#zooplankton ecology

[bethanythebogwitch]

Wet Beast Wednesday: arrow worms

Get ready for a wriggly Wednesday, because we have wormsign! When people think of animals, we tend to think of things like dogs, cats, elephants, and so on. However, animals like that are actually on the large side, most animals are much smaller. There are whole ecosystems out there filled with creatures so small you wouldn't even notice them unless you were looking. And any ecosystem needs a predator. This is where arrow worms come in, the apex predators of the planktonic realm.

(Image: a microscope image of an arrow worm. It is an elongated, tube-shaped animal with fins on either side and a small tail fin. The animal is a translucent white and organs are visible through the skin. Next to it are a measuring instrument and a small crustacean. End ID)

Arrow worms are members of the phylum Chaetognatha, which means "bristle jaw". They used to be thought of as their own thing with no surviving relatives, but they have recently been grouped together with rotifers and other tiny animals in a clade called Gnathifera. You know how there's no such thing as a fish because all the different things we call fish are actually really distinct from each other? Yeah, it's even worse for worms. At least most things we call fish are all in the same phylum. Arrow worms are in a completely different phylum from roundworms, flatworms, proboscis worms, segmented worms, etc, but most people just lump them all together as worms. Arrow worms are really small, the largest species getting to about 10 cm long and most being considerably smaller than that. They have torpedo-shaped bodies with external fins that are the source of the name. People thought they looked like the fletching on arrows. Most species are transparent, but some deep-sea species are orange.

(Image: the front end of an arrow worm seen biting a larval fish. The fish is translucent and skeletal. The worm has sharp bristles at the bout that are gripping the fish. End ID)

Arrow worms have three body segments, the head, trunk, and tail, divided from each other by internal membranes. The outside of the body is protected by a tough but flexible cuticle. The head is elongated and at the tip is the mouth. On either side of the mouth 4 - 14 curved spines that are attached to flexible muscle. The spines are used to grab prey and move it into the mouth. In some species, the spines can inject neurotoxin into prey to help kill it. When not in use, the mouth and spines are covered by a membrane to help streamline the animal. The mouth leads to a muscular pharynx (throat) that uses mucus to help food pass into the intestine, where the food is digested. I have found sources that say the intestine leads to an anus and other sources that say that arrow worms have no anus and excrete their waste through the skin. Most sources go with the worms having no anus. Also on the head are a pair of compound eyes (which are reduced or absent in some deep-sea or cave species) and a ring of cilia that probably sense chemicals. All over the body are bristles that sense the movement of the water. The nervous system is very simple and is centered on a nerve ring that circles the pharynx and leads out to the rest of the body. Arrow worms have no respiratory system, they absorb dissolved oxygen through the skin. The circulatory system is very simple. Arrow worms have a pair of lateral fins on either side of the body and a tail fin post-anus. Arrow worms are also one of the few animals species that act as host for giant viruses.

(Image: an image of an arrow worm with the organs and body parts labeled. Sourced from Wikipedia. End ID))

Arrow worms are simultaneous hermaphrodites, meaning they possess male and female sex organs at the same time. The male gonads develop first, making them protandric. The testicles are located at the base of the neck. Sperm is placed in a capsule called the spermatophore and ejected from the body at an organ called the seminal vesicle. During mating, each partner puts a spermatophore on the other's back. The spermatophore then releases sperm, which swim down a groove on the back to reach the oviduct, where eggs are released from the ovaries, along the tail. Fertilization happens either as the eggs are released or just after. Most species release their eggs to the water, but some will attach them to algae or carry them in a pouch on the back. Most arrow worms are semelparous, meaning they mate only once then die. Unusually for marine invertebrates, arrow worms do not have a larval stage. The offspring are miniature adults. The maximum observed lifespan for an arrow worm was 15 months.

(Image: an electron microscope image of the head of an arrow worm. The mouth is wide and has the scythe-like bristles emerging from either side. The head is attached to a long neck that is narrower than the mouth. End ID)

Arrow worms live worldwide in every marine habitat, including the deep sea and caves. Of all the marine zooplankton, only copepods have a greater global biomass. Most species are swimmers, but about 20% of known species live on the seafloor. They are ambush predators, moving slowly or staying still until prey comes within range, then darting forward to catch it. Arrow worms have the fastest muscle contractions of any animal, which helps with their quick charges. To swim, they wriggle their bodies up and down. A common swimming pattern is to swim upwards then glide downwards, over and over again. Pelagic species are known to practice diel vertical migration, a mass migration of countless species of animal that migrate to shallow water at night, then back to deep water in the day. Juveniles tend to live in shallower water than adults and larger species are generally found in colder water. Their primarily prey is copepods and water fleas, but they will also eat amphipods, krill, and the eggs and larvae of fish and invertebrates. Some species are cannibalistic. Some reports indicate certain species may be omnivores who also feed on algae and organic detritus. Arrow worms are a crucial food source for many larger animals, including commercially important species. Not a lot is known about their natural behavior as it is hard to simulate their conditions in the lab and hard to observe them in the wild.

