Wet Season Upwelling and Dry Season Chlorophyll-a Describe Interannual Growth Rates of Porites in Southern China

ABSTRACT Dissolved silicate (DSi) in coastal waters plays a crucial role in phytoplankton growth particularly diatom. This study aimed to determine DSi concentration seasonally in waters of the western coast of South Sulawesi in relation to coastal water quality indicator. Water, chlorophyll-a, and diatom samples were collected from the coastal areas of the Tallo-Makassar, Maros, and Pangkep, in April 2013 (transitional season), June 2013 (dry season), and February 2014 (wet season). Factorial analysis of variance was used to identify significant seasonal and temporal variations, and linear regression was used to test the relationship of chlorophyll-a and diatom abundance to DSi concentrations. The results showed that the DSi concentration was higher in the wet season of 35.2-85.2 µM than in the other seasons (transitional season: 10.8-68.4 µM, dry season: 9.59-24.1 µM). The abundance of diatoms during the transitional season reached ~9.7x107 cell/m3 in the Pangkep river, 2.3x107 cell/m3 in the Tallo river, and 1.3 x 107 cell/m3 in the Maros river. Chaetoceros, Nitzschia, and Rhizosolenia dominated the diatom composition. The mean concentration of chlorophyll-a in the Makassar coastal waters was 4.52±4.66 mg/m3, while in the Maros and Pangkep waters of 1.40±1.06, and 2.72±1.94 mg/m3, respectively. There was no strong linear corelation between DSi and diatom abundances, nor chlorophyll-a. These results suggested that DSi become a non-limiting factor for the diatom growth and potentially reduce the water quality via eutrophication and diatom blooms. Keywords: dissolved silicate, diatom, chlorophyll-a, coastal waters, South Sulawesi

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DISSOLVED SILICATE IN COASTAL WATER OF SOUTH SULAWESI

Jurnal Ilmu dan Teknologi Kelautan Tropis ◽

10.28930/jitkt.v6i2.9022 ◽

2015 ◽

Vol 6 (2) ◽

Author(s):

Muhammad Lukman ◽

Andriani Nasir ◽

Khairul Amri ◽

Rahmadi Tambaru ◽

Muhammad Hatta ◽

...

Keyword(s):

Water Quality ◽

Chlorophyll A ◽

Coastal Water ◽

Coastal Waters ◽

Dry Season ◽

Limiting Factor ◽

Western Coast ◽

Wet Season ◽

South Sulawesi ◽

Dissolved Silicate

ABSTRACT Dissolved silicate (DSi) in coastal waters plays a crucial role in phytoplankton growth particularly diatom. This study aimed to determine DSi concentration seasonally in waters of the western coast of South Sulawesi in relation to coastal water quality indicator. Water, chlorophyll-a, and diatom samples were collected from the coastal areas of the Tallo-Makassar, Maros, and Pangkep, in April 2013 (transitional season), June 2013 (dry season), and February 2014 (wet season). Factorial analysis of variance was used to identify significant seasonal and temporal variations, and linear regression was used to test the relationship of chlorophyll-a and diatom abundance to DSi concentrations. The results showed that the DSi concentration was higher in the wet season of 35.2-85.2 µM than in the other seasons (transitional season: 10.8-68.4 µM, dry season: 9.59-24.1 µM). The abundance of diatoms during the transitional season reached ~9.7x107 cell/m3 in the Pangkep river, 2.3x107 cell/m3 in the Tallo river, and 1.3 x 107 cell/m3 in the Maros river. Chaetoceros, Nitzschia, and Rhizosolenia dominated the diatom composition. The mean concentration of chlorophyll-a in the Makassar coastal waters was 4.52±4.66 mg/m3, while in the Maros and Pangkep waters of 1.40±1.06, and 2.72±1.94 mg/m3, respectively. There was no strong linear corelation between DSi and diatom abundances, nor chlorophyll-a. These results suggested that DSi become a non-limiting factor for the diatom growth and potentially reduce the water quality via eutrophication and diatom blooms. Keywords: dissolved silicate, diatom, chlorophyll-a, coastal waters, South Sulawesi

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Variation in growth and reproduction of Bolomys lasiurus (Rodentia: Muridae) in an Amazonian savanna

