Seagrass characterization on the southern Pacific coast of Costa Rica: history, vegetation, and environment

2020 ◽  
Vol 63 (5) ◽  
pp. 429-438
Author(s):  
Jimena Samper-Villarreal ◽  
Jorge Cortés
Keyword(s):  
Costa Rica ◽  
Pacific Coast ◽  
Management Strategies ◽  
Shoot Density ◽  
Nutrient Concentrations ◽  
Seagrass Habitat ◽  
Spatial And Temporal Variability ◽  
Seagrass Species ◽  
Seagrass Biomass ◽  
Herbarium Collections

AbstractSeagrass conservation and management requires scientific understanding of spatial and temporal variability, information that is currently limited for the Eastern Tropical Pacific (ETP). Here, we analysed seagrass presence based on previous reports, herbarium collections and stakeholder knowledge, combined with field characterization in Golfo Dulce, southern Pacific coast of Costa Rica. Seagrasses were found at multiple locations along a narrow border close to shore and in up to 6 m depth within Golfo Dulce, dating back to 1969. Two seagrass species were found, Halophila baillonii and Halodule beaudettei. Seagrass biomass values for Golfo Dulce (12.0 ± 8.5 g DW m−2) were lower and water nutrient concentrations were higher than previously reported in the gulf. Shoot density (1513 ± 767 shoots m−2) was similar to previous reports. Stable isotope values in seagrass were −11.3 ± 1.0‰ δ13C and 1.2 ± 0.9‰ δ15N; while those in sediments were −26.1 ± 1.3 and 2.5 ± 0.9‰. In Golfo Dulce, isotopic values of both seagrass species do not overlap with other known primary producers. Management strategies should aim to minimize known seagrass stressors, protect potential seagrass habitat, and take into account the dynamic life strategies of the two seagrass species found.

scholarly journals Carbon Stock of Seagrass Community in Barranglompo Island, Makassar (Stok Karbon pada Komunitas Lamun di Pulau Barranglompo, Makassar)

2014 ◽  
Vol 19 (1) ◽  
pp. 1 ◽  
Author(s):  
Supriadi Supriadi ◽  
Richardus F Kaswadji ◽  
Dietrich G Bengen ◽  
Malikusworo Hutomo
Keyword(s):  
Carbon Stock ◽  
Carbon Stocks ◽  
Blue Carbon ◽  
Total Carbon ◽  
Root Penetration ◽  
Enhalus Acoroides ◽  
Seagrass Community ◽  
Seagrass Biomass ◽  
Depth Relationship ◽  
Seagrass Density

Konsep blue carbon yang diperkenalkan oleh UNEP, FAO dan UNESCO pada tahun 2009 memasukkan padang lamun sebagai salah satu ekosistem yang mempunyai peran dalam penyerapan karbon global. Karbon yang diserap disimpan dan dialirkan dalam beberapa kompartemen, antara lain di sedimen, herbivora, kolom air, ekosistem lain dan dalam bentuk biomassa. Penelitian dilakukan di Pulau Barranglompo, Makassar, untuk melihat potensi stok karbon yang tersimpan dalam biomassa lamun. Kepadatan lamun diukur dengan melakukan sampling menggunakan metode transek kuadrat dengan ukuran 50cm x 50cm. Sedangkan untuk biomassa dilakukan dengan transek 20cm x 20cm. Hubungan antara kepadatan, biomassa dan kandungan karbon dari lamun digunakan untuk menentukan jumlah stok karbon. Kepadatan lamun disurvei pada 236 titik, sedangkan untuk pengambilan sampel biomassa dilakukan pada 30 titik. Hasil penelitian menunjukkan bahwa komunitas lamun mempunyai total stok karbon sebesar 73,86 ton dari total luas padang lamun 64,3 ha. Karbon di bawah substrat sebesar 56,55 ton (76,3%), lebih tinggi dibanding karbon di atas substrat yang hanya 17,57 ton (23,7%). Jenis lamun Enhalus acoroides menyumbang lebih dari 70% terhadap total stok karbon. Berdasarkan kelas karbon, kontribusi terbesar ditemukan pada kelas 100-200 gC.m-2 sebesar 29,41 ton (39,7%). Hasil ini menunjukkan bahwa ekosistem lamun berperan sangat penting dalam menjaga stok karbon di laut sehingga perlu mendapatkan perhatian untuk konservasinya. Kata kunci: konsep blue karbon, lamun, Barranglompo   Blue carbon concept as introduced by UNEP, FAO and UNESCO in 2009 included seagrass beds as one ecosystem having a significant role in global carbon absorption. Absorbed carbon was stored and distributed in various compartments such as in sediments, herbivores, water column, other ecosystems and in form of biomass. The research was conducted in Barranglompo Island, Makassar City to analyze the potency of carbon stock that stored within seagrass biomass. Seagrass density was sampled using quadrat transect method with size of 50cm x 50cm. While for biomass was done by harvesting seagrass at transect of 20cm x 20cm in root penetration depth. Relationship between density, biomass and carbon content of seagrass were used to determine total carbon stock. Seagrass density was surveyed at 236 points, while for biomass sampling was conducted in 30 points. The results showed that seagrass community had total carbon stocks as much as 73.86 tonnes from overall 64.3 ha of seagrass bed areas.  Below ground carbon had 56.55 tonnes (76.3%), higher compared to that aboveground which only 17.57 tonnes (23.7%). Seagrass species Enhalus acoroides contributed more than 70% to the total carbon stocks, whereas, based on the carbon classes, the highest contribution was found at class 100-200 gC.m-2 i.e. 29.41 tonnes (39.7%). These results suggest that seagrass ecosystem plays an important role in maintaining the carbon stock in the ocean and should receive good attention for its conservation. Keywords: blue carbon concept, seagrass, Barranglompo

