Ocean Primary Productivity

Plankton merupakan komponen penting dalam ekosistem perairan yang berperan sebagai indikator kualitas air dan dasar rantai makanan akuatik. Komposisi dan kepadatan plankton diketahui sangat dipengaruhi oleh fluktuasi harian faktor lingkungan seperti cahaya, suhu, serta parameter fisika-kimia lainnya. Penelitian ini bertujuan untuk menganalisis komposisi, kepadatan, serta hubungan antara fluktuasi harian plankton dengan parameter fisika-kimia air di kolam Universitas Andalas.

Pengambilan sampel dilakukan selama 24 jam secara interval setiap 3 jam pada tanggal 25–26 Mei 2024 menggunakan plankton net No. 25. Parameter fisika-kimia yang diukur meliputi suhu, pH, oksigen terlarut (DO), karbon dioksida terlarut (CO₂), dan Biochemical Oxygen Demand (BOD₅). Identifikasi plankton dilakukan di laboratorium hingga tingkat genus.

Hasil penelitian menunjukkan bahwa kepadatan plankton tertinggi terjadi pada pukul 00.00 WIB sebesar 6,60 individu/L, sedangkan kepadatan terendah tercatat pada pukul 12.00 WIB sebesar 4,93 individu/L. Komposisi harian plankton menunjukkan dominasi fitoplankton pada siang hari, terutama pukul 10.00–12.00 WIB, sementara zooplankton mendominasi pada malam hingga dini hari, khususnya pukul 22.00 dan 02.00 WIB. Kelas fitoplankton yang paling melimpah adalah Chlorophyceae.

Parameter lingkungan juga mengalami fluktuasi harian, di mana suhu air tertinggi tercatat sebesar 26°C pada siang hari, pH tertinggi 6,00 pada malam hari, CO₂ terlarut tertinggi sebesar 1,34 mg/L pada siang hari, dan BOD₅ tertinggi sebesar 2,71 mg/L juga pada siang hari.

Kesimpulan dari penelitian ini menunjukkan bahwa fluktuasi harian plankton berkaitan erat dengan migrasi vertikal diel, intensitas cahaya, serta perubahan suhu. Fitoplankton lebih aktif melakukan fotosintesis pada siang hari, sementara zooplankton bermigrasi ke permukaan pada malam hari untuk menghindari predator dan memanfaatkan kondisi lingkungan yang lebih stabil.

Kata Kunci: fluktuasi harian, plankton, fitoplankton, zooplankton, parameter fisika-kimia, kolam

Abstract: Ocean Color Monitor (OCM) onboard the Indian Remote Sensing Satellite IRS-P4 has been used to retrieve chlorophyll concentration in the Bay of Bengal and the Arabian Sea using a bio-optical algorithm. Cloud masking and atmospheric corrections have been performed before applying mapping function to derive chlorophyll concentration from IRS-P4 OCM data. Chlorophyll concentrations have been retrieved from IRS P4 OCM, and used MODIS chlorophyll product during the summer and winter seasons at every 1 degree ...

Recibido en junio de 1995; aceptado en marzo de 1996 RESUMEN Con base en un modelo lineal, se estiman los principales parámetros de las mareas y ondas internas semidiumas de altas frecuencias para la plataforma y pendiente continental cerca de las costas mexicanas de los estados de Jalisco y Colima. Por datos de la distribución vertical de la frecuencia de Brunt-Väisälä y por medio de cartas batimttricas actualizadas, se calculan las trayectorias de los flujos de energía (y) de la marea interna y la pendiente del fondo marino (a) en el talud continental, respectivamente. Se muestra que para la mayoría de las secciones del fondo se encuentran valores cercanos al crítico aly = 1, lo cual testifica que existen las condiciones favorables para la generación de las mareas internas en el area de estudio de la costa del Océano Pacífico. Con base en el modelo de Baines (1982), se realizan los cálculos del flujo de energía de la onda barotrópica M2 a las ondas internas y se estiman sus amplitudes. Se muestra que los flujos de energía y amplitud de la marea interna dependen no sólo de la intensidad de la marea barotrópica, sino también de los iingulos de su llegada al borde de la plataforma.

One of the problems of working on lochs that are slightly saline is a group of tiny (1-4mm) molluscs called mudsnails (Hydrobiidae). The rarest of these, Hydrobia acuta neglecta, was first identified in the UK in the Uists. This project aimed to eliminate any doubt about the identity. Genetic analyses funded by SNH and conducted by scientists at the National Museum of Scotland and Heriot-Watt University confirmed that there were healthy populations of this snail in three lochs in North Uist.

MSA is measured at Ny Ålesund (78.9 N, 11.9 E) and Thule Air Base (76.5 N, 68.8 W). Primary production (PP) is calculated by a bio-optical model in the surrounding seas. PP explains about the 30% of MSA variability in both the Arctic sites. MSA and sea ice melting are correlated (slope: 39 ng m À3 of MSA/ 10 6 km 2). MSA and ice free marginal ice zone are correlated (slope: 56 ng m À3 of MSA/10 6 km 2).

This study was conducted in June 2021. Data collection of phytoplankton abundance and primary productivity was carried out in the waters of Kasiak Island of West Sumatra Province. The aim of the study was to analyze phytoplankton abundance, primary productivity vertically, and the effect of phytoplankton abundance on primary productivity in the waters of Kasiak Island. Based on the results of this study obtained that the abundance of phytoplankton on the surface (0 m) ranges from 41.67-187.50 ind/L. The abundance of phytoplankton in the depth of 5 ranges from 20.83-104.17 ind/L. While the primary productivity level of the results of the measurement of dissolved oxygen of the surface (0 meters) is obtained ranging from 7.6-11.2 mg/L while at a depth (5 m) ranges from 8-10.4 mg/L. Based on simple linear regression analysis on the surface (0) obtained the equation Y = 42.26x + 0.48x. The value of r2 = 0.2031 while the correlation coefficient value (r) is 0.4507. Based on the results of...