Journal of Tropical Ecology ◽

10.1017/s0266467400008889 ◽

1995 ◽

Vol 11 (3) ◽

pp. 419-428 ◽

Cited By ~ 23

Author(s):

Angelo De Lima Francisco ◽

William E. Magnusson ◽

Tânia M. Sanaiotti

Keyword(s):

Direct Effect ◽

Growth Rates ◽

Reproductive Output ◽

Dry Season ◽

Consistent Pattern ◽

Wet Season ◽

Relative Growth ◽

Relative Growth Rates ◽

Lactating Females ◽

Growth And Reproduction

ABSTRACTReproduction by Bolomys lasiurus is strongly seasonal in the Amazonian savanna of Alter do Chāo, Pará, Brazil. No pregnant or lactating females were recorded during the early dry season (July-September). Relative growth rates showed a similar though less consistent pattern. These patterns do not appear to be due to a direct effect of rainfall as high reproduction and growth were recorded during the late dry season (October-November), even though rainfall and the availability of fruits of shrubs were low during that period. It is likely that reinitiation of reproduction during the dry season is due to an increase in the availability of invertebrates and/ or wind-dispersed seeds. Fire at the end of the dry season appears to affect the diet of the rats, causing an increase in the ingestion of invertebrates during the following wet season. However, our data do not indicate that fire affects individual reproductive output or growth.

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ANALYSIS OF WATER PRODUCTIVITY IN THE BANDA SEA BASED ON REMOTE SENSING SATELLITE DATA

International Journal of Remote Sensing and Earth Sciences (IJReSES) ◽

10.30536/j.ijreses.2020.v17.a3280 ◽

2020 ◽

Vol 17 (1) ◽

pp. 25

Author(s):

Sartono Marpaung ◽

Risky Faristyawan ◽

Anang Dwi Purwanto ◽

Wikanti Asriningrum ◽

Argo Galih Suhada ◽

...

Keyword(s):

Chlorophyll A ◽

El Niño ◽

El Nino ◽

Dry Season ◽

La Niña ◽

Wet Season ◽

Conservation Areas ◽

Conservation Area ◽

Chlorophyll A Concentration ◽

La Nina

Abstract. This study examines the density of potential fishing zone (PFZ) points and chlorophyll-a concentration in the Banda Sea. The data used are those on chlorophyll-a from the Aqua MODIS satellite, PFZ points from ZAP and the monthly southern oscillation index. The methods used are single image edge detection, polygon center of mass, density function and a Hovmoller diagram. The result of the analysis show that productivity of chlorophyll-a in the Banda Sea is influenced by seasonal factors (dry season and wet season) and ENSO phenomena (El Niño and La Niña). High productivity of chlorophyll-a occurs during in the dry season with the peak in August, while low productivity occurs in the wet season and the transition period, with the lowest levels in April and December. The variability in chlorophyll-a production is influenced by the global El Niño and La Niña phenomena; production increases during El Niño and decreases during La Niña. Tuna conservation areas have as lower productivity of chlorophyll-a and PFZ point density compared to the northern and southern parts of the Banda Sea. High density PFZ point regions are associated with regions that have higher productivity of chlorophyll-a, namely the southern part of the Banda Sea, while low density PFZ point areas are associated with regions that have a low productivity of chlorophyll-a, namely tuna conservation areas. The effect of the El Niño phenomenon in increasing chlorophyll-a concentration is stronger in the southern part of study area than in the tuna conservation area. On the other hand, the effect of La Niña phenomenon in decreasing chlorophyll-a concentration is stronger in the tuna conservation area than in the southern and northern parts of the study area.

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Ground-based observation of clusters and nucleation-mode particles in the Amazon

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-13245-2018 ◽

2018 ◽

Vol 18 (17) ◽

pp. 13245-13264 ◽

Cited By ~ 4

Author(s):

Daniela Wimmer ◽

Stephany Buenrostro Mazon ◽

Hanna Elina Manninen ◽

Juha Kangasluoma ◽

Alessandro Franchin ◽

...