(Image: the head of an arrow worm emerging from off-screen. The mouth is open and a copepod is in the process of being consumed. End ID)

[lake-lady]

Zooplankton are tiny crustaceans that occupy a variety of roles in Great Lakes food webs, from open water filter feeding to benthic decomposers 🩵

[cuicuit]

Cyclops and its nauplius (x50)

A common specie of freshwater copepod, microscopic crustaceans which compose an important part of fresh-water zooplankton.

Their name is due to the fact that they have only one eye (a red point in front of their body, between their two front legs). They eat paramecies and are eaten in large quantities by baby fishes (as other zooplaktons, they reproduce very quickly so the population is stable). The nauplius (picture on the right) is the larva stade of the cyclops.

[temeraire]

i wish i was eating zooplankton like a tiny livebearing fish fry

[guardian-of-local-forest]

Leptodora kindtii looks like a menace. and it IS a menace. it makes Daphnia so stressed that their next generation has "helmets".

[preservationofnormalcy]

Ok, so, I just got introduced to the paranormal, it's a lot to take in, but I have a question that I haven't been able to find any answers on from sources familiar with the supernatural.

Is the Antarctica really that barren past the coasts? My good pal (who I just found out is a fairy or something similar) has no clue.

I've always had a deep-seated interest in the place and a desire to go there, but I want to know if there's gonna be anything inland besides ice and wind.

Anything? You mean besides a thriving polar desert and underwater ecosystem, with a remarkably intact food web and very little sapient interference?

There's phyto and zooplankton, fish, krill, the penguins and squid that eat them, the seals and whales that eat them...

Just because it's not hospitable to most humanoid sapients, people write it off as being nothing but ice and wind! Ughhh, anthropocentrism really boils my kra'thak! And that's not even getting into the complex ecological and social interactions of Cryptid species like the Outsider Penguins, or Ice Ghosts...

And of course, the Sovereign of Antarctica.

Well, obviously the Sovereign of Antarctica.

[thecreaturecodex]

Trunko

“New Trunko Design” © deviantArt user Kryptid, accessed at his gallery here

[The appearance of a sea monster on the shore of Margate, South Africa, attracted some press attention at the time. The Daily Mail covered it, and from there the story appeared in Charles Fort’s Lo! , where he dismissed it as a hoax. When Charles Fort thinks your paranormal phenomenon is a hoax, you know it’s built on flimsy evidence. The Margate Monster gained popularity, and its current name, in the writings of Karl Shuker, who resurfaced the story and put it into several popular books (like 1996′s The UneXplained, which is where I first heard of it). To his credit, Shuker continued to do research and follow up on the story, and when photographs appeared (as opposed to just reprints of the article), he was savvy enough to recognize the actual Trunko as a globster, the catchall category of mutilated carcasses interpreted as sea monsters.

Pathfinder already has globsters, but I wanted to make a Trunko that represented the fantastical creature alive, if it were actually some sort of hairy white sea elephant. My concept draws on Opabinia (my favorite Cambrian weirdo) and the orangutan crab]

Trunko CR 5 N Vermin This creature looks something like a furry whale, except that it has rippling fins running along its sides instead of separate limbs. It has a paddle-like tail at one end, and at the other, a short but very flexible trunk ending in a clasper.

A trunko is a large aquatic invertebrate found in cold seas. They are related to anomalocarids and opabinias, with a trunk like structure used to pull food into an underslung mouth. They eat primarily zooplankton, which they gather by literally swimming through their masses. The hairs covering a trunko’s body are sticky, and the trunko can groom itself at its leisure to remove and consume the various marine invertebrates glued to it. These hairs also act as a defensive mechanism, gumming the jaws of sharks and orcas.

Trunkos are social creatures who live in mixed-sex pods. They are ovoviparous, carrying eggs internally that hatch to release free-living young. The young are born sticky, and can feed themselves almost immediately, but remain in their own pods until full grown. The undulating fins of a trunko allow it remarkable dexterity in the water, and they often live in areas with strong winds and currents, too choppy for ships to sail through easily. As such, they are rarely seen by landlubbers and have something of a mythical air.

Trunko CR 5 XP 1,600 N Huge vermin (aquatic) Init +4; Senses darkvision 60 ft., Perception +6 Defense AC 18, touch 12, flat-footed 14 (-2 size, +4 Dex, +6 natural) hp 67 (9d8+27) Fort +9, Ref +7, Will +5 Immune vermin traits Defensive Abilities sticky Offense Speed swim 60 ft. Melee slam +10 (1d8+9) Space 15 ft.; Reach 10 ft. Statistics Str 23, Dex 19, Con 16, Int -, Wis 15, Cha 6 Base Atk +6; CMB +14; CMD 28 Skills Perception +6, Swim +18; Racial Modifiers +4 Perception, +4 Swim Ecology Environment cold aquatic Organization solitary, pair or shoal (3-12) Treasure none Special Abilities Sticky (Ex) A trunko’s body is covered in thousands of sticky hairs. Any creature coming into contact with a trunko must succeed a DC 17 Reflex save or be smeared with glue, being entangled for 1d4+1 rounds. This glue is sticky in air, salt and fresh water, but a pint of strong alcohol dissolves it. The save DC is Constitution based.