scholarly journals Carbon storage in seagrass soils: long-term nutrient history exceeds the effects of near-term nutrient enrichment

2016 ◽  
Vol 13 (1) ◽  
pp. 313-321 ◽  
Author(s):  
A. R. Armitage ◽  
J. W. Fourqurean
Keyword(s):  
Organic Carbon ◽  
Soil Carbon ◽  
Carbon Stock ◽  
Seagrass Beds ◽  
Nutrient Input ◽  
High Carbon ◽  
Phosphorus Addition ◽  
Seagrass Biomass ◽  
Near Term

Abstract. The carbon sequestration potential in coastal soils is linked to aboveground and belowground plant productivity and biomass, which in turn, is directly and indirectly influenced by nutrient input. We evaluated the influence of long-term and near-term nutrient input on aboveground and belowground carbon accumulation in seagrass beds, using a nutrient enrichment (nitrogen and phosphorus) experiment embedded within a naturally occurring, long-term gradient of phosphorus availability within Florida Bay (USA). We measured organic carbon stocks in soils and above- and belowground seagrass biomass after 17 months of experimental nutrient addition. At the nutrient-limited sites, phosphorus addition increased the carbon stock in aboveground seagrass biomass by more than 300 %; belowground seagrass carbon stock increased by 50–100 %. Soil carbon content slightly decreased ( ∼  10 %) in response to phosphorus addition. There was a strong but non-linear relationship between soil carbon and Thalassia testudinum leaf nitrogen : phosphorus (N : P) or belowground seagrass carbon stock. When seagrass leaf N : P exceeded an approximate threshold of 75 : 1, or when belowground seagrass carbon stock was less than 100 g m−2, there was less than 3 % organic carbon in the sediment. Despite the marked difference in soil carbon between phosphorus-limited and phosphorus-replete areas of Florida Bay, all areas of the bay had relatively high soil carbon stocks near or above the global median of 1.8 % organic carbon. The relatively high carbon content in the soils indicates that seagrass beds have extremely high carbon storage potential, even in nutrient-limited areas with low biomass or productivity.

scholarly journals Biomasa dan Simpanan Karbon pada Ekosistem Lamun di Perairan Batulawang dan Pulau Sintok Taman Nasional Karimunjawa, Jepara

2021 ◽  
Vol 10 (3) ◽  
pp. 413-420
Author(s):  
Annisa Rhamadany ◽  
Chrisna Adhi Suryono ◽  
Delianis Pringgenies
Keyword(s):  
Carbon Content ◽  
Carbon Storage ◽  
Thalassia Hemprichii ◽  
Enhalus Acoroides ◽  
Halophila Ovalis ◽  
A Value ◽  
Seagrass Biomass ◽  
Seagrass Ecosystems ◽  
Cymodocea Rotundata ◽  
Thalassodendron Ciliatum

