Konsentrasi Logam Tembaga (Cu), Krom Heksavalen (Cr+6) dan Padatan Tersuspensi (TSS) dalam air Sungai Plumbon, Kecamatan Tugu, Kota Semarang dalam Kaitannya dengan Kelimpahan Fitoplankton

Logam tembaga (Cu), krom heksavalen (Cr+6) dan dan padatan tersuspensi total (TSS) dalam konsentrasi tertentu diketahui dapat menghambat pertumbuhan fitoplankton dalam perairan. Beberapa penelitian yang dilakukan sebelumnya menunjukkan bahwa logam Cu, Cr+6 dan TSS terdeteksi di perairan Sungai Plumbon Penelitian ini dilakukan untuk mengetahui konsentrasi logam Cu, Cr+6 dan TSS di dalam air sungai Plumbon dalam kaitannya dengan kelimpahan fitoplankton di dalam perairan tersebut. Penelitian dilakukan pada 3 stasiun penarikan contoh yang mewakili bagian hulu, tengah dan hilir sungai. Pengumpulan contoh air dan fitoplankton dilakukan sebanyak 2 kali dengan selang waktu 2 minggu. Konsentrasi logam Cu dan Cr+6 ditentukan dengan metode spektrofotometri dengan AAS. Konsentrasi TSS ditentukan secara gravimetri. Identifikasi dan pencacahan jumlah individus fitoplankton dilakukan dibawah mikroskop. Selanjutnya dilakukan pemeriksaan perbedaan konsentrasi logam, TSS dan kelimpahan fitoplankton antar stasiun dan antar waktu sampling dengan analisis ragam nonparamerik menurut Kruskal-Wallis. Hubungan antara konsentrasi logam dan TSS dengan kelimpahan fitoplankton dianalisis dengan model regresi berganda. Untuk menghindari masalah kolinieritas dalam model regresi, dilakukan analisis kolinieritas regresi. Hasil penelitian menunjukkan bahwa konsentasi Cu berkisar 0.218 – 0.320 mg/l, Cr+6 berkisar 0.018 – 0.043 mg/l, TSS berkisar 235.670 - 370.350 mg/l dan kelimpahan fitoplankton berkisar 509.554 - 1953.291 ind/ml. Hasil analisis regresi berganda dan pemeriksaan kemungkinan timbulnya masalah kolinieritas dalam regresi, menunjukkan bahwa hanya TSS yang berpengaruh terhadap kelimpahan fitoplankton, oleh karena fitoplankton mendominasi komponen TSS. Persamaan regresi Y (kelimpahan fitoplankton) = - 1673 + 8,69 X (konsentrasi TSS) (R2 = 0.693). Kata Kunci: Tembaga, Krom Heksavalen, TSS, Sungai Plumbon, Kelimpahan Fitoplankto

BIOCONCENTRATION FACTORS OF HEAVY METALS COPPER (CU) AND ZINC (ZN) IN GREEN MUSSELS (Perna viridis) IN THE WATERS OF TAMBAK LOROK SEMARANG

Tambak Lorok is a coastal area in Semarang. These waters have the potential to be contaminated with heavy metals Copper (Cu) and Zinc (Zn). The study aimed to determine the concentration of Cu and Zn in water, sediment and soft tissues of Perna viridis, knowing the effect of shell size on heavy metal absorption, knowing the bioconcetration factors of heavy metals and knowing the maximum limit of weekly consumption of Perna viridis. The study was conducted in November 2020. Determination of the location of the study using the Purposive sampling method.Concentrations of Cu and Zn in water, sediment and Perna viridis by the Atomic Absorption Spectrophotometer method. The results showed the content of Copper in water ranged from 0.06-0.151mg/l; sediments 26.634-38.433 mg/l and green mussels 4.76-11.00mg/l. Heavy metal Zinc is not detected in water, sediment and green shells one factor is that the tools used are insensitive to low concentrations of metals. Based on the results of statistical tests the difference in shell size has no effect on the absorption of  Cu in soft tissues. Bioaccumulation levels belong to the low-moderate category. The safe limit of consumption of green mussels for weight 40 kg is 15.683 mg/weeks and for weight 60 kg is 23.524 mg/weeks

