Empirical modeling of chlorophyll a from MODIS satellite imagery for trophic status monitoring of Lake Victoria in East Africa

ABSTRAKEkosistem mangrove merupakan suatu interaksi yang terjadi antara tanaman – tanaman mangrove dengan faktor lingkungan perairan mangrove sehingga dapat menyebabkan terjadinya kesuburan perairan dan sebagai tempat mencari makan alami bagi biota – biota perairan. Tujuan penelitian ini adalah untuk mengetahui sebaran klorofil-a, nitrat dan fosfat serta plankton pada ekosistem mangrove yang berguna untuk kelestarian hidup biota – biota perairan Mangrove. Penelitian ini dilaksanakan bulan Oktober – November 2017 di Mangrove Tapak Tugurejo Semarang. Hasil penelitian ini didapatkan kandungan klorofil a rata – rata 0,165 mg/l, kandungan nitrat rata – rata 2,188 mg/l dan kandungan fosfat rata – rata 0,045 mg/l. Kelimpahan fitoplankton ditemukan sebanyak 23 spesies dan zooplankton ditemukan sebanyak 5 spesies. Berdasarkan status indeks trofik perairan Mangrove Tapak Tugurejo Semarang termasuk dalam kategori perairan mesotrofik, yakni unsur hara dan nutrien dalam perairan mangrove kurang tersedia banyak atau sedang dan belum tercemar. Kondisi kesuburan ekosistem mangrove terpantau cukup baik bila dibandingkan dengan kandungan – kandungan unsur hara, klorofil a dan plankton yang melimpah di perairan penelitian, sehingga memungkinkan banyak terdapat kehidupan biota – bioata perairan. Kesimpulan dari penelitian ini adalah kandungan unsur hara (nitrat dan fosfat) dan klorofil a serta plankton diperairan mangrove sangat mempengaruhi kesuburan ekosistem perairan, serta plankton yang mendominasi tempat penelitian ialah dari kelas Baccilariophyceae sebanyak 21 spesies.Kata kunci: Status trofik, Plankton, Ekosistem Mangrove, Mangrove Tapak Tugurejo Semarang.ABSTRACTMangrove ecosystem is an interaction that occurs between mangrove plants with environmental factors of mangrove waters that can cause the occurrence of water fertility and as a place of natural foraging for aquatic biota. The purpose of this research is to know the distribution of chlorophyll a, nitrate and phosphate and plankton in mangrove ecosystem which is useful for the preservation of biota life of Mangrove waters. This research was conducted in October - November 2017 at Tapak Mangrove Tugurejo Semarang. The results of this study obtained an average chlorophyll-1 content of 0.165 mg / l, an average nitrate content of 2.188 mg / l and an average phosphate content of 0.045 mg / l. Abundance of phytoplankton found as many as 23 species and zooplankton found as many as 5 species. Based on the trophic index status of Mangrove waters Tapak Tugurejo Semarang included in the category of mesotrophic waters, the nutrients and nutrients in the mangrove waters are less available or moderate and not contaminated. The condition of mangrove ecosystem fertility is observed quite well when compared with nutrient content, chlorophyll-a and plankton abundant in research waters, thus allowing many life biota - bioata waters. The conclusion of this research is the content of nutrients (nitrate and phosphate) and chlorophyll a and plankton in mangrove waters greatly affect the fertility of aquatic ecosystems, and the plankton that dominate the research site is from the Baccilariophyceae class of 21 species.Keywords : Trophic Status, Plankton, Mangrove Ecosystem, Mangrove Tapak Tugurejo SemarangCitation: Prihatin, A, Setyono, P dan Sunarto (2018). Sebaran Klorofil-a, Nitrat, Fosfat dan Plankton Sebagai Indikator Kesuburan Ekosistem di Mangrove Tapak Tugurejo Semarang. Jurnal Ilmu Lingkungan, 16(1), 68-77, doi:10.14710/jil.16.1.68-77

