This week we start at the beginning of the marine food web – with algae blooming in the SW Atlantic, and plumbing the depths around Hawaii. In marine exploitation we see plans to mine hydrothermal vents in Papua New Guinea. Conservation worries in the Indian Ocean, with extensive bleaching now occurring due to high water temperatures. Coccolithophores make a guest appearance in climate change – responsible for absorbing large amounts of the CO₂ we’re pumping into the atmosphere – an understanding of their biology takes on global significance…

Marine science

Algal bloom in SW Atlantic: The fisheries of the Patagonian shelf are of global significance, and depend upon algal blooms that occur each year between December and January. The algae may be responding to the presence of seasonally available nutrients (see previous posts, however), but the shelf is very complex, with large river inputs, and further low salinity seawater entering from the South Pacific through the Magellan Straights, in this work five distinct interacting water masses are identified. During the cruise a large bloom of coccolithophores (Emiliania huxleyi) was observed at the shelf edge in water with a high concentration of calcite – calcium salts are required for the formation of coccoliths, the armouring plates that coccolithophores coat themeselves with. ScienceDaily (Oct. 21, 2010)

Algae plumb the depths: Plants are not happy in the dark, but the sybiotic algae have been found in black corals (Antipathes griggi) to depths approaching 400m. (I have seen claims of macroalgae living at depths in excess of 100m in clear waters. In most UK waters the compensation depth is less than 30m, which places a limit on the depth algae can grow to – keep an eye out for encrusting pink algae down to 40m in Atlantic waters, however! At 400m I suspect that the algae are parasitic, relying on food from the coral host, rather than contributing food through photosynthesis.) The Spill, Thursday, October 21, 2010.

Lizardfish: This review article looks at the Synodontidae, a group of fish that have been around for 145M years. Only seen in tropical waters, they do, however, exhibit a facinating range of adaptations (it’s the eyes that do it…). Deep-Sea News, October 20th, 2010

Hermit crab house-swap: Hermit crabs have been seen queuing up outside a desirable, but oversized shell – when a crab that fits the shell shows up, they are likely to shed their shell which becomes available to other crabs in the queue. After hours of queuing, the exchange activity can be over in a few seconds as every crab makes a mad dash for their des-res. To see this scientists had to monitor the crabs 24-7, but it sounds like a cool thing to keep your eye out for in the wild. EurekaAlert, 26-Apr-2010

Leopards and leopard sharks: Markings on big cats are associated with comoflage, and related to the type of environment that the cats inhabit. Apparently sats living in dense (jungle/forest) habitats and low light levels aremost likely to be patterned, whilst cats that exploit a range of habitats are likely to have the most diverse fur patterns. The paper notes that paterns can change very quickly in evolutionary terms. It is intriguing to wonder how patterning might be related to the environment in marine organisms – though, of course, many marine organisms can change their colours and patterns in a matter of seconds… ScienceDaily (Oct. 19, 2010)

Conservation

UN Convention on Biological Diversity: Nagoya 18-29 October 2010: An overview of the convention, what it is, who’s involved, its importance. From The Spill, Wednesday, October 20, 2010

Beyond the limits to growth: The WWF’s Living Planet Report for 2010 makes sobering reading. In short, we’re using resources more rapidly than they can be replaced. Follow the link above to explore interactive maps – showing how the UK compares to other countries, and infographics. The loss of wildlife in the tropics is highlighted as being of particular concern. WWF.

Bayous rebuilt? One impact of the oil spill in the Gulf of Mexico has been to turn the spotlight on the perilous state of Louisiana’s bayous – salt water marshes that are valuable habitats, as well as being an important barrier to hurricane surges. These marshes rely on inputs of sediment from the Mississippi, which have been cut off by dams and the canalisation of the river. Additional damage has been done by dredging channels through the marshes. Without intervention it is estimated that the bayou ecosystem will be lost entirely within the next 50 years. New Scientist, 9th October 2010, p8-10;

Coral mega-death: Reefs in the Indian Ocean are suffering what scientists are claiming may be the worst ever die-off. Some estimates indicate that coral cover could drop from 50% to 10% in the region. The die off is caused by high water temperatures of 34°C, 4°C above the regional average. Scientists are claiming that the run of high temperature years has been due to CO₂ induced climate change. ScienceDaily (Oct. 19, 2010)

Fisheries and exploitation

Steel from the deep: Papua New Guinea’s government has given the go-ahead for extraction of minerals from hydrothermal vents in the Manus Basin at a depth of 1600m. The vents are thought to be rich in Copper, zinc and gold. Deep Sea News, October 21st, 2010