1. un mapeado rápido al principio y al fin de la campaña para localizar el filamento y observar los cambios en el contexto general durante el estudio; Agradecimientos Quisieramos agredecer al Capitán Ramón Argibay Fernández y a la tripulación del barco por su apoyo magnífico durante la campaña. También agradecemos al equipo de la UTM sin el cuál no hubiese sido posible llevar a cabo el estudio. Damos las gracias al servicio NEODAAS del Plymouth Marine Laboratory, UK, especialmente a Dr Peter Miller, que nos proporcionó diariamente las imagenes AVHRR y Modis Aqua durante el trabajo de campo. CAIBEX es un proyecto del Plan Nacional financiado por el Ministerio de Ciencia e Innovación (CTM2007-66408).

Mesozooplankton biomass in the North Pacific Subtropical Gyre (NPSG), as measured by the Hawaii Ocean Time-series program at Station ALOHA (22.45°N 158°W), increased significantly from 1994 to 2002. The changes occurred at a rate of 60 mg DW m−2 yr−1 for night-time collections and 45 mg DW m−2 yr−1 for daytime collections. Principal components analysis indicates that the 9-year trend was driven by an increase in small (0.5–2.0 mm) zooplankton that do not migrate on a diel cycle. This plankton class is known to increase during the summer at Station ALOHA when the water column is most stratified, and a strong summertime response is also apparent within the long-term trend from 1998 through 2002. Both long-term and seasonal changes in zooplankton biomass at Station ALOHA can be linked to an enhanced role of nitrogen fixation in ecosystem productivity. Climate forcing from El Niño–Southern Oscillation (ENSO) events may have influenced nitrogen fixation, general ecosystem productivity, a...

This paper provides an explanation of the condition of phytoplankton in the estuary waters of the west coast of South Sulawesi. The study was carried out on four estuaries namely Tallo, Marusu, Polong and Battoe with spatial sampling from inside the estuary to the outside of the estuary. The results obtained were found in three classes, namely Bacillariophyceae class, Cyanophyceae class, and Dinophyceae class with 19 phytoplankton genera. With an abundance of phytoplankton ranging from 352 - 5304 cells / L, the highest abundance is in the Tallo estuary. Meanwhile, the highest diversity index (H ') was found in Tallo estuary and the highest dominance index (D) was in Tallo estuary. Parameters that characterize high abundance estuaries are nitrate and TSS.

MSA is measured at Ny Ålesund (78.9 N, 11.9 E) and Thule Air Base (76.5 N, 68.8 W). Primary production (PP) is calculated by a bio-optical model in the surrounding seas. PP explains about the 30% of MSA variability in both the Arctic sites. MSA and sea ice melting are correlated (slope: 39 ng m À3 of MSA/ 10 6 km 2). MSA and ice free marginal ice zone are correlated (slope: 56 ng m À3 of MSA/10 6 km 2).

Volcanic eruptions have been hypothesized as an iron supply mechanism for phytoplankton blooms; however, little direct evidence of stimulatory responses has been obtained in the field. Here we present the results of twenty‐one 1–2 day bottle enrichment experiments from cruises in the South Atlantic and Southern Ocean which conclusively demonstrated a photophysiological and biomass stimulation of phytoplankton communities following supply of basaltic or rhyolitic volcanic ash. Furthermore, experiments in the Southern Ocean demonstrated significant phytoplankton community responses to volcanic ash supply in the absence of responses to addition of dissolved iron alone. At these sites, dissolved manganese concentrations were among the lowest ever measured in seawater, and we therefore suggest that the enhanced response to ash may have been a result of the relief of manganese (co)limitation. Our results imply that volcanic ash deposition events could trigger extensive phytoplankton bloom...

Kajian ini bertujuan untuk mengetahui kondisi perairan semi-tertutup dari karakteristik fisika dan kimia. Penelitian dilaksanakan pada Musim Peralihan di Teluk Ekas, Lombok Timur, Indonesia. Lokasi perairan Teluk Ekas, Lombok Timur dilewati arus dari Samudera Pasifik yang menuju Selat Lombok dan di perairan teluk ditemukan dua muara sungai, yaitu Muara Sungai Awang dan Kelongkong serta banyaknya kegiatan budidaya biota pada perairan. Metode yang digunakan dengan pengambilan data lapangan secara langsung, pengolahan, visualisasi dan analisisis. Hasil penelitian menunjukkan bahwa nilai DO berkisar 5 mg/l, nilai kecerahan yang cukup optimal berkisar antara 0,391-18,5 meter, pH berkisarantara 8-9, salinitas berkisar antara 34-36 psu, suhu yang diperolehberkisarantara 28-30 o C. Hasil ini menunjukkan bahwa perairan Teluk Ekas dipengaruhi oleh massa air yang berasal dari laut (atau daratan). Kemudian analisis terhadap kondisi kualitas air menunjukkan bahwa wilayah ini masih sesuai dengan standar baku Kementerian Lingkungan Hidup No.51 Tahun 2004 untuk biota laut.