Ekosistem lamun memiliki fungsi ekologi dan ekonomi yang tinggi. Peran ekosistem lamun dalam penyimpanan karbon akan tetapi masih belum menjadi sorotan. Tujuan dari penelitian ini yaitu untuk mengetahui nilai biomassa dan estimasi simpanan karbon pada ekosistem lamun di Perairan Batulawang, Pulau Kemujan serta Pulau Sintok, Taman Nasional Karimunjawa. Penelitian ini dilaksanakan pada 7 – 14 Noevmber 2019 di Perairan Batulawang dan Pulau Sintok, Taman Nasional Karimunjawa. Metode penelitian di lapangan menggunakan metode SeagrassWatch, sementara nilai biomassa dan nilai estimasi simpanan karbon dihitung menggunakan metode Metode Loss of Ignition (LOI) di laboratorium. Data yang diperoleh berupa pengukuran berat kering untuk menghitung biomassa dan analisa kandungan karbon pada lamun dan sedimen. Hasil penelitian didapatkan empat jenis lamun di Perairan Batulawang yaitu Enhalus acoroides, Thalassia hemprichii, Cymodocea serrulata, dan Thalassodendron ciliatum sedangkan di Pulau Sintok terdapat tiga jenis lamun yang ditemukan yaitu Thalassia hemprichii, Cymodocea rotundata, dan Halophila ovalis. Nilai total biomassa lamun terbesar pada Perairan Batulawang yaitu Enhalus acoroides dengan nilai 849,75 gbk/m2 dan nilai total biomassa lamun terkecil Thalassodendron ciliatum dengan nilai 29 gbk/m2. Nilai total biomassa lamun terbesar pada Pulau Sintok yaitu Cymodocea rotundata dengan nilai 177,75 gbk/m2dan nilai total biomassa lamun terkecil Halophila ovalis dengan nilai 4,75 gbk/m2. Hasil pengukuran karbon lamun pada Perairan Batulawang yaitu 12,97 – 359,87 gC/m2­ dan 258,20 – 541,51 gC/m2 pada sedimennya. Hasil pengukuran karbon pada lamun di Pulau Sintok yaitu 2,35 – 85,80 gC/m2 dan 204,92 – 765,92 gC/m2 pada sedimen. Kandungan karbon paling besar terdapat pada bagian bawah substrat (below ground). Kandungan karbon pada bagian bawah substrat tidak terganggu oleh faktor lingkungan (gelombang, arus, dan ulah manusia) sehingga terakumulasi baik. Seagrass ecosystems have high ecological and economic functions. The role of seagrass ecosystems in carbon storage, however, has not yet been highlighted. The purpose of this study was to determine the value of biomass and estimated carbon storage in seagrass ecosystems in Batulawang waters, Kemujan Island and Sintok Island, Karimunjawa National Park. This research was conducted on 7 − 14 November 2019 in Batulawang waters and Sintok Island, Karimunjawa National Park. The research method in the field uses the SeagrassWatch method, while the biomass value and the estimated value of carbon storage are calculated using the Loss of Ignition (LOI) method in the laboratory. The data obtained were measurements of dry weight to calculate biomass and analysis of carbon content in seagrass and sediments. The result shows that there are four species of seagrass in Batulawang Waters, they are Enhalus acoroides, Thalassia hemprichii, Cymodocea serrulata, and Thalassodendron cliatum meanwhile in Sintok Island there are three species, they are, Thalassia hemprichii, Cymodocea rotundata, and Halophila ovalis. The measurement of carbon is done by using Loss on Ignition Method. The highest total seagrass biomass in Batulawang waters is Enhalus acoroides with a value of 849.75 gbk/m2 and the lowest total seagrass biomass is Thalassodendron ciliatum with a value of 29 gbk/m2. The highest total seagrass biomass on Sintok Island is Cymodocea rotundata with a value of 177.75 gbk/m2 and the lowest total seagrass biomass is Halophila ovalis with a value of 4.75 gbk/m2. The results of measurements of seagrass carbon in Batulawang waters are 12,97 – 359,87 gC/m2­ and 258,20 – 541,51 gC/m2 on the sediments. The result of seagrass carbon measurement in Sintok Island is 2,35 – 85,80 gC/m2 and 204,92 – 765,92 gC/m2 on the sediments. The largest carbon content is at the bottom of the substrate (below ground). The carbon content at the bottom of the substrate is not disturbed by environmental factors (waves, currents, and human activities) so that it accumulates well.

scholarly journals Cadangan Karbon pada Ekosistem Padang Lamun di Siantan Tengah Taman Wisata Perairan Kepulauan Anambas