Keyword(s):

Growth Rates ◽

Ground Level ◽

Dry Season ◽

Amazon Region ◽

Amazon Rainforest ◽

Wet Season ◽

Ion Concentrations ◽

Nucleation Mode ◽

Rain Events ◽

Spectrometer Data

Abstract. We investigated atmospheric new particle formation (NPF) in the Amazon rainforest using direct measurement methods. To our knowledge this is the first direct observation of NPF events in the Amazon region. However, previous observations elsewhere in Brazil showed the occurrence of nucleation-mode particles. Our measurements covered two field sites and both the wet and dry season. We measured the variability of air ion concentrations (0.8–12 nm) with an ion spectrometer between September 2011 and January 2014 at a rainforest site (T0t). Between February and October 2014, the same measurements were performed at a grassland pasture site (T3) as part of the GoAmazon 2014/5 experiment, with two intensive operating periods (IOP1 and IOP2 during the wet and the dry season, respectively). The GoAmazon 2014/5 experiment was designed to study the influence of anthropogenic emissions on the changing climate in the Amazon region. The experiment included basic aerosol and trace gas measurements at the ground, remote sensing instrumentation, and two aircraft-based measurements. The results presented in this work are from measurements performed at ground level at both sites. The site inside the rainforest (T0t) is located 60 km NNW of Manaus and influenced by pollution about once per week. The pasture (T3) site is located 70 km downwind from Manaus and influenced by the Manaus pollution plume typically once per day or every second day, especially in the afternoon. No NPF events were observed inside the rainforest (site T0t) at ground level during the measurement period. However, rain-induced ion and particle bursts (hereafter, “rain events”) occurred frequently (643 of 1031 days) at both sites during the wet and dry season, being most frequent during the wet season. During the rain events, the ion concentrations in three size ranges (0.8–2, 2–4, and 4–12 nm) increased up to about 104–105 cm−3. This effect was most pronounced in the intermediate and large size ranges, for which the background ion concentrations were about 10–15 cm−3 compared with 700 cm−3 for the cluster ion background. We observed eight NPF events at the pasture site during the wet season. We calculated the growth rates and formation rates of neutral particles and ions for the size ranges 2–3 and 3–7 nm using the ion spectrometer data. The observed median growth rates were 0.8 and 1.6 nm h−1 for 2–3 nm sized ions and particles, respectively, with larger growth rates (13.3 and 7.9 nm h−1) in the 3–7 nm size range. The measured nucleation rates were of the order of 0.2 cm−3 s−1 for particles and 4–9×10-3 cm−3 s−1 for ions. There was no clear difference in the sulfuric acid concentrations between the NPF event days and nonevent days (∼9×105 cm−3). The two major differences between the NPF days and nonevent days were a factor of 1.8 lower condensation sink on NPF event days (1.8×10-3 s−1) compared to nonevents (3.2×10-3 s−1) and different air mass origins. To our knowledge, this is the first time that results from ground-based sub-3 nm aerosol particle measurements have been obtained from the Amazon rainforest.

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Stem growth of woody species at the Nkuhlu exclosures, Kruger National Park: 2006–2010

Koedoe ◽

10.4102/koedoe.v53i1.1035 ◽

2011 ◽

Vol 53 (1) ◽

Cited By ~ 10

Author(s):

Peter F. Scogings

Keyword(s):

Ecosystem Management ◽

Growth Rates ◽

Woody Species ◽

Dry Season ◽

Stem Growth ◽

Wet Season ◽

Conservation Areas ◽

Large Herbivores ◽

Chemical Defences ◽

Conservation Implications

An important aspect of managing African conservation areas involves understanding how large herbivores affect woody plant growth. Yet, data on growth rates of woody species in savannas are scarce, despite its critical importance for developing models to guide ecosystem management. What effect do browsing and season have on woody stem growth? Assuming no growth happens in the dry season, browsing should reduce stem growth in the wet season only. Secondly, do functional species groups differ in stem growth? For example, assuming fine-leaved, spiny species’ growth is not compromised by carbon-based chemical defences, they should grow faster than broad-leaved, chemically defended species. Dendrometers were fixed at 20 cm in height on the main stems of 244 random plants of six woody species in three plots (all large herbivores excluded, partial exclusion, and control) and observed from late 2006 to early 2010. Average monthly increment (AMI) per dendrometer and season (dry, wet) was calculated and the interaction between plot and season tested per species, controlling for initial stem girth. AMIs of Combretum apiculatum, Dichrostachys cinerea and Grewia flavescens were zero in the dry season, whilst those of Acacia exuvialis, Acacia grandicornuta and Euclea divinorum were either positive or negative in the dry season. Wet-season AMI of D. cinerea and dry-season AMI of G. flavescens tended to be reduced by browser exclusion. Net AMI (sum of the seasonal AMIs) was tested per species, but results suggested that only D. cinerea tended to be affected by browser exclusion. The results also suggested that stem radial growth of some fast-growing species is more prone to reduction by browser exclusion than the growth of other species, potentially reducing their competitiveness and increasing their risk of extirpation. Finally, the usefulness of grouping woody species into simple functional groups (e.g. fine-leaved vs. broad-leaved) for ecosystem management purposes in savannas requires further consideration. Conservation implications: Growth rates of woody plants are important parameters in savanna models, but data are scarce. Monitoring dendrometers in manipulative situations over several years can help fill that gap. Results of such studies can be used to identify species prone to high risk of extirpation.

