A good couple of weeks of marine science here – from fun to fundamental stuff, and often both together! Fundamental and important is the possibility that studies of nitrogen uptake in the marine ecosystem may have have underestimated the amounts of nitrogen being fixed by marine organisms. Fundamental and fun – well, take your choice from scampering scallops to the secretive sex-life of snails!

In conservation the emerging issue is deep-sea bottom trawling; there doesn’t seem to be any way of controlling this, so I guess the industry will continue until the stocks crash, taking an entire ecosystem with them (if you care, buy fish from sustainable sources – this does not include any deep sea species!). In pollution the important stories are still with the Gulf Oil Slick, with the publication of BP’s report into the accident, and some interesting strands in the debate as to where the oil has gone…

The chemistry of fear – or how scallops fuel their escape swimming response: Molluscs are not in general known for their speed, so the ability of several marine species to snap, jump or even swim away from predators is quite surprising. All divers will be familiar with the way that scallops take off like a set of demented false teeth when your shadow passes over them! This paper is an in-depth analysis of the biochemistry involved with converting chemistry into quick release energy in the aductor muscles, that permits the scallop to escape in this way. The study is particularly nice in that the protein conformation changes involved have been followed in solution, using nuclear magnetic resonance, rather than by trying to crystallise out all the intermediates for crystallography. This helps avoid artefacts that might occur in the crystallisation process. As such the study has a broader importance in improving our understanding of how life works at a molecular level.
Smits SHJ, Meyer T, Mueller A, van Os N, Stoldt M, et al. (2010) Insights into the Mechanism of Ligand Binding to Octopine Dehydrogenase from Pecten maximus by NMR and Crystallography. PLoS ONE 5(8): e12312. doi:10.1371/journal.pone.0012312

Coordinated crabs: A nice review article on how cold blooded animals keep their coordination over a wide range of temperatures – so they just slow down when it gets cold, rather than stumble. As neural activity is the process of a number of chemical reactions and transport processes – all of which have different rate responses to changes in temperature – this is not a trivial trick!
Robinson R (2010) Firing Hot, Firing Cold: How Poikilotherms Compensate for Temperature Swings. PLoS Biol 8(8): e1000470. doi:10.1371/journal.pbio.1000470

Nitrogen update: Historically experiments may have underestimated the ability of marine organisms to fix nitrogen gas, converting it into useful biological compounds. Experimental techniques rely on the organisms being incubated with ¹⁵N₂, and the rate at which this appears in biological molecules is used to guage the rate of fixation. However, the new study shows that under standard conditions the amount of bubbles of ¹⁵N₂ only equilibrate with the nitrogen dissolved in the seawater very slowly. As a consequence, if the solution is not either vigorously shaken or left for several days, there is a lot less ¹⁵N₂ present in the seawater for the organism to make use of – and consequently its rate of uptake is very low. The authors cite a number of anomalous carbon-nitrogen fixation ratios in the literature that suggest that under-estimation is common. This is a fundamental measurement for the marine food-web, as fixed, organic nitrogen is an essential component of proteins and nucleic acids, which are in turn essential for life itself. Nitrogen fixation is commonly a choke point in the web of life, so in short, the more nitrogen you can fix, the more biomass you can sustain.
Mohr W, Großkopf T, Wallace DWR, LaRoche J (2010) Methodological Underestimation of Oceanic Nitrogen Fixation Rates. PLoS ONE 5(9): e12583. doi:10.1371/journal.pone.0012583

Is it a bird, is it a fish? Latest research indicates that flying fish can glide as efficiently as any bird, and rather better than the flying insects. Making use of the Coandă effect, which comes into play close to the sea surface, flying fish can reach speeds of 70 km/hr and cover distances of up to 400m in a single glide. ScienceDaily (Sep. 11, 2010)

The rough with the smooth: Female snails usually leave behind a scent trail that is eaily followed by courting mails. Not so the rough periwinkle (Littorina saxatilis), common on European coastlines. In this species the lady snail does her best to hide her scent – so the amorous male has to expend at least twice the energy chasing down a prospective mate. It seems as though the retiring females are already getting a lot more attention than they like (or is needful in a population biology sense).
Johannesson K, Saltin SH, Duranovic I, Havenhand JN, Jonsson PR (2010) Indiscriminate Males: Mating Behaviour of a Marine Snail Compromised by a Sexual Conflict? PLoS ONE 5(8): e12005. doi:10.1371/journal.pone.0012005

Neat current meter: One of the things that has always frustrated me when trying to understand a site is how it is effected by currents when you are not diving on it – we all say ‘plumose anemones – must have a lot of water flow’ – but we can only dive and view it at slack water. This nifty SeaHorse tilt current meter looks like a possible solution, though I guess you’ll still need some funding to use them however cheap they are… ScienceDaily (Sep. 14, 2010)