[rjzimmerman]

Excerpt from this story from Inside Climate News:

Just last year wildfires generated over 2.1 billion metric tons of carbon dioxide emissions around the globe. That’s the equivalent of driving 500 million gas-powered cars around for a year, according to the EPA. With the wildfire season burning its way through this summer, several research groups are now working to demonstrate one small plant species’ ability to offset some of those pollutants.

Tiny phytoplankton thrive on the surface of oceans, estuaries and rivers across the globe. They’re first on the menu for zooplankton and small fish. But aside from supporting the food chain, these nearly invisible organisms also take on a major mission: carbon dioxide sequestration that boosts the oceanic carbon sink effect. Their behavior serves as a buffer against the effects of natural and human-driven climate change, reducing the dangerous levels of carbon emissions building up in the atmosphere. 

Phytoplankton interact with an aerosol called black carbon, a dark and very fine particulate commonly known as soot. Black carbon is a pollutant released by burning fossil fuels, biomass and wood. It’s associated with increased risk of asthma and a range of respiratory diseases, said Will Barrett, senior director of nationwide clean air advocacy with the American Lung Association.

But black carbon does have one saving grace: It’s rich in iron and nitrogen, of which certain phytoplankton species are in desperate need.

“Those are nutrients that they require, and often they don’t have enough of them in the ocean,” said David Hutchins, a professor of marine and environmental biology whose lab focuses on phytoplankton behavior. His team recently published a paper in the journal Nature Geoscience that lays new groundwork for how global warming affects different phytoplankton populations. 

Large forest fires can emit anywhere from 40 to 250 million metric tons of black carbon a year, said Rodrigo Riera, an associate professor of marine sciences and author of a separate paper examining wildfire ecology. These emissions can take days or weeks to reach a nearby ocean. But the consequences of such fires can affect local ecosystems for months, as they did with the massive Australian wildfires in 2019 and 2020 that burned through 59 million acres of land. 

It’s situations like these where phytoplankton thrive. Researchers studying the wildfires that covered the northern portion of the Indo-China peninsula in March of 2019 recently found that the fires released 430,000 metric tons of carbon. Of that amount, 64 metric tons were black carbon aerosols that traveled eastward in a matter of days, settled into the Pacific Ocean and turned into fodder for hungry phytoplankton. 

With enough nutrients from black carbon, phytoplankton colonies grew and started capturing more of the other carbon particulates that reached the ocean. The study predicted that of all the carbon dioxide emissions released from those March wildfires, phytoplankton helped the ocean absorb and tuck away over half that amount by turning it into the solid carbon they need to survive.

[mariacallous]

For nearly a year now, a bizarre heating event has been unfolding across the world’s oceans. In March 2023, global sea surface temperatures started shattering record daily highs, and have stayed that way since.

You can see 2023 in the orange line below, the other gray lines being previous years. That solid black line is where we are so far in 2024—way, way above even 2023. While we’re nowhere near the Atlantic hurricane season yet—that runs from June 1 through the autumn—keep in mind that cyclones feed on warm ocean water, which could well stay anomalously hot in the coming months. Regardless, these surface temperature anomalies could be triggering major ecological problems already.

“In the tropical eastern Atlantic, it’s four months ahead of pace—it’s looking like it’s already June out there,” says Brian McNoldy, a hurricane researcher at the University of Miami. “It’s really getting to be strange that we’re just seeing the records break by this much, and for this long.”

You’ll notice from these graphs and maps that the temperature anomalies may be a degree or two Celsius warmer, which may not sound like much. But for the seas, it really is: Unlike land, which rapidly heats and cools as day turns to night and back again, it takes a lot to warm up an ocean that may be thousands of feet deep. So even an anomaly of mere fractions of a degree is significant. “To get into the two or three or four degrees, like it is in a few places, it’s pretty exceptional,” says McNoldy.

So what’s going on here? For one, the oceans have been steadily warming over the decades, absorbing something like 90 percent of the extra heat that humans have added to the atmosphere. “The oceans are our saviors, in a way,” says biological oceanographer Francisco Chavez of the Monterey Bay Aquarium Research Institute in California. “Things might be a lot worse in terms of climate impacts, because a lot of that heat is not only kept at the surface, it’s taken to depths.”

A major concern with such warm surface temperatures is the health of the ecosystems floating there: phytoplankton that bloom by soaking up the sun’s energy and the tiny zooplankton that feed on them. If temperatures get too high, certain species might suffer, shaking the foundations of the ocean food web.

But more subtly, when the surface warms, it creates a cap of hot water, blocking the nutrients in colder waters below from mixing upwards. Phytoplankton need those nutrients to properly grow and sequester carbon, thus mitigating climate change. If warming-induced stratification gets bad enough, “we don’t see what we would call a ‘spring bloom,’” says Dennis Hansell, an oceanographer and biogeochemist at the University of Miami. “Those are much harder to make happen if you don’t bring nutrients back up to the surface to support the growth of those algae.”

