In this week’s science section the life history of the Nautilus is being revealed. It proves to be an animal with a long life span, and low fecundity, so in severe danger of becoming the once and future fossil, if it is placed under much pressure. On a more aggressive note, female squid select their males by proxy – encouraging them to fight it out amongst themselves for the privilege of passing on their genes.

A couple of videos this week in the fisheries and exploitation section. These come from the HMAP (History of Marine Animal Populations) project, which endeavours to quantify what the ocean food web looked like before we had such a dominant, and apparently disastrous, impact.

Finally in climate change we have a couple of reports showing how plankton can be used to monitor ocean circulation patterns – past and present.

Marine science

Twenty thousand leagues beneath the sea: The life history and ecology of Nautilus pompilius is being elucidated through a mixture of capture and release and baited underwater video cameras. Mature nautili are between 115 and 240mm in size, with males being slightly larger than females. They take 15 years to reach maturity, and their lifespan is estimated to be greater than 20 years. To date egg laying has not yet been observed in this animal.
Dunstan AJ, Ward PD, Marshall NJ (2011) Nautilus pompilius Life History and Demographics at the Osprey Reef Seamount, Coral Sea, Australia. PLoS ONE 6(2): e16312. doi:10.1371/journal.pone.0016312

In a separate paper it is noted that the the slow rate of maturation, low fecundity and long life span place these animals at considerable risk from habitat disturbance and very susceptible to over-exploitation.
Dunstan A, Bradshaw CJA, Marshall J (2011) Nautilus at Risk – Estimating Population Size and Demography of Nautilus pompilius. PLoS ONE 6(2): e16716. doi:10.1371/journal.pone.0016716

Why barcodes loose count: Genetic bar coding has become a very popular means of counting marine bacteria and other small unicellular plankton, in fact it is techniques like this that make it possible for us to estimate the diversity of these forms of life at all. This paper looks at some problems with using a single DNA marker (18S rDNA) to count species, pointing out that many bacterial species differ in their proteomics but not in the 18S rDNA marker.
Piganeau G, Eyre-Walker A, Grimsley N, Moreau H (2011) How and Why DNA Barcodes Underestimate the Diversity of Microbial Eukaryotes. PLoS ONE 6(2): e16342. doi:10.1371/journal.pone.0016342

Small, cryptic sponge: DNA bar coding techniques are used to differentiate species of Plocamionida. The authors use a mix of DNA markers and morphological studies to differentiate between species.
Reveillaud J, van Soest R, Derycke S, Picton B, Rigaux A, et al. (2011) Phylogenetic Relationships among NE Atlantic Plocamionida Topsent (1927) (Porifera, Poecilosclerida): Under-Estimated Diversity in Reef Ecosystems. PLoS ONE 6(2): e16533. doi:10.1371/journal.pone.0016533

Apoptosis in molluscs: Apoptosis, or programmed cell death, is a core control feature in the development and survival of most [all?] multicellular animals. Added to this, sedentary marine molluscs such as the mussel Mytilus galloprovincialis have to sit and cope with whatever the water washes over them – pollutants and pathogens both. This paper looks at how apoptosis is controlled in galloprovincialis, and finds a system as complex as that in vertebrates, with some added features that are probably geared to its unusually difficult environment.
Romero A, Estévez-Calvar N, Dios S, Figueras A, Novoa B (2011) New Insights into the Apoptotic Process in Mollusks: Characterization of Caspase Genes in Mytilus galloprovincialis. PLoS ONE 6(2): e17003. doi:10.1371/journal.pone.0017003

Volcanic vents in the southern seas: Scientists aboard the RV James Cook has discovered a new set of volcanic vents in the Southern Ocean 500 kilometres south-east of South Georgia. ScienceDaily (Feb. 14, 2011)

Fight you for it! Female squid put a pheromone into their eggs that triggers intense aggression in any male squid that comes into contact with it. This may ensure that the males compete more ardently to fertilise the eggs, and so ensure that only the fittest males get to pass their genes on – a sort of selection by proxy. ScienceDaily (Feb. 11, 2011)

Any old iron? Iron is is in short supply in the open oceans, yet it is vital for a range of enzymes, including those for nitrogen fixation and for photosynthesis. The cyanobacterium Crocosphaera watsonii has a novel way of using the iron it has more efficiently, by recycling it between nitrogen fixation enzymes and photosynthetic pigments. At night, the iron is part of the nitrogen fixation enzymes, some of which are broken down to release iron for photosynthesis during the hours of daylight. As night falls again the process is reversed. The energy cost of breaking up and re-building enzymes is out-weighed by the ability to re-use iron. ScienceDaily (Feb. 13, 2011)

