Goodbye for now

Hello everyone - it's been a good ride. I intend to pick up this blog again in future when I have more time on my hands, but thank you for all your time and comments. I have thoroughly enjoyed writing here and I've learnt a lot, and I hope you all have as well (Or else I haven't done a very good job!). I'd like to leave you with one closing thought, or ramble as it may turn out to be.

Should we be optimistic? In writing this blog, I think I've definitely made more negative conclusions than I have positive. Whilst some of the facts and figures I, and many of my colleagues, have come across and written about are pretty sobering, I feel that it is important to maintain some kind of positive outlook, as hard as it may be. Yes, probably some things are set in stone from the emissions, chemicals and otherwise that are already in the earth systems but unless we try to fight to stop anything else being written off, the black list of species is going to be a lot longer. That fight is a hell of a lot easier if we don't give up, and that attitude needs to grow and extend beyond the reaches of academia.

As I've emphasised in many of my posts there is a relationship between society and the media and the sciences that we are wise not to ignore. Personally, I feel that there should be a dialogue between the public and academics and that those of us who have been privileged enough to learn have a responsibility to communicate some of these ideas to everyone else. In fact, I think this is an essential part of how we should approach global environmental issues such as climate change, mass extinctions and the rest of it. The interface between science and society is now more important than ever and I hope through this blog I have done (some of) my part in bridging that gap.

Thank you!

Thank you everyone!; Source.

Estimating Extinction

The extinction of a species can be a difficult thing to precisely pinpoint in the fossil record. Beyond recent history, extinction is not something we can directly observe. Some species may survive after our last known record of them, and we have no way of knowing how long. There might be instances where, for whatever reason, no remains of that species were preserved or simply instances where the remains have been lost through tectonic movements. Some remains might still be waiting for us to stumble upon them, given that there is a considerable geographic bias in palaeontological research. 

Extinction is actually something we have gotten wrong in the past. For years, it was thought that coelacanths went extinct in the End-Cretaceous mass extinction 65 million years ago. In 1938, a living coelacanth was found in the western Indian Ocean and although it was a distinct species from the fossil variants, it was anatomically very similar and what is called a "living fossil". "Living fossils" are species that are, mostly superficially, morphologically similar to their extinct ancestors and are thought (wrongly) to have undergone little to no evolutionary change. Whilst these species may retain the plesiomorphic phenotypical states, it does not mean they are not still evolving and palaeontologists dislike the misleading using of the term in pop-sci press. Another species of coelacanth was discovered in South East Asia in 1997, cementing the idea that we were wrong, both about its apparent extinction and also its static evolution. Whilst this doesn't happen very often, it begs the question, what if we're wrong about other organisms?

The Coelacanth, a "living fossil"; Source.

Two mockumentaries (fake documentaries) aired by the Discovery Channel over the last year or so attempt to answer exactly that question. The focus of the two programmes was the Megalodon, a gigantic shark which patrolled the seas between 15.9 - 2.6 million years ago. These are interesting programmes, but do have a tendency to spread misinformation, with 73% of viewers thinking that the Megalodon is still roaming our oceans. Many actual scientists, as oppose to the actors posing as scientists in the programme, were unhappy about the misrepresentation of palaeontological research, calling Discovery Channel "the rotting carcass of science on TV". Others, however, created a positive outcomes from the documentaries and worked on more robust mechanisms of estimating the extinction of the Megalodon, if only to put the rumours to bed once and for all. The authors, novelly, utilised a method that had previously been used to estimate the extinction of more modern species, such as the dodo. The method, a model called Optimal Linear Estimation (OLE), infers time to extinction from the temporal distribution of species sightings, or in the case, fossil instances. This method may not be applicable to all fossil taxa, but is an excellent step in out-of-the-box thinking towards a better extinction estimations.

I wasn't joking about them being big; Source.

Extinction is something we should be aware of and it can be a great tool to provoke changes in peoples outlook on human activity. Whilst "lazarus taxa", "living fossils" and the rest of it make for great sci-fi, their place in actual science should be profoundly separate from this.

Hunting - A Bear Necessity?

A nasty note on which to start the new year, but the US Fish and Wildlife Service (FWS) has announced that their intend to remove protection from Yellowstone's grizzly bear population in the coming year. As someone who has had a grizzly bear themed calender for the last two years, my immediate reaction to this is one of shock and disgust. For a moment, however I will attempt to step back from my bear loving self and take a look at the reasons behind this decision.

Adorable animal which should clearly not be hunted; Source.

For the past 40 years, the bears of Yellowstone have been protected by hunting and have enjoyed population increases and range expansion under this protection from the Endangered Species Act (ESA). This protection was not undue, the grizzly population suffered huge losses from excessive hunting during the 1900s which earned them a place on the IUCN red list. The recovery of their population, however, has put pressure of the US FWS to revoke their special status, from state officials. The proposed new system would involve handing over the management of bear population to state level, after the delisting would remove federal protection. The agreement places no limit on the hunting of bears outside of the central Yellowstone management area, and within that splits the bears between the three states which share the region - Wyoming, Montana and Idaho. There are some loose pledges to maintain the bear population in the management area above 600, but nothing concrete except an apparent need to shoot at things.

