Plankton Air: September 2018

Sunday, September 30, 2018

Sikuliaq researchers find odd, abundant animal-plant plankton in Gulf of Alaska

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Sikuliaq researchers find odd, abundant animal-plant plankton in Gulf of Alaska Fairbanks Daily News-Miner

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Thursday, September 27, 2018

The making of a plankton toxin

A toxic algal bloom clouds open ocean waters.
PHOTO: JAMES R. D. SCOTT/GETTY IMAGES

Phytoplankton are unicellular photosynthetic organisms that occur in vast abundance in the world's oceans. This diverse group of algae is responsible for nearly half of the total global CO₂ fixation and forms the base of the marine food web. However, some phytoplankton taxa produce toxins that can poison marine wildlife and humans. Mass occurrences of such toxic unicellular algae in the plankton occur periodically and are known as harmful algal blooms (see the first photo). For example, the toxic diatom Pseudo-nitzschia (see the second photo) regularly emerges in the Pacific. In 2015, this microalga formed the largest harmful algal bloom ever recorded, which stretched along nearly the entire coast from Alaska to Mexico and caused massive ecologic and economic damage (1). On page 1356 of this issue, Brunson et al. (2) describe the biosynthesis of the toxin domoic acid that is produced by this diatom.

Domoic acid is the causative agent responsible for amnesic shellfish poisoning in humans after eating contaminated seafood. Interest in this toxin increased after 1987, when consumption of blue mussels from Prince Edward Island led to an incident of severe poisoning and human fatalities (3). Single cells of the algae produce only picogram or smaller amounts of domoic acid, but the compound accumulates as it is transferred through the food web. Mussels feeding on the diatoms enrich the toxin without being affected. Fish are also vectors that are not poisoned themselves but transfer the toxin to higher trophic levels.

In humans, domoic acid acts as an analog of the neurotransmitter glutamate in the central nervous system, leading to symptoms that range from nausea and diarrhea, to confusion and other neurological effects, before coma and death (4). As a safety measure, many countries have installed surveillance programs to monitor Pseudo-nitzschia in coastal waters and the domoic acid concentration in seafood; fisheries are shut down and beaches closed at times of contamination. Incidents of domoic acid poisoning of sea lions with more than 400 dead animals further boosted interest in the toxin (5). Seabirds are also affected, and historic samples from the 1960s suggest that the inspiration for Alfred Hitchcock's famous movie The Birds came from crazed animals affected by domoic acid poisoning (6).

The structures of many natural toxins, including that of domoic acid, have been known for decades, but their biosynthesis is not always understood. Knowledge of how nature assembles a complex toxin can facilitate follow-up research. For example, identification of the genes responsible for biosynthesis allows the heterologous expression and modification of a toxin and drug candidate for production in large quantities, or the monitoring of toxin producers in the environment (7). In recent years, we have seen a number of biosyntheses that have been unraveled, including the biosynthetic pathway of the anticancer drug vinblastine and the identification of all enzymes involved in morphine biosynthesis, more than a century after its isolation in pure form in 1895 (8, 9). These breakthroughs have been made possible by the combination of advanced genetic methods, natural product chemistry, and physiological studies.

Brunson et al. use such a combined approach to uncover central steps in the biosynthesis of domoic acid in the harmful alga Pseudo-nitzschia multiseries. The endeavor was based on earlier observations that toxicity of the diatom increases under phosphate limitation and elevated CO₂ concentration. A comparison revealed that the transcription of ∼500 genes increases under phosphate starvation. Transcription of only 43 of these genes also increased under high-CO₂ conditions; the authors used these transcripts to look for domoic acid biosynthetic genes.

