Bacterial abundance and production, and their relation to primary production in tropical coastal waters of Peninsular Malaysia

2008 ◽  
Vol 59 (1) ◽  
pp. 10 ◽  
Author(s):  
Choon Weng Lee ◽  
Chui Wei Bong
Keyword(s):  
Primary Production ◽  
Chlorophyll A ◽  
Coastal Waters ◽  
Bacterial Production ◽  
Bacterial Abundance ◽  
Net Primary Production ◽  
Correlation Coefficients ◽  
Peninsular Malaysia ◽  
Chl A ◽  
The Relationship

In the present study, the relationship between bacteria and phytoplankton in tropical coastal waters was investigated. The bacterial abundance, bacterial production, chlorophyll a concentration and net primary production were measured at several locations in the coastal waters of Peninsular Malaysia. Chlorophyll a concentration ranged from 0.40 to 32.81 μg L–1, whereas bacterial abundance ranged from 0.1 to 97.5 × 106 cells mL–1. Net primary production ranged from 8.49 to 55.95 μg C L–1 h–1, whereas bacterial production ranged from 0.17 to 70.66 μg C L–1 h–1. In the present study, the carbon conversion factor used to convert bacterial production (cells mL–1 h–1) into carbon units ranged from 10 to 32.8 fg C cell–1, and was estimated from the bacterial size distribution measured at each location. Both phototrophic and heterotrophic biomass (bacteria–chlorophyll a) and activity (bacterial production–net primary production) were significantly correlated, although their correlation coefficients (r2) were relatively low (r2 = 0.188 and r2 = 0.218 respectively). Linear regression analyses provided the following equations to represent the relationship between: bacteria and chlorophyll a (Chl a), log Bacteria = 0.413 log Chl a + 6.057 (P = 0.003); and between bacterial production (BP) and net primary production (NPP), log BP = 0.896 log NPP – 0.394 (P = 0.004), which fitted with published results well. Comparison of annual carbon fluxes confirmed the prevalence of net heterotrophy in these coastal waters, and together with the low correlation coefficients, suggested the role of allochthonous organic matter in supporting heterotrophic activity.

scholarly journals Evaluation of Trace Metal Levels in Tissues of Two Commercial Fish Species in Kapar and Mersing Coastal Waters, Peninsular Malaysia

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Fathi Alhashmi Bashir ◽  
Mohammad Shuhaimi-Othman ◽  
A. G. Mazlan
Keyword(s):  
Trace Metal ◽  
Fish Species ◽  
Coastal Waters ◽  
Positive Association ◽  
Peninsular Malaysia ◽  
International Standards ◽  
Metal Concentrations ◽  
Commercial Fish ◽  
Metal Levels ◽  
The Relationship

This study is focused on evaluating the trace metal levels in water and tissues of two commercial fish species Arius thalassinus and Pennahia anea that were collected from Kapar and Mersing coastal waters. The concentrations of Fe, Zn, Al, As, Cd and Pb in these coastal waters and muscle, liver and gills tissues of the fishes were quantified. The relationship among the metal concentrations and the height and weight of the two species were also examined. Generally, the iron has the highest concentrations in both water and the fish species. However, Cd in both coastal waters showed high levels exceeding the international standards. The metal level concentration in the sample fishes are in the descending order livers > gills > muscles. A positive association between the trace metal concentrations and weight and length of the sample fishes was investigated. Fortunately the level of these metal concentrations in fish has not exceeded the permitted level of Malaysian and international standards.

scholarly journals Global distribution and variability of subsurface chlorophyll a concentration

2021 ◽  
Author(s):  
Sayaka Yasunaka ◽  
Tsuneo Ono ◽  
Kosei Sasaoka ◽  
Kanako Sato
Keyword(s):  
Chlorophyll A ◽  
Mixed Layer ◽  
Net Primary Production ◽  
Thermal Structure ◽  
Mixed Layer Depth ◽  
Subsurface Layer ◽  
Spatiotemporal Variability ◽  
Shortwave Radiation ◽  
Concentration Data ◽  
Chl A