Fluorometric measurements were taken from a CTD at San Jorge Bay (northern Chile) to adjust a Gaussian model, in order to determine the vertical distribution of phytoplankton biomass using satellite-derived chlorophyll a data. Calibration was done using two in situ data sets. Each chlorophyll a profile was smoothed by a moving average and adjusted with a Gaussian model, obtaining the mean Gaussian parameters for both data sets. The mean Gaussian model obtained for one of the data sets was valid for a chlorophyll a range between 1.17 and 51.8 mg m-3 , and the maximum concentration was located at 19.20 and 0.25 m depth, respectively. The 20 January 2011 color image was analyzed for the study area, and the modal concentration was 0.78 mg m-3 , with 95% of the data varying between 0.5 and 20.0 mg m-3. The adjusted mean Gaussian model was valid for 80.26% of the study area. The analysis was expanded to the rest of January 2011 (14 images), and the model was valid for 84.40% (±12.48%) of the study area. The same procedure was followed but without applying the moving average to the in situ data, and the Gaussian model obtained in this case was valid for 93.72% (±8.89%) of the study area. Other studies of the optical properties of water are required for a better interpretation of the color images for this coastal system.

Fluorometric measurements were taken from a CTD at San Jorge Bay (northern Chile) to adjust a Gaussian model, in order to determine the vertical distribution of phytoplankton biomass using satellite-derived chlorophyll a data. Calibration was done using two in situ data sets. Each chlorophyll a profile was smoothed by a moving average and adjusted with a Gaussian model, obtaining the mean Gaussian parameters for both data sets. The mean Gaussian model obtained for one of the data sets was valid for a chlorophyll a range between 1.17 and 51.8 mg m–3, and the maximum concentration was located at 19.20 and 0.25 m depth, respectively. The 20 January 2011 color image was analyzed for the study area, and the modal concentration was 0.78 mg m–3, with 95% of the data varying between 0.5 and 20.0 mg m–3. The adjusted mean Gaussian model was valid for 80.26% of the study area. The analysis was expanded to the rest of January 2011 (14 images), and the model was valid for 84.40% (±12.48%) of th...

The Bay of Bengal (BoB) is a low saline basin owing to large influx of freshwater from precipitation and river runoff. To maintain the salt balance of the BoB, the incessant lowering of salinity is to be balanced by the inflow of saltier water into the basin. In the present work, various processes that contribute to the saltening of the BoB, viz. coastal upwelling, eddies and their interaction, lateral advection from Arabian Sea and tropical cyclones are discussed. In the near-shore regions, the coastal upwelling due to wind induced Ekman transport plays a dominant role in increasing the surface salinity. On the other hand, in the open ocean, the divergence induced by eddies and their mutual interaction contributes significantly to the salt water pumping. In the southern BoB, the advection from the Arabian Sea increases the salinity. The formation of cyclones in the BoB also leads to an increase in the surface salinity. However, the magnitude of saltening of the Bay due to these pro...

Cahaya merupakan salah satu faktor penting dalam proses fotosintesis dinoflagellate dan pertumbuhan variabilitas harian. Intensitas cahaya memengaruhi aktivitas fotosintesis dan kelimpahan dinoflagellate. Studi ini bertujuan untuk menunjukkan pola kecenderungan kelimpahan dinoflagellate dan klorofil serta lama penyinaran terhadap kelimpahan dinoflagellate di Perairan Pulau Samalona. Penelitian dilakukan dengan menginkubasi sampel dinoflagellate kedalam botol sejak pagi-sore hari dengan inkubasi waktu pengamatan setiap 2 jam dengan ulangan sebanyak 3 kali. Pengambilan mencakup kelimpahan dinoflagellate, nutrient dan intensitas cahaya dalam perairan. Analisis data menggunakan regresi linear sederhana. Hasil penelitian menunjukkan bahwa nilai intensitas cahaya berkisar antara 50-3000 lux; kelimpahan dinoflagellate berkisar antara 9-1105 sel.L-1 , dan kandungan klorofil a lebih dominan dengan kisaran 0,00069-0,50321 µg.L-1. Intensitas cahaya mempengaruhi kelimpahan dinoflagellate, namun pengaruh kandungan nutrient sangat kecil terhadap kelimpahan dinoflagellate. Pola kelimpahan dinoflagellate bervariasi dari pagi hingga sore hari yang dipengaruhi oleh intensitas cahaya dalam melakukan proses fotosintesis serta kondisi lingkungan lain seperti klorofil a dan nutrient. Hasil penelitian ini memberikan informasi variasi temporal harian kelimpahan dinoflagellate di Pulau Samalona, Makassar.

MSA is measured at Ny Ålesund (78.9 N, 11.9 E) and Thule Air Base (76.5 N, 68.8 W). Primary production (PP) is calculated by a bio-optical model in the surrounding seas. PP explains about the 30% of MSA variability in both the Arctic sites. MSA and sea ice melting are correlated (slope: 39 ng m À3 of MSA/ 10 6 km 2). MSA and ice free marginal ice zone are correlated (slope: 56 ng m À3 of MSA/10 6 km 2).

In remote marine areas, biogenic productivity and atmospheric particulate are coupled through dimethylsulfide (DMS) emission by phytoplankton. Once in the atmosphere, the gaseous DMS is oxidized to produce H 2 SO 4 and methanesulfonic acid (MSA); both species can affect the formation of cloud condensation nuclei. This study analyses eight years of biogenic aerosol evolution and variability at two Arctic sites: Thule (76.5 • N, 68.8 • W) and Ny Ålesund (78.9 • N, 11.9 • E). Sea ice plays a key role in determining the MSA concentration in polar regions. At the beginning of the melting season, in April, up to June, the biogenic aerosol concentration appears inversely correlated with sea ice extent and area, and positively correlated with the extent of the ice-free area in the marginal ice zone (IF-MIZ). The upper ocean stratification induced by sea ice melting might have a role in these correlations, since the springtime formation of this surface layer regulates the accumulation of phytoplankton and nutrients, allowing the DMS to escape from the sea to the atmosphere. The multiyear analysis reveals a progressive decrease in MSA concentration in May at Thule and an increase in July August at Ny Ålesund. Therefore, while the MSA seasonal evolution is mainly related with the sea ice retreat in April, May, and June, the IF-MIZ extent appears as the main factor affecting the longer-term behavior of MSA.

