Seasonal dynamics influencing coastal primary production and phytoplankton communities along the southern Myanmar coast

Maung-Saw-Htoo-Thaw,; Ohara, Shizuka; Matsuoka, Kazumi; Yurimoto, Tatsuya; Higo, Shota; Khin-Ko-Lay,; Win-Kyaing,; Myint-Shwe,; Sein-Thaung,; Yin-Yin-Htay,; Nang-Mya-Han,; Khin-Maung-Cho,; Si–Si-Hla-Bu,; Swe-Thwin,; Koike, Kazuo

doi:10.1007/s10872-016-0408-7

Cited by 16 publications

(4 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Linear and multiple regression analyses showed that the coefficient of determination (r 2 ) was >0.5 for 22 of the 24 sensors. Several other studies conducted in lakes ( Kuha et al , 2020 ), rivers and reservoirs ( Gregor & Maršálek, 2004 ), fish farms ( Brager et al , 2015 ) or in the marine environment ( Aiken et al , 2011 ; Maung-Saw-Htoo-Thaw et al , 2017 ) have identified similar relationships for in-situ fluorescence and in-vitro measurements, the latter based on HPLC measurements, microscopy or spectrophotometry. It is important to note that the results of these other studies were not obtained using the same brand of sensors and that fluorescence readings can vary, especially among sensors from different manufacturers (e.g.…”

Section: Discussionmentioning

confidence: 75%

High resolution chlorophyll-a in-situ fluorescence sensors versus in-vitro chlorophyll-a measurements in mesocosms with contrasting nutrient and temperature treatments

Levi,

Jeppesen,

Nejstgaard

et al. 2024

Open Res Europe

View full text Add to dashboard Cite

Harmful algal blooms (HABs) are a significant threat to freshwater ecosystems, and monitoring for changes in biomass is therefore important. Fluorescence in-situ sensors enable rapid and high frequency real-time data collection and have been widely used to determine chlorophyll-a (Chla) concentrations that are used as an indicator of the total algal biomass. However, conversion of fluorescence to equivalent Chla concentrations is often complicated due to biofouling, phytoplankton composition and the type of equipment used. Here, we validated measurements from 24 Chla and 12 phycocyanin (cyanobacteria indicator) fluorescence in-situ sensors (Cyclops-7F, Turner Designs) against spectrophotometrically (in-vitro) determined Chla and tested a data-cleaning procedure for eliminating data errors and impacts of non-photochemical quenching. The test was done across a range of freshwater plankton communities in 24 mesocosms (i.e. experimental tanks) with a 2x3 (high and low nutrient x ambient, IPCC-A2 and IPCC-A2+50% temperature scenarios) factorial design. For most mesocosms (tanks), we found accurate (r2 ≥ 0.7) calibration of in-situ Chla fluorescence data using simple linear regression. An exception was tanks with high in-situ phycocyanin fluorescence, for which multiple regressions were employed, which increased the explained variance by >16%. Another exception was the low Chla concentration tanks (r2 < 0.3). Our results also show that the high frequency in-situ fluorescence data recorded the timing of sudden Chla variations, while less frequent in-vitro sampling sometimes missed these or, when recorded, the duration of changes was inaccurately determined. Fluorescence in-situ sensors are particularly useful to detect and quantify sudden phytoplankton biomass variations through high frequency measurements, especially when using appropriate data-cleaning methods and accounting for factors that can impact the fluorescence readings.

show abstract

Section: Discussionmentioning

confidence: 75%

High resolution chlorophyll-a in-situ fluorescence sensors versus in-vitro chlorophyll-a measurements in mesocosms with contrasting nutrient and temperature treatments

Levi,

Jeppesen,

Nejstgaard

et al. 2024

Open Res Europe

View full text Add to dashboard Cite

show abstract

“…In the Tanintharyi River estuary along the coastal Myeik, the abundance of diatoms and dinoflagellates was higher during the dry season than the wet season (Lett-Wai-Nwe et al 2021). The rainy season exhibited the lowest amount of primary production owing to the extensive discharge of turbid water from the rivers, which lowered the euphotic layer depth (Saw-Htoo-Thaw et al 2017). High primary production in the estuary during the dry season would have provided suitable food condition for bivalves and promoted their sexual maturation.…”

Section: Discussionmentioning

confidence: 99%

Reproductive Cycle of the Edible Oyster <i>Crassostrea belcheri</i> in the Myeik Coastal Area of Southern Myanmar