KAJIAN PERUBAHAN SPASIAL DELTA WULAN DEMAK DALAM PENGELOLAAN KEBERLANJUTAN WILAYAH PESISIR

Pengelolaan wilayah pesisir secara terpadu merupakan suatu pendekatan pengelolaan wilayah pesisir yang melibatkan dua atau lebih ekosistem, sumberdaya, dan kegiatan pemanfaatan secara terpadu untuk pembangunan wilayah pesisir secara berkelanjutan. Salah satu ekosistem yang potensial di wilayah pesisir adalah delta. Delta merupakan daerah yang terbentuk karena adanya suplai sedimen dari sungai ke pantai dengan kecepatan lebih daripada proses pendistribusian oleh tenaga marin. Delta yang sedang berkembang saat ini di Indonesia, salah satunya adalah Delta Wulan Demak. Delta ini sedang mengalami perkembangan dari tahun ke tahunnya sehingga perlu adanya penelitian terkait dengan perubahan spasial Delta Wulan Demak yang dapat mendukung perencanaan dalam pengelolaan wilayah pesisir yang berkelanjutan. Penelitian ini menggunakan data citra satelit Landsat tahun 1994, 2002, 2010, dan 2015. Peta citra satelit ini akan diolah secara kualitatif dan kuantitatif menggunakan software ArcGIS untuk menghasilkan gambaran peta dan luasan dari perubahan yang terjadi di Delta Wulan Demak. Hasil yang diperoleh dari penelitian ini menggambarkan Delta Wulan Demak telah mengalami perubahan yang cukup siginifikan dalam perkembangannya di tahun 1994 sampai 2015 diantaranya : (1) Wilayah pantai telah mengalami abrasi; (2) Wilayah pantai telah mengalami sedimentasi; (3) Wilayah pantai yang semula mengalami abrasi menjadi sedimentasi; (4) Wilayah pantai yang semula mengalami sedimentasi menjadi abrasi; (5) Wilayah pantai yang mengalami sedimentasi dan stabil; dan (6) Wilayah dengan pola stagnan, yaitu tidak mengalami perubahan sejak dari tahun 1994 sampai 2015

Dinamika Perubahan Luasan dan Kerapatan Ekosistem Mangrove Di Kawasan Taman Nasional Sembilang Menggunakan Citra Satelit Landsat 8

The Mangrove Ecosystem is the most extensive forest in the Sembilang National Park (TNS) area. This area is located on the east coast of South Sumatra Province. The Sembilang National Park area has a natural mangrove forest of 88,555 ha. This area is known as the largest natural mangrove forest on the island of Sumatra. The purpose of this study was to determine changes in the area and density of mangroves in a period of 5 years using Landsat 8 satellite imagery. The results of the analysis show that the mangrove area in 2014 was 92,731 ha and the mangrove area in 2019 was 88,586 ha, the area decreased by 4,145 ha or about 4.5%. The main factors influencing changes in mangrove area and density are human activities such as land clearing near mangrove forest areas. In addition, there are natural factors that are dominantly influenced by abrasion and river sedimentation.   Ekosistem Mangrove merupakan hutan paling luas yang terdapat di kawasan Taman Nasional Sembilang (TNS). Kawasan ini terletak di pesisir timur Provinsi Sumatera Selatan. Kawasan TN Sembilang memiliki hutan mangrove alami seluas 88.555 ha. Kawasan ini dikenal sebagai hutan mangrove alami terluas di Pulau Sumatera. Tujuan penelitian ini adalah untuk mengetahui perubahan luasan dan kerapatan mangrove dalam kurun waktu 5 tahun menggunakan citra satelit Landsat 8. Teknik analisis spasial yang digunakan untuk mengkelaskan mangrove dan non mangrove serta kerapatan dengan menggunakan Supervised Classification dan NDVI. Hasil analisa menunjukkan bahwa luasan mangrove pada tahun 2014 seluas 92.731 ha dan luasan mangrove tahun 2019 seluas 88.586 ha, luasan mengalami penurunan sebesar 4.145 ha atau sekitar 4,5%. Faktor-faktor yang mempengaruhi perubahan luas dan kerapatan mangrove yang utama adalah aktivitas manusia seperti pembukaan lahan di dekat area hutan mangrove. Selain itu, terdapat faktor alam mempunyai yang dominan dipengaruhi oleh abrasi dan sedimentasi sungai