The oxidase with the most pronounced increase in transcription was located in a genomic region where additional genes showed up-regulated expression. This clustering facilitated the breakthrough, because it turned out that all these genes were involved in domoic acid biosynthesis. The genes could be expressed in bacteria and yeast; application of tailored synthetic substrates, together with elaborate chemical analysis, led to the assignment of the biosynthesis of isodomoic acid. The authors have thereby uncovered the assembly line for producing an isomer of domoic acid, and in theory, this isomer can be transformed in one enzymatic step to the toxin, but the enzyme responsible is not yet known. Isodomoic acid is formed from two common primary metabolites, the amino acid glutamic acid and a terpenoid precursor geranyl pyrophosphate, in a few steps. The two precursors are first linked via N-prenylation and then further transformed by two oxygenases.

Knowledge of the biosynthetic pathway offers the opportunity to establish screening techniques for genetic sequences that indicate toxin production in plankton samples. These techniques will enable rapid bloom monitoring and environmental consulting. More importantly, the biosynthetic pathway could pave the way to answering scientific questions about this toxin. For example, the sequence opens the opportunity to address how metabolites with structural similarity to domoic acid are synthesized in red algae. Initial screening in these red algae has already revealed oxidases similar those required for domoic acid biosynthesis (2). Also, the observed gene clustering, which is not common in diatoms but widespread in fungi and bacteria, will stimulate evolutionary discussion.

Answering the more fundamental question of why the diatoms produce the toxin is now also within reach. Given that there is no direct ecological connection between mammals or birds and the unicellular algae, toxicity to the top consumers might be considered as collateral damage caused by a compound that has different importance for the unicellular producer. Many studies have been undertaken to evaluate the role of domoic acid in inhibiting competing phytoplankton (3), defending against herbivorous predators (10), or facilitating iron uptake (11). However, findings have been contradictory and do not provide a conclusive picture. Knowledge of the biosynthetic pathway can be used to elucidate domoic acid's function for the diatom by studying the induction of toxin production and by studying the physiological and ecological performance of mutant strains that lack domoic acid biosynthesis genes.

Electron microscopy reveals the silicified cell wall of a *Pseudo-nitzschia* diatom from the Gulf of Naples.
PHOTO: DIANA SARNO AT STAZIONE ZOOLOGICA NAPLES

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Plankton Records celebrate 40 years of existence with two November releases

Thursday 27th September 2018

Plankton Records celebrate 40 years of existence with two November releases

BRITAIN'S long-running independent Christian label, Plankton Records, are releasing on 9th November two titles to celebrate their 40th anniversary. Said Plankton's Keith Dixon, "We are releasing a 20-track compilation album (CD with 12 page book and digital) called 'The Second Twenty Years' which, as the title suggests, features music from our last 20 years 1999 - 2018. We've sneaked in four tracks from before that period which for various reasons we couldn't feature on our 'First 20 Years' album - these include one previously unreleased track. Plankton's founding partner Simon Law has also recorded a brand new song which will close the album and will also be released as a single around 26th October.

"Also on 9th November we are releasing a special 2CD slipcase set (which will also be available digitally) called 'b.6th May 1978. FORTY YEARS 1978 - 2018' which will include the new CD plus the 21 track compilation we released in 1998 to mark our 20th anniversary called 'THE FIRST 20 YEARS'. The slipcase has the strap line 'Celebrating the history and musical journey of Plankton Records' and we think the 41 tracks included do just that. The cover art reflects our original vinyl side labels!"

The opinions expressed in this article are not necessarily those held by Cross Rhythms. Any expressed views were accurate at the time of publishing but may or may not reflect the views of the individuals concerned at a later date.

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Wednesday, September 26, 2018

Manta rays have an unusual mouth filter that resists clogging

Manta rays were built for speed — and to filter feed.

The aerodynamic ocean dwellers efficiently separate plankton from seawater using a previously unknown kind of filtration system that resists clogs and captures tiny bits of plankton, researchers report September 26 in Science Advances.

