scholarly journals The influence of phytoplankton pigments composition and dominant cell size on fluorescence-derived photophysiological parameters and implications for primary production rates

2016 ◽  
Author(s):  
Maria Fernanda Colo Giannini
Keyword(s):  
Primary Production ◽  
Cell Size ◽  
Production Rates ◽  
Phytoplankton Pigments

scholarly journals A 15-million-year-long record of phenotypic evolution in the heavily calcified coccolithophore <i>Helicosphaera</i> and its biogeochemical implications

2020 ◽  
Vol 17 (11) ◽  
pp. 2955-2969 ◽  
Author(s):  
Luka Šupraha ◽  
Jorijntje Henderiks
Keyword(s):  
Cell Size ◽  
Resource Limitation ◽  
Tropical Indian Ocean ◽  
Adaptive Strategies ◽  
Cellular Level ◽  
Phenotypic Evolution ◽  
Production Rates ◽  
Environmental Forcing ◽  
Modern Species ◽  
Mean Size

Abstract. The biogeochemical impact of coccolithophores is defined not only by their overall abundance in the oceans but also by wide ranges in physiological traits such as cell size, degree of calcification and carbon production rates between different species. Species' sensitivity to environmental forcing has been suggested to relate to their cellular PIC : POC (particulate inorganic carbon : particulate organic carbon) ratio and other physiological constraints. Understanding both the short-term and longer-term adaptive strategies of different coccolithophore lineages, and how these in turn shape the biogeochemical role of the group, is therefore crucial for modeling the ongoing changes in the global carbon cycle. Here we present data on the phenotypic evolution of a large and heavily calcified genus Helicosphaera (order Zygodiscales) over the past 15 million years (Myr), at two deep-sea drill sites in the tropical Indian Ocean and temperate South Atlantic. The modern species Helicosphaera carteri, which displays ecophysiological adaptations in modern strains, was used to benchmark the use of its coccolith morphology as a physiological proxy in the fossil record. Our results show that, on the single-genotype level, coccolith morphology has no correlation with growth rates, cell size or PIC and POC production rates in H. carteri. However, significant correlations of coccolith morphometric parameters with cell size and physiological rates do emerge once multiple genotypes or closely related lineages are pooled together. Using this insight, we interpret the phenotypic evolution in Helicosphaera as a global, resource-limitation-driven selection for smaller cells, which appears to be a common adaptive trait among different coccolithophore lineages, from the warm and high-CO2 world of the middle Miocene to the cooler and low-CO2 conditions of the Pleistocene. However, despite a significant decrease in mean coccolith size and cell size, Helicosphaera kept a relatively stable PIC : POC ratio (as inferred from the coccolith aspect ratio) and thus highly conservative biogeochemical output on the cellular level. We argue that this supports its status as an obligate calcifier, like other large and heavily calcified genera such as Calcidiscus and Coccolithus, and that other adaptive strategies, beyond size adaptation, must support the persistent, albeit less abundant, occurrence of these taxa. This is in stark contrast with the ancestral lineage of Emiliania and Gephyrocapsa, which not only decreased in mean size but also displayed much higher phenotypic plasticity in their degree of calcification while becoming globally more dominant in plankton communities.

Phytoplankton Productivity Changes in a Small, Double-Basin Lake in Response to Termination of Experimental Fertilization

1987 ◽  
Vol 44 (S1) ◽  
pp. s47-s54 ◽  
Author(s):  
J. A. Shearer ◽  
E. J. Fee ◽  
E. R. DeBruyn ◽  
D. R. DeClercq
Keyword(s):  
Numerical Model ◽  
Primary Production ◽  
The Other ◽  
Production Rates ◽  
Nitrogen And Phosphorus ◽  
Phytoplankton Productivity ◽  
Phytoplankton Primary Production ◽  
Carbon And Nitrogen ◽  
Model Technique ◽  
Reference Lakes

One basin of a small, double-basin lake was fertilized with carbon, nitrogen, and phosphorus for eight years, and then fertilization was stopped. The other basin was fertilized simultaneously with equivalent amounts of carbon and nitrogen only. Phytoplankton primary production was monitored using an incubator–numerical model technique. Production increased dramatically in the basin receiving artificial additions of C, N, and P. The increase was particularly large in the epilimnion where Cyanophyte blooms occurred during each year of fertilization and production rates averaged 2 to 10 times higher than in nearby, unfertilized reference lakes. Phosphorus, not nitrogen or carbon, was the critical nutrient. The productivity of the other basin also increased, but to a lesser degree and no Cyanophyte blooms were observed in this basin. When all fertilization was terminated, production in both basins immediately decreased. No more surface blooms were observed in either basin. Within 3 yr, the production had dropped to levels typical of reference lakes.

scholarly journals Net community production and gross primary production rates in the western equatorial Pacific

2010 ◽  
Vol 24 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Rachel H. R. Stanley ◽  
John B. Kirkpatrick ◽  
Nicolas Cassar ◽  
Bruce A. Barnett ◽  
Michael L. Bender
Keyword(s):  
Primary Production ◽  
Gross Primary Production ◽  
Equatorial Pacific ◽  
Production Rates ◽  
Net Community Production ◽  
Western Equatorial Pacific ◽  
Community Production

scholarly journals The Western Maine Coastal Current reduces primary production rates, zooplankton abundance and benthic nutrient fluxes in Massachusetts Bay

2014 ◽  
Vol 71 (5) ◽  
pp. 1158-1169 ◽  
Author(s):  
M. Conor McManus ◽  
Candace A. Oviatt ◽  
Anne E. Giblin ◽  
Jane Tucker ◽  
Jefferson T. Turner
Keyword(s):  
Primary Production ◽  
Environmental Changes ◽  
Monitoring Program ◽  
Sediment Oxygen Demand ◽  
Nutrient Concentrations ◽  
Coastal Current ◽  
Zooplankton Abundance ◽  
Massachusetts Bay ◽  
Production Rates ◽  
Annual Primary Production