Algae vs. corals, round 1: Coral reefs are delicate environments depending on the interactions between a range of organisms. Disturbed reefs are often overgrown with algae, which can add considerable stress to the underlying coral, and reduce its chances of survival. This study looks at how the presence of algae effects the chemical and physical environment around the corals. Parameters evaluated include pH, O_2,, alkalinity, dissolved carbon, silicic acid, phosphorus and sunlight. The largest effects are seen for algal mats, which can form a carpet over the coral, rather than for macro algae (‘seaweed’) that forms a canopy above the coral.
Hauri C, Fabricius KE, Schaffelke B, Humphrey C (2010) Chemical and Physical Environmental Conditions Underneath Mat- and Canopy-Forming Macroalgae, and Their Effects on Understorey Corals. PLoS ONE 5(9): e12685. doi:10.1371/journal.pone.0012685

The Queen Conch, castrated: The queen conch (Strombus gigas) is a marine snail that lives off the Florida Keys. For some years scientists had noted that many of the conches living close to the shore failed to reproduce, whilst those further off shore had no problems. This recent piece of research shows that heavy metal pollution is probably to blame. Molluscs are, apparently, very sensitive to trace amounts of copper and zinc in the environment, and these metals prevent testis development.
Spade DJ, Griffitt RJ, Liu L, Brown-Peterson NJ, Kroll KJ, et al. (2010) Queen Conch (Strombus gigas) Testis Regresses during the Reproductive Season at Nearshore Sites in the Florida Keys. PLoS ONE 5(9): e12737. doi:10.1371/journal.pone.0012737

Baltic Sea biodiversity: Semi-enclosed, the salinity Baltic has a lower salinity than the North Sea, falling to 3ppt in the Bay of Bothnia, in comparison to 34-35ppt in the open sea. This results in an interesting ecosystem, as many truely marine organisms cannot tollerate brackish waters, whilst fresh water organisms don’t like salt! This report details the numbers of known species in these waters by phylum, and how the biodiversity changes through the Baltic, from the Kattegat to the Bay of Bothnia. An interesting inclusion is a look at introduced species, and their origins.
Ojaveer H, Jaanus A, MacKenzie BR, Martin G, Olenin S, et al. (2010) Status of Biodiversity in the Baltic Sea. PLoS ONE 5(9): e12467. doi:10.1371/journal.pone.0012467

Farmed conches: The size of the pacific conch Strombus gibberulus has been shown to have increased over the last 3000 years or so – as human populations have increased in the area. The conch is an important food, so it is possible that the conches have been farmed, selecting for the larger meatier individuals. The findings are in contradiction to earlier studies on smaller sample sizes, and the size increase is a modest 5%. ScienceDaily (Aug. 31, 2010)

The once and future reef: Remains of a coral reef have been found around Lord Howe island outside the current range for reefs, few of which can survive in waters colder than 20°C. The reef was thought to have thrived between 9000 and 7000 years ago. While the remains are quite deep, it is thought that they may form a foundation for future reefs, if sea-water temperatures rise as expected. ScienceDaily (Aug. 31, 2010)

Conservation

Deep seafloor under threat: The North East Atlantic is one of the most heavily used bodies of oceanic water in the world, human impact in the shelf seas is well documented, this report evaluates how the deep seafloor (more than 200m depth) is being changed. The seabed is used for a range of activities – communications cables, oil and gas drilling, waste disposal (including munitions and radioactive waste), the main impact, however, is through bottom trawling. There is a large uncertainty in the actual area of sea bottom damaged by bottom trawls, but this is likely to be an increasing problem.
Benn AR, Weaver PP, Billet DSM, van den Hove S, Murdock AP, et al. (2010) Human Activities on the Deep Seafloor in the North East Atlantic: An Assessment of Spatial Extent. PLoS ONE 5(9): e12730. doi:10.1371/journal.pone.0012730

Oceans need management? In conclusions from a study on the Chilean marine coastal resources, the claim has been made that fisheries may depend on creating agreements between fishermen and scientists that are both voluntary and flexible enough to cope with changes in the ocean environment. Apparently sweeping changes are called for. This is not the best press release ever! ScienceDaily (Sep. 15, 2010)

US waters dying: The risk of extensive low-oxygen dead zones in US waters is increasing due to increased discharges of nutrients from human terrestrial activity. The nutrients spur bacterial activity that strips oxygen out of the water, killing anything that cannot move away quickly. Anoxic waters are common in the Gulf of Mexico, mid- and South- Atlantic regions and Chesapeake Bay, they commonly occur in the summer, when waters are calm, so nutrients and bacteria are not dispersed. ScienceDaily (Sep. 14, 2010)