This paper presents the results on simultaneous high time resolution measurements of biogenic aerosol (methane sulfonic acid-MSA, non-sea salt sulfate nssSO4 2-) with its gaseous precursor dimethylsulfide (DMS) performed at the Italian coastal base Mario Zucchelli Station (MZS) in Terra Nova Bay (MZS) during two summer campaigns (2018-2019 and 2019-2020). The study provides information on marine biological activity in the nearby polynya in the Ross Sea and on the influence of biogenic and atmospheric processes on biogenic aerosol formation. Data on atmospheric DMS concentration are scarce especially in Antarctica. The DMS-maximum at MZS occurs in December, one month earlier than at other Antarctic stations. The maximum of DMS concentration is connected with the phytoplanktonic senescent phase following the bloom of Phaeocystis antarctica that occurs in the polynya when sea ice opens up. The second plankton bloom occurs in January and, despite the high Dimethylsulfopropionate (DMSP) concentration in sea water, atmospheric DMS remains low probably due to its fast biological turnover in sea water in this period. The intensity and timing of the DMS evolution during the two years suggests that only the portion of the polynya close to the sampling site produces a discernible effect on the measured DMS. The closeness to the DMS source area, and the occurrence of air masses containing DMS and freshly formed oxidation products allow to study the kinetic of biogenic aerosol formation and the reliable derivation of the branch ratio between MSA and nssSO4 2from DMS oxidation that is estimated to be 0.84 ±0.06. Conversely, for aged airmasses with low DMS content, an enrichment of nssSO4 2with respect to MSA, due to the presence of background concentration of nssSO42from volcanic origin (Erebus) or from long range transport, takes place. Therefore, the aged air mass presents an MSA/ nssSO4 2ratio lower than in newly formed biogenic aerosol. By considering the sum of MSA and biogenic nssSO4 2-, we estimate that the mean contribution of biogenic particulate matter to PM10 is 17%, with a maximum of 56%. The high contribution of biogenic aerosol to the total PM10 mass in summer in this area highlights the dominant role of the polynya on

MSA is measured at Ny Ålesund (78.9 N, 11.9 E) and Thule Air Base (76.5 N, 68.8 W). Primary production (PP) is calculated by a bio-optical model in the surrounding seas. PP explains about the 30% of MSA variability in both the Arctic sites. MSA and sea ice melting are correlated (slope: 39 ng m À3 of MSA/ 10 6 km 2). MSA and ice free marginal ice zone are correlated (slope: 56 ng m À3 of MSA/10 6 km 2).

Benthic microalgal communities often contribute more than 30% of the primary production of shallow coastal and estuarine areas. At Muka Head Penang (Pulau Pinang) and the Songsong Islands (Pulau Songsong), Kedah, Malaysia, high concentrations of suspended solids and phytoplankton biomass (10.6 mg Chl a m−3) has reduced water clarity such that the euphotic zone of these areas is less than 2 m and 3 m deep respectively. The benthic microalgal communities, which were composed of the diatom genera Cocconeis, Fragilaria, Paralia and Pleurosigma, had a low biomass, had low maximum quantum yields (0.325 ± 0.129), were poorly adapted to their light environment and were constantly light limited. These characteristics suggest that the benthic microalgal communities were likely to have made only a minor contribution to the total primary production of the area.

The capability of a physical-biogeochemical model configured using Regional Ocean Modeling System (ROMS) in simulating upper ocean biogeochemical dynamics of the Bay of Bengal (BoB) is evaluated with available remote sensing and in situ observations. The accuracy of model-simulated and satellite (MODIS-Aqua) retrieved surface chlorophyll-a (chl-a) are individually assessed against in situ data, measured in surface waters of the western BoB, from March 2008 to November 2015. Model-simulated chl-a showed better correlation (R 2 = 0.80) with the in situ observations as compared to that retrieved from satellite (R 2 = 0.72). Although, the model underestimates chl-a (slope = 0.84), significant correlation proves its capability to reproduce the in situ trend. The root mean square error (RMSE) between model simulated and satellite retrieved chl-a against measured chla are 0.33 and 0.36, respectively. Additionally, a comparison with remote sensing time series data indicates that the model realistically simulates the seasonal variability of chl-a. Further, temperature, salinity, nitrate, chl-a and dissolved oxygen (DO) profiles obtained from two biogeochemical Argo floats deployed in the central BoB, are also compared with model-simulated profiles. In comparison, the model adequately simulates the observed subsurface variability of chl-a as well as persistent Deep Chlorophyll Maximum (DCM) at depths between 20 and 90 m having concentration 0.75-1.0 mg-m −3. The undulations in the subsurface spatial variability of chl-a are appreciably well captured by the model and comparable with the observations albeit the magnitude is overestimated in the model. It is noted that the temporal variability of the DCM and oxycline in the BoB is significantly influenced by the vertical movement of the thermocline.

Baaz cyclone is a slow moving weak cyclone in the south central Bay of Bengal (SCBoB) and it lingered for 3 days and caused a significant cooling (2.6°C) and enhancement of chlorophyll-a (5.6 mg/m 3) at the right side of the cyclone track. In this study multi-satellite observations are used to explore the bio-physical changes due to the cyclone. We found that the speed of the Ekman pumping velocity is ten times more and the mixed layer is deepened about 19 meters during the cyclone than pre cyclone period. The maximum sea surface cooling (1.2-2.6°C) took place when the translation speed of cyclone is only 1.2-2.3 m/s. So the extent of the sea surface temperature drop is probably related to the moving speed of cyclone and the mixed layer depth. In addition, the area with large decline of the SSH can signify the location where the maximum cooling occurs.

