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Time series of Chl-a concentration in the WWI. e value of Chl-a concentration is calculated annually to nd out what year the maximum concentration is. e red vertical line represents the year with the maximum Chl-a concentration (~1.4 mg.m -3 ).
Source publication
The Western Waters of Indonesian (WWI) present a diverse interaction of ocean-atmosphere dynamics. One of them represents the event of Indian Ocean Dipole (IOD), El Niño–Southern Oscillation (ENSO), and upwelling. The objective of this study is to determine the dynamics of chlorophyll-a concentration (Chl–a), especially during IOD and ENSO. Also, t...
Contexts in source publication
Context 1
... distribution annual cycle of Chl-a in the WWI is presented in Fig. 3. It was noted that the concentration reached 30 mg.m -3 in 2011. Because the Chl-a value uctuates throughout the year, it is not enough if it merely displays the distribution of values in a time series sequence. e further step is to collect Chl-a values in the same year to be compared in subsequent years, as presented in Fig. 3. e ...
Context 2
... is presented in Fig. 3. It was noted that the concentration reached 30 mg.m -3 in 2011. Because the Chl-a value uctuates throughout the year, it is not enough if it merely displays the distribution of values in a time series sequence. e further step is to collect Chl-a values in the same year to be compared in subsequent years, as presented in Fig. 3. e spatial distribution of Chl-a in western Indonesia is concentrated at 100 0 and 104 0 east longitude. is is related to the exchange of river water in the Malacca Strait ( Siswanto and Tanaka, 2004). Meanwhile, when reviewed temporally, it was noted in the middle of 2006, 2008, 2010, 2011, 2013, and 2016 that Chl-a concentration ...
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... negative DMI took place in 2004, 2005, mid-2010, 2013, 2014, and 2016. Furthermore, the N3.4 (Niño 3.4 Index) (El niño) with the average category emerged in 2003, 2007, mid-2009, and mid-2015. As for the N3.4 (Niño 3.4 Index) (La Nina), the average category emerged in mid -2007, mid-2010, mid- 2011, and mid-2016. When Fig. 4a is connected to Fig. 3, it is discovered that the temperature difference in the Indian Ocean (IOD) and Paciic Ocean (N3.4/Niño 3.4 Index) which is not too uctuation results in high Chl-a concentrations. It is indicated by the vertical red line in Fig. 3. It is required for further study to explain the event. Furthermore, to see how much the effect of the IOD ...
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... (La Nina), the average category emerged in mid -2007, mid-2010, mid- 2011, and mid-2016. When Fig. 4a is connected to Fig. 3, it is discovered that the temperature difference in the Indian Ocean (IOD) and Paciic Ocean (N3.4/Niño 3.4 Index) which is not too uctuation results in high Chl-a concentrations. It is indicated by the vertical red line in Fig. 3. It is required for further study to explain the event. Furthermore, to see how much the effect of the IOD and N3.4 (Niño 3.4 Index) on the chlorophyll index is calculated through the coefficient of determination. e results are 0.56 (Fig. 4b). It shows there is a dominant relationship between Chl-a concentration and the changes of ...
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... values (Fig. 5), the higher (lower) the standard deviation of SST, the lower (higher) the SST produced. 2000 -2017 (monthly effect and trends have been removed). e magenta plot shows the DMI value ≥ 0.4 0 C, while the cyan color states the DMI value ≤ 0.4 0 C. e red vertical line represents the year in which the Chl-a reached its peak (see Fig. 3). (b) Relationship between the difference in the value of IOD with N3.4 (Niño 3.4 Index) (blue line) to the Chl-a index (brown line) from 2003 to ...
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... The western waters of Sumatra are a unique and complex area because their geographical location is crossed by the equator and flanked by the Asian continents-the Australian continent and the Indian Ocean-the Pacific Ocean [1], making these waters dynamic [2]. It is due to the significant influence of the monsoon system, Sumatra's west coast, and Indonesian Crossflow (ARLINDO/Arus Lintas Indonesia), the Indian Ocean Dipole (IOD), and El-Nino Southern Oscillation (ENSO) phenomena on the dynamics of the water mass characteristics of Sumatra's western waters [3]. ...
The eastern Indian Ocean is western tropical waters with very complex dynamic and physical processes affecting the area along the line of the West Sumatra coast. This study aims to analyze the water masses in the West Sumatra waters adjacent to the equatorial latitude based on the seasonality of December–February (DJF), March–May (MAM), June–August (JJA), and September–November (SON) from 2003 to 2018 which uses World Ocean Database (WOD) data. The tendency of the observed water mass characteristics to be dominant in the surface layer is more concentrated by the influence of water masses from the area around West Sumatra and intrusion from the surrounding waters. Meanwhile, in the middle to deep layers, more water mass patterns are observed from the western Indian Ocean region with a temperature range of −10 ˚C and salinity of 34.6−36.7 PSU. Characteristics based on seasonality are more indicative of a water mass mixing process. The DJF season tends to have a more uniform sea surface temperature than the JJA season. In addition, transitional seasons I and II (MAM and SON) tend to approach the main seasonal conditions. This is evidenced by the different Mixed Layer Depth (MLD) contours in the DJF season, which are thinner than in the JJA season. The temperature uniformity in the horizontal profile seems to vary in the JJA season compared to the DJF, so the thermocline observed in the JJA season is deeper. The identified water column density conditions show the same pattern seasonally.