Mantas are filter feeders, like many other ocean creatures. They pull plankton-laden seawater into their mouths, where arrays of cartilaginous fibers helps them swallow the plankton but release the seawater. For most filter feeders, the process can be compared to straining a pot of pasta and letting the water run through, says coauthor Misty Paig-Tran, a marine biologist at California State University, Fullerton. But for mantas, that analogy doesn’t quite work. Some of the plankton that mantas eat is small enough to slip through the gaps — more like grains of rice than chunky pasta shells. And mantas don’t have sticky filter mucus to snag these small particles, as sponges and bryozoans do.

Paig-Tran and her colleagues took CT scans of several manta ray species specimens from museums, then 3-D printed a replica of the filter found in one species, the giant oceanic manta ray (Manta birostris). The team placed the model filter in a tank filled with dye to track how water and planktonlike particles move through it. Computer programs also helped calculate the trajectories of particles of different sizes.

a close up photo of the mouth of a manta ray

The manta ray’s mouth filter defies convenient kitchen analogies, the team found. The filter is made of a series of long, cartilaginous lobes arranged in parallel, with tiny gaps in between. When water comes into the manta’s mouth, it flows between the lobes forming swirling vortices before eventually swooshing out to exit the ray’s mouth. But bits of plankton, instead of getting sucked into these vortices, ricochet off the lobes back toward the manta’s esophagus, to be swallowed.

Pinballing plankton

A manta ray’s mouth filter is comprised of a series of parallel cartilaginous lobes, shown in this animation, that direct water into turbulent vortices (blue) before flushing it out of the animal’s mouth. But plankton (red dots) doesn’t get pulled into the filter, and instead bounces off the lobes toward the manta’s esophagus, to be swallowed.

an animation showing how plankton keeps from clogging a manta ray's mouth filter

“What's unique about this particular mechanism is that the particles aren't captured by the filter” like they would be in a colander, says coauthor James Strother, a theoretical biologist at Oregon State University in Corvallis. “Instead, they're pushed away from the filter, so it remains clean.”

That’s an advantage for the mantas. “If there's no clogging, they don't have to shut their mouth and try to clean off all these little particles,” Paig-Tran says. Instead, they can eat continuously.

“This system might conceivably enable larger animals to exist in areas with less food ” because it’s energy efficient, says Stuart Humphries, an evolutionary biophysicist at the University of Lincoln in England who wasn’t part of the study.

The strategy could inform better filter designs at wastewater treatment plants, which fail to catch microplastics. A filter inspired by the manta ray’s mouth might trap tiny pollutants before they escape into waterways and harm wildlife.

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Hiu Tutul Mati di Sekitar Kilang TPPI

MATI : Hiu tutul dengan berat sekira 5 Kwintal jadi tontotan anak-anak.

Tuban- Seekor ikan Hiu Tutul dengan panjang kurang lebih tiga meter dan berat lima kwintal ditemukan mati di bibir pantai Desa Kaliuntu, Kecamatan Jenu, Kabupaten Tuban, Jawa Timur, atau sekitar Kilang PT Trans Pasific Petrochemical Indotama (TPPI).

Matinya ikan yang kerab disebut Cucut geger lintang ini, diduga tersangkut jaring nelayan setempat.

"Tadi pagi tahu informasi ada ikan hiu di bibir pantai dari Sosmed, kerena penasaran terus saya datangi," ujar Khistin, kepada suarabanyuurip.com, Rabu (26/9/2018).

Gadis yang menempuh studi di SMKN Manbaul Huda Jenu mengaku, baru pertama kali ini dia bersama dua orang temanya melihat langsung ikan hiu tutul. Selama ini tahunya hanya di televisi, saat ada program selam.

"Ternyata besar sekali ikannya," terangnya.

Di lokasi yang sama, nelayan Dusun Tajung, Desa Kaliuntu, Nurul mengatakan, ikan hiu ini tersangkut jaring milik nelayan Kaliuntu pada Selasa (25/9) kemarin. Melihat ada ikan pemakan plankton, nelayan tak berani melepaskannya di tengah laut.

"Baru sampai di tepi pantai ikan itu dilepas," sambungnya.