The phenomenon of phytoplankton blooms often occurs in the waters of the Thousand Islands (Jakarta Bay). On October 15, 2020, the blooming occurred again. Therefore, this study was conducted to determine the types of phytoplankton that were blooming in Jakarta Bay. Real time sampling of the blooming phytoplankton was carried out. Furthermore, the samples were directly analysed at the Laboratory of Productivity and Aquatic Environment, IPB University. The parameters analysed were the composition of phytoplankton species and water quality. Phytoplankton underwent blooming was Trichodesmium. Blooming frequently occurred in the waters of the Thousand Islands. This is closely related to seasonal changes and increased nutrient content in the waters, especially nitrate and orthophosphate, which support the rapid growth of phytoplankton (blooming).

Mixed Layer Depths (MLD) on the basis of temperature and density were calculated for the Bay of Bengal area. Long term archive data from World Ocean Database (WOD09) were used for calculating MLD in the study area. During the pre monsoon period the lowest thermal MLD was observed in the mid basin area with a value of 25 m. But within the monsoon period MLD was gradually increase in all area up to a layer of 50 m. In the post monsoon period MLD increase in the upper Northern region and during winter period highest MLD of 95 m was observed. In this time it creates a high depressed zone in this area. Density oriented Mixed Layer was found thinner for the whole year. It was observed as 5 m in the upper Northern part, but southern area MLD change with season to season and MLD show highest 65m in the winter monsoon and lowest 20 m pre monsoon period. Surface current flows of the ocean and sea surface temperature (SST) seem to control to change the MLD with seasonality, which was also disc...

Benthic microalgal communities often contribute more than 30% of the primary production of shallow coastal and estuarine areas. At Muka Head Penang (Pulau Pinang) and the Songsong Islands (Pulau Songsong), Kedah, Malaysia, high concentrations of suspended solids and phytoplankton biomass (10.6 mg Chl a m−3) has reduced water clarity such that the euphotic zone of these areas is less than 2 m and 3 m deep respectively. The benthic microalgal communities, which were composed of the diatom genera Cocconeis, Fragilaria, Paralia and Pleurosigma, had a low biomass, had low maximum quantum yields (0.325 ± 0.129), were poorly adapted to their light environment and were constantly light limited. These characteristics suggest that the benthic microalgal communities were likely to have made only a minor contribution to the total primary production of the area.

Cahaya merupakan salah satu faktor penting dalam proses fotosintesis dinoflagellate dan pertumbuhan variabilitas harian. Intensitas cahaya memengaruhi aktivitas fotosintesis dan kelimpahan dinoflagellate. Studi ini bertujuan untuk menunjukkan pola kecenderungan kelimpahan dinoflagellate dan klorofil serta lama penyinaran terhadap kelimpahan dinoflagellate di Perairan Pulau Samalona. Penelitian dilakukan dengan menginkubasi sampel dinoflagellate kedalam botol sejak pagi-sore hari dengan inkubasi waktu pengamatan setiap 2 jam dengan ulangan sebanyak 3 kali. Pengambilan mencakup kelimpahan dinoflagellate, nutrient dan intensitas cahaya dalam perairan. Analisis data menggunakan regresi linear sederhana. Hasil penelitian menunjukkan bahwa nilai intensitas cahaya berkisar antara 50–3000 lux; kelimpahan dinoflagellate berkisar antara 9–1105 sel.L-1, dan kandungan klorofil a lebih dominan dengan kisaran  0.00069–0.50321 µg.L-1. Intensitas cahaya mempengaruhi kelimpahan dinoflagellate, namun...

Tiram oyster adalah biota laut kelas bivalvia berprotein tinggi yang menjadi salah satu tangkapan atau buruan minoritas nelayan Kuala Langsa, Kota Langsa, khususnya bagi para istri nelayan. Pada penelitian ini peneliti ingin mengetahui faktor hubungan biologis perairan terhadap pertumbuhan tiram oyster pada perairan ujung perling yang tinggi akan kuantitasnya dengan mengukur kepadatan dan jenis fitoplankton yang dominan hidup di periaran tersebut. Metode yang digunakan dalam penelitian ini adalah metode deskripsi dengan jenis metode survei langsung. Metode yang digunakan pada penelitian ini yaitu metode deskriptif dengan melihat langsung ke lokasi penelitian. Pengukuran kerapatan fitoplankton dilakukan dengan pengambilan contoh air yakni dengan menggunakan Plankton net no. 20 dengan mesh size 76 µm. Hasil dari penelitian ini ditemukan jenis fitoplankton pada ketiga stasiun terdiri dari dua kelas yaitu Bacillariophyceae, Dinophyceae. Sedangkan bagi parameter fisika perairan, diperol...

Field data collected during June 2005 were used to determine the relationship between the second fluorescence maximum (FMax), the top of the oxygen minimum zone (OMZ), and physical processes (coastal currents, eddies, and upwelling) in the northern region of the Eastern Tropical Pacific off Mexico (ETPM). A recurrent second FMax was observed in the ETPM, which was formed only when the upper limit of the OMZ (9.0 µmol L–1) overlapped with the 1% downwelling blue irradiance depth (Ed490). The presence of the second FMax increased the total integrated water column chlorophyll from 20% to 40%. The second FMax was absent from areas where oxygenated California Current Water (CCW) deepened the upper limit of the OMZ below 1% Ed490. The poleward Mexican Coastal Current carried less oxygenated Subtropical Subsurface Water into the area, and enabled the formation of the second FMax. The variability of the second FMax driven by mesoscale physical processes was related to coastal upwelling and ...