That puts serious pressure on an ecosystem that depends on these phytoplankton. Making matters worse, the warmer water gets, the less oxygen it can hold. “We have seen the growth of these oxygen minimum zones,” says Hansell. “Organisms that need a lot of oxygen, they’re not too happy when the concentrations go down in any way—think of a tuna that is expending a lot of energy to race through the water.”

In addition to plankton dealing with ever-higher temperatures due to global warming, there’s also natural variability to consider here. Less dust has been blowing off the Sahara Desert recently, for example. Normally this plume wafts over to the Americas, forming a giant umbrella that shades all that Atlantic water. But now the umbrella has partially folded up, allowing more of the sun to beat down on the ocean.

Weirder still, another contributing factor to ocean warming might be the 2020 regulations that drastically reduced the amount of sulfur allowed in shipping fuels. “Basically overnight, it cut this aerosol pollution by about 75, 80 percent,” says Robert Rohde, lead scientist at Berkeley Earth, a nonprofit that gathers climate data. “That was a good thing for human health—the air pollution was toxic.”

But sulfur aerosols attract water vapor, meaning that previously those ships would produce clouds in their wake—known as ship tracks—which, similar to Saharan dust, would bounce some of the sun’s energy back into space. “Now that we’ve cut it back, it has the side effect that some of that air pollution—that marine smog, if you might—is no longer there,” Rohde says. “The sky is clearer, so a little bit more sunlight is coming through.” Thus shipping regulations may have contributed a little bit of ocean warming in heavily trafficked areas like the North Atlantic. (In the graph above, the solid black line again shows 2024’s temperatures, this time specifically in the North Atlantic. Orange is 2023.)

Over in the Pacific, an El Niño band of warm water formed last summer and is now waning, both accounting for a good chunk of ocean warming globally and adding heat to the atmosphere to influence weather around the world. El Niño is now waning. The phenomenon and its counterpart La Niña—a band of cold water in the same area—are perfectly natural, but now they’re happening on top of that warming of the oceans that humans are responsible for. “One of our challenges,” says Chavez, “is trying to tease out what these natural variations are doing in relation to the steady warming due to increasing CO2 in the atmosphere.”

Now check out the graph above, which shows sea surface temperature anomalies since the late 1800s. Things really started warming up in the 1980s, but notice the red spikes well before, in the early 1940s. That’s associated with El Niños, says Chavez, showing just how powerful the events can be in influencing global ocean temperatures.

Still, sea surface temperatures started soaring last year well before El Niño formed. Also, independent of that band of warm water in the Pacific Ocean, the Atlantic Ocean has been boiling, as you can see in this map of January’s temperature anomalies relative to the mean between 1910 and 2009. “The Atlantic has been record-breakingly warm since early March of 2023,” says McNoldy. “It’s not even close. That’s kind of the head-scratcher: Will it ever be back to just normal record-breaking instead of record-crushing? It’s just kind of crazy.”

If you know that a warm ocean fuels Atlantic hurricanes, you might be wondering whether we’re now in danger of a cyclone forming in February. But worry not. “There are quite a few ingredients that hurricanes need, and warm ocean temperatures is just one of them,” says McNoldy. For one, the low wind shear that hurricanes require to form isn’t there yet. But, McNoldy adds, when those conditions do appear, they’ll take advantage of that warm ocean. “We actually did see that a year ago with two named storms, Brett and Cindy, both in June in the middle of the tropical East Atlantic, which is incredibly odd,” he says. “We were also looking at extremely warm ocean temperatures out there, where normally they would have been a little too cool.”

Last week, the US Climate Prediction Center put the odds of La Niña developing between June and August at 55 percent. Whereas El Niño tends to create wind shear in the Atlantic, which beats down hurricanes, La Niña reduces wind shear. “All other things being equal, La Niña acts to enhance Atlantic hurricane activity,” says McNoldy. “When you have that influence on top of a very warm ocean, it’s probably cause for some concern.”

[ekaijsl]

2023年日本陸水学会若手の会を開催しました

2023年10月13日に、日本陸水学会大分大会の自由集会にて若手の会を開催しました。今年度は4年ぶりの対面開催となり、コロナ禍で交流が制限されていた若手の皆様に気軽な交流の場を提供できればと集会を企画しました。

当日は27名と例年以上に多くの方が発表をしてくださり、生物や化学分野にわたる複合分野の陸水学らしく、対象・フィールド・アプローチのいずれも多様な演題が集まりました。心より御礼申し上げます。

当日は聴講参加の方も多くいらしてくださり、30名を超える方にご参加をいただきました。

今回はありがたいことに大変多くの方にご参加いただいたため、自由集会中に議論の時間を十分に設けることができませんでしたが、ほとんどの方が懇親会にもご参加下さり、対面開催を存分に活かした交流をすることができました。

ご参加いただいた皆様のご協力なしには、このような活発な交流を実現することはできませんでした。改めて心より御礼申し上げます。お忙しい中、本当にありがとうございました。