Abstract. Chlorophyll a (Chl-a) often retains its maximum concentration not at the surface but in the subsurface layer. The depth of the Chl-a maximum primarily depends on the balance between light penetration from the surface and nutrient supply from the deep ocean. However, a global map of subsurface Chl-a concentrations based on observations has not been presented yet. In this study, we integrate Chl-a concentration data not only from recent biogeochemical floats but also from historical ship-based and other observations, and present global maps of subsurface Chl-a concentration with related variables. The subsurface Chl-a maximum deeper than the mixed layer depth was stably observed in the subtropics and tropics (30° S to 30° N), only in summer in midlatitudes (30–40° N/S), and rarely at 45–60° S of the Southern Ocean and in the northern North Atlantic (north of 45° N). The depths of the subsurface Chl-a maxima are deeper than those of the euphotic layer in the subtropics and shallower in the tropics and midlatitudes. In the subtropics, seasonal oxygen increases below the mixed layer implied substantial biological new production, which corresponds to 10 % of the net primary production there. During El Niño, the subsurface Chl-a concentration in the equatorial Pacific is higher in the middle to the east and lower in the west than that during La Niña, which is opposite that on the surface. The spatiotemporal variability of the Chl-a concentration described here would be suggestive results not only for the biogeochemical cycle in the ocean but also for the thermal structure and the dynamics of the ocean via the absorption of shortwave radiation.

scholarly journals Factors Regulating the Relationship Between Total and Size-Fractionated Chlorophyll-a in Coastal Waters of the Red Sea

2019 ◽  
Vol 10 ◽  
Author(s):  
Robert J. W. Brewin ◽  
Xosé Anxelu G. Morán ◽  
Dionysios E. Raitsos ◽  
John A. Gittings ◽  
Maria Ll. Calleja ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Red Sea ◽  
Coastal Waters ◽  
The Relationship

The contribution of heterotrophic nanoflagellate grazing towards bacterial mortality in tropical waters: comparing estuaries and coastal ecosystems

2011 ◽  
Vol 62 (4) ◽  
pp. 414 ◽  
Author(s):  
Chui Wei Bong ◽  
Choon Weng Lee
Keyword(s):  
Coastal Waters ◽  
Bacterial Production ◽  
Trophic Status ◽  
Bacterial Abundance ◽  
Temperature Optimum ◽  
Viral Lysis ◽  
Tropical Waters ◽  
Order Of Magnitude ◽  
Heterotrophic Nanoflagellate ◽  
Straits Of Malacca

Heterotrophic nanoflagellate (HNF) grazing depends on both temperature and trophic status of an ecosystem. As most microbes already function at their temperature optimum in tropical waters, we hypothesised that HNF grazing rates would be higher in more productive sites such as estuaries than in less productive areas such as coastal waters. We sampled two estuaries and three coastal sites along the Straits of Malacca and the South China Sea near the Malaysia Peninsula. Bacterial abundance ranged 0.9–6.3 × 106 cells mL–1, whereas HNF abundance ranged 1.8–10.1 ×103 cells mL–1. Bacterial production ranged 1.1–12.7 × 105 cells mL–1 h–1, whereas HNF grazing rates were an order of magnitude lower at 1.0–78.5 × 104 cells mL–1 h–1. Bacterial abundance, net bacterial production and HNF grazing rates were higher in estuaries than coastal waters but HNF abundance did not differ between the two areas. Across all stations, HNF grazing rates increased with bacterial production, and accounted for ~33% of bacterial production. Our results suggest that in the tropical waters studied, there was a bacterial production–grazing imbalance. Other loss factors such as viral lysis, sedimentation or the presence of benthic filter feeders could account for this imbalance.

scholarly journals Particulate organic carbon dynamics in the Gulf of Lion shelf (NW Mediterranean) using a coupled hydrodynamic–biogeochemical model