In this work, 16 stations in Cienfuegos Bay were optically classified in the period from 2009 to 2014 and the spatio-temporal variation of the average attenuation coefficient of light was determined, as well as its relationship with chlorophyll a and suspended solids. The average attenuation coefficient was estimated from an empirical relationship ReVIsTA INVesTIGACIONes MARINAs

To constrain the energy fueling photosynthesis in the North Pacific Subtropical Gyre (NPSG) we characterize the variability of phytoplankton absorption spectra in conjunction with that of the light field at Station ALO-HA (22845 0 N, 158800 0 W). Furthermore, we decompose the phytoplankton absorption into photosynthetic and photoprotective components based on high-performance liquid chromatography pigment analysis. Between January 2006 and December 2012 the variability in chlorophyll-specific absorption (a à /) above the deep chlorophyll maximum (DCM) layer was driven by changes in photoprotective carotenoid concentrations while the chlorophyll-specific absorption of photosynthetic pigments (a Ã

The processing of ocean satellite images has as goal the detection of phenomena related with ocean dynamics. In this context, Mesoscale Oceanic Structures (MOS) play an essential role. In this chapter we will present the tool developed in our group in order to extract knowledge rules for the retrieval of MOS in ocean satellite images. We will describe the implementation of the tool: the workflow associated with the tool, the user interface, the class structure, and the database of the tool. Additionally, the experimental results obtained with the tool in terms of fuzzy knowledge rules as well as labeled structures with these rules are shown. These results have been obtained with the tool analyzing chlorophyll and temperature images of the Canary Islands and North West African coast captured by the SeaWiFS and MODIS-Aqua sensors. Keywords Remote sensing • Satellite images • Mesoscale oceanic structures • Image processing • Tools • SeaWiFS • MODIS-Aqua

 Pulau Rubiah merupakan salah satu pulau yang terletak di sebalah barat-laut dari  pulau weh, Kota Sabang, Provinsi Aceh. Monitoring terhadap perubahan struktur dan populasi harus dilakukan secara berkala agar diketahui kondisi umum ekosistem di sekitarnya. Salah satu cara untuk memantau perubahan struktur dan komposisi keanekaragaman dilakukan melalui pengamatan langsung. Observasi dilakukan dengan cara pengamatan secara langsung pada lokasi penelitian dan identifikasi dilakukan di Laboratorium Pendidikan Biologi FTK UIN Ar-Raniry. Tempat dan Waktu  Penelitian ini dilakukan di kawasan Pulau Rubiah, Kota Sabang, pada hari Rabu tanggal 11 Agustus 2021. Hasil penelitian ditemukan 11 jenis plankton yang berada di perairan laut Pulau Rubiah yang telah melalui proses penyaringan dan identifikasi. Adapun spesies yang mendominasi yang berada di perairan laut Pulau Rubiah yaitu Nitzschia Sp. , Euglena  Sp., Lyngbya Sp., Skeletonema Sp., Hantzschia Sp., Diaptomus Sp., Scenedesmus quadricauda...

Satellite-derived ocean colour data was used to identify the phytoplankton bloom associated with tropical cyclones Thane and Phailin in the Bay of Bengal (BoB). Cyclone Thane was category 2 cyclone (25-31 December 2011), and Phailin was category 5 cyclone (8-14 October 2013), and both occurred during the post-monsoon season. The present study examined the effect of cyclone intensity difference on the chlorophyll a (Chl-a) production in the BoB. Two and seven times Chl-a enhancement was observed after the passage of Phailin and Thane respectively. Possible causes were examined using the satellite-derived sea surface temperature, sea surface height anomalies and sea surface winds. In both cases, cyclone intensified the strength of the pre-existing cyclonic eddies after its passage. Our study shows that the strong stratification along the Phailin track suppresses the Chl-a enhancement after its passage. However, comparatively weaker stratification along the Thane track promotes entrainment of more nutrients and enhances the Chl-a production even though with lesser intensity. In this study, the extent of Chl-a production associated with cyclones was attributed to upper ocean physical processes than the intensity.

Mesoscale eddies play a major role in controlling ocean biogeochemistry. By impacting nutrient availability and water column ventilation, they are of critical importance for oceanic primary production. In the eastern tropical South Pacific Ocean off Peru, where a large and persistent oxygen deficient zone is present, mesoscale processes have been reported to occur frequently. However, investigations on their biological activity are mostly based on model simulations, and direct measurements of carbon and dinitrogen (N<sub>2</sub>) fixation are scarce.…

Ocean-atmosphere interactions have been increasingly acknowledged to play an important role in climate change. It is necessary to understand ocean behavior, including the sea surface temperature (SST) that is a basis for initiating atmospheric models and climate change studies. In this paper, we analyze the spatial and temporal patterns of SST using monthly MODIS data of 2001-2012 from north Arabian Sea (11.9-25.68°N, 56.7-75.03°E). Seasonally, four phases of SST have been observed namely warming, cooling, warming and again cooling. Further, an empirical statistical model was fitted to the observed data that describes the annual SST pattern with significant accuracy.

Between 1989 and 1991 the authors made observations that confirm and elucidate the coupling between harbor seiches at Puerto Princesa on Palawan Island in the Philippines and tide-generated internal solitons in the Sulu Sea. Published tidal current predictions for Basilan Strait in the Sulu Archipeligo were used to produce an index to the daily ebb tidal flows nea•r Pearl Bank where the solitons originate. The coherence between predicted maximum ebb tidal current speed and observed seiche activity was 0.60 and the phase lag between the two quantities closely matched published estimates of the time required for solitons to cross the Sulu Sea. Arrival of the Sulu Sea waves immediately offshore of Puerto Princesa in the form of internal bores corresponded in time to the initiation of harbor seiche activity. A more precise estimate of soliton travel time was determined from the time difference between predicted maximum ebb current and the initiation •of seiche activity, and it was found to have a remarkably regular seasonal pattern, which can be largely explained by seasonal variations in Sulu Sea temperature and salinity stratification. Therefore, the timing of seiche events at Puerto Princesa can be forecast based on Sulu Archipeligo tide predictions and soliton travel time. In general, the fortnightly pattern of seiche magnitude follows that of tidal current predictions, but day-today deviations are common. Seiche magnitude varies seasonally with generally low activity during the winter (northeast) monsoon and usually maximum activity late in the summer (southwest) monsoon. VOLUME 28 * Woods Hole Oceanographic Institution Contribution Number 9343.

