save our blue planet

Let's save our blue planet by saving the ocean. Every little step counts.

shark of the week: Gummy shark — 5. June 2017

shark of the week: Gummy shark

Many different shark species are used for fish-and-chips (under the name flake) in Australia: School sharks, several species of wobbegongs, and also the Gummy shark or Australian smooth hound (Mustelus antarcticus). It is named after its gummy-like, boneless fillets (don’t all sharks have no bones?) in English and its habitat off southern Australia (near Antarctica) in Latin.

Like all sharks of the family houndsharks, the Gummy shark has a smooth skin with tiny denticles and is viviparous. Every one of the one to 57 embryos (depending on the size of their mother) stays in their own separate compartment in one of the two uteri of their mother during the year long gestation. Born at a length of approximately 13 in -33 cm-, female mature at 5 years and reach a length of up to 73 in -185 cm-, males at 4 years with a maximal length of 58 in -148 cm. Gummy sharks live up to 16 years.

Living in two genetically distinct sub-populations, the Gummy shark is abundant in shallow waters off southern Australia. Nevertheless, regulations to manage fisheries like gillnets with a mesh-size around 6 in -16 cm- to protect smaller (juveniles) as well as larger (big female) sharks or a bag limit for recreational fishermen (see spotted wobby) and conservation measures like marine protected areas (MPAs) are in place to protect this shark species, too. It seems that climate change and subsequently warmer water “might trigger a change from the biennial reproductive cycle presently characteristic of Bass Strait to an annual cycle characteristic of the other regions (Walker 2007), which may increase pup production and hence productivity of the population and yield from the fishery.” This is no reason to give the all-clear, however.

Sources: here and here

Shark of the week: Japanese bullhead shark — 19. September 2016

Shark of the week: Japanese bullhead shark

Did you know that there are female bullhead sharks that deposit their eggs at the same place – like a communal nesting site? Up to 15 eggs of the Japanese bullhead shark (Heterodontus japonicus) can be found in the same patch. Each egg has to rotate out of the mothers cloaca during several hours, as with all bullheads. The reason is the auger shape of the egg case – even if the egg of the Japanese bullhead shark is a little less elaborate. The eggs take about a year to hatch, and the newborns are 7.1 in -18 cm- long.

The Japanese bullhead shark is up to 3.9 ft -1.2 m- long and lives in the northwestern Pacific Ocean off the coasts of Japan, Korea and China at depths of 20 to 121 ft -6 to 37 m- over rocky bottoms or kelp beds. Just like all bullhead sharks, it has a pig-like snout, a ridge above each eye and fin spines. It has a characteristic pattern of irregularly shaped, vertical brown bands and stripes.

The Japanese bullhead shark can often be found in aquariums in Japan. It is harmless to humans and can even easily be hand-caught by divers. Considered as Least concern by the IUCN, it vanished from the gulf of Bohai in China, assumedly due to climate change. But, given that there is one of the busiest seaways in the world, there could be other reasons as well.

Sources: here and here

EFSA: dangerous contaminants in palm oil — 31. August 2016

EFSA: dangerous contaminants in palm oil

During food production, contaminants can develop. One example is Acrylamide during the frying of potatoes, but also Esters of 3- and 2-MCPD and glycidyl esters (glycidol) are such harmful substances in our food. They cause tumors and are especially dangerous to children. Generated during the production of vegetable oils, they can be found in these oils and consequently in processed foods containing these oils. Their highest levels are, by far, in palm oil or fat. That is worrying, since it is difficult to evade palm oil in our supermarkets. Difficult, but not impossible, in my opinion. Alarming are the high doses found in baby formula.

Source: ESFA-report

Pew: Cartoon crash course about ocean terminologies — 23. August 2016
theconversation.com: The oceans are changing too fast for marine life to keep up | Die Meere ändern sich zu schnell, als das ihre Bewohner mithalten können — 19. August 2016

theconversation.com: The oceans are changing too fast for marine life to keep up | Die Meere ändern sich zu schnell, als das ihre Bewohner mithalten können

Regarding those who point out that there where periods with much higher (not human-caused) carbon dioxide levels than today, implying it is only natural and no reason to change anything, I found this article that was originally published on The Conversation on October 13, 2015.

Yes, rising carbon dioxide levels happened in the past, but either so slow that nature could adapt, or as rapidly as now, but then coupled with a mass extinction event (Source). The sharks survived the last times (as below mentioned they wouldn’t now), and I think (and hope) mankind would survive, but: how would we live in the world we would find ourselves in after?


Bezüglich denen, die aufzeigen, dass es Perioden mit viel höheren (nicht vom Menschen verursachten) CO2-Pegeln als heute gab, damit unterstellend, dass es nur natürlich ist und es keinen Grund gibt irgendetwas zu ändern, habe ich diesen Artikel gefunden, der ursprünglich am 13. Oktober 2015 auf The Conversation veröffentlicht wurde.