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Perairan Spermonde merupakan perairan yang mengelilingi pulau-pulau Spermonde dengan dangkalan yang berada di sebelah barat daya Sulawesi Selatan yang berada di wilayah tropis dan dilintasi garis khatulistiwa yang menyebabkan perairan tersebut mengalami dua musim berbeda yaitu musim barat dan musim timur. Tujuan penelitian ini untuk menganalisis fenomena upwelling di perairan spermonde. Perairan spermonde pada musim timur (juni-agustus) berpotensi terjadi upwelling karena memiliki angin dan arus yang cukup kuat sehingga terjadi transpor ekman yang meyebabkan pembelokkan arus bergerak dari tenggara kearah barat. Indikasi upwelling dapat dilihat dari kenaikan massa air temperatur dan salinitas dari dalam yang terjadi di semua stasiun sehingga kuat untuk terjadi upwelling. Pola konsentrasi klorofil-a di laut tengah dan laut lepas upwelling yang terjadi lemah karena klorofil tertinggi berada di dekat pantai karena pengaruh air sungai dan beberapa kegiatan industri lainnya sehingga daerah lepas pantai memiliki klorofil yang tidak terlalu tinggi yang dihubungkan dengan menurunnya suhu permukaan laut.
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Water temperature controls the physiology, growth rate, distribution, and behavior of most plankton populations in the sea and thus affects the energy transfer in marine ecosystems. The present study focuses on the influence of seasonal changes in sea surface temperature on phytoplankton and the size distribution of copepods in the Arraial do Cabo Upwelling System (Brazil), where a wind-driven coastal upwelling can lead to multiple distinct bottom-up cascade effects on the food web. To address the potential effect of the seasonal changes, environmental data were obtained and the abundance of plankton determined from monthly samples collected in triplicate from 2010 to 2014. The samples were analyzed on a Benchtop FlowCAM (FC), and copepods (<1000 µm) were classified according to their Ellipses Equivalent Major Axis using image analysis software ImageJ (IJ). For IJ analysis, a batch-processing macro was built to open all FC raw images and then crop each copepod individually into a single picture. Using these images, prosome and urosome lengths were manually measured with the straight-line tool in IJ. With the combinations of measurements obtained in the IJ adjusted as FC measurements, we established a new, faster, and more effective way to measure copepods. With the copepod size classification, we found that there is a cycle in copepod size combined with the upwelling cycle that is related to temperature rather than to phytoplankton growth. Copepod abundance as a whole peaked during the autumn, winter, and spring seasons. The method performed here proved that FC is an effective tool for classifying copepod sizes and detecting seasonal variation.
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Perairan Karimata merupakan perairan tropis yang berada dalam wilayah Negara Kesatuan Republik Indonesia. Sehingga dengan adanya sinar matahari sepanjang tahun, produktivitas penghasil organisme di perairan tersebut dapat terus berlanjut. Produktivitas yang berkelanjutan dengan memproduksi organisme di perairan menyediakan sumber makanan bagi ikan dan organisme lainnya. Perairan Karimata mempunyai potensi sebagai daerah upwelling. Dengan memetakan sebaran wilayah upwelling tentunya memberikan jalan bagi para pelaku sektor perikanan responsif laut untuk mengidentifikasi wilayah yang potensial sebagai daerah penangkapan ikan. Penelitian ini bertujuan untuk memetakan kriteria upwelling di Wilayah Kepulauan Karimata pada bulan Mei 2023 dengan menggunakan parameter suhu permukaan laut dan konsentrasi klorofil-a untuk mengidentifikasi dan memetakan wilayah upwelling beserta kriterianya. Penelitian ini bersifat deskriptif eksploratif dengan menggunakan variabel suhu permukaan laut dan konsentrasi klorofil-a yang diolah melalui metode overlay pada perangkat lunak. Sebaran wilayah upwelling diperoleh dengan kriteria upwelling sangat kuat, upwelling kuat, upwelling sedang, dan upwelling lemah. Berdasarkan hasil pemetaan, wilayah yang dekat dengan daratan mempunyai kriteria upwelling yang sangat kuat sehingga menunjukkan tingkat produktivitas air yang sangat tinggi dibandingkan wilayah lain dalam pemetaan.