Vertical temperature profiles were measured near the shelf edge off the coast of Palawan Island (Philippines) during the passage of several "rip bands" of choppy surface waves. Such rip bands are commonly associated with internal waves. Coincident with the passage of one of the rip bands, the temperature near the bottom decreased by 2.5°C within 1.4 min, becoming colder than any water on the shelf. Furthermore, the apparent depth of our CTD decreased by about 8 m despite the fact that the "line-out" was held fixed. We interpret these limited data, along with a sea-level record, as evidence of internal swash created by breaking internal solitary waves which are generated by tidal flow over a shallow bank in the southeastern Sulu Sea (described by

Planktonic primary production and respiration in 2 coastal oligotrophic sites of the Northwest Mediterranean Sea were examined. Primary production was quantified using 3 methods (light and dark changes in dissolved O 2 , 18 O-labeling and 14 C uptake technique) using in situ bottle incubations. Gross primary production (GPP) based on the O 2 light-dark technique was not significantly different from that using the 18 O-labeling technique, indicating that the former technique provides accurate estimates of GPP in these environments. Respiration in the dark was not significantly different from respiration in the light. Total 14 C uptake (including the dissolved and particulate organic carbon fractions) during the whole duration of the light period approached GPP and consequently overestimated net primary production.

Plankton in aquatic ecosystems has a very important role, especially in the food chain, because plankton is the main producer that makes the largest contribution to the total primary productivity of an aquatic area. This Field Work Practice aims to determine the species and abundance of plankton that is good and correct according to widely used standards. This Field Work Practice was carried out on 10 January – 10 February 2023. Determination of field work practice stations using the purposive sampling method at 1 location and three plankton sampling points. In situ measurement of water quality parameters includes temperature, dissolved oxygen (DO), pH and salinity. Plankton samples were identified and analyzed at the Aquatic Resources Laboratory, Faculty of Fisheries and Marine Sciences, University of Papua. The results of field work practice obtained eight classes of plankton and classes consisting of 33 genera. Phytoplankton found 29 genera from 5 classes namely Bacillariophyceae...

Sungai Pisang Bay is located in South Padang. At this location, there are various activities including Pasumpahan Island water tourism, fishing, and settlement activities. This condition is expected to pollute the sea and have an impact on marine biota, especially phytoplankton. The purpose of this study was to examine the quality of seawater based on the composition and structure of the phytoplankton community in Sungai Pisang Bay Waters, Padang. The research was conducted using survey methods and field sampling using plankton net at three sample stations on Pasumpahan Island, Ujung and Setan Island. The result from 100 species of phytoplankton found that 4 classes of Bacillariphyceae consisting of 66 species, 1 species of Chlorophycaeae, 3 species of Cyanophyceae and 30 species of Dinophyceae. The phytoplankton diversity index in April ranged from 2.056 to 3.165 and in May from 2.644 to 2.977. The phytoplankton equitability index in April ranged from 0.565 to 0.836 and in May from 0.727 to 0.809. The phytoplankton dominance index in April ranged from 0.054 to 0.087 and in May from 0.096 to 0.131. Physical Chemistry was in good condition base on Decision of Environmental Ministry No. 51/2004. It can be concluded that the condition of Sungai Pisang Bay Waters based on the presence of phytoplankton in dry conditions was categorized as good. PENDAHULUAN Sungai Pisang masuk ke dalam administrasi wilayah Kecamatan Bungus Teluk Kabung Kota Padang, dengan luas wilayah 9,14 Km 2 yang didalamnya terdapat 2 RW dan 9 RT.

Satellite-derived ocean colour data was used to identify the phytoplankton bloom associated with tropical cyclones Thane and Phailin in the Bay of Bengal (BoB). Cyclone Thane was category 2 cyclone (25-31 December 2011), and Phailin was category 5 cyclone (8-14 October 2013), and both occurred during the post-monsoon season. The present study examined the effect of cyclone intensity difference on the chlorophyll a (Chl-a) production in the BoB. Two and seven times Chl-a enhancement was observed after the passage of Phailin and Thane respectively. Possible causes were examined using the satellite-derived sea surface temperature, sea surface height anomalies and sea surface winds. In both cases, cyclone intensified the strength of the pre-existing cyclonic eddies after its passage. Our study shows that the strong stratification along the Phailin track suppresses the Chl-a enhancement after its passage. However, comparatively weaker stratification along the Thane track promotes entrainment of more nutrients and enhances the Chl-a production even though with lesser intensity. In this study, the extent of Chl-a production associated with cyclones was attributed to upper ocean physical processes than the intensity.