Ja, in der Vergangenheit passierten steigende CO2-Pegel, aber entweder so langsam dass die Natur sich anpassen konnte, oder so schnell wie heute, aber dann  mit einem Massenaussterben gekoppelt (Quelle). Die Haie überlebten es die letzten Male (wie unten erwähnt würden sie das jetzt nicht mehr), und ich denke (und hoffe) die Menschheit würde überleben, aber: wie würden wir leben in der Welt, in der wir uns danach befinden würden?

The oceans are changing too fast for marine life to keep up

Ivan Nagelkerken, University of Adelaide

Some of the ocean’s top predators, such as tuna and sharks, are likely to feel the effects of rising carbon dioxide levels more heavily compared other marine species.

That’s just one of the results of a study published today in Proceedings of the National Academy of Science.

Over the past five years we’ve seen a significant increase in research on ocean acidification and warming seas, and their effect on marine life. I and my colleague Sean Connell looked at these studies to see if we could find any overarching patterns.

We found that overall, unfortunately, the news is not good for marine life, and if we do nothing to halt climate change we could lose habitats such as coral reefs and see the weakening of food chains which support our fisheries.

Acidifying and warming oceans

Humans have been adding carbon dioxide to the atmosphere largely through burning fossil fuels. Under a worst-case scenario, without doing anything to stop increasing emissions, we’d expect concentrations of carbon dioxide to reach around 1,000 parts per million by the end of the century.

This increase in greenhouse gases is “acidifying” the oceans. It’s happening now. Carbon dioxide concentrations have reached around 400 parts per million, compared with around 270 parts per million before the industrial revolution.

This extra carbon dioxide, when it dissolves into the seas, is reducing the pH of the oceans – that is, making them more acidic.

Many ocean creatures, particularly those that build habitats such as corals and shellfish, make skeletons out of calcium carbonate, which they get from ions dissolved in sea water.

When carbon dioxide dissolves in seawater, it makes these calcium carbonate ions harder for marine life to collect and turn into skeletons. It’s like a person going on a diet without calcium.

At first this results in marine life producing brittle skeletons, but can ultimately lead to the skeletons dissolving.

A calcium-free diet

Many studies have looked at what will happen to these lifeforms that produce skeletons, but we wanted to look at how rising carbon dioxide would affect the ocean at a broader scale.

We analysed more than 600 experiments on ocean acidification and warming seas.

Overall it seems warming temperatures and acidifying oceans will have a negative effect on species and ecosystems. This means reduced growth, abundance, and diversity of marine species.

We also found these results were mostly consistent across latitudes – they weren’t just limited to tropical oceans.

The oceans will warm as they acidify, so it’s important to look at these two changes together. Previous analyses typically looked at specific life stages or different ecosystems.

It’s likely that acidification will interact with warming to have a worse effect. For instance, if you would see a 20% reduction in calcification rates because of rising temperatures, and a 25% reduction in calcification because of acidification, then the combined reduction might be 60%. We see these effects regularly in the studies we looked at.

Of course not every species will show the same response. We expect some species to be able to acclimate or adapt to changes, particularly over longer time periods perhaps like a couple of decades. For example, a recent study on a coral living in a tropical lagoon found it has some capacity to adapt. We found that more generalist species like microorganisms seem to be doing particularly well under climate change, and also some fish species at the bottom of the food chain may show increases in their populations.

Changing whole ecosystems

Most worrying are not only the changes to individual species but also whole ecosystems.

We found that reef habitats are vulnerable: coral reefs, but also temperate reefs built by molluscs such as oysters and mussels. A lot of shallow temperate waters used to have oysters reefs, but there are few natural reefs remaining.

There are also cold-water reefs formed by other species of coral, which grow slowly over thousands of years in the cooler temperatures. In our analysis we found that acidification could cause these habitats to show reduced growth. These habitats are often located in deep waters and are very sensitive to human impacts.

We also found that these changes affect whole ocean food webs.

We found that warmer temperatures mean more phytoplankton – the tiny plant-like lifeforms that form the basis of many ocean food chains. This means more food for grazing species that feed on phytoplankton.

Warmer temperatures also mean faster metabolisms, which require more food. However this didn’t translate into higher growth rates in grazing species. That’s fatal because the next level up in the food chain (the species that eat the grazing animals) would have less food, but still need more food because of faster metabolisms.

This effect is expected to become stronger as you go up the food chain, so predatory species like tuna, sharks, and groupers will be the species that would feel the strongest effects.

These species are also threatened by overfishing, which adds another level of stress. Overfishing alters important food web interactions (e.g. top-down control of prey species) and may also reduce the gene pool of potentially strong individuals or species that could form the next generation of more resilient animals. And this is on top of other threats such as pollution and eutrophication.