2020 ◽  
Vol 24 (1) ◽  
pp. 45-54
Author(s):  
Muhammad Al Rizky Ratno Budiarto ◽  
Johan Iskandar ◽  
Tri Dewi Kusumaningrum Pribadi
Keyword(s):  
Carbon Stock ◽  
Carbon Sink ◽  
Gravimetric Method ◽  
Total Carbon ◽  
Seagrass Beds ◽  
Thalassia Hemprichii ◽  
Enhalus Acoroides ◽  
Value Range ◽  
Seagrass Biomass ◽  
Cymodocea Rotundata

Secara global, ekosistem lamun dianggap sebagai penyerap karbon sehingga dapat berkontribusi terhadap mitigasi perubahan iklim. Penelitian bertujuan untuk mengetahui komposisi jenis, biomassa dan cadangan karbon pada komunitas padang lamun di perairan Siantan Tengah Taman Wisata Perairan (TWP) Kepulauan Anambas. Penelitian dilaksanakan pada bulan Agustus 2019 s.d Januari 2020. Uji kandungan karbon dilakukan dengan metode Welkley and Black sedangkan untuk mendapatkan biomassa menggunakan metode gravimetrik. Hasil penelitian menunjukkan bahwa terdapat tiga jenis lamun, yaitu Enhalus acoroides, Thalassia hemprichii, dan Cymodocea rotundata. Nilai biomassa lamun berkisar antara 171,89 – 275,68 gbk/m2 dan nilai cadangan karbon berada pada kisaran 51,89 – 80,66 gC/m2. Padang lamun di Siantan Tengah memiliki luas 130,45 ha, sehingga total Cadangan karbon pada ekosistem padang lamun di perairan Siantan Tengah diperkirakan 95,88 ton C. Penelitian ini membuktikan adanya kandungan karbon pada biomassa lamun sehingga dapat disimpulkan bahwa padang lamun berperan sebagai penyerap karbon (carbon sink).  Globally, seagrass ecosystems are considered as carbon sink so that it can contribute to climate change mitigation. This research aims to determine the species composition, biomass, and carbon stock in seagrass communities in Siantan Tengah Marine Tourism Park of Anambas Islands. The research was conducted in Agustus 2019 – January 2020.  The carbon content test was carried out by the Walkley and Black method while to obtain biomass using the gravimetric method. The result od study showed that there are three species of seagrasses, namely Enhalus acoroides, Thalassia hemprichii, and Cymodocea rotundata. Seagrass biomass value range 171,89 – 275,68 gbk/m2 and seagrass carbon stock value range 51,89 – 80,66 gC/m2. The area of seagrass beds in Central Siantan is 130,45 ha so that the total carbon stock estimated reach 95,88 tons C. This research proves the presence of carbon in the biomass of seagrass beds, so it can be concluded that seagrass beds act as carbon sinks.

Temporal variations of Halodule wrightii meadows and associated fauna near their southern distribution limit in the southwestern Atlantic

2020 ◽  
Vol 63 (3) ◽  
pp. 215-228
Author(s):  
Laura Sordo ◽  
Paulo Lana
Keyword(s):  
Temporal Variations ◽  
Halodule Wrightii ◽  
Associated Fauna ◽  
Benthic Species ◽  
Southern Limit ◽  
Distribution Limit ◽  
Seagrass Biomass ◽  
Sw Atlantic ◽  
Number Of Leaves ◽  
Ecosystem Changes

AbstractHalodule wrightii meadows in Southern Brazil have been regressing in an unsheltered area of the subtropical Paranaguá Bay, near their southern limit in the SW Atlantic, since 2006. To identify early indicators of regression events, we assessed variations in plant and macrobenthic structure in two local meadows under unsheltered and protected conditions. Differences between sites increased after an epiphytic overgrowth of the alga Hincksia mitchelliae at the unsheltered site. Seagrass growth was suppressed and the numbers of burrowing and opportunistic benthic species increased with the increase of algal biomass. In the protected meadow, seagrass biomass and number of leaves changed seasonally, but macrobenthic abundance and species richness remained stable. Ecosystem changes were evident when the unsheltered meadow was already collapsing. The number of leaves per shoot, the horizontal internode length, the abundance and structure of the macrofaunal associations, and the host-epiphyte surface interactions, were the first variables to reflect the early stages of seagrass regression. Our results suggest that the persistence of H. wrightii meadows at their southern distribution limit in the SW Atlantic will be affected by local hydrodynamics and their ability to compete with ephemeral macroalgal species under stress conditions.