Fixing sick clams: The Manila clam (Venerupis philippinarum) has been treated with antibiotics in Chinese fisheries with some success, but the release of antibiotics into the environment is linked to the development of antibiotic resistant bacteria, raising human health concerns. As a consequence Chinese researchers have been looking at using antimicrobial peptides (AMPs), which are used by the clams to fight diseases. This paper documents the isolation of the DNA of one of the clams AMPs called ‘big defensin’, and follows its development to in-vitro anti-bacterial studies.
Zhao J, Li C, Chen A, Li L, Su X, et al. (2010) Molecular Characterization of a Novel Big Defensin from Clam Venerupis philippinarum. PLoS ONE 5(10): e13480.doi:10.1371/journal.pone.0013480

Are squid sustainable? They grow quickly under ideal conditions, and can produce vast numbers of offspring. Their populations are, however, volatile, as they are eaten by just about everything. As a consequence population crashes are common, even without the impact of human fisheries. Large scale commercial squid fisheries are a relatively new phenomenon, and as they develop there will be need for caution, as some species may be particularly endangered by the new human predator. By Danna Staaf (October 17th 2010).

Oysters washed out: The amount of fresh water flowing through the rivers draining into the Gulf of Mexico was increased during the oil spill to protect coastal marshes from oil. While there is broad agreement that this was an important action that prevented serious long-term contamination, it has killed a large proportion of the oysters accustomed to living in the brackish waters. New Scientist 25th September 2010, p12.

Pollution

How badly damaged? An evaluation of the health of the Gulf of Mexico after the DeepWater Horizon spill indicates its ecological health score has fallen from 71 to 64 out of 100. This reflects the view that many scientists have, that the Gulf was already in bad shape from farm runoff, overfishing and smaller spills. By Seth Borenstein and Cain Burdeau in The Huffington Post, 18th October 2010

Whats changed? Blog posts from a Greenpeace scientist in the Gulf of Mexico. One point made was that it is very difficult to determin what has changed as a result of the spill, when there is very little baseline information to compare current conditions with… The Spill, Tuesday, October 19, 2010

Mother Nature – dirty in tooth and claw: Natural oil and gas seeps are estimated to contribute 600 kilotons annualy to the amounts of oil and gas in the world’s oceans. This is equivalent to 47% of the estimated total impact of hydrocarbon pollution (the balance is anthropogenic). It is why there are bacteria in the environment geared to digest hydrocarbons as a fuel source. Natural seepages are usually slow and diffuse, however, while human spills are concentrated. I guess it is like a little ketchup on your dinner, and a bottle of ketchup on your carpet, there is no denying that the latter is a mess… BlogFish, Thursday, October 14, 2010

Climate change

Where’s King Cnut when you need him? Sea levels are reported to be rising around the Falkland Islands, with acceleration in recent decades. Sea levels were first recorded on South Georgia in 1842, when the polar explorer James Clark Ross cut a set of benchmarks into the cliffs at Port Louis. These benchmarks are still visible today, and have allowed modern measurements to be compared with historic sea levels. The rate of sea-level rise was 0.75mm per annum to 1980’s, increasing to 2.5mm per annum since 1992. These rates are reported to be in good agreement with those measured in other places around the globe. ScienceDaily (Oct. 20, 2010)

It’s a gas: A range of factors impact global climate, but the latest modelling reinforces the long held understanding that it is carbon dioxide levels that control the temperature. ScienceDaily (Oct. 14, 2010)

Bitter twisting phytoplankton: Coccolithophores are thought to be important in absorbing carbon from the world’s oceans into their shells, but previous work had show this ability to be impaired at higher acidities, expected as a result of increased carbon dioxide concentrations in the atmosphere and water. This paper shows that some species are a lot less influenced by acidity, and that there is some capacity for these phytoplankton to evolve to cope with the changed conditions. After all, whilst increased carbon dioxide does increase acidity, it also increases the amounts of carbonate essential for the formation of calcium carbonate these guys use in their shells.
Irie T, Bessho K, Findlay HS, Calosi P (2010) Increasing Costs Due to Ocean Acidification Drives Phytoplankton to Be More Heavily Calcified: Optimal Growth Strategy of Coccolithophores. PLoS ONE 5(10): e13436. doi:10.1371/journal.pone.0013436

La plus ça change: If climate changes, then climatic cycles may change too, it this too obvious for comment? In this instance the focus of attention is how climate change might influence El Nino events in the Pacific. ScienceDaily (Oct. 18, 2010)