Hydrographical study is an important prerequisite in nearshore waters as it is very susceptible to natural and manmade influence. In this paper, attempt has been made to study the spatial and temporal variations in hydrographical properties of the nearshore waters of Keni and Belekeri, Ankola, Uttara Kannada district, Southwest coast of India during the period from October 2020 to September 2021. The air and water temperatures ranged from 25.5 to 33.5 °C and 26.0 to 34.5 °C respectively, pH varied from 8.0 to 8.6, salinity fluctuated from 16 to 34PSU, dissolved oxygen ranged from 4.88 to 8.54 mg/l, ammonianitrogen varied from 0.63 to 32.52 µg-at./l, concentrations of nutrients, viz., nitrite-nitrogen and nitratenitrogen ranged from 0.06 to 8.13 µg-at./l and 0.13 to 15.67 µg-at./l respectively, phosphate-phosphorus and silicate-silicon varied from 0.29 to 3.53 µg-at./l and 2.44 to 72.71 µg-at./l respectively were recorded. The higher values of temperature, pH and salinity were recorded during pre-monsoon season. In contrast, an increase in dissolved oxygen, ammonia, nitrite, nitrate, phosphate and silicate were observed during monsoon season. Dissolved oxygen, ammonia and silicate showed significant positive correlations with each other, nitrite showed a significant positive correlation with nitrate and salinity showed significant negative correlations with dissolved oxygen, ammonia and silicate. The hydrographical parameters showed significant spatial and temporal variations.The present baseline information is useful for the further ecological monitoring and assessment along the coastal beaches.

Most attempts to link seabirds and climate/oceanographic effects have concerned the Atlantic and Pacific Oceans with comparatively few studies in the tropical Indian Ocean. This paper examines the reproductive response of the lesser noddy Anous tenuirostris to temporal fluctuations in oceanographic and climatic conditions using 8 years of monitoring data from Aride Island (Seychelles), tropical Western Indian Ocean. We tested the hypothesis that breeding parameters (mean hatching date, mean egg size, hatching and fledging successes) and chick growth are influenced by local, seasonal oceanographic conditions as expressed by ocean primary productivity (surface chlorophyll-a concentrations; CC), sea surface temperature (SST) and wind speed. We also examined the relationship between lesser noddy breeding parameters and climate conditions recorded at the basin-wide scale of the Indian Ocean (Indian Ocean Dipole Mode Index, DMI). Our findings suggest that birds had a tendency to lay slightly larger eggs during breeding seasons (years) with higher CC during AprileJune (pre-laying, laying and incubation periods). Hatching date was positively related to SST in AprileJune, with the regression parameters suggesting that each 0.5 C increase in SST meant a delay of approx.10 days in hatching date. A negative linear relationship was also apparent between hatching success and SST in JuneeAugust (hatching and chick-rearing periods), while the quadratic regression models detected a significant effect of wind speed in JuneeAugust on fledging success. Body mass increments of growing chicks averaged over 7-day periods were positively related with (2-week) lagged CC values and negatively related with (2-week) lagged SST values. No significant relationship between DMI and lesser noddy breeding parameters was found, but DMI indices were strongly correlated with local SST. Altogether, our results indicate that the reproduction of this top marine predator is dictated by fluctuations in local environmental conditions around the colony, while the effects of large-scale oceanographic processes (DMI) on our study population might be mediated by an effect on local SST.

We use continuous and discrete measurements of the dissolved O 2 /Ar ratio in the mixed layer to investigate the dynamics of biological productivity during the Southern Ocean Gas Exchange Experiment in March and April 2008. Injections of SF 6 defined two water masses (patches) that were followed for up to 2 weeks. In the first patch, dissolved O 2 /Ar was supersaturated, indicating net biological production of organic carbon. In the second patch, rapidly decreasing O 2 /Ar could only be reasonably explained if the mixed layer was experiencing a period of net heterotrophy. The observations rule out dominant contributions from vertical mixing, lateral dilution, or respiration in the ship's underway seawater supply lines. We also compare nine different estimates of net community, new, primary, or gross production made during the experiment. Net community and new production estimates agreed well in the first patch but disagreed in the second patch, both during an initial net heterotrophic period but also during the apparently autotrophic period at the end of the observations. Rapidly changing productivity during the second patch complicated the comparison of methods that integrate over daily and several week timescales. Primary productivity values from on-deck 24 h 14 C incubations and gross carbon production values from photosynthesis-irradiance experiments were nearly identical even during highly dynamic periods of net heterotrophy, while gross oxygen production measurements were 3.5-4.2 times higher but with uncertainties in that ratio near AE2. These comparisons show that the photosynthesis-irradiance experiments based on 1-2 h 14 C incubations underestimated gross carbon production.

Arctic sea ice is shifting from a year-round to a seasonal sea ice cover. This substantial transformation, via a reduction in Arctic sea ice extent and a thinning of its thickness, influences the amount of light entering the upper ocean. This in turn impacts under-ice algal growth and associated ecosystem dynamics. Field campaigns have provided valuable insights as to how snow and ice properties impact light penetration at fixed locations in the Arctic, but to understand the spatial variability in the under-ice light field there is a need to scale up to the pan-Arctic level. Combining information from satellites with state-of-the-art parameterizations is one means to achieve this. This study combines satellite and modeled data products to map under-ice light on a monthly time-scale from 2011 through 2018. Key limitations pertain to the availability of satellite-derived sea ice thickness, which for radar altimetry, is only available during the sea ice growth season. We clearly show t...

This paper investigates the dynamics of the deep chlorophyll maximu m layer (DCM L) along the Fernando de Noronha Ridge in the oligotrophic western equatorial Atlantic off northeast Brazil. M ixing processes between water masses above and below the thermocline may occur in a scale of tens of meters around the 24.5 to 25.5 isopycnals, where photoautotrophs are concentrate at the bottom of the euphotic zone. The primary production at the DCM L can provide 210 (±170) metric tons of Carbon per day to the benthic community at the Rocas atoll. The behavior of isopycnals in deeper and strongly stratified waters suggest that internal waves may imp rove primary production, by lift ing the deeper and nutrient-rich South Atlantic Central Water upwards and carrying the autotrophs to brighter depths.