Lots of interesting articles over the last week, some physiology – how sharks and seals find their food, and how far can crocodiles migrate? Prehaps my favourite was the article on classifying arrow-worms, a group I knew nothing about them before the article. There is also a nice set of maps of North Americal marine ecosystems, which you can view on Google Earth. Maps almost had a separate section this week, with 3D maps of the oil-spill being computed by the University of Texas at Austin. Unfortunately the article was so uninformative that I couldn’t see any point in referencing it…
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Conditions for the dive at Roa Island on Saturday 5th. June were almost perfect, bright sun.little wind, calm and undisturbed water which gave underwater visibility  in excess of  3 metres.

Swimming approx. SW from the jetty towards the middle of the channel, initially over  a sea bed of cobbles covered with tube worms, common winkles and dog whelks with numerous clumps of dog whelk eggs.  At about 4 metres deep the bed changed to small boulders with a dense  covering of  various seaweeds which included sea lettuce and  bootlace weed.  continuing downward at minus 6 metres the weed  disappeared  to be replaced on the boulders by a number of species of sponge. Between the boulders were many varied and different animals including peacock worms, anemones, and various species of crab.  After a short distance the sea bed changed again to  pebbles with hard mud patches, this continued to max. depth of dive at 10.3 metres. There was still lots of life to see on this gentle slope, including hermit crabs, whelks, anemones and the greater pipe fish. The pipe fish were quite common at all depths through-out the dive. On this deeper part of the dive there were many common starfish, a large number with parts of arms missing.  They had not been shed, more like cut or torn off, the detached parts were also strewn over the sea bed. All in all an excellent and very interesting dive.

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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In early April the British Government declared the Chagos islands and the seas surrounding them as a  marine protected area, MPA. It also includes a no-take marine reserve where commercial fishing will be completely banned.  The new MPA is the world’s largest, and it will double the global coverage of the world’s oceans under protection.

Professor Charles Sheppard of Warwick University has spent many years undertaking scientific research and campaigning for protection for the Chagos. In an interview  Professor Sheppard outlines the importance of the Chagos itself  and the much wider influence it can have on the Indian Ocean as a whole.

Listen to this interview

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).

A  dive weekend held in conjunction with Preston SAC  to the sea lochs north of Oban was held over the third weekend in May. Diving in the Kerrera Sound and Loch Creran was quite interesting with the usual tremendous diversity of marine life although it was quite gloomy with underwater visibility down to only a couple of metres at best. A dive on the underwater cliff about 200 metres  to the west of the old railway pier at Kentallon inLoch Linnhe was the highlight of the trip. Underwater visibility was at least five metres at the top of the the wall which plunges down in a series of steps to approx. 35 metres deep. The wall is covered in a profusion of life, with vast numbers of peacock  worms Sabella pavonina & sea squirts,  Ciona intestinalis. This was an excellent dive to conclude the weekend. Many thanks to Gordon Fletcher for organising the trip to co-incide brilliant sunny weather.

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.

Prior to this trip I had thought that diving the Scapa Flow wrecks would be a bit dull – large piles of scrap iron in the deep dark cold of Scapa Flow. I was wrong. The wrecks are covered in life – thick fields of plumose anemones, sea-firs, colourful feather stars and fish adorn the hulls, which are coloured with orange rust and pink encrusting algae. And in amidst it all, you catch the occasional glimpse of ordnance, or the the viewing slot of the armoured bridge, just to remind you that you are, after all, diving a state of the art killing machine from the early years of the last century…

Thanks to Lewis Bambury for organising and inviting us along on this trip, and to all the members of Lunesdale Sub-Aqua Club who made us feel so welcome!

More information on the wrecks in Scapa Flow from Scapa Map

Thanks to Laura Bates for coming to our meeting on 12th May to tell us more about the Irish Sea Conservation Zones project. The project has a group of 41 delegates, each looking after a specific interest group – fishing, gas, conservation etc. Their remit is to establish a set of conservation zones in the Irish sea, that will ultimately link to similar zones around the UK. The purpose of the current phase is to identify areas of high conservation potential, and determine what level of protection might be appropriate to minimise the impact of any legislation on other activities.

For more information, or to make your views heard, please see the Irish Sea Conservation Zones website:

Irish Sea Conservation Zones