Khin-May-Chit-Maung,

TOYOKAWA,

SAITO

et al. 2023

JARQ

Self Cite

View full text Add to dashboard Cite

This study investigated the reproductive cycle of the edible oyster, Crassostrea belcheri, harvested originally from creeks near Pedaing village in the southern part of Myanmar in September 2017-October 2018 through histological analysis. Five maturity stages were detected in the C. belcheri gonads: indifferent, developing, mature, spawning, and spent. The overall sex ratio of males to females of 1:0.98 showed no statistically significant difference from the expected sex ratio of 1:1 in any month. Hermaphrodites could not be observed in 250 oysters. Moreover, the quantitative monthly gonad index values varied from 1.5 in November and June to 2.75 in March. Histological analysis of C. belcheri revealed that mature male and female gonads were detected in almost all months, except in November-December 2017 and June 2018. Spawning occurred throughout the study period, except in January-March 2018, peaking at the beginning and end of the dry season in October-November and April-May, respectively.

show abstract

“…3e and 3f). Based on that Fv/Fm is an indicator of nutrient stress (Cleveland & Perry 1987, Higo et al 2017, it was assumed that these rich nutrient levels led to the highest Fv/Fm values in December and January (Fig. 2f right graph), indicating the phytoplankton population was active, and initiated the January chlorophyll a peaks.…”

Section: A Notable Phytoplankton Bloom and Productivity In Wintermentioning

confidence: 99%

“…We employed this method to research fine details at different depths (3 depths per site) and sampling sites horizontally scattered over the study areas (4-6 stations) monthly for almost 4 years. This method also has the advantage of demonstrating alterations in photosynthetic responses in terms of ETR or RLC that respond well to in situ changes in various environmental factors (Cleveland & Perry 1987, Geider et al 1993, Lippemeier et al 1999, 2001, Shelly et al 2005, Higo et al 2017.…”

Section: Introductionmentioning

confidence: 99%

Environmental and seasonal dynamics altering the primary productivity in Bingo-Nada (Bingo Sound) of the Seto Inland Sea, Japan

Ohara

Yano

Hagiwara

et al. 2020

Plankton Benthos Res

Self Cite

View full text Add to dashboard Cite

Monthly phytoplankton monitoring with primary productivity estimation using pulse amplitude modulation (PAM) fluorometry was conducted from May 2014 to March 2018 in Bingo-Nada, center of the Seto Inland Sea, Japan, where oligotrophication has been a concern. The average chlorophyll a concentration, 7.24 µg L −1 , was even higher than the values of previous studies; therefore, it should not be assumed that the primary productivity has decreased. However, some seasonal trends seemed to drastically change; one of them was notable diatom blooms from December to January. PAM fluorometry revealed that high Fv/Fm of the diatoms due to rich nutrients and high α values (initial slope of ETR versus light) enabled them to actively photosynthesize even under low-light conditions in winter. This winter bloom further caused severe nutrient depletion in spring, which resulted in notable drops in overall photosynthesis and the ETR-based primary production rate (PPR ETR) in March or April. From May, Fv/Fm and rETR max , which began to increase from their minimum values in April, peaked in July or August when the highest PPR ETR was recorded. However, over 70% of the total phytoplankton population consisted of dinoflagellates, raphidophytes and silicoflagellates, not diatoms. The PPR ETR then drastically decreased from August to September, regardless of the fact that there were rich nutrients in the entire water column. Rather, decreased light level, as well as increased turbidity caused by non-phytoplankton particles, especially those abundant in this season, might hinder photosynthesis in autumn, further resulting in nutrient-rich conditions leading to the winter bloom.

show abstract

Seasonal dynamics influencing coastal primary production and phytoplankton communities along the southern Myanmar coast

Cited by 16 publications

References 44 publications

High resolution chlorophyll-a in-situ fluorescence sensors versus in-vitro chlorophyll-a measurements in mesocosms with contrasting nutrient and temperature treatments

High resolution chlorophyll-a in-situ fluorescence sensors versus in-vitro chlorophyll-a measurements in mesocosms with contrasting nutrient and temperature treatments

Reproductive Cycle of the Edible Oyster <i>Crassostrea belcheri</i> in the Myeik Coastal Area of Southern Myanmar

Environmental and seasonal dynamics altering the primary productivity in Bingo-Nada (Bingo Sound) of the Seto Inland Sea, Japan

Contact Info

Product

Resources

About