200-500 mu m, 500-1000 mu m and 1000-2000 mu m) within the euphotic zone were measured during the Survey 1 (February/March) and Survey 2 (August/September) cruises of the 1992 United States Joint Global Ocean Flux Study (U.S. JGOFS) in the central equatorial Pacific (EqPac).


Read more

Influence of Nitrogen Source and Availability on Amino Acids, Pigments and Tissue Nitrogen of Gracilaria edulis (Rhodophyta) (Page 1)

Influence of Nitrogen Source and Availability on Amino Acids, Pigments and Tissue Nitrogen of Gracilaria edulis (Rhodophyta)

Jones AB ·
1994

Increasing eutrophication of coastal marine environments has led to the development of nutrient sampling programs to monitor water quality. Various shortcomings of chemical analyses have identified the need to develop biological indicators (bioindicators) that can be used to detect available nutrient concentrations. Macroalgal tissue nutrient content, pigments, and amino acids appear to be responsive to water column nutrient availability.


Read more

Predation Mortality of Bay Anchovy Anchoa-Mitchilli Eggs and Larvae Due to Scyphomedusae and Ctenophores in Chesapeake Bay

Purcell JE, Nemazie DA, Dorsey SE, Houde ED, and Gamble JC ·
1994

We measured predation on bay anchovy Anchoa mitchilli eggs and larvae by abundant scyphomedusae Chrysaora quinquecirrha and ctenophores Mnemiopsis leidyi from gut contents, digestion rates, and densities of predators and prey during 9 d in July 1991 at 4 stations in Chesapeake Bay, USA, These predation rates were compared to egg and larval mortality rates measured concurrently in ichthyoplankton surveys.


Read more

Ammonium Excretion by Gelatinous Zooplankton and Their Contribution to the Ammonium Requirements of Microplankton in Chesapeake Bay

Nemazie DA, Purcell JE, and Glibert PM ·
1993

Ammonium excretion rates of recently collected specimens of gelatinous zooplankton. the scyphomedusan Chrysaora quinquecirrha DeSor and the ctenophore Mnemiopsis leidyi A. Agassiz, were correlated with body mass and water temperature in measurements made from April to October 1989 and 1990. Rates ranged between 3.5 and 5.0 mug atoms NH4+-N (g dry wt)-1 h-1 for C. quinquecirrha and 3.0 to 4.9 mug atoms NH4-N (g dry wt) -1 h-1 for M. leidyi.


Read more

Culture studies on two morphological types of Caulerpa (Chlorophyta) from Perth, Western Australia, with a description of a new species (Page 1)

Culture studies on two morphological types of Caulerpa (Chlorophyta) from Perth, Western Australia, with a description of a new species

Carruthers TJB, Walder DI, and Huisman JM ·
1993

The phenotypic plasticity and performance of two growth-forms of Caulerpa racemosa (Forsskal) J. Agardh, one found in estuarine conditions, the other growing in a coastal reef environment was studied in laboratory culture. There was no change in the morphology of either growth-form when cultured through a range of salinity (10—40%o) and light (20—140 μEm-2s-1) conditions.


Read more

Nitrogen Versus Phosphorus Limitation for Growth of an Estuarine Population of Eelgrass (Zostera marina L) (Page 1)

Nitrogen Versus Phosphorus Limitation for Growth of an Estuarine Population of Eelgrass (Zostera marina L)

Murray L, Dennison WC, and Kemp WM ·
1992

The relative importance of nitrogen (N) and phosphorus (P) limitation for growth and biomass accumulation in an estuarine population of eelgrass (Zostera marina L.) was examined by in situ additions of nitrogen (+N), phosphorus (+P) and nitrogen plus phosphorus (+N+P) to sediments at low and high loading rates. Nitrogen treatments resulted in no significant increases in leaf tissue N levels and only a small increase in the N content of root plus rhizome tissues.


Read more

Quantitative Feeding Ecology of the Hydromedusan Nemopsis-Bachei in Chesapeake Bay

Purcell JE and Nemazie DA ·
1992

We determined feeding rates of the hydromedusan Nemopsis bachei L. Agassiz in the mesohaline region of Chesapeake Bay, USA during the spring of 1989 and 1990 from gut contents, digestion rates and abundances of medusae and zooplankton. The medusae consumed primarily copepodites of Acartia tonsa, selecting against naupliar stages.


Read more