オンライン開催にはオンライン開催の良さがあると思いつつ、やはり対面での交流は楽しいと強く実感した回となりました。

次回の熊本大会でもお会いできますと幸いです。

また、E会では企画運営に携わってくださる方を募集しています。ご興味のある方はぜひお知らせください。

＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿

2023年　日本陸水学会若手の会　実施概要

日時：2023年10月13日 16:00 ~ 18:00

会場：ホルトホール大分

参加者所属：東北大学、横浜国立大学、富山県立大学、Kyung Hee University、奈良女子大学、滋賀県立大学、海洋研究開発機構、東京大学、神戸大学、兵庫県立大学・姫路科学館、信州大学　ほか（敬称略）

プログラム：

16:00 ~ 16:02      鈴木 碩通（東北大）         趣旨説明・案内

16:03 ~ 16:06      鈴木 碩通（東北大）         水中のハイエナ？ 行動実験で分かったケンミジンコ類の新たな餌利用様式

16:07 ~ 16:10        伊藤 青葉（東北大）           環境DNAを用いた魚類分布推定法の開発

16:11 ~ 16:14        笠原 剛樹（東北大）           植物プランクトン群集を対象とした動的結合ネットワークのアグリゲーション

16:15 ~ 16:18        中西 博亮（横浜国大）      色づいた雪に棲む特殊な微生物たち

16:19 ~ 16:22        仲才 香鈴（横浜国大）      ダム湖におけるコットンストリップを用いた有機物分解能の測定

16:23 ~ 16:26        Duangmany Phongsa（横浜国大）  The Role of Fungi on Decomposition of Large Algae

16:27 ~ 16:30        高階 眞丈（横浜国大）      青森県八甲田山における彩雪現象：緑雪や赤雪の色の違いは何の違い？

16:31 ~ 16:34        田中 駿（横浜国大）           湖面カメラを用いた高頻度モニタリング手法の検討〜花粉編〜

16:35 ~ 16:38        高江洌 鈴奈（横浜国大）  淡水湖の琵琶湖にいる海浜性のトビムシの起源を探る。

16:39 ~ 16:42        米山 貴将（富山県大）      餌環境によるカブトミジンコの生活史特性とろ過スクリーン面積への影響

16:43 ~ 16:46        Hye-Ji Oh（Kyung Hee Univ.）        How to use zooplankton quantitative information more effectively in lentic ecosystem surveys and assessments

16:47 ~ 16:50        Yerim Choi（Kyung Hee Univ.）      Ecological role of artificial water channel in fish diversity and food web structure

16:51 ~ 16:54        Dae-Hee Lee（Kyung Hee Univ.）  Monitoring of isotope trophic level of redlip mullet(Planiliza haematocheilus)

16:55 ~ 16:58        Geun-Hyeok Hong（Kyung Hee Univ.）        The effect of tributary species composition on mainstream fish biodiversity

16:59 ~ 17:02        原 直子（奈良女子大）      ダム下流域で働く濾過食者の仕事

17:03 ~ 17:06        中村 萌（奈良女子大）      伝統的河川工法が創った一時的水域に棲んでいる底生動物

17:07 ~ 17:10        藤田 安優（奈良女子大）  コサナエTrigomphus melampus種特異的プライマーの開発と生息地調査への適用

17:11 ~ 17:14        宇留賀 千佳（奈良女子大）伝統的河川工法聖牛によって生じた一時的水域に生息するプランクトン群集

17:15 ~ 17:18        Deb Soumya（滋賀県大）  Algae: A form of blessings to mankind

17:19 ~ 17:22        Amare Mezgebu Alamrew（滋賀県大）　Food quality of Arthrospira for Daphnia magna

17:23 ~ 17:26        ツジ ジャクソン（海洋研究開発機構）           Studying Canadian lakes as a gateway to inter-disciplinary and inter-cultural science!

17:27 ~ 17:30        板倉 拓人（東京大）           トビケラが纏う装飾の機能

17:31 ~ 17:34        山崎 駿（東京大）               ナベブタムシの空間分布を左右する生息地の連結性

17:35 ~ 17:38        國政 祐太（神戸大）           河川横断構造物とニホンウナギ

17:39 ~ 17:42        宮下 直也（兵庫県大・姫路科学館）               播磨地域のため池における溶存二酸化炭素・溶存無機炭素観測

17:43 ~ 17:46        竹中 將起（信州大）           分子マーカーを用いた河川昆虫の研究

17:47 ~ 17:50        大川 晴菜（奈良女子大）  河床間隙水域と環境DNA

17:51 ~ 17:54        大竹 裕里恵（東北大）      画像解析による動物プランクトンの自動種判別：システム構築中に出会う多様なプランクトン

18:45 ~ 20:45        懇親会

日本陸水学会若手の会企画者

鈴木碩学　中西博亮　大竹裕里恵

[auroraborus]

Something about the alphabet completionist blog scratches an itch in the back of my head. I love all the weird little theme blogs returning to Tumblr like zooplankton repopulating and cleaning coastal waters after an ecological disaster. Tumblrinas are upturning the sediment of old posts and bringing nutrients back into the food chain like a bunch of queer little isopods and worms