My degenerate cousin: If an organism is simple, is it because it hasn’t bothered to evolve? – Or is it that it was quite complex, but let itself slip… Acoelomorphs are simple marine flat-worms that have neither a nervous system nor a gut. As such they have been assumed to have retained the primitive form of an organism fitting in somewhere between the jellyfish and the rest of the animal kingdom in terms of complexity of body structure. DNA analysis has now shown, however, that they share a common ancestor with vertebrates and starfish – so presumably had a gut and nervous system, which they have subsequently lost… ScienceDaily (Feb. 9, 2011)

Predicting benthic biomass: A global map of seafloor biomass has been estimated by taking existing data from oceanographic institutes participating in the Census of Marine Life (CoML), and feeding this into the ‘Random Forests’ computer model. The approach circumvents problems with the nature of existing data on the sea-floor, which is based on tiny, discrete and largely un-connected samples. It compares oceanographic conditions at each sample site with the life found at that site, and then weights these results in comparison to other sites to give an estimate for biomass for each bottom type, depth and latitude.
Wei C-L, Rowe GT, Escobar-Briones E, Boetius A, Soltwedel T, et al. (2010) Global Patterns and Predictions of Seafloor Biomass Using Random Forests. PLoS ONE 5(12): e15323. doi:10.1371/journal.pone.0015323

Killer plant! The dinoflagelate Oxyrrhis marina is a voraceous predator, usually feeding on photosynthetic bacteria (such as the bluegreen algae). At some point in the past it acquired the genetic code from its prey for producing its own photosynthetic pigment (rhodopsin). The authors here believe that the dinoflagelate is now able to photosynthesise using this pigment, as well as adopting its characteristic pink colouration. ScienceDaily (Feb. 8, 2011)

Sub-bugs cosy up in families: Bacteria often have two DNA components – the core chromosomal bacterial DNA and plasmids, which are separate sections of code that are able to replicate independently. While they may be physically separate from the chromosomal DNA, plasmids are often the cause of virulence in the host (i.e. they make you sick by producing toxins etc.). This study looks at a plasmid in a Vibrio bacterium that infects clams. Whilst this is big for a plasmid, it is quite a small DNA loop, and the authors have mapped this out and compared it with plasmids from other marine bacteria to work out the function of each section of code. While most of the plasmid’s code is simply associated with replicating itself, there may also be a toxin code present. The authors suggest that the plasmid may be part of a broader family of marine plasmids that co-exist with a range of different bacteria.
Erauso G, Lakhal F, Bidault-Toffin A, Le Chevalier P, Bouloc P, et al. (2011) Evidence for the Role of Horizontal Transfer in Generating pVT1, a Large Mosaic Conjugative Plasmid from the Clam Pathogen, Vibrio tapetis. PLoS ONE 6(2): e16759. doi:10.1371/journal.pone.0016759

CoML founder gets lobsters*: A new genus of lobster has been described from deep waters near the Phillipines. Dinochelus ausubeli has one long thin claw for catching prey (see linked article), and is named after Jesse Ausubel of the Census of Marine Life. ScienceDaily (Feb. 5, 2011)
* Lucky it wasn’t an animal in the genus Carcinus!

Conservation

Shark management: Capture and release studies of sharks provide the first ever population estimates for Galapagos sharks (Carcharhinus galapagensis), and may help to develop reef management strategies.
Dale JJ, Stankus AM, Burns MS, Meyer CG (2011) The Shark Assemblage at French Frigate Shoals Atoll, Hawai‘i: Species Composition, Abundance and Habitat Use. PLoS ONE 6(2): e16962. doi:10.1371/journal.pone.0016962

Runoff on the reef: Terrestrial runoff is closely associated with disease on the Great Barrier Reef.
Haapkylä J, Unsworth RKF, Flavell M, Bourne DG, Schaffelke B, et al. (2011) Seasonal Rainfall and Runoff Promote Coral Disease on an Inshore Reef. PLoS ONE 6(2): e16893. doi:10.1371/journal.pone.0016893

Acoustic tags monitor endangered fish: The movements of tagged smalltooth sawfish (Pristis pectinata) along a 27 km stretch of the Caloosahatchee River estuary, Florida, were folloed using acoustic receivers. The fish were found to favour water with a salinity between 18 and 24 ppt, which may be an important limit on their effective range within the river estuary, and suggests river management may be important in their conservation.
Simpfendorfer CA, Yeiser BG, Wiley TR, Poulakis GR, Stevens PW, et al. (2011) Environmental Influences on the Spatial Ecology of Juvenile Smalltooth Sawfish (Pristis pectinata): Results from Acoustic Monitoring. PLoS ONE 6(2): e16918. doi:10.1371/journal.pone.0016918