Setibanya ikan terbesar di dunia ini menepi, kurang lebih 12 orang berusaha mengangkatnya tapi sia-sia. Sekalipun sudah tercium aroma tak sedap, tapi hingga sekarang ikan dengan nama latin Rhincodon typus menjadi tontonan warga.

Sebatas diketahii, Hiu ini mengembara di samudera tropis dan lautan yang beriklim hangat, dan dapat hidup hingga berusia 70 tahun. Spesies ini dipercaya berasal dari sekitar 60 juta tahun yang lalu.

Cucut geger lintang merupakan hewan terbesar yang masih hidup di dunia, di luar Paus. Ukuran rata-rata hewan dewasa diperkirakan sekira 9,7 meter (31,8 ft) dan seberat sembilan ton.

Sebagai pemakan plankton yang memperoleh mangsanya dengan menyaring air laut, hiu paus memiliki mulut yang berukuran besar, hingga selebar 1,5 meter (4,9 ft) yang berisikan 10 lembaran penyaring dan sekira 300 hingga 350 deret gigi kecil-kecil.

Ikan jenis ini juga memiliki lima pasang insang berukuran besar. Dua mata yang kecil terletak di ujung depan kepalanya yang datar dan lebar. Warna tubuhnya umumnya keabu-abuan dengan perut putih, tiga gigir memanjang terdapat di masing-masing sisi tubuhnya, serta lukisan bintik-bintik dan garis kuning keputih-putihan yang membentuk pola kotak-kotak.

Pola bintik-bintik yang mengesankan sebagai taburan bintang itu bersifat khas untuk masing-masing individu, dan acap digunakan dalam perhitungan populasi.

Kulitnya hingga setebal 10 sentimeter (3,9 in). Sirip punggung dan sirip dada masing-masing sepasang. Pada hewan muda, sirip ekornya lebih panjang yang sebelah atas. Sementara pada hewan dewasa sirip ini lebih berbentuk seperti bulan sabit. (Aim)

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Tuesday, September 25, 2018

Bukan dari Awal, Ini Alasan Paus Biru Bisa Sangat Besar Menurut Ahli

Banyak mamalia darat berukuran besar, sebut saja gajah, badak dan kuda nil. Namun, semua mamalia darat tersebut gak ada yang bisa mengalahkan ukuran mamalia laut. Adapun, mamalia laut yang paling besar sekaligus jadi hewan terbesar di dunia adalah paus biru.

Meski begitu, kamu penasaran gak sih kenapa ukuran paus biru sangat besar? Dilansir dari National Geographic, ukuran paus biru bahkan bisa mencapai 33 meter dengan berat 200 ton! Berikut penjelasan para ahli!

1. Paus berukuran besar karena adaptasi pada zaman es baru-baru ini

Bukan dari Awal, Ini Alasan Paus Biru Bisa Sangat Besar Menurut Ahli

sciencenews.org

Dilansir dari The Atlantic, menurut Nick Pyenson, seorang ahli biologi evolusi di Smithsonian Institution, tubuh raksasa paus berasal dari proses adaptasi pada zaman es baru-baru ini. Itu karena iklim gak menentu sehingga pasokan makanan gak stabil. Paus menjadi besar dan dapat menyimpan banyak cadangan lemak. Selain itu, tubuh yang besar juga memungkinkan untuk bermigrasi. Tujuannya untuk mencari tempat makan terbaik.

2. Lautan memungkinkan hewan untuk mengembangkan tubuh, daripada di daratan

animalsake.con

Masih dilansir dari The Atlantic, lautan membebaskan tubuh mamalia untuk mengembangkan tubuh mereka, yang gak didukung jika di daratan. Selain itu, lautan juga membebaskan mamalia untuk mencari makan di area yang lebih luas. Mereka bisa mencari beraneka ragam makanan, seperti plankton, udang-udangan dan ikan.