Arguably, the new laws would promote, rather than limit the killing of bears. There are underlying societal and economic reasons why there is such animosity towards bears, and other large carnivores. Whilst states would plead that bears area threat to humans, the reasoning is more likely to do with their role as competitors for big game. However, the problems of hunting these animals also have multiple dimensions. Culturally, they hold high significance for many native people who also live in the Yellowstone management area and have not been consulted in the decision to delist bears. Ecologically, there are many issues in play. Bears are, arguably, still in a very vulnerable position in Yellowstone and are dying in disproportionate numbers each year even with the protection of the ESA. For example, climate change induced drought and invasive species have extirpated one of the bears main food sources, the cutthroat trout, as well as damaging other food sources including Whitebark pines and elk. Grizzlys have very low reproductive rates, with huge amounts of parental investment, meaning that they are very slow to react to changes in the environment and colonise new territories. This means that they will feel the pressures of climate change more than most, causing their population to suffer alongside hunting.

My personal bias aside, I feel that there is not a great case for delisting the grizzly bear from the ESA protection. There is a very real chance that hunting would lead to extirpation outside of the Yellowstone management area, where there are no limits in place. Isolating the population within Yellowstone, whilst hunting them as well, could have disastrous impacts on then stability of the population as their numbers dwindle and their genetic diversity lessens. Let me know your thoughts below, but I feel that there is no necessity behind this law change, simply a demand for blood.

Could the removal of the 'ESA Safety Net' mean extirpation for Yellowstone's grizzlys?; Source.

Paralleling Ocean Acidification to the Permian

The "evil twin of global warming", better known as ocean acidification, is considered an often overlooked but serious environmental impact from anthropogenic CO2 emissions. Ocean surface pH has been decreasing at an alarmingly rapid rate throughout the last 200 years, faster than at any point within the last 300 million years. In fact, as revealed by a study in April last year, the last time ocean acidification occurred this fast, it was a major contributing factor to the End-Permian mass extinction. The Permian, as a quick reminder from earlier posts, was the largest mass extinction event of the Big Five, with over 90% of species becoming extinct. The study found new evidence that extensive Siberian Trap volcanism triggered Ocean acidification during the end of the Permian era which drove the mass extinction and loss of 96% of marine life.

The study collected data using boron isotopes as a proxy for ocean pH and generated models based on this. They found the most likely scenario was two pulses of extinction in a setting where the Earth system began as "primed" for rapid increases in ocean acidity. The first pulse was a slow injection of CO2 into the atmosphere by ongoing volcanism over tens of thousands of years during which the extinctions were mostly terrestrial. The second phase there was a large and rapid injection of CO2, likely from a huge eruption, which caused abrupt acidification of the oceans and drove the loss of the many marine species that went extinct during the event.

An example of what ocean acidification can do to marine biota; Source. 

What does this mean for modern oceans? And why do we need to care? The quantity of CO2 injected into the atmosphere during the end of the Permian was probably greater than today's fossil fuel reserves, however, the rate of CO2 release and subsequent interactions with the oceans was likely similar to current emissions. The rate of release is crucial because it there is a correlation between rate of release and rate of absorption, meaning more CO2 absorbed by oceans ends up as H+ ions, as oceans cannot just hold all the CO2 being released. This means on the whole, more acidification than there otherwise would be. It also means that there is much less time for any species to adapt to changing conditions. 

Modern oceans are estimated to have seen a 30% increase in the concentration of H+ ions since the late 18th Century, which corresponds in a fall in pH from 8.25 to 8.14. This is estimated to reach 7.75 by 2100 if there is not considerable intervention. We can see the impacts of ocean acidification in our oceans already, and many of them mirror the events of the End-Permian extinction event. For example, a group of snails known as pteropods have been identified in multiple studies as experiencing shell dissolution, sometimes as soon as they are born. It is thought that 50% of pteropods species are currently affected by acidification and that this has doubled since the 1800s, and will likely triple by 2050. In fact, all marine organisms which use calcareous materials are at risk of experiencing dissolution. This includes corals, crustaceans, echinoderms and foraminifera as well as the aforementioned molluscs. Additionally, we see coral reef bleaching as the symbiotic relationship between coral polyps and dinoflagellate algae is disrupted due to the algae having a narrow range of pH tolerance. Corals themselves, suffering from both dissolution and bleaching, are a massively important component of shallow water marine ecosystems - they provide habitat for 25% of marine species and drive fishing and tourist industries for many developing nations. (For more on this check out my colleagues blog on Tourism and the Environment).

Coral bleaching; Source.

This is likely what happened in the Permian extinction, the vast majority of marine life in that era had exoskeletal components composed of calcium which made them extremely vulnerable to rapid drops in ocean pH. Whilst modern marine biota is more morphologically diverse, there is still a large component of our ecosystems which is already suffering. Indeed, this component cannot be separated from the system just as it could not be in the Permian and any losses will have unavoidable trophic impacts on non-calcareous species. The "evil twin of global warming" cannot rationally be ignored any longer, and thankfully there was some recognition of that in the recent COP21 talks. Whilst they may not be the most spectacular or interesting of animals (to some), small molluscs, foraminifera and other calcareous micro-organisms form the basis of most, if not all, marine food webs and we need to truly recognise the importance of protecting them and reflect that in policy.

For a practical demonstration of the impacts of ocean acidification, check out this interesting video below!