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Effects of precipitation on soil respiration and its temperature/moisture sensitivity in three subtropical forests in Southern China

Biogeosciences Discussions ◽

10.5194/bgd-9-15667-2012 ◽

2012 ◽

Vol 9 (11) ◽

pp. 15667-15698

Author(s):

H. Jiang ◽

Q. Deng ◽

G. Zhou ◽

D. Hui ◽

D. Zhang ◽

...

Keyword(s):

Soil Moisture ◽

Soil Respiration ◽

Temperature Sensitivity ◽

Southern China ◽

Dry Season ◽

Wet Season ◽

Moisture Sensitivity ◽

Masson Pine ◽

Subtropical Forests ◽

Extreme Flood

Abstract. Both long-term observation data and model simulations suggest an increasing chance of serious drought in the dry season and extreme flood in the wet season in Southern China, yet little is known about how changes in precipitation pattern will affect soil respiration in the region. We conducted a field experiment to study the responses of soil respiration to precipitation manipulations – precipitation exclusion to mimic drought, double precipitation to simulate flood, and ambient precipitation (Abbr. EP, DP and AP, respectively) – in three subtropical forests in Southern China. The three forests include Masson pine forest (PF), coniferous and broadleaved mixed forest (MF) and monsoon evergreen broadleaved forest (BF). Our observations showed that altered precipitation can strongly influence soil respiration, not only through the well-known direct effects of soil moisture, but also by modification on both moisture and temperature sensitivity of soil respiration. In the dry season, soil respiration and its temperature sensitivity in the three forests showed rising trends with precipitation increase, and its moisture sensitivity showed an opposite trend. In the wet season, the EP treatment also decreased soil respiration and its temperature sensitivity, and enhanced moisture sensitivity in all three forests. Soil respiration under the DP treatment increased significantly in the PF only, and no significant change was found for either moisture or temperature sensitivity. However, the DP treatment in the MF and BF reduced temperature sensitivity significantly. Our results indicated that soil respiration would decrease in the three subtropical forests if soil moisture continues to decrease in the future. More rainfall in the wet season could have limited effect on the response of soil respiration to the rising of temperature in the BF and MF.

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OCEANOGRAPHIC CHARACTERISTICS OF KLABAT BAY, BANGKA ISLAND, INDONESIA

Marine Research in Indonesia ◽

10.14203/mri.v32i2.437 ◽

1970 ◽

Vol 32 (2) ◽

pp. 49-54

Author(s):

Suhendar I. Sachoemar ◽

Agus Kristijono ◽

Tetsuo Yanagi

Keyword(s):

Chlorophyll A ◽

Inorganic Nitrogen ◽

Outer Part ◽

Total Suspended Solid ◽

Inorganic Phosphorus ◽

Suspended Solid ◽

Dry Season ◽

Wet Season ◽

High Precipitation ◽

Observation Results

The oceanographic characteristics of Klabat Bay in Bangka Island of Indonesia were investigated by using a series of temperature, salinity, turbidity, TSS (total suspended solid), transparency, DIN (Dissolved Inorganic Nitrogen), DIP (Dissolved Inorganic Phosphorus), DO (Dissolved Oxygen) and chlorophyll-a data in the wet season (Northwest Monsoon) and dry season (Southeast Monsoon) of 2003, respectively. The observation results show that the hydro-oceanographic characteristics of Klabat Bay in the inner part and the outer part of the bay were dominantly influenced by the terrestrial and oceanic environment, respectively. High precipitation during the wet season decreased salinity, DO and transparency and increased total suspended solid (TSS), turbidity, DIN and chlorophyll-a within the bay. The reverse occurred during the dry season, except DIP.