3. Paus menjadi besar karena menjaga panas tubuhnya

Lanjutkan membaca artikel di bawah

Editors’ picks

hurriyetdailynews.com

Sementara, menurut William Gearty dari Stanford University paus menjadi besar karena ingin menjaga panas tubuhnya. Saat memasuki air, manusia akan mulai kehilangan panas tubuh, hal berbeda terjadi saat di darat atau udara. Untuk melawannya, manusia akan menggunakan pakaian selam; berang-berang memiliki bulu tebal; sementara paus memiliki lemak.

Gearty menambahkan cara termudah untuk menjaga panas tubuh paus dengan berubah menjadi lebih besar. Karena itu paus mulai mencari, menangkap dan menelan hewan dalam jumlah besar.

4. Fakta menunjukkan bahwa mamalia laut rata-rata memiliki ukuran yang lebih besar

animalsake.com

Bersama tim, Gearty mengumpulkan data dari hampir 7 ribu spesies mamalia, baik yang masih hidup maupun yang telah punah. Data menunjukkan bahwa mamalia laut, seperti paus, lembu laut dan anjing laut masing-masing mencapai massa tubuh rata-rata 500 kg.

5. Namun, paus banyak diburu karena diincar lapisan lemak dan minyaknya

underseahunter.com

Meski menjadi yang paling besar, gak berarti eksistensi paus menjadi aman. Dilansir dari National Geographic, perburuan besar-besaran pada 1900 hingga 1960-an membuat jumlahnya berkurang drastis. Saat ini pun paus biru masuk dalam kategori terancam punah.

Itu tadi fakta-fakta kenapa paus bisa jadi hewan terbesar yang masih hidup hingga sekarang. Meski begitu, keberadaannya terancam karena perburuan liar. Karena itu, yuk dukung terus kampanye antiperburuan hewan, terutama untuk hewan yang hampir punah, seperti paus biru ini.

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Thursday, September 20, 2018

Its My School Tampilkan Yamaha Lexi, Tanpa Canggung Guru dan Murid Skensa Mencoba Ketangguhannya

TRIBUN-BALI.COM, DENPASAR - Kegiatan Yamaha Its My School masih berlangsung.

Kali ini SMKN 1 Denpasar lah yang menjadi tuan rumahnya.

Namun, berbeda dari kegiatan sebelumnya, kegiatan kali ini diadakan berbarengan dengan acara serangkaian perayaan HUT ke-56 Skensa.

Saat Tribun-Bali.com tiba di sekolah tersebut, siswa sudah berkumpul di lapangan basket.

Saat itu sedang berlangsung lomba LKBB yang diadakan oleh ekstrakurikuler Pramuka.

Para siswa antusias menanti tim dari kelasnya untuk berlaga di lapangan yang disaksikan oleh seluruh komponen sekolah itu.

Di tengah-tengah perlombaan, para siswa dihibur tim teater sekolah yang namanya sudah tak asing, yakni Teater Sangsaka.

Kali ini Sangsaka hadir dengan suguhan pentas pantomimnya.

Kelucuan tokoh kartun Spongebob, Mr. Crab, dan Plankton mampu meneduhkan suasana siang yang panas itu.

Selanjutnya, para siswa diperbolehkan mencoba Yamaha Lexi yang dibawa oleh pihak Yamaha.

Para siswa bahkan guru-guru tanpa malu-malu mencoba motor baru keluaran Yamaha ini.

Menurut Sales, Yamaha DDS, Ni Komang Juliani, Lexi punya beberapa fitur menarik, di antaranya menggunakan lampu LED, spidometer yang full digital, ada jam digital, bagasi yang luas, dan menggunakan sistem blue core.

“Ini N-Max baru buat perempuan karena didesain lebih ramping. Jadi kalau ibu guru bawa barang banyak, bisa ditaruh di depan,” ujarnya. (*)

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Wednesday, September 19, 2018

Mirip Alien, Makhluk Laut Apakah yang Terdampar di Selandia Baru?