[evoldir]

Fwd: Job: Berlin_Germany.GlobalChangeEvolution

Begin forwarded message: > From: evoldir@evol.biology.mcmaster.ca > Subject: Job: Berlin_Germany.GlobalChangeEvolution > Date: 10 September 2024 at 05:28:26 BST > To: rdmpage@gmail.com > > > The Department of Evolutionary and Integrative Ecology at the Leibniz > Institute of Freshwater Ecology and Inland Fisheries (IGB) in Berlin > invites applications for a tenure track group leader position on Global > Change Evolutionary Ecology. The new group leader is expected to start > a research program on global change evolutionary ecology contributing to > a mechanistic understanding of responses to environmental change through > trait-based analyses. A zooplankton focus is preferred but we are open to > applicants working on other aquatic organism groups. The expected research > program involves experimental work on trait changes through evolution, > epigenetics, or plasticity, combined with analyses of field data and > potentially modelling. This position fits in the strategic development > of IGB to empower its capacity for predictive ecology, through a better > mechanistic understanding of the structure and functioning of freshwater > systems, informing projections on future scenarios and its implications > for the distribution and abundance of organisms, and for using mechanistic > insights to optimize management of our freshwater resources. > > > Your role > >  *   Development of an independent research group on evolutionary >      and trait-based ecology of freshwater invertebrates, testing >      ecological theory and novel concepts in the ecology of lakes >      and ponds. >  *   Analysis of global change responses of freshwater ecosystems, >      ideally with a focus on zooplankton and their abiotic and biotic >      interactions. >  *   Linking trait-based mechanistic insights to management of standing >      waters and future scenario development. >  *   Participation in and further development of IGB’s long-term >      monitoring program of lakes. >  *   A creative and cooperative integration into the research of IGB, >      especially with groups working on microbial ecology, plankton, >      fish and lake ecosystem ecology, and modelling. >  *   A proactive collaboration to use the regional research >      infrastructure from small-scale incubators or mesocosms to >      artificial pond systems or IGB’s LakeLab

[lake-lady]

Deep in my love/hate relationship with R.....

[tutoroot]

What are the Limitations of Ecological Pyramids? 

A graphical depiction of the relation between various living species at different trophic levels is an ecological pyramid. The pyramid of numbers was invented by Charles Elton. Later, G.Evylen Hutchinson and Raymond Lindeman proposed the energy or production pyramid.  

These pyramids are genuine pyramids, with the base being the broadest and being covered by the lowest trophic level, i.e., producers. The next trophic level, i.e., the primary consumers, occupies the next level, and so on.  

All calculations for the creation of these sorts of ecological pyramids must take all the organisms into consideration at a certain trophic level since a sample space of a few numbers or a few species will result in a high degree of inaccuracy. 

Importance of Ecological Pyramids 

An ecological pyramids demonstrates how effectively energy is transported from one level to the next and aids in quantifying energy in a food chain.  

This pyramid also demonstrates how different creatures in different ecosystems feed on one another, highlights their dietary patterns, and illustrates the relationship between the many layers inside it.  

The ecological pyramid also aids in monitoring an ecosystem’s general health and condition and in restoring equilibrium. It also aids in understanding how additional harm to an environment might be avoided.  

Types of Ecological Pyramids 

There are three types of ecological pyramids.  

Pyramids of Number 

The number of creatures in each trophic level is considered a level in this form of ecological pyramid. Except in rare cases, such as the detritus food chain, where numerous creatures feed on a single dead plant or animal, the number pyramid is normally vertical.  

Pyramid of Biomass 

The total mass of living creatures in a population present at a given moment and location is represented by biomass. The biomass pyramid illustrates the biomass of an ecosystem’s different trophic levels, grouped in the shape of a pyramid, with the lowest trophic level at the bottom and rising further up. Except in extreme circumstances, the pyramid is upright, such as in the ocean, where the quantity of phytoplanktons is fewer than the number of zooplanktons that rely on them.  

Pyramid of Energy 

The energy pyramid is the only form of an ecological pyramid that is always upright since energy transfer in a food chain is always unidirectional. In addition, when trophic levels rise, some energy is wasted in the environment.  

Limitations of Ecological Pyramids 

The ecological pyramid ignores saprophytes and regards them as inconsequential in the ecosystem, even though they play a critical role in maintaining environmental equilibrium.  

This pyramid makes no mention of diurnal or seasonal fluctuations; the idea of climate or seasons is totally absent.  

The ecological pyramid is only valid in the scenario of simple food chains, which are uncommon in and of themselves.  

The ecological pyramid also does not explain the notion of a food chain.  

This pyramid makes no mention of the rate of energy transfer from one trophic level to the next.  

Important sources of energy, such as trash and humus, are largely neglected in the ecological pyramid, despite their immense value in the ecosystem.  

The presence of the same species at different levels of a pyramid is not considered.  

To know more about ecological pyramids and other topics in Biology, enroll in Tutoroot Biology classes. Our experienced faculty will help you improve your grades with exclusive personalized one on one classes. 