Bitter pill: Ocean acidification will increase the conservation effort required to safeguard coral reefs. ScienceDaily (Feb. 13, 2011)

Turtle tracker: Satellite tracking of leatherback turtles has provided a better understanding of how they use the marine ecosystem, and suggest targeted conservation techniques that will cause less friction with fishermen. ScienceDaily (Feb. 8, 2011)

The crabs are listening: It looks like crustacea listen out for sounds of trouble on the Great Barrier Reef, this research played back sounds to a wide variety of crustacea at various stages of their life history, and demonstrates that they respond to auditory cues. Taxa that live near (but not on) reefs actively avoid reef noise, whilst the larvae of organisms that make the reef their home are attracted to it.
Simpson SD, Radford AN, Tickle EJ, Meekan MG, Jeffs AG (2011) Adaptive Avoidance of Reef Noise. PLoS ONE 6(2): e16625. doi:10.1371/journal.pone.0016625

Fisheries and exploitation

Poisonous genes: The saxitoxin biosynthetic gene cluster in the cyanobacterium Lyngbya wollei has been identified. Saxitoxin is responsible for paralytic shellfish poisoning, and identification of the genetic markers related to the poison will permit the development of toxin probes.
Mihali TK, Carmichael WW, Neilan BA (2011) A Putative Gene Cluster from a Lyngbya wollei Bloom that Encodes Paralytic Shellfish Toxin Biosynthesis. PLoS ONE 6(2): e14657. doi:10.1371/journal.pone.0014657

Farmed sea-lice: This paper demonstrates a correlation between the presence of fish-farms and sea-lice in wild salmon (specifically Canadian sockeye salmon, Oncorhynchus nerka).
Price MHH, Proboszcz SL, Routledge RD, Gottesfeld AS, Orr C, et al. (2011) Sea Louse Infection of Juvenile Sockeye Salmon in Relation to Marine Salmon Farms on Canada’s West Coast. PLoS ONE 6(2): e16851. doi:10.1371/journal.pone.0016851

Home truths about the fish on your plate: U-Tube video of Poul Holm (Professor of Environmental History and Academic Director of the humanities research centre at Trinity College Dublin) speaking at IGNITE Dublin, documenting the global decline of the world’s fisheries. (via Kevin Zelnio at Deep Sea News, February 9th, 201) Also of interest: History of Marine Animal Populations, also by Poul Holm.

Comb jelly no threat to cod: The comb jelly Mnemiopsis leidyi, which has recently invaded the Baltic, has been shown not to pose a direct threat to cod eggs. The jellys may out-compete the cod larvae and so pose an indirect threat. The appearance of Mnemiopsis leidyi in the Black Sea had been associated with the fisheries collapse there – this is more likley to have been coincidental with the effects of eutrophication and over-exploitation. ScienceDaily (Feb. 9, 2011)

Veggie salmon: Salmon can be reared on a diet in which 50% of the usual fishmeal components are replaced with vegetable alternatives, without detriment to the fish quality. ScienceDaily (Feb. 10, 2011). But, some combinations of vegetable proteins don’t work. ScienceDaily (Feb. 11, 2011)

Soybean replacement for fishmeal: The increased cost of fishmeal is making alternatives more attractive to pig farmers. One option is soybean treated so that younger pigs can eat it. ScienceDaily (Feb. 7, 2011)

Submerged cages: Salmon rarely need to surface to top up their swim bladders, so for much of the time they can be housed in submerged cages, avoiding storm damage, sea lice and algae. ScienceDaily (Feb. 11, 2011)

Pollution

Gas and oil: 500,000 tons of gaseous [at STP] hydrocarbons were released during the Gulf Oil Spill. ScienceDaily (Feb. 14, 2011)

Waste for water treatment: Certain types of mining by-product spread onto agricultural land can help filter nutrients out of the ground water before it reaches watercourses. ScienceDaily (Feb. 6, 2011)

Climate change

Diatoms probe the past: Diatoms are sensitive to temperature, so looking at their distribution in the geological record has allowed scientists at Southampton to rebuild the oceanographic circulation patterns linked to past climates in greater detail than previously possible. Their work suggests that previous warming cycles were not associated with a collapse of the broad scale ocean circulation patterns. ScienceDaily (Feb. 14, 2011)

Forams show heat transfer: This review of an original article in Science shows how the arctic foram population has recently been displaced by sub-polar species. Miriam in Deep Sea News (Feb. 8th, 2011).

Atlantic trades slow: Climate change is still hard to pick out of random weather events, but recent analysis suggests that over the past 60 years trade winds over the tropical Atlantic have slowed, resulting in increased rainfall in South America, and reduced rainfall in the Sahel. ScienceDaily (Feb. 6, 2011)