Abstract Primary production was measured from 1992–2010 in Massachusetts Bay and just outside Boston Harbor for the Massachusetts Water Resources Authority's outfall monitoring program. In 2003, annual primary production decreased by 221–278 g C m−2 year−1, with decreased rates continuing through 2010. Based on a conceptual model, oceanographic and meteorological variables were analysed with production rates to determine if concurrent environmental changes were responsible for the reduced primary production in Massachusetts Bay. Results indicated that a stronger influx of low salinity water from the Western Maine Coastal Current (WMCC) in recent years might be responsible for the decreases. The WMCC appeared to have become fresher due to increased river discharge in the western Gulf of Maine. Northeasterly winds in recent years promoted the WMCC intrusion into Massachusetts Bay. Correlation between primary production and surface salinities suggested an impact of the WMCC on production rates. We hypothesized that increased stratification resulted in reduced vertical mixing and reduced nutrient concentrations in surface waters for phytoplankton growth. However, no significant correlations were observed between the annual primary production and nutrient concentrations in Massachusetts Bay. Reduced production rates in Massachusetts Bay have, however, been associated with reduced zooplankton abundances, benthic ammonium fluxes and sediment oxygen demand in summer months.

scholarly journals New constraints on biological production and mixing processes in the South China Sea from triple isotope composition of dissolved oxygen

2021 ◽  
Author(s):  
Hana Jurikova ◽  
Osamu Abe ◽  
Fuh-Kwo Shiah ◽  
Mao-Chang Liang
Keyword(s):  
South China Sea ◽  
Primary Production ◽  
South China ◽  
Isotope Composition ◽  
Gross Primary Production ◽  
Northeast Monsoon ◽  
Production Rates ◽  
Mixing Processes ◽  
China Sea ◽  
Net Heterotrophy

Abstract. South China Sea (SCS), world’s largest marginal sea, plays an important role in the global as well as regional biogeochemical cycling of carbon and oxygen. However, its overall metabolic balance, primary production rates, and their link to East Asian Monsoon forcing still remain poorly constrained. Here, we report seasonal trends in triple oxygen isotope composition (17Δ) of dissolved O2, a tracer for biological O2, gross primary production (GP; inferred from δ17O and δ18O values), and net community production (NP; evaluated from oxygen–argon ratios) from the SouthEast Asian Time-series Study (SEATS) in SCS. Our results suggest stable mixed-layer GP rates of 1.8 g C m−2 d−1 and NP of −0.02 g C m−2 d−1 during the summer southwest monsoon, indicating the prevalence of net heterotrophy. During winter months characterised by stronger northeast monsoon forcing, the system is more dynamic with variable production rates, which may shift the metabolism from net heterotrophy to net autotrophy (NP up to ~0.15 g C  m−2 d−1). These findings underscore the importance of monsoon intensity on tilting the carbon balance from source to sink in a warm oligotrophic sea, and on driving the regional circulation pattern. Finally, our data from the deeper regions show that SCS circulation is strongly affected by monsoon wind forcing, with a larger part of the water column down to at least 400 m depth fully exchanged during a winter, suggesting the 17Δ of deep O2 as a valuable novel conservative tracer for probing mixing processes from a new perspective.

Nearshore–offshore comparison of chlorophyll a and phytoplankton production in the dreissenid-colonized eastern basin of Lake Erie

2006 ◽  
Vol 63 (5) ◽  
pp. 1115-1129 ◽  
Author(s):  
David C Depew ◽  
Stephanie J Guildford ◽  
Ralph E.H Smith
Keyword(s):  
Primary Production ◽  
Chlorophyll A ◽  
Total Phosphorus ◽  
Lake Erie ◽  
Light Attenuation ◽  
Phytoplankton Production ◽  
Light Climate ◽  
Production Rates ◽  
Chl A ◽  
Underwater Light Climate

Planktonic primary production, chlorophyll a (chl a), underwater light climate, and total phosphorus were measured at 18 stations during 2001 and 2002 in eastern Lake Erie to characterize spatial and seasonal patterns in this system colonized by dreissenid mussels (Dreissena spp.). Areal production rates and chl a displayed a seasonal pattern typical of the Laurentian Great Lakes, with highest production in the early and late summer. Daily and seasonal (May–October) primary production was significantly lower nearshore than offshore. Although light attenuation was similar between nearshore and offshore, the nearshore light climate was generally more favorable for phytoplankton because of shallower mixing depths. However, chl a was significantly lower nearshore, which accounted for most of the depression in production rates. Nearshore chl a was lower than predicted from relationships with total phosphorus in comparable dreissenid-free systems. Offshore, subepilimnetic communities contributed up to 67% of daily production but only up to 19% of seasonal production. The depression of chl a and primary production in the nearshore was a reversal from historic patterns in eastern Lake Erie and from the pattern traditionally expected in large lakes. Decreased external nutrient loading and dreissenid colonization may both have contributed to this new spatial pattern, but dreissenids appear to be key agents.

Will low primary production rates in the Amundsen Basin (Arctic Ocean) remain low in a future ice-free setting, and what governs this production?

2020 ◽  
Vol 205 ◽  
pp. 103287 ◽  
Author(s):  
Lars Chresten Lund-Hansen ◽  
Jørgen Bendtsen ◽  
Tanja Stratmann ◽  
Rasmus Tonboe ◽  
Steffen Malskær Olsen ◽  
...  
Keyword(s):  
Primary Production ◽  
Arctic Ocean ◽  
Production Rates
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