The spatiotemporal variability of oceanic fronts in the Indonesian seas was investigated using high-resolution satellite observations. The study aimed to understand the underlying mechanism driving these fronts and their impact on chlorophyll-a variability. A high value of frontal probability was found near the coasts of major islands, exhibiting a distinct seasonal cycle with peaks occurrences during austral winter. The distribution variability of chlorophyll-a was generally consistent with the presence of active frontal zones, although a significantly positive relationship between fronts and chlorophyll-a was limited to only some specific areas, e.g., south Java Island and the Celebes Sea. Wind-driven upwelling played a major role in front generation in the Java upwelling region and enhanced frontal activity can promote the growth of phytoplankton, leading to higher chlorophyll-a. Furthermore, the study demonstrated that wind patterns preceded variations in front probability and chlorophyll-a by approximately two months. This lag suggests that the spatiotemporal variability of fronts and chlorophyll-a in this region is primarily influenced by the monsoon system. In addition, the sea surface temperature (SST) simultaneously modulated the chlorophyll-a variability. Negative SST anomalies were typically associated with positive anomalies in front probability the chlorophyll-a in most areas. Notably, the interannual variability of fronts and chlorophyll-a are prominent in the Java upwelling region. During El Niño years, this region experienced an enhanced monsoon, resulting in a negative SST anomaly alongside positive anomalies in front probability and chlorophyll-a. A comprehensive description and underlying dynamics of frontal activity in the Indonesian seas are provided by this study. The findings are helpful to delineate the variability in chlorophyll-a, thereby facilitating the future understanding of local primary production and the carbon cycle.
Significance Statement
As typical mesoscale processes, oceanic fronts have significant impacts on biological processes and fisheries in marginal seas. The complex spatiotemporal variability of fronts and their effects on biological processes in the Indonesian seas remain poorly understood. This study aimed to address this knowledge gap by investigating the seasonal and interannual variability of fronts and their influence on chlorophyll-a, a key indicator of phytoplankton biomass and primary productivity. The study identified a high frontal probability in south Java Island during austral winter and El Niño years. Wind-driven upwelling was found to be a major factor in front generation and promoting phytoplankton growth. The findings of this study will improve the theoretical knowledge of regional dynamics, local primary production, and the carbon cycle in the Indonesian seas, benefiting fisheries management and ecosystem conservation efforts.
O fenômeno da ressurgência na costa do Brasil, ocorre com o deslocar da massa d’água superficial quente, combinados com vento nordeste, efeito Coriolis e auxílio de uma plataforma continental, que é substituída por águas frias e ricas em nutrientes. A ressurgência aumenta a produção primária do fitoplâncton e, como consequência, há um aumento na biomassa de herbívoros e dos peixes ao longo da teia trófica. O efeito inverso é conhecido como subsidência, quando o ambiente não é muito influenciado pelo fenômeno da ressurgência, e assim predomina água quente e pobre em nutrientes. O zooplâncton é essencial para a manutenção das teias tróficas marinhas e, sua composição e abundância, variam em função da temperatura que muda bruscamente em região de ressurgência e a ao longo do ano. O objetivo do presente estudo é investigar os efeitos dos processos oceanográficos, no ciclo offshore-onshore, no Atlântico Sul Ocidental, Brasil-RJ, sobre a comunidade mero e holoplanctônicas, na região de ressurgência de Arraial do Cabo. Os processos oceanográficos associados às massas d’água registradas na região, a direção/velocidade dos ventos, a concentração de clorofila-a e altura da maré, mostraram que a comunidade meroplanctônica está relacionada com a floração de fitoplâncton em uma estação fora da Enseada dos Anjos (estação Sonar). Na estação Sonar o efeito offshore, ocorreu com mais frequência e intensidade, devido ao vento nordeste que dispersa as larvas em direção ao oceano. Os maiores picos de larvas são encontrados na presença do vento sudoeste e com a influência da Água Tropical, e os menores são encontrados em Águas Costeiras, períodos de subsidência. Em contrapartida, em uma estação dentro da enseada (Praia do Forno) com temperatura quente; favoreceu a abundância de larvas de Polychaeta, mas as Larvas em D (Bivalvia) não apresentaram correlação com os parâmetros testados. Além disso, foram realizadas contagem e medições de copépodes, em microscopia tradicional e correlacionadas com os valores da FlowCAM. O acoplamento do algoritmo ImageJ e as medidas obtidas pelo Software de Planilha Visual, demostrou mais eficácia do que técnicas tradicionais, como microscopia, facilitando o entendimento das mudanças sazonais e interanuais na abundância e estrutura de tamanho dos copépodes. As classes de tamanho dos copépodes variou sazonalmente de acordo com o período de ressurgência, subsidência e bloom de fitoplâncton. Com o novo método é possível avaliar as mudanças de classes de tamanho do prossoma: antes, durante e após o fenômeno da ressurgência. Os copépodes >300µm controlam o fitoplâncton durante a maior parte do ano, enquanto que os <300µm estão correlacionados com a diminuição da temperatura e início da floração durante a primavera. Os efeitos da ressurgência e subsidência possuem relação com a abundância da comunidade meroplanctônica e da classe de tamanho da assembleia de copépodes, pois como a temperatura varia ao longo do ano, assim como a disponibilidade de biomassa fitoplanctônica, que foram os principais fatores responsáveis pela mudança na abundância de larvas e distribuição da classe de tamanho dos copépodes.
