We’ve caught a couple of pre-reports on this, but now the full paper is available for all to read at PLoS 1. The report is based on historical fish landings reported from the Firth. This sees a healthy and diverse fishery in the early 19th century. After this date the fisheries effort intensified, and commercial landings for each species targeted in turn is seen to go through a boom followed within a few decades with collapse.

The only commercial fisheries that remain today are reported to be for Nephrops and scallops (Pecten maximus, Pectinidae). The report damns the fishing industry for forcing a repeal of the trawl ban in 1984 that had been put in place since 1889. It further argues that modern intensive Nephrops fisheries are preventing the recovery of other fish stocks.

Thurstan RH, Roberts CM (2010) Ecological Meltdown in the Firth of Clyde, Scotland: Two Centuries of Change in a Coastal Marine Ecosystem. PLoS ONE 5(7): e11767. doi:10.1371/journal.pone.0011767

Oil spills, chemical weapons, global warming, even toxic octopuses in this week’s episode. Just when you thought it couldn’t get any worse, a report has surfaced over the last two days that the levels of global marine primary production are in free-fall. This story links with our report last week, that phytoplankton actually start to bloom in the winter, when turbulence reduces the density of predators (Acepted theory of algal blooms wrong). This week global warming is blamed for increasing the temperature of surface waters, causing them to become more stratified, and reducing the chance of mixing with deeper cold water masses. The worrying thing is that this week’s report is based on evaluation of historic data for phytoplankton levels in seawater, so it looks like the feedback loop we predicted last week is already picking up speed… Our second article is a calibration exercise to allow us to quantify phytoplankton blooms from space more accurately, I hope that this will show up some errors in the estimates made in the first paper.
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A quick turn-around on this occasion – with hopeful news from the Gulf of Mexico, though even if the leak has been blocked successfully, it will be a long time before the effects of this disaster have been fully understood (never mind fixed). To another man-made disaster, this time off the southwest coast of Africa. Here over-fishing in the 1960’s resulted in ecosystem collapse, and only now are there a few hopeful signs of recovery, with the arrival of some tough gobies that can cope with anoxic waters and eat jellyfish…

First though, have we got the theory of algal blooms wrong? If we have, this could have serious implications for climatic modelling!
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The usual mixed bag of marine science, trawled from the Google deeps. This week we have tales of eels, shrimp, fish and octopuses (ar at least one octopus, called Paul, who has had a significant impact on the social behaviour of a certain species of terrestrial apes).
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Themes this week include climate change, and in particular how phytoplankton, some of the smallest plants on the planet, have a vital role in managing the Earth’s carbon dioxide budget. Otherwise, scientists are starting to evaluate how climate change will effect key organisms in the marine ecosystem, and results from these studies are beginning to come in. Fisheries are an important component of many maritime economies, and there are a few interesting papers in this area this week. Historic studies of fisheries are important for understanding how and why they develop, and what economic pressures can lead to collapse. Otherwise, husbandry is becomming important in the marine field, as demonstrated by the breeding of new ‘super prawns’ for the Australian market.

If climate control and resources are two positive things, it is less easy to find good things to say about pollution and the continuing oil spill. The importance of monitoring marine systems for organic mercury compounds is emphasised – while the marine ecosystem dilutes these compounds, the marine food chain concentrates them right back up again, and guess who is at the top of that food chain…

On the oil spill there is a very interesting blog post on how likely the spill was to occur – was it an event so unlikely that (as the US regulators agreed when they licensed the Deepwater Horizon) there was no likelihood of environmental damage? Beyond that, we look at some of the less visible casualties of the spill, and start to quantify just how much of the Gulf marine ecosystem has been wiped out.
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This roundup has a focus on oceanography, physical and chemical processes in the worlds oceans. The chemistry and biology of natural seawaters are very tightly linked, with most reactions being biologically mediated. The physical side, however, dominates what chemical species marine biology has to work with, an interaction that scientists are now claiming to be able to model. Many marine systems are rather less than ‘natural’, with a range of human influences. In the oceanography section we look at the underlying science of these man-made changes, whilst in our pollution section we look at the dirty stuff…

We finish on a few general papers that don’t fit into the two main themes for the week – living underwater, mapping the salmon genome, dolphins and ichthyosaurs. Finally, if you can only conserve one thing, what would it be? – This is the root of a difficult question facing coral reef conservators. Do you concentrate on the core of the reef? – science is starting to show that the fringes of the reef (an other eco-systems?) are more genetically diverse, and may offer a stronger pool of organisms better able to survive ongoing climatic change…
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This week’s science news is a mixed bag – so I’ve not tried to pull out articles by theme. Many of the articles have a strong central thread of common sense running through them, however! If the amount of fresh water entering the Baltic is reduced, the Baltic will become saltier, dispersing an oil-slick is not the same as making it disappear…
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Lots of new species, and excess nutrients encouraging algal blooms. I’ve avoided the oil-spill, which still contributes a lot to the scientific news, but I don’t have anything new or insightful to say on this. I’m afraid that disasters breed liggers even in the scientific community, all too often I find myself stripping out tenuous links to the disaster of the moment (climate change or oil-spill) added to spice up the press report, to try and find the meat of the scientific study…

