STUDI KOMPETISI TURF ALGAE DAN KARANG GENUS ACROPORA DI PULAU MENJANGAN KECIL, KEPULAUAN KARIMUNJAWA, KABUPATEN JEPARA

Turf algae dapat menempel dan tumbuh dengan cepat sehingga mengakibatkan efek besar terhadap pertumbuhan karang. Pertumbuhan turf algae yang cepat dapat dipengaruhi beberapa faktor, diantaranya: peningkatan nutrisi perairan (eutrofikasi), penurunan ikan herbivora pemakan alga, dan faktor lingkungan lainnya. Tujuan dari penelitian ini adalah untuk mengetahui laju pertumbuhan tutupan turf algae pada karang Genus Acropora dan laju pertumbuhan karang hidup Genus Acropora pada koloni yang telah mati atau mengalami kerusakan. Penelitian ini dilaksanakan pada bulan Oktober 2014 – April 2015. Sampel yang digunakan ada 30 karang dari 7 koloni dengan 3 kelompok ukuran (1-3 cm (Kelompok A), 5-7 cm (Kelompok B), dan 10-12 cm (Kelompok C)). Metode survei deskriptif digunakan dalam metode penelitian ini. Data penelitian meliputi data primer dan data sekunder. Data diambil dengan mengukur tutupan turf algae dan karang hidup serta mengukur pertumbuhan keduanya. Hasil penelitian menunjukkan bahwa rerata laju pertumbuhan tutupan turf algae tertinggi terjadi pada ukuran awal karang 5-7 cm (Kelompok B) yaitu 0,028 cm/hari dan rerata laju pertumbuhan tutupan turf algae terendah terjadi pada ukuran awal karang 10-12 cm (kelompok C) yaitu 0,007 cm/hari. Sedangkan rerata laju pertumbuhan karang hidup semua mengalami laju pertumbuhan yang negatif, sehingga menjadi ancaman bagi kehidupan terumbu karang. Kata kunci : kompetisi, turf algae, karang hidup, laju pertumbuhan

Effects of turf algae on recruitment and juvenile survival of gorgonian corals

8 páginas, 4 figuras.During the last 2 decades, the widespread temperate gorgonian Eunicella singularis has been among the species most affected by climate-induced mortalities. Recruitment and juvenile survival play crucial roles in the recovery process of this species, but turf algae may affect these early life history processes. We investigated the effects of turf algae on recruitment and juvenile survival of E. singularis using in situ turf-removal and turf-exposure experiments. The experiments were performed at a depth of 15 to 20 m off the island of Menorca (Balearic Islands, NW Mediterranean Sea) between April 2008 and July 2009. The turf-removal experiment indicated that exposure to turf algae caused up to a 5-fold reduction in the recruitment of the gorgonian species. The turf-exposure experiment revealed that transplanted juveniles exposed to turf algae overgrowth lost biomass and exhibited a threefold increase in juvenile mortality. These results demonstrate the negative effects that turf algae can exert on early stages of gorgonian species; in turn, this may affect their recovery capacity and population dynamics. Given that most Mediterranean invasive algae form a persistent turf, an increase in turf algae abundance may exacerbate these negative effects.Financial support was provided by the ‘Consell Insular de Menorca’ and the ‘Ministerio de Ciencia e Innovació (MCI)’ projects CGL2010-18466 and CTM2009-08045. C.L. and E.C. were funded by a Juan de la Cierva Postdoctoral Fellowship from the MCI and are part of the Marine Conservation research group (2009SGR174); R.C. is a member of the Marine Biogeochemistry and Global Change research group (2009SGR142) from the Generalitat Catalunya.Peer reviewe

A report of biological observations at Pacific Beach artificial reef, Oceanside artificial reef, and Santa Monica Bay artificial reef

(Document pdf contains 16 pages

Biological surveys of Santa Monica Bay artificial reef and Topanga artificial reef