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Prolific Lightning and Thunderstorm Initiation over the Lake Victoria Basin in East Africa

Monthly Weather Review ◽

10.1175/mwr-d-19-0260.1 ◽

2020 ◽

Vol 148 (5) ◽

pp. 1971-1985 ◽

Cited By ~ 2

Author(s):

Katrina S. Virts ◽

Steven J. Goodman

Keyword(s):

East Africa ◽

Hot Spots ◽

Seasonal Cycle ◽

Lake Victoria ◽

Intertropical Convergence Zone ◽

Lake Victoria Basin ◽

The Earth ◽

Total Lightning ◽

Average Cluster

Abstract The Lake Victoria basin of East Africa is home to over 30 million people, over 200 000 of whom are employed in fishing or transportation on the lake. Approximately 3000–5000 individuals are killed by thunderstorms yearly, primarily by outflow winds and resulting large waves. Prolific lightning activity and thunderstorm initiation in the basin are examined using continuous total lightning observations from the Earth Networks Global Lightning Network (ENGLN) for September 2014–August 2018. Seasonal shifts in the intertropical convergence zone produce semiannual lightning maxima over the lake. Diurnally, solar heating and lake and valley breezes produce daytime lightning maxima north and east of the lake, while at night the peak lightning density propagates southwestward across the lake. Cluster analysis reveals terrain-related thunderstorm initiation hot spots northeast of the lake; clusters also initiate over the lake and northern lowlands. The most prolific clusters initiate between 1100 and 1400 LT, about 1–2 h earlier than the average cluster. Most daytime thunderstorms dissipate without reaching Lake Victoria, and annually 85% of clusters producing over 1000 flashes over Lake Victoria initiate in situ. Initiation times of prolific Lake Victoria clusters exhibit a bimodal seasonal cycle: equinox-season thunderstorms initiate most frequently between 2200 and 0400 LT, while solstice-season thunderstorms initiate most frequently from 0500 to 0800 LT, more than 12 h after the afternoon convective peak over land. More extreme clusters are more likely to have formed over land and propagated over the lake, including 36 of the 100 most extreme Lake Victoria thunderstorms. These mesoscale clusters are most common during February–April and October–November.

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Fishing Ground Mapping Based on Chlorophyll-A Distribution Using Aqua Modis Satellite Imagery in The Fisheries Management Area (FMA) 712

E3S Web of Conferences ◽

10.1051/e3sconf/202132401007 ◽

2021 ◽

Vol 324 ◽

pp. 01007

Author(s):

Yulius Yulius ◽

Vaninda Aidina ◽

Muhammad Ramdhan ◽

August Daulat

Keyword(s):

Chlorophyll A ◽

Fisheries Management ◽

Satellite Imagery ◽

Time Series Data ◽

Monsoon Season ◽

Fishing Ground ◽

Series Data ◽

Chlorophyll A Concentration ◽

Management Area ◽

Java Sea

The fishing ground is identical and closely related to chlorophyll-a abundance in the waters, associated with its fisheries potential. This research has been conducted to determine the concentration and distribution of chlorophyll-a in the seas, especially in the Fisheries Management Area (FMA) 712 encompassing the Java Sea. The analysis used monthly time-series data collected from the satellite imagery over the last 11 years, taken through the ERDDAP website. The mean concentration of chlorophyll-a in the study area was 1.13 mg/l in June 2013. Based on 11 years of data processing, it can be concluded that the highest concentration of chlorophyll-a occurred in the west monsoon season from November to April, where increased rainfall caused the nutrient wash from terrestrial to the open waters. The lowest chlorophyll-a concentration happened in the east monsoon season from April to November, where the dry season arrived. The existence of pelagic fishes in FMA 712, such as Sardinella Lemurs and Sardinella Fimbriata, in waters highly influenced by the chlorophyll-a concentration, while Thunnus Sp. and Exocoetidae Sp. not affected significantly to the existence of chlorophyll-a concentration and its distribution.