Therein lies an opportunity. We cannot change climate change (or ocean acidification) in the short term. But if we can mitigate the effects of overfishing and other human stressors we can potentially buy some time for various species to adapt to climate change.

Species can genetically adapt to changes over geological timescales of thousands of years – as we can see from modern species’ survival over many ups and downs in the climate. But the changes we have wrought on the oceans will take place over decades – not even one generation of a long-lived sea turtle or shark.

With such fast changes, many species in the ocean will likely be unable to adapt.

The Conversation

Ivan Nagelkerken, Associate Professor, Marine Biology, University of Adelaide

Read the original article.

about climate change denial | über Klimawandel-Leugnung — 13. August 2016

about climate change denial | über Klimawandel-Leugnung

Since I often stay helpless in the face of climate change denial (or rather human-caused global warming denial), I post some links I found to make sense of their arguments (including their motives and why discussing with facts doesn’t work):

skepticalscience.com

short videos on global warming

Denial 101 – Massive Open Online Course 

for instance

climatecentral

George Monbiot from The Guardian


Weil ich oft hilflos bin angesichts Klimawandel-Leugnung (oder eher Menschen-verursachte-Erderwärmungs-Leugnung), poste ich einige Links die Sinn in ihre Argumente bringen (inklusiver ihrer Motive und warum mit Fakten diskutieren nichts bringt):

übersetzte Seite skepticalscience.com

Erklärungvideo zur Erderwärmung

Denial 101 – Massive Open Online Course 

z.B. 

klimafakten.de

George Monbiot from The Guardian (teilweise Übersetzung hier)

 

Palm oil giant IOI has lost customers for destroying forests | Palmöl-Gigant IOI hat Kunden verloren, weil es Wälder vernichtet – Greenpeace International — 2. August 2016

Palm oil giant IOI has lost customers for destroying forests | Palmöl-Gigant IOI hat Kunden verloren, weil es Wälder vernichtet – Greenpeace International

IOI has even been banned from RSPO.

via Palm oil giant IOI has lost customers for destroying forests, but will it change? | Greenpeace International


IOI wurde sogar von RSPO ausgeschlossen.

siehe Palmöl-Gigant IOI hat Kunden verloren, weil es Wälder vernichtet, aber wird es sich ändern? | Greenpeace International

Cold deep water: hope for corals? | Kaltes tiefes Wasser: Hoffnung für Korallen? – Oceana — 31. July 2016
El Niño, warming up the tropics with some devastating global consequences — 5. July 2016

El Niño, warming up the tropics with some devastating global consequences

Facts about El Niño and corals | Fakten über El Niño und Korallen

The Fisheries Blog

Most of us have probably heard the term El Niño. But what exactly is El Niño and what impact does it have on our oceans and climate?  Another important question to ask is: what can we expect from El Niño in a future with a warmer climate and ocean?  In this week’s article I attempt to answer some of these questions and give you an idea of what is currently happening to our oceans and the world as a result of El Niño. 

elnino_main_205673The earth centered on the Pacific Ocean shows patterns of sea surface temperature during El Nino (left) and La Nina (right). The colors along the equator show areas that are warmer or cooler than the long-term average. Images courtesy of Steve Albers, NOAA. Source: http://www.whoi.edu/main/topic/el-nino-other-oscillations

El Niño is one half (La Niña being the other half) of a complex weather pattern called the El Niño-Southern Oscillation (ENSO)…

View original post 991 more words

climate catastrophe coming even sooner?| Klimakatastrophe kommt noch eher – The New York Times — 1. April 2016

climate catastrophe coming even sooner?| Klimakatastrophe kommt noch eher – The New York Times

“The researchers concluded that just a few more decades of “unabated” carbon emissions could result in more than three feet of sea-level rise from WAIS [West Antarctic Ice Sheet] by the end of this century. (The over-all rise would be much greater, as ice would also be lost from Greenland and from mountain glaciers.) Over the longer term, melt from Antarctica could raise sea levels by fifty feet.”


“Die Forscher schlussfolgerten, dass nur ein paar mehr Jahrzehnte von unverminderten Treibhausgas-Emissionen ausreichen könnten, um bis zum Ende des Jahrhunderts den Meeresspiegel wegen des WAIS [West Antarctic Ice Sheet=Eisdecke des westlichen Teils der Antarktis] um einen Meter steigen zu lassen (wegen Schmelzeis von Grönland und Gletschern würde der Gesamt-Anstieg viel höher sein). Auf lange Sicht könnte Schmeltzeis von der Antarktis den Meeresspiegel um 15 Meter ansteigen lassen.”

via NewYorker

see also: New York Times