This report details the development of the biological communities on 2 artificial reefs off southern California (Figure 1). Santa Monica Bay Artificial Reef(SMBAR) and Topanga Artificial Reef(TAR) were both constructed in 1987 with 20,000 and 10,000 tons of quarry rock respectively. SMBAR was constructed in the manner of replication reefs which were designed by researchers to study the effects of environmental and structural variables on reef productivity in situ and TAR was built to promote kelp habitat. SMBAR is composed of 24 module pairs of varying height and rock size arranged along three depth strata while TAR was built in 3 piles along one depth strata (Table 1, Figure 2 & Figure 3). SMBAR is located at 34°00'47''N; 118°32'33" W approximately 5 nautical miles from the Marina del Rey entrance along a course of 290° magnetic. TAR is located at 34°01'38.10" N; 118°31'54.80"W; approximately 5.25 nautical miles from the Marina del Rey entrance along a course of 302° magnetic. The modules of SMBAR cover 3.58 acres of the 256 acres allotted in the permit. Each module has a footprint of about 0.07 acres. The modules of TAR cover 2 acres of 13 acres allotted in the permit. Each module has a footprint of about 0.70 acres. During the late fall of 1995 both reefs were surveyed by Department divers to assess how closely their biological communities had progressed towards a stable "equilibrium" community. Due to the relatively young age of the reefs and the rapid successional change which occurs in the associated biotic communities of new reefs (Carlisle et al. 1964; Turneretal. 1969; Carteretal. 1985; Matthews 1985; Solonsky 1985; Ambrose and Swarbrick 1989; Anderson et al. 1989; Hueckel and Buckley 1989; and WIlson et al. 1990), only qualitative surveys were conducted. (17pp.

A report of biological observations at Oceanside #1 and #2 artificial reefs, Carlsbad artificial reef, Pacific Beach artificial reef, and Mission Bay Park artificial reef

(Document pdf contains 22 pages

Soil algae - A bibliography

Soil algae - bibliograph

A novel interaction between nutrients and grazers alters relative dominance of marine habitats

Copyright © 2005 Inter-Research.Strong top-down control by grazers is considered a moderating influence on the negative effects of elevated nutrients on marine algae. Little experimental work has been done in a system that has weak grazing pressure (weak top-down control), which is also subjected to elevated nutrients. We experimentally elevated nutrient concentration to test (1) the effects of nutrient enrichment on algal assemblages in the presence and absence of canopies (Ecklonia radiata) and (2) the interactive effects of nutrients and molluscan grazers (meso-grazers) on algal assemblages in the absence of canopies. We established that the loss of canopy-forming algae is likely to be a key precursor to nutrient-driven changes of assemblages of benthic algae, because nutrients had no effects on algal assemblages in the presence of canopy-forming algae. In the absence of canopy-forming algae, space was monopolised by filamentous, turf-forming algae, and it was only in the presence of grazers that nutrients caused a change to the relative covers of algal habitat that monopolise canopyfree space. When grazers were present at natural densities, elevated nutrients reduced the monopoly of turf-forming algae in favour of foliose algae. These results demonstrate a novel interaction between nutrients (bottom-up control) and grazing pressure (top-down control), which are fundamental to predictions about management of human activities that continue to reduce densities of herbivores and increase nutrient availability on temperate coasts.Bayden D. Russell and Sean D. Connel

Sensitivity of Antarctic Urospora penicilliformis (Ulotrichales, Chlorophyta) to ultraviolet radiation is life stage dependent

The sensitivity of different life stages of the eulittoral green alga Urospora penicilliformis (Roth) Aresch. to ultraviolet radiation (UVR) was examinedin the laboratory. Gametophytic filaments and propagules (zoospores and gametes) released from filaments were separately exposed to different fluence of radiation treatments consisting of PAR (P = 400700 nm), PAR + ultraviolet A (UVA) (PA, UVA = 320400 nm), and PAR + UVA + ultraviolet B (UVB) (PAB, UVB = 280320 nm). Photophysiological indices (ETRmax, Ek, and a) derived from rapid light curves were measured in controls, while photosynthetic efficiency and amount of DNA lesions in terms of cyclobutane pyrimidine dimers (CPDs) were measured after exposure to radiation treatments and after recovery in low PAR; pigments of propagules were quantified after exposure treatment only. The photosynthetic conversion efficiency (a) and photosynthetic capacity (rETRmax) were higher in gametophytes compared with the propagules. The propagules were slightly more sensitive to UVB-induced DNA damage; however, both life stages of the eulittoral inhabiting turf alga were not severely affected by the negative impacts of UVR. Exposure to a maximum of 8 h UVR caused mild effects on the photochemical efficiency of PSII and induced minimal DNA lesions in both the gametophytes and propagules. Pigment concentrations were not significantly different between PAR-exposed and PAR + UVRexposed propagules. Our data showed that U. penicilliformis from the Antarctic is ratherinsensitive to the applied UVR. This amphi-equatorial species possesses different protective mechanisms that can cope with high UVR in coldtemperatewaters of both hemispheres and in polar regions under conditions of increasing UVR as a consequence of further reduction of stratosphericozone