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The application of day and night time ASTER satellite imagery for geothermal and mineral mapping in East Africa

International Journal of Applied Earth Observation and Geoinformation ◽

10.1016/j.jag.2019.101991 ◽

2020 ◽

Vol 85 ◽

pp. 101991 ◽

Cited By ~ 4

Author(s):

Rob Hewson ◽

Elisante Mshiu ◽

Chris Hecker ◽

Harald van der Werff ◽

Frank van Ruitenbeek ◽

...

Keyword(s):

East Africa ◽

Satellite Imagery ◽

Night Time ◽

Mineral Mapping

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Imagining ‘Atlanta’: The Cultural Politics and Poetics of Experimental Medicine in East Africa

Cultural Studies Review ◽

10.5130/csr.v20i1.2659 ◽

2014 ◽

Vol 20 (1) ◽

Cited By ~ 1

Author(s):

Denielle Elliott

Keyword(s):

East Africa ◽

State Of The Art ◽

Lake Victoria ◽

Field Research ◽

Experimental Medicine ◽

Research Station ◽

Scientific Practices ◽

Global Science ◽

Rural Town ◽

The Social

In East Africa there is a field research station that locals call ‘Atlanta.’ It sits on the outskirts of a rural town, near Lake Victoria, equipped with ‘state-of-the-art’ biotechnological and entomological equipment for monitoring and exploring malaria, HIV, tuberculosis, rotavirus, and other tropical diseases. Drawn from ethnographic fieldwork with clinical trials in East Africa, this paper considers the stories people tell about the landscapes and spaces of experimental medicine to explore the uneven movement of knowledge, scientific practices, and scientists in global medicine. I begin this analytical journey at ‘Atlanta’ to consider what local idioms about such places might tell us about the encounters and travels of science and scientists in East Africa. Last, I draw attention to the social and material effects of global science projects on the lives and landscapes of East Africa.

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Fluctuations of the population of Daphnia laevis Birge 1878: a six-year study in a tropical lake

Brazilian Journal of Biology ◽

10.1590/s1519-69842012000300010 ◽

2012 ◽

Vol 72 (3) ◽

pp. 479-487 ◽

Cited By ~ 12

Author(s):

LPM. Brandão ◽

T. Fajardo ◽

E. Eskinazi-Sant'Anna ◽

S. Brito ◽

P. Maia-Barbosa

Keyword(s):

Chlorophyll A ◽

Total Phosphorus ◽

Trophic State ◽

Trophic Status ◽

Seasonal Pattern ◽

Ecological Research ◽

Total Phosphorous ◽

Long Term Ecological Research ◽

Physical And Chemical

The fluctuation of the population of Daphnia laevis in Lake Jacaré (Middle River Doce, Minas Gerais) was monitored monthly (at one point in the limnetic region) for six years (2002-2007) as part of the Program of Long-Term Ecological Research (LTER/UFMG). The following parameters were also monitored: water temperature, pH, electrical conductivity, dissolved oxygen, chlorophyll a, total phosphorus, phosphate, total nitrogen, nitrate, nitrite, ammonia, and densities of Chaoborus and ephippia of Daphnia laevis in the sediment. A seasonal pattern was observed in the fluctuation of D. laevis, with higher densities recorded during periods of circulation (May-August). A significant correlation was found between the density of D. laevis and temperature (r = -0.47, p = 0.0001), chlorophyll-a (r = -0.32, p = 0.016) and indicators of the lake's trophic status (total phosphorus, r = 0.32, p = 0.007 and trophic state, r = 0.36, p = 0.003), as well as Chaoborus density (r = 0.43 and p = 0.002). These results indicate that changes in the physical and chemical characteristics of the water related with stratification and circulation of the lake may have a direct (temperature, total phosphorous) or an indirect (food availability, presence of predators, ephippia eclosion) influence on the fluctuation of the D. laevis population.

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