Mapping of Coastal Vulnerability using the Coastal Vulnerability Index and Geographic Information System

The mapping of coastal vulnerability using the Coastal Vulnerability Index (CVI) and the Geographic Information System (GIS) at Doreri Bay, Manokwari Regency, West Papua Province was carried out from September 2013 to March 2014. The aims of this study are to analyze and map the coastal vulnerability of Doreri Bay. The study was conducted using a combination of the CVI and GIS methods to assess the geological and physical parameters of the coastal region. The geological parameters consisted of geomorphology, coastline changes (accretion/erosion), the coastline slope, and physical processes. The physical parameters consisted of the relative changes in the sea surface height, the average wave height, and the average tidal height. The results of this research show that the CVI values were within the range of 6.7–43.3, and there were five class categories of coastal vulnerability: (1) very low vulnerability with an area of 6,635.4 Ha or 47.8%, (2) low vulnerability with an area of 2,654.1 Ha or 19.1%, (3) medium vulnerability with an area of 1,692.8 Ha or 12.2%, (4) high vulnerability with an area of 992.7 Ha or 7.2%, and (5) very high vulnerability with an area of 1,904.2 Ha or 13.7%

The influence of biological, sedimentological and physical factors on sediment stability in intertidal waters

In situ studies on sediment stability and macrobenthic organisms are described; these were undertaken over a 28 month period at Solent Breezes Southampton Water. The study consisted of the monthly collection of field data, including the shear strength of the surficial sediment and the tube density of Lanice conchilega. Sediment cores were collected also for the analysis of macrobenthic organisms and other parameters. The data obtained are analysed statistically, to establish correlation between the parameters under investigation.Solent Breezes is a relatively stable environment, with no distinct accretional or erosional patterns. The majority of the velocity profiles measured in the overlying waters, during a spring tidal cycle, are logarithmic in character. Critical friction velocities range from 0.25 cm s-1 to 5.71 cm s-1; these correspond to critical bed shear stresses of 0.01 N m-2 and 3.36 N m-2. Roughness lengths range from 0.02 cm to 14.30 cm.Biological investigations have revealed the presence of 29 species of benthic macrofauna. The total number of species and individuals varies seasonally. Lanice tube densities range from 3.13 per 100 cm2 (July 1993) to 8.80 per 100 cm2 (November 1991). Tube density is affected by failure of larval recruitment, mortality, species interactions and predation. Principal components analysis reveals that the factors responsible for the existing pattern are: (i) bioavailability of organic matter (protein, bacterial protein, organic matter and grain size characteristics); (ii) sediment strength; and (iii) physical controls (temperature, salinity and moisture content).</p

The Effectiveness of Salt Business Empowering Program (Pugar) on Salt Farmers’ Income Improvement in Kedungmutih Village of Demak Regency and Kedungmalang Village Of Jepara Regency