Restoring coastal wetlands: Research emphasises the important of monitoring the water in the sediment – for salinity and saturation – and developoing plans that match these to species requirements. ScienceDaily (Sep. 7, 2010)

Whales flee oil-boom: The activities of the Russian oil and gas company Rosneft have come under criticism from whale conservationists. Seismic surveys around Sakhalin island, in the Russioan Far East, are said to have driven away populations of the critically endangered gray whale (Eschrichtius robustus). Conservationists have asked for the surveys to be delayed until after the brief feeding season, to give the whales chance to put on weight for the winter. ScienceDaily (Sep. 7, 2010)

The seabird bycatch: Seabirds try to take bait off long lines used by fishermen because it is a free meal. They usually try to take bait when the lines are cast, and still close to the surface. One third of attempts are successful in that the bird gets the bait and gets away. 57% of attempts by the seabird are unsuccessful, while 3% result in the bird getting caught. The numbers of birds caught are counted when the line is recovered, however, at this point many of the birds killed have become detatched from the line, so the total numbers of seabirds killed taking bait is greatly underestimated.
Brothers N, Duckworth AR, Safina C, Gilman EL (2010) Seabird Bycatch in Pelagic Longline Fisheries Is Grossly Underestimated when Using Only Haul Data. PLoS ONE 5(8): e12491. doi:10.1371/journal.pone.0012491

Fishing and exploitation

$240,000,000,000 of fish: The estimated value of the fish landed each year by the fishing industry globally. Unfortunately this total has been reduced by 36% through overfishing… The article is not clear as to whether this sum is the value of the fish, or the value of the fish plus ancillary industries. ScienceDaily (Sep. 14, 2010)

Stop deep sea fishing? Claire Nouvian makes a passionate plea to stop deep sea fishing – she says that a small number of boats are responsible for enourmous amounts of damage. Only a tiny fraction of the catch is saleable – to rich westerners, and the entirety of it is unsustainable. Marine Conservation News, Tuesday, September 14, 2010

Better nets for aquaculture: Basic research on how to make better nets to keep aquaculture fish in, whilst not impeding the flow of seawater through the enclosure. ScienceDaily (Sep. 13, 2010)

Pollution

BP’s oil-spill report: Lots of technical detail in the full report, including logging data from the rig covering significant periods up to the point of failure. There is also a six-page executive summary, this includes a 1 page cover and 1 page legal caveat – so really brief! In this report BP makes its first attempt to describe the events that led to failure. The material evidence presented here is incomplete, as the blow-out preventer, a critical piece of safety equipment, and other sub-surface equipment has yet to be examined. Otherwise it is probably accurate – there is far too much at stake to be caught lying here. I guess, however, you should be a little careful about how you read the inferences from this evidence made in the executive summary. Essentially the reason for the accident lies somewhere in the spectrum between incompetent management or personel, and inadequate technology for (deep*) drilling. A lot of money rests on where in this spectrum the bottle stops spinning. None of this money will make any difference to the sealife that has been killed by the accident, and there is no guarantee that a future accident will be less likely after the money has been spent (go on, call me a cynic!).
*I’ve bracketed the word ‘deep’, as a lot of the stuff that failed appears to be standard drilling gear and practice, not specific to the deep water environment. Anyway, more content for my talk in November! BP.com, 8th September 2010

New model for surface slicks: A new model for how oil slicks move was used to predict the Gulf oil spill up to three days in advance, using information about the current and predicted sea-state to work out how the slick would break up into filaments. ScienceDaily (Sep. 2, 2010)

Where did the oil go? This report reviews the fate of oil that has been buried in beach sediments from a number of locations around the world. The generaly conclusion is that when oil gets buried there is not enough oxygen present in many sediments to allow bacteria to digest it. As a consequence it is likely to stay there for a long time – oil is still present at a depth of 8 inches in the sands of Buzzards Bay, Massachusettes US, 41 years after a spill there. Marine Conservation News, Thursday, September 16, 2010

Move along – nothing to see here! The US’s National Oceanic and Atmospheric Administration (NOAA) reports that the Gulf Oil spill has reduced oxygen concentrations by 20% from their long-term averages in the Gulf of Mexico. This is not low enough to create ‘dead zones’, where most life will perish. The oil has mostly been digested in deep water, away from the coastal regions of the Gulf, which regularly go anoxic, probably due to nutrients from human activity on land (See ‘US waters dying’). ScienceDaily (Sep. 13, 2010)

Oil may still be present in deep Gulf waters: Current mapping in the Gulf of MExico by the WAVCIS program indicate that current water movement is
pushing the oil off shore, where it will float up the water column to be brought into coastal areas again by storm events. My reading of this is that people are looking for the deep water oil slick in the wrong place… ScienceDaily (Sep. 9, 2010)