KOMPAS.com - Keluarga Dickinson tak sengaja menemukan gumpalan berwarna merah muda aneh yang menyerupai gunung berapi saat sedang jalan-jalan di pantai Auckland Utara, Selandia Baru, pada Senin lalu.

Bukan alien menyerupai gunung berapi, makhluk itu ternyata adalah spesies ubur-ubur besar dengan ruas-ruas putih mengelilingi senter berwarna merah.

"( Ubur-ubur) ada di mana-mana dan itu sungguh mengagumkan. Kemudian kami melihat seekor (ubur-ubur) yang berbeda dari lainnya," ujar saksi mata Eve Dickinson kepada Auckland Now.

"Kami menghabiskan waktu cukup lama untuk mengamati mereka, karena bentuk dan warnanya yang cantik. Anak saya berkata, (ubur-ubur) ini mengingatkannya pada gunung berapi," imbuhnya.

Suami Eve Dickinson pun menuturkan bahwa ubur-ubur itu sempat berdenyut. "Mirip seperti otot yang berkontraksi," ujar suami Eve, Adam Dickinson kepada Yahoo7.

Ubur-ubur surai singa

Dalam laporan Science Alert Rabu (19/9/2018), ubur-ubur yang ditemukan keluarga Dickinson adalah ubur-ubur surai singa (Cyanea capillata).

Ubur-ubur C. capillata juga dikenal sebagai ubur-ubur raksasa atau ubur-ubur rambut jeli. Spesies ini lebih mudah dikenali saat mengambang di bawah air.

Di bagian bawah puncak jamurnya, terdapat beberapa helai tipis yang membentuk tentakel jeli. Namun, saat ubur-ubur C. capillata terdampar di pantai, bentuknya menjadi pipih mirip alien.

Ubur-ubur surai singa merupakan ubur-ubur yang dapat hidup di seluruh dunia, mulai dari Arktik sampai Australia dan Selandia Baru.

Diameter tubuhnya umumnya sekitar 50 sentimeter. Namun ahli pernah menemukan ubur-ubur surai singa dengan diameter 2,3 meter pada tahun 1870 di Teluk Massachusetts, Samudra Atlantik.

Ahli biologi kelautan Diana Macpherson dari National Institute of Water and Atmospheric Research, Selandia Baru, mengatakan bahwa populasi ubur-ubur surai singa sangat umum di sekitar pulau, tapi tidak saat akhir musim dingin.

"Mereka (ubur-ubur) biasanya ada di sekitar pulau selama musim semi dan musim panas karena bertepatan dengan mekarnya plankton, jadi mereka (ubur-ubur) datang," jelas Macpherson.

"Ketika musim itu tiba, mereka datang dan menggunakan tentakelnya untuk menangkap segala sesuatu. Mereka bisa memperoleh banyak makanan sekaligus," ujar Lisa-Ann Gershwin seorang ahli biologi kelautan dari Commonwealth Scientific and Industrial Research Organisation Australia dalam wawancara dengan Wired tahun 2014.

Saat suhu berubah karena perubahan iklim, makhluk unik ini mungkin mulai muncul di saat tak terduga sepanjang tahun.

Makanan yang paling disukai ubur-ubur surai singa adalah plankton dan ubur-ubur kecil yang didapat saat mengapung di lautan.

Mereka juga berperan sebagai oase bagi para ikan kecil dan udang yang kebal terhadap racunnya, sehingga bisa memakan sisa makanan ubur-ubur.

Kemudian, ubur-ubur surai singa diincar oleh ikan besar dan penyu belimbing sebagai santapan.

Meski bentuknya sangat menarik, para ahli menyarankan untuk tidak memegang mereka bila kita menemukannya di pantai.

Meski sengatannya tidak menyebabkan kerusakan serius, tapi tetap saja rasanya sakit.

"Mereka memiliki racun di tentakel yang menyakitkan bila kita terlalu dekat dengan mereka. Perlakukan mereka dengan hati-hati," tutup Macpherson.

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