Indonesian national low productivity of salt which is unequal between the need level and salt consumption eventually results in salt import made mainly to meet the industrial needs. The government through the Ministry of Marine Affairs and Fisheries has released a Public Salt Business Empowering Program (known as PUGAR/Pemberdayaan Usaha Garam Rakyat). PUGAR is an empowering program focusing on the improvement of job opportunities and welfare for salt farmers/managers to achieve the self-sufficiency of salt for consumptions and industries. This research aims at examining the influence of salt business empowering program on the salt farmers’ income improvement in Kedungmalang village of Jepara Regency; the implementation level of salt business empowering program in Kedungmutih Village of Demak Regency when compared to that in Kedungmalang Village of Jepara Regency; and the influence of salt business empowering program on the salt farmers’ income improvement in Kedungmutih village of Demak regency. The research was conducted using a descriptive method with a case study approach. The program implementation was quantitatively analyzed. Furthermore, the effectiveness of PUGAR on income was analyzed using T-test. The test result showed that there were income differences in Kedungmutih and Kedungmalang Village before and after the implementation of PUGAR. This finding showed that PUGAR was proven as an effective program to improve the salt farmers’ welfare through income improvement

Sediment Characteristic of the Ebb-Tidal Delta in Western Segara Anakan Lagoon

Western Segara Anakan Lagoon (WSAL) is a semi-enclosed lagoon located in the Cilacap, Central Java Province, Indonesia which has two outlets called pelawangan. West Pelawangan is an open channel from WSAL and the Indian Ocean, which has vast sediment input. It impacts the sediment deposits and delta formations in WSAL. This research aimed to determine the sediment characteristics deposited in the WSAL specifically in the delta formation area, and the mean size of sediments (D50), sorting, and skewness. The research used the survey method while data collected were sediment-bed, bathymetry, and satellite imagery Sentinel 2A with the ebb-tide condition. Sediment was analyzed by sieve and gravimetry and interpreted as a Ternary diagram, D50, sortation, skewness, and fraction percentage spreading map. Satellite imagery Sentinel 2A was searched by the ebb-tide condition. Shorelines and delta was extracted by the Normalized Different Water Index. Bathymetry built from depth points data 2018. The results of the Ternary diagrams analysis were the Citanduy River had a sand grain size, the Pelawangan Barat Waters (PBW) were dominated by sand and the lagoon was dominated by a fine grain size and silt. The result of sediment D50, sortation, and skewness in the Citanduy River and the PBW were dominated by sand, and the lagoon was dominated by fine sediment: silt, and clay grain size. The sediment fractions were sorted very well; skewness was dominated by the fine skewed (positive skewed). The delta formation in the lagoon covers a large area, presumably due to the consolidation of the fine sediment. Keywords: Sediment Characteristics, Ebb-Tidal Delta, Western Segara Anakan Lagoo

The Partial Pressure of CO2 and Fluxes of CO2 in Semarang Bay, Indonesia

The CO2 characteristics of the Semarang Bay system on the Northern coast of Java were investigated to understand the roles in carbon dioxide flux. The flux of carbon dioxide at the sea surface between seawater and atmosphere is essential for mitigating atmospheric CO2. The aims of this study were to assess the variation of CO2 partial pressure seawater (pCO2sea) and CO2 flux and to analyse the water quality variable which has the larger influence on CO2 flux in the waters of Semarang Bay. The variables in this study were temperature, pH, salinity, and DO. Different methods were adopted in the analysis of water samples: spectrophotometric to measure chlorophyll-a and phosphate and titration method to measure Total Alkalinity (TA) and Dissolved Inorganic Carbon (DIC). A CO2 meter was used to measure the CO2atm. The lowest CO2 flux value was (1.86 mmol CO2 m-2 day-1) during the morning period while the pCO2sea reached 461.04 μatm and CO2 flux 83.79 mmol CO2 m-2 day-1 at night. At noon time, with increased temperature, pCO2sea was 461.04 μatm, and CO2 flux was 83.79 mmol CO2 m-2 day-1. The high concentration of chlorophyll-a ranged between 3.55–4.11 mg.L-1. This chlorophyll-a concentration has a negative correlation with CO2 flux, and it was found that TA and DIC concentrations have no relationship with CO2 flux. Based on PCA analysis, it was found that the variability of CO2 flux in Semarang Bay is influenced by the variability of pCO2sea, sea surface temperature and kwa (affected by wind speed).Environmental Fluid Mechanic