Observations on dugongs at Calauit Island, Busuanga, Palawan, Phillipines

1994 ◽  
Vol 21 (6) ◽  
pp. 709 ◽  
Author(s):  
LV Aragones
Keyword(s):  
The Philippines ◽  
Thalassia Hemprichii ◽  
Halophila Ovalis ◽  
Direct Observations ◽  
Seagrass Biomass ◽  
Wet Weight ◽  
Cymodocea Rotundata ◽  
Syringodium Isoetifolium ◽  
Study Sites ◽  
Vantage Points

A simultaneous monitoring system that used a team of local observers to count dugongs around Calauit Island, Busuanga, Palawan, Philippines, from eight vantage points was employed from March 1989 to May 1990 to identify important dugong habitats around the island. On average, five dugongs were seen per survey day. More dugongs were observed during March and July 1989 than in other months. These periods coincided with the bimodal peaking of seagrass biomass in the region and the lull between monsoons for that year. The site where dugongs were most often sighted was about 1.5 m deep, had the largest area of seagrass on the island (approximately 50 ha) and supported a seagrass (above-ground) biomass averaging 1060 g m-2 (wet weight). The dugongs were shy, making observations difficult. They were observed to graze at the study sites once per day, usually starting in the late afternoon or at night. Animals usually stayed on the seaward side of the spur-and-groove sections of the reefs. Short seagrasses such as Halophila ovalis, Halodule uninervis, Cymodocea rotundata, C. serrulata, Syringodium isoetifolium and Thalassia hemprichii showed more evidence of being grazed than the taller Enhalus acoroides. By direct observations of the area grazed by a single dugong, an average consumption rate of 30.5 kg (wet weight) of seagrass (above ground only) per day was estimated. The methodology developed in this study may be used to identify reserve areas for the protection of dugong habitats in the Philippines. The dugong populations of Palawan require further attention and implementation of conservation measures.

scholarly journals Circadian Photoentrainment in Mice and Humans

Biology ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 180
Author(s):  
Russell G. Foster ◽  
Steven Hughes ◽  
Stuart N. Peirson
Keyword(s):  
Ganglion Cells ◽  
Light Exposure ◽  
Bright Light ◽  
Functional Expression ◽  
Time Of Day ◽  
High Irradiance ◽  
Intermittent Light ◽  
Long Duration ◽  
Light History

Light around twilight provides the primary entrainment signal for circadian rhythms. Here we review the mechanisms and responses of the mouse and human circadian systems to light. Both utilize a network of photosensitive retinal ganglion cells (pRGCs) expressing the photopigment melanopsin (OPN4). In both species action spectra and functional expression of OPN4 in vitro show that melanopsin has a λmax close to 480 nm. Anatomical findings demonstrate that there are multiple pRGC sub-types, with some evidence in mice, but little in humans, regarding their roles in regulating physiology and behavior. Studies in mice, non-human primates and humans, show that rods and cones project to and can modulate the light responses of pRGCs. Such an integration of signals enables the rods to detect dim light, the cones to detect higher light intensities and the integration of intermittent light exposure, whilst melanopsin measures bright light over extended periods of time. Although photoreceptor mechanisms are similar, sensitivity thresholds differ markedly between mice and humans. Mice can entrain to light at approximately 1 lux for a few minutes, whilst humans require light at high irradiance (>100’s lux) and of a long duration (>30 min). The basis for this difference remains unclear. As our retinal light exposure is highly dynamic, and because photoreceptor interactions are complex and difficult to model, attempts to develop evidence-based lighting to enhance human circadian entrainment are very challenging. A way forward will be to define human circadian responses to artificial and natural light in the “real world” where light intensity, duration, spectral quality, time of day, light history and age can each be assessed.

scholarly journals The Structure of the Envelopes of Symbiotic Novae

1990 ◽  
Vol 122 ◽  
pp. 431-432
Author(s):  
G.B. Baratta ◽  
A. Damineli Neto ◽  
C. Rossi ◽  
R. Viotti
Keyword(s):  
High Resolution ◽  
Uv Spectra ◽  
Emission Lines ◽  
Broad Line ◽  
Line Profiles ◽  
Composite Spectrum ◽  
Multiple Structure ◽  
Broad Emission ◽  
Light History

Symbiotic novae are composite spectrum stars whose light history is characterized by one single major outburst. At high resolution their optical and UV spectra are very rich of emission lines belonging to a wide ionization range. Generally one can identify both narrow and broad line systems. The latter includes emission lines with multiple structure, broad emission wings, WR features, and P Cygnl lines. Frequently the broad line profiles are largely variable with time. They should be associated with the major stellar outburst. An overview of the problem with extensive references can be found in Viotti (1989).

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