Algal blooms

Sewage: From source to sea: In a recent study, engineers from Stanford University have shown that sewage can contaminate bathing beaches after percolating through groundwater from septic tank leach-fields. The main contaminants entering the seawater were nitrates, which cause localised blooms of phytoplankton, rather than bacteria, which might be a direct risk to human health. Overall, the authors did not cite a preference between septic tank and leach field vs piping to a sewage treatment facility, largely due to the lower energy costs of the former system. From ScienceDaily (May 25, 2010)

Algal blooms can hit the poor hard: The south west Indian coast is particularly prone to algal blooms. These are triggered by excess nutrients in the coastal seawater, from monsoon runoff from the land. The problem is amplified by the increased use of fertilisers. As Indian authorities encourage aquaculture along the coast to provide local income, and a source of protein for a booming population, it is becoming more important to understand how and when blooms are likely to occur, and how this might change in future, possibly as a result of climate change. From ScienceDaily (May 31, 2010)

New species discovered

Top ten new species in 2010: The new list from Arizona State University includes a multi-coloured frog fish (found in Indonesia), an electric fish (that had been used for demonstrations of the ‘electric effect’ for many decades, but not described and formally identified untill this year!) and a killer sponge. There is a nice photo of the spicules from this sponge (see ‘Why we have bones, and not spicules’ in evolution, below), but this is one you probably wouldn’t want to scrub your back with.

Six new antarctic gorgonians discovered: Gorgonians are cnidaria with large branched calcareaous skeletons, the surfaces of which are covered by tiny feeding polyps. The branches of a gorgonian are usually held in one plane across the current so the animal can capture food particles efficiently. This gives the animal a fan-like appearance, and they are commonly referred to as ‘sea-fans’. They are closely related to sea pens, which are common around the UK on muddy bottoms below about 20m depth. From ScienceDaily (May 30, 2010)

New fish species described: Nine new species of handfish – small fish that use their fins to ‘walk’ along the bottom – have been described in Tasmania. The discoveries are part of an urgent project to catalogue and protect Australia’s marine life. The discovery brings the total number of known handfish species to fourteen. From ScienceDaily (May 24, 2010).

Evolution

Genetic divergence in coral reefs: This study from PLoS 1 analyses changes in the DNA of individuals of the coral Seriatopora hystrix and its symbiotic alga (Symbiodinium). Their data show that there are changes in genetics of both coral and symbiont between individuals sited in diffferent locations on the same reef (e.g. back reef, deep slope and upper slope). However, inviduals on different reefs, but in a similar habitat, are genetically similar despite being isolated by distance. Similar changes have been documented before in Littorina (periwinkle), and I suspect this is quite common for a wide range of sedentary organisms (seaweed, anemones, sponges, tunicates). From Bongaerts P, Riginos C, Ridgway T, Sampayo EM, van Oppen MJH, et al. (2010) Genetic Divergence across Habitats in the Widespread Coral Seriatopora hystrix and Its Associated Symbiodinium. PLoS ONE 5(5): e10871. doi:10.1371/journal.pone.0010871

35 million years of whale evolution: Whales are a diverse bunch of marine mammals – showing great variations in size and a large number of different adaptations to the marine environment. The study shows that whale species diverged quickly shortly after adopting a fully marine life-style, and have since maintained a relatively conservative pace of change. From ScienceDaily (May 31, 2010)

Early power cell: Researchers at the University of Leeds suggest that pyrophosphite might have been an important energy source for the earlies forms of life on earth. The mineral is thought to have played a similar role to that of ATP in modern cells. From ScienceDaily (May 25, 2010)

Why we have bones, and not silicate spicules: Sponges are very simple multicellular animals. So simple, in fact, that I am told that you can liquidise many of them, and the cells will slowly go back together again afterwards. For structure, and some measure of protection, sponges secrete silica or calcium carbonate ‘spicules’ (often quite intricately shaped, the microscopic examination of these structures is an important aid for their identification). Deposition of carbonate minerals – used to make the bones of many animals (including ourselves) – relies on αCarbonic Anhydrase enzymes, which have been shown to appear first in the sponges about 530 MYA. From Deep Sea News, May 27 2010.