2021 ◽  
Vol 18 (19) ◽  
pp. 5513-5538
Author(s):  
Gaël Many ◽  
Caroline Ulses ◽  
Claude Estournel ◽  
Patrick Marsaleix
Keyword(s):  
Organic Carbon ◽  
Primary Production ◽  
Particulate Organic Carbon ◽  
Chlorophyll A ◽  
Net Primary Production ◽  
Biogeochemical Model ◽  
Eastern Region ◽  
Gulf Of Lion ◽  
Poc Export ◽  
Nw Mediterranean

Abstract. The Gulf of Lion shelf (GoL, NW Mediterranean) is one of the most productive areas in the Mediterranean Sea. A 3D coupled hydrodynamic–biogeochemical model is used to study the mechanisms that drive the particulate organic carbon (POC) dynamics over the shelf. A set of observations, including temporal series from a coastal station, remote sensing of surface chlorophyll a, and a glider deployment, is used to validate the distribution of physical and biogeochemical variables from the model. The model reproduces the time and spatial evolution of temperature, chlorophyll a, and nitrate concentrations well and shows a clear annual cycle of gross primary production and respiration. We estimate an annual net primary production of ∼ 200 × 104 t C yr−1 at the scale of the shelf. The primary production is marked by a coast-slope increase with maximal values in the eastern region. Our results show that the primary production is favoured by the inputs of nutrients imported from offshore waters, representing 3 and 15 times the inputs of the Rhône in terms of nitrate and phosphate. In addition, the empirical orthogonal function (EOF) decomposition highlights the role of solar radiation anomalies and continental winds that favour upwellings, and inputs of the Rhône River, in annual changes in the net primary production. Annual POC deposition (27 × 104 t C yr−1) represents 13 % of the net primary production. The delivery of terrestrial POC favours the deposition in front of the Rhône mouth, and the mean cyclonic circulation increases the deposition between 30 and 50 m depth from the Rhône prodelta to the west. Mechanisms responsible for POC export (24 × 104 t C yr−1) to the open sea are discussed. The export off the shelf in the western part, from the Cap de Creus to the Lacaze-Duthiers canyon, represents 37 % of the total POC export. Maximum values are obtained during shelf dense water cascading events and marine winds. Considering surface waters only, the POC is mainly exported in the eastern part of the shelf through shelf waters and Rhône inputs, which spread to the Northern Current during favourable continental wind conditions. The GoL shelf appears as an autotrophic ecosystem with a positive net ecosystem production and as a source of POC for the adjacent NW Mediterranean basin. The undergoing and future increase in temperature and stratification induced by climate change could impact the trophic status of the GoL shelf and the carbon export towards the deep basin. It is crucial to develop models to predict and assess these future evolutions.

scholarly journals Temperature Affects the Time Required to Discern the Relationship between Primary Production and Export Production in the Ocean

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3085
Author(s):  
Edward Laws ◽  
Kanchan Maiti
Keyword(s):  
Primary Production ◽  
Food Web ◽  
Net Primary Production ◽  
Weighted Average ◽  
Time Interval ◽  
High Latitudes ◽  
New Production ◽  
Return To Equilibrium ◽  
Export Production ◽  
The Relationship

Knowledge of the relationship between net primary production (NPP) and export production (EP) in the ocean is required to estimate how the ocean’s biological pump is likely to respond to climate change effects. Here, we show with a theoretical food web model that the relationship between NPP and EP is obscured by the following phenomena: (1) food web dynamics, which cause EP to be a weighted average of new production (NP) over a previous temperature-dependent time interval that can vary between several weeks at 25 °C to several months at 0 °C and, hence, to be much less temporally variable than NP and (2) the temperature dependence of the resiliency of the food web to perturbations, which causes the return to equilibrium to vary from roughly 50 days at 0 °C to 5–10 days at 25 °C. The implication is that the relationship between NPP and EP can be discerned at tropical and subtropical latitudes if measurements of NPP and EP are averages or climatologies over a timeframe of roughly one month. At high latitudes, however, measurements may need to be averaged over a timeframe of roughly one year because the food webs at high latitudes are very likely far from equilibrium with respect to NPP and EP much of the time, and the model can describe only the average behavior of such physically dynamic systems.

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