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Importance of predation and viral lysis for bacterial mortality in a tropical western Indian coral-reef ecosystem (Toliara, Madagascar)

Marine and Freshwater Research ◽

10.1071/mf14253 ◽

2015 ◽

Vol 66 (11) ◽

pp. 1009 ◽

Cited By ~ 2

Author(s):

M. Bouvy ◽

P. Got ◽

Y. Bettarel ◽

T. Bouvier ◽

C. Carré ◽

...

Keyword(s):

Bacterial Growth ◽

Growth Rates ◽

Free Water ◽

Dry Season ◽

Nutrient Concentrations ◽

Wet Season ◽

Viral Lysis ◽

Bacterial Mortality ◽

Heterotrophic Nanoflagellate ◽

Bacterial Growth Rates

Size fractionation was performed using water from the Great Reef of Toliara (Madagascar) taken from two different habitats (ocean and lagoon) during the dry and wet seasons, to study the growth and mortality rates of bacterioplankton. Experiments were conducted with 1 and 100% of heterotrophic nanoflagellate (HNF) concentrations and virus-free water was obtained by tangential filtration (10kDa). During the dry season, in both environments, bacterial abundance and production were significantly lower than values recorded during the wet season. Bacterial growth rates without grazers were 0.88 day–1 in the lagoon and 0.58 day–1 in the ocean. However, growth rates were statistically higher without grazers and viruses (1.58 day–1 and 1.27 day–1). An estimate of virus-induced bacterial mortality revealed the important role played by viruses in the lagoon (0.70 day–1) and the ocean (0.69 day–1). During the wet season, bacterial growth rates without grazers were significantly higher in both environments than were values obtained in the dry season. However, the bacterial growth rates were paradoxally lower in the absence of viruses than with viruses in both environments. Our results suggest that changes in nutrient concentrations can play an important role in the balance between viral lysis and HNF grazing in the bacterial mortality. However, virus-mediated bacterial mortality is likely to act simultaneously with nanoflagellates pressure in their effects on bacterial communities.

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Environmental Factors Influencing Chlorophyll-a Concentration in Tri An Reservoir, Vietnam

VNU Journal of Science Earth and Environmental Sciences ◽

10.25073/2588-1094/vnuees.4535 ◽

2021 ◽

Vol 37 (2) ◽

Author(s):

Tran Thi Hoang Yen ◽

Tran Thanh Thai ◽

Nguyen Van Tu ◽

Ngo Xuan Quang ◽

Pham Thanh Luu

Keyword(s):

Environmental Factors ◽

Chlorophyll A ◽

Linear Regression Analysis ◽

Surface Water Quality ◽

Dry Season ◽

Wet Season ◽

Chl A ◽

Physico Chemical ◽

Assessment And Monitoring ◽

The Relationship

Chlorophyll-a (Chl-a) has been used extensively as an essential indicator of trophic state in the assessment and monitoring of surface water quality environments. The environmental factors can influence Chl-a concentrations; thus, to determine the relationship between Chl-a concentration and factors. The research was carried out in dry season (March 2016) and wet season (September 2016) in Tri An reservoir, Dong Nai Province, Vietnam and performed by Spearman's correlation analysis and Linear regression analysis. The result showed that Chl-a varied between 12.84 and 783.51 µg/L and was quite different a cross stations in two surveys. Factor analysis and the best models revealed the association of strong physico-chemical with Chl-a concentration. The Chl-a was significantly positively correlated with Total Suspended Solids (TSS) and negative with Nitrate (NO3-) in the dry season, while in the wet season the positive relationships between Chl-a concentration and Dissolved Oxygen (DO), Temperature and a strong negatively correlated with Phosphate (PO43-) correlation were found. This relationships inferred that the nutrients brought by the influx of reservoir into the study area have contributed to control the growth and abundance of phytoplankton. Thus, the importance of environmental factors in structuring Chl-a concentration may be used to guide the conservation of the aquatic ecosystems in the reservoir.

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