Other stuff

Hurricanes stir the bottom at 90m: Hurricane Ivan, a category-4 storm, crossed the Gulf of Mexico in 2004, right over a network of sensors laid by the US Navy. These showed sediment clouding the water column to a height of 25m above the bottom at 90m, indicating considerable scouring even at this depth. The hurricane set up powerful currents in the deep water that persisted for a week after the event. The authors suggest that these currents may be a threat to oil pipelines. From ScienceDaily (May 26, 2010)

Jellyfish in motion: Video of jellyfish from the Monteray acquarium, California. From KQED, May 25 2010

Scripps Institution of Oceanography Library available through Google books: About half of the Scripps Institution of Oceanography Library has been digitised – focussing on rare out of print publications and expedition reports. Unfortunately, it appears that this resource is only freely available in the US. From Library Journal 5th May 2010. (Link to Google Books)

Shark attack Sunday: Apparently sharks are more likely to attack people on Sundays during a new moon. Other statistically significant parameters included depth of water (less than 6ft/2m) and colour of bathing costume (black and white preferred). From ScienceDaily (May 27, 2010)

Historical Atlas of Marine Ecosystems (HMAP): The Historical Atlas of Marine Ecosystems shows where species and ecosystems have been reported to occur, with data displayed on a Google World view. They have recently added areas showing where Sperm whales were caught between 1760 and 1920. (I think this might be a really useful resource, but I found it hard to use).

As anyone attending our ID course will know, species names are undergoing considerable upheaval currently, as a consequence of DNA analysis. This is resulting in species disappearing (for example the ‘breadcrumb sponge – a single species with 50+ scientific names) or appearing (for example with cryptic species ), or are moved between genuses.

The ‘Catalogue of Life’ is a potentially helpful resource for anyone wanting to check on a scientific name for a species, as it permits searches against an extensive library of scientific synonyms (so it should tell you if you have an older name, and what the current name should be). It is not entirely infalible – it still quotes Laminaria saccharina as the accepted scientific name for ‘sugar kelp’, where I believe this has recently been updated to Saccharina latissima based on DNA evidence (this is a recent change though – so probably just not have come through yet).

The site also permits you to browse through the taxonomic tree of marine life – which is fun, though without keys you will need some knowledge of the biological classification to use it. The site also carries broad distribution data, and links to off-site resources.

Image top right: The common lobster Homarus gammarus, with inset a simplified taxanomic tree from the Catalogue of Life.

Catalogue of Life: 2010 Annual Checklist You will need Javascript enabled to use this site.

Soft bodied fossils, invasive species, and fishing stocks, some of the science reported over the last ten days:

Invasive tunicates in Oregon: Didemnum vexillum has been added to Oregons’s most dangerous species list. This is an unusual status for a tunicate, a group of animals that usually live a blameless existance filtering seawater for food. Apparently, however, vexillum is an alien species that grows over surfaces and can block water intakes and foul fishing nets. The species can also grow over clams and oyster beds, killing them. From ScienceDaily (May 13, 2010)

Fossil haul illuminates Ordovician ocean: 1500 fossils of soft bodied marine animals, including sponges, annelid worms and molluscs, have been found in southeastern Morocco. The animals date from the Ordovician (490-440 MYA), a period that saw many of the groups we know today establish themeselves. The absence of Ediacaran organisms confirm that these unusual early life forms had become extinct by the start of the Ordovician period. From ScienceDaily (May 14, 2010)

Personal care products polute rivers: Biocides and aroma chemicals added to modern personal care products are finding their way into our fresh-water systems. From ScienceDaily (May 14, 2010). While the European study did not believe that their findings posed any risk to humans, research in the States indicates that the common antibacterial agent triclosan is contributing to rising levels of dioxins in river sediments in the Missippi. From ScienceDaily (May 18, 2010).

Coral larvae listen out for reefs: Coral larvae swim towards the sounds of coral reefs. From ScienceDaily (May 16, 2010)

Altantic swordfish stocks recover: A small number of fish stocks saw an improvement in the latest NOAA fisheries report to Congress. For the first time since 1997 no additional species were added to the overfishing list. From ScienceDaily (May 17, 2010)

Greatest grand-daddy: The largest study to date confirms Darwin’s conjecture that all life originates from a single common ancestor. The study was based on the analysis of 23 ‘essential’ proteins, which are found to be related in a simple way accross the entire range of organisms, including eukaryotes (like ourselves), bacteria and archaea. From ScienceDaily (May 17, 2010)

Crews remove lost nets: Fishing gear abandonned or lost at sea, called ‘ghost gear’, continues to ensnare and kill marine animals, as well as posing a risk to boats. Resistant to degredation, the only way to end the cycle of death is to physically remove the gear. From USA Today, May 18, 2010, via The Spill.