[sapling-hoshii]

Sapling's Creator Diary #1: Dive Into Naiadeus!

Hi, this is Sap from FanonMonsterHunter! Kicking things off with my first Creator Diary entry, I want to cover my favorite FanonMH Elder Dragon OC, Naiadeus - the Chorus of Calamity!

Before I give you, the reader, a peek into the creation of Naiadeus, let's learn more about this gigantic Elder Dragon, its abilities, and its role in the story of my Monster Hunter Stories fan project.

What is Naiadeus?

Naiadeus is the final boss and the main antagonistic force of my fan project's "Expansion DLC" of sorts, which is entitled Chorus of Calamity. It is a gigantic Elder Dragon, around the size of Zorah Magdaros, which lives in temperate, oceanic habitats. Filling a similar niche to our world's baleen whales, these massive Elder Dragons feast on vast quantities of zooplankton via filter-feeding. While usually docile, these marine giants experience drastic behavioral changes every 100 years--their mating season. This is where Naiadeus become massive ecological threats; their ear-splitting roars, howls, and calls are known to destroy and cleave islands and even countries. One such instance of this dangerous behavior can be found deep within the Guild's records, wherein a mating Naiadeus pair's calls split the country of Nievella in half, with the latter chunk breaking into smaller islands and forming into the archipelagic region known in the present day as the Shattered Lands. These roars also emit certain sound frequencies, which only Monsters could hear. Any creature unfortunate enough to hear Naiadeus' terrifying calls is driven into a rabid frenzy, which may threaten local settlements and wildlife. If the threat of landmasses getting destroyed and berserk wildlife wasn't enough: Naiadeus also releases ashen particles containing the Dragon element through these roars to regulate the draconic energies flowing through its body. This substance's incredible solubility combined with its high concentrations of the Dragon element causes the particles to dissolve into vapors and clouds and cause air pollution, which may threaten entire ecosystems within the affected area!

Whew...I went on for a while, haha! But that should be everything you need to know about this titanic Elder Dragon! If you want to learn more, you can click on this hyperlinked text, which should lead you to its wiki page. Now - it's time for the part you've been (probably) waiting for: how I created Naiadeus.

Behind the Scenes: Naiadeus' Creation

Believe it or not - Naiadeus' concept started from an old, at-the-time scrapped idea of an Elder Dragon pair similar to Wind Serpent Ibushi and Thunder Serpent Narwa. The male and female individuals would sing as they soared through the air in search of each other, but it is due to these songs that the many creatures who roam the earth are driven mad. The male Elder Dragon would scorch the land, while the female would freeze it. Early on, it was evident that I wanted to create an Elder Dragon based on Sirens from Greek/Roman Mythology, even down to its songs' ability to drive Monsters berserk. There were two reasons why I scrapped this concept: 1.) I simply didn't vibe with it. The concept felt a little bit too much like Ibushi and Narwa in my opinion, and; 2.) Whatever the heck this concept artwork was.

Looking back at it - I didn't know what I was thinking. It was an atrocious mess of a design and this really hammered the nail in the coffin for this concept for me.

But then I binge-watched the second How to Train Your Dragon movie one night...and suddenly, everything started clicking. Across the length of that movie, Drago's Bewilderbeast made itself known as a menacing force, manipulating the minds of any Dragon - including Toothless himself, might I add - and forcing them to bend to its will. By the movie's climax, it had a whole army of Dragons...and that, quite frankly, enamored me. Suddenly, ideas flooded my mind of what I wanted this Elder Dragon to be: an ancient whale - a cephalopod, perhaps? No - what if it was some sort of turtle, like Zorah Magdaros? But I eventually settled on one...Dire Miralis. I wanted this to be a relative of Dire Miralis. The Monster Hunter Stories franchise has never had a final boss based on marine creatures, so I thought taking the opportunity to write my own final boss themed around the ocean for Chorus of Calamity sounded like a fun idea. Plus - I had never written a fanmade aquatic Monster prior, so doing this would allow me to learn about making marine creatures. It's a win-win if ya ask me! Before making Naiadeus' first designs, I had a conversation with a few friends over Discord, who were also FanonMonsterHunter Wiki content creators like me. I brought up my idea for Naiadeus - who didn't have a name at the time - and how I wanted it to be a sound-based Dire Miralis relative. One of my friends suggested that the vents on this Miralis-like Elder Dragon's body could act as loudspeakers or amplifiers. When I heard that, I was in love with the idea. This is what eventually led to the conceptualization of Naiadeus' utterly terrifying ability to destroy entire countries with its voice. Meanwhile, my scrapped Elder Dragon duo's ability to drive Monsters berserk with their voice was used. It was pretty much the only thing from that scrapped concept that I used in the end, as I've been wanting to make a fanmade Monster based on Sirens for a while at this point. Early designs (which I, unfortunately, have thrown into the trash) were quite heavy on the Dire Miralis inspiration, taking on more draconic designs while being light on the aquatic animal features. Was not a fan of 'em. They felt like a Dire Miralis with some features from Blue Whales if anything - and I did not want that. I wanted this to be a completely original-looking Elder Dragon. Alas, it was back to the drawing board for me. This time, I decided to completely ditch the Dire Miralis body type and instead opt for something similar to Leviathans like Lagiacrus. Learning from my past mistakes, I decided to ditch the Blue Whale motifs from a design standpoint, and instead leave it as my main basis for its ecology and abilities. Now, what other marine animals do I know that can be used as inspiration...? Saltwater Crocodiles sound cool, but there are people in the FanonMonsterHunter Wiki who tried their hand at that. Also, Lagiacrus exists (despite being a Leviathan and not an Elder Dragon). Ceadeus...definitely. It was fought underwater, and it looks like a genuine "sea monster". I could definitely learn a thing or three from it! But...I wanted something more. I wanted this to be an Elder Dragon. An Elder Dragon... ...Dragons... ...Sea Dragons! Aha! I finally knew what I wanted - and it was to make Naiadeus a BIIIIIIIIIG Leafy Sea Dragon! With motivation and steadfast determination empowering my mind, body, and spirit, I used as many images of Leafy Sea Dragons as I could get my hands on, using their wavy body shape and - more importantly - those leafy spines and colorful hues as my main inspirations. ...And around a quarter of an hour later - I did it. The first completed concept design of Naiadeus.

It was beautiful. ...Until I started to dislike the design the more I looked at it. I unintentionally made it feel more crocodilian than I wanted it to be. WHOOPS. Drained of energy from all that drawing, I called it a day and hit the bunk, the thought of coming so close to a final design - and soon, its final ecology - lingering at the back of my mind. I cannot stop now. I mustn't. I'm so close to finally creating a full, complete design. And so, the next day, I got up, made myself some breakfast, blasted the Xenoblade Chronicles 3 OST in my ears...and got to work. As I drove the tip of my pencil across the paper, only one thought lingered in my mind: if I wanted this to be a sea monster, I must embrace its aquatic heritage. Going for the squiggly, zig-zaggy bodily shape of Leafy Sea Dragons, combining it with the webbed limbs of crocodilians, and the tail of a shark...I made sure every stroke counted... ...And they sure as hell did.

And with that, my first Creator Diary concludes! If you've read up to this point, I just want to give you a HUUUUUUUUUUUGE "thank you" for reading this blog! I hope you look forward to more. This has been Sap - signing out.

[aquariuminfobureau]

Greater siren

I have seen greater siren, Siren lacertina, for sale in dealers lists. These are unusual amphibians, entirely aquatic, and so odd that some authorities once had the sirenids at ordinal rank, Meantes, alongside the anurans, caudatans, and caecilians. Nowadays it is clear they are a salamander, combining neoteny and axolotl-like external gills, with unusually efficient and well developed lungs; a cylindrical, eel-like morphilogy: forelimbs but no hindlimbs; a horny beak, a powerful bite, and a lengthened, complex hindgut.

Siren lacertina is found in varied freshwater habitats in the USA, both permanent and semi-permanent. This species is considered to be entirely aquatic, but is able to wether the dy season in the mud. Compared to most salamander adults, sirens have powerful lungs, to enable an animal their size to breathe air efficiently, during the dry season, or in anoxic waters. Where S. lacertina is sympatric with its congener, the lesser siren (S. intermedia), the larger S. lacertina prefers freshwaters of a circum-neutral pH, whereas S. intermedia prefers the more acidic freshwaters, which can be more prone to drying up.

This ecological difference is an example of partitioning, and the habits of these related species, ought to be heeded by the aquarist. Siren habitat includes soft substrates, leaf litter, and dense vegetation. The juvenile sirens hide in leaf litter. Sirens, despite being obligatory aquatic, possess an eel-like ability to migrate short distances between suitable water bodies, if the ground conditions are damp and the air humid, and may climb out of an aquarium. Therefore the lid should be fit firmly, and the siren still able to breathe atmospheric air, from a space maintained between the water surface and the lid.

Though sirens are from the Nearctic realm, of which only part of Florida is tropical, they naturally experience high water tempertures. As such, they can be considered "coldwater tropical", requiring a temperture between 18 and 26 degrees centigrade. Sirens are unsuited to community aquaria with fish, newts, crayfish, or the like. They have predatory tendencies, and they themselves, have vulnerable gills, prone to suffering nips from other animals. Juvenile sirens hatch at 2.5 cm or 1/2 an inch, and consume zooplankton, graduating with size, through larger arthropod and annelid prey, until maturity. This is, incidentally, a big species, that grows to 97 centimeters, or 38 inches.

Adult sirens are predators on arthropods, gastropods, bivalves, annelid worms, and small vertebrates such as fishes and anuran tadpoles. In some settings, terrestrial prey is consumed after floods, and they are also scavengers. Unusually for an amphibian, sirens also consume algae and vascular plants, their hindgut being moderately expanded and complicated, for the purpose of digesting plant life. In the aquarium, they will eat sinking and defrosted foods, which can constitute a balanced diet, that has an algal as well as a carnivorous component. "Prey" does not need to move, because these are sniffed out, the siren having a powerful olfactory sense.