A life and death issue, with a look at the short lives of copepods in our science sections, followed in exploitation by a look at how tunicates may hold the secret of a prolonged life for all of us. In conservation we ask if traditional conservation practice is the best way of protecting the marine ecosystem, and see that anoxic waters don’t stay buried!

Marine science

85 years of underwater photography: Iconic marine photos from National Geographic.

Land based challenge: I’ve always believed that most of life’s early developments happened at sea. Fossils from Loch Torridan in Scotland, however, suggest that some of the key stages of the development of the Eukaryotic cell may have happened in fresh water lakes. ScienceDaily (Apr. 14, 2011)

Any old bones: For a reason that escapes me, the bone eating worms of the family Osedax have become a bit of a biological celebrity. First discovered about a decade ago munching on whale skeletons in the deeps of Monteray, California, they have now been found not to be fussy about their diet – fish bones will do! ScienceDaily (Apr. 18, 2011)

Crop dusting: Dust from Saharan desert storms, and the plankton it helps to fertilize, are shown in a satellite image from Envisat. ESA via ScienceDaily (Apr. 17, 2011)

Climate and evolution: Fossil forams have been investigated in greater detail than ever before to unlock some of the secrets of their evolution. It looks like climate change is one of the main causes of extinctions, whilst new species appear when the ecosystem is relatively free of competitors. The number of species or diversity of the ecosystem is not related to extinctions. ScienceDaily (Apr. 19, 2011)

Fishing for divers: Underwater visual surveys conducted by scuba divers can be a good way of comparing the density of fishes in different locations. The very presence of divers, however, causes many fish to flee the area (up to 70% of some species leave the vicinity of divers) – so they are never counted. Best practice involves carrying out a count along a pre-layed transect of fixed length.
Dickens LC, Goatley CHR, Tanner JK, Bellwood DR (2011) Quantifying Relative Diver Effects in Underwater Visual Censuses. PLoS ONE 6(4): e18965. doi:10.1371/journal.pone.0018965

Virgin survivors: Copepods are an important component of the zooplankton, but not much is known about their life history. This study elucidates a number of interesting facts – virgin males can expect to live for about 40 days, whilst those with access to mates survived only 20 days. Virgin females survived for nearly 80 days, with less reduction for those with access to mates. Males swim faster than females, in order to find mates, and this may be the cause of their shortened lives (more interesting observations in the paper!).
Ceballos S, Kiørboe T (2011) Senescence and Sexual Selection in a Pelagic Copepod. PLoS ONE 6(4): e18870. doi:10.1371/journal.pone.0018870

We’ve all got to die: Given their short life-spans, it is inevitable that many copepods die of causes other than predation. In this study they estimate that 10% of all copepods die of ‘natural causes’, leaving tiny copepod corpses floating in the water. More seriously, copepods are a vital food source for fish, so knowing the actual biomass that can be converted into fish protein improves our quantitative understanding of the ecosystem. ScienceDaily (Apr. 13, 2011)

Peak of diversity: The peak in decapod (crabs, shrimps and lobsters) diversity occurs just below the low water mark on rocky shores, correlating with the peak in macro-algal biomass.
Pohle G, Iken K, Clarke KR, Trott T, Konar B, et al. (2011) Aspects of Benthic Decapod Diversity and Distribution from Rocky Nearshore Habitat at Geographically Widely Dispersed Sites. PLoS ONE 6(4): e18606. doi:10.1371/journal.pone.0018606

Life and times of the lancelet: Lancelets are fish-like animals closely related to the vertebrates. This study looks at a natural population of the coast of France during the spawning season.
Desdevises Y, Maillet V, Fuentes M, Escriva H (2011) A Snapshot of the Population Structure of Branchiostoma lanceolatum in the Racou Beach, France, during Its Spawning Season. PLoS ONE 6(4): e18520. doi:10.1371/journal.pone.0018520

Cold homes for corals: Increasing the resolution of habitat modeling has identified more regions suitable for cold water corals.
Davies AJ, Guinotte JM (2011) Global Habitat Suitability for Framework-Forming Cold-Water Corals. PLoS ONE 6(4): e18483. doi:10.1371/journal.pone.0018483

Photosynthetic fluorescence: Fluorescence of chlorophyll occurs when energy captured form sunlight leaks out of the photosynthetic pathway. It is usually associated with low iron concentrations, and is often used to diagnose this problem in the field.
Schrader PS, Milligan AJ, Behrenfeld MJ (2011) Surplus Photosynthetic Antennae Complexes Underlie Diagnostics of Iron Limitation in a Cyanobacterium. PLoS ONE 6(4): e18753. doi:10.1371/journal.pone.0018753

Touch, or caress? Study shows that shrimps express the sex hormones (Z)-9-octadecenamide on the surface of their carapaces. The hormone is lipophilic (‘fat loving’) – so it does not disperse into the water column quickly, and is probably used as a contact cue to the male of the species. This may be the first report of the presence of this type of hormone in a marine organism, though it is well known in insects, prompting the question of how wide-spread this type of interaction is in the marine environment.
Zhang D, Terschak JA, Harley MA, Lin J, Hardege JD (2011) Simultaneously Hermaphroditic Shrimp Use Lipophilic Cuticular Hydrocarbons as Contact Sex Pheromones. PLoS ONE 6(4): e17720. doi:10.1371/journal.pone.0017720

Child rearing costs: Study on Tilapia (Oreochromis spp.) shows that brooding young in your mouth is not without cost. Parents need to change the chemistry of their mouths while they are looking after young, and increase the amount of protective mucus they generate. (While tilapia are a fresh-water fish, a number of marine species also use mouth brooding to protect very young fish).
Iq KC, Shu-Chien AC (2011) Proteomics of Buccal Cavity Mucus in Female Tilapia Fish (Oreochromis spp.): A Comparison between Parental and Non-Parental Fish. PLoS ONE 6(4): e18555. doi:10.1371/journal.pone.0018555

Broken habitats not broken lineages: The limpet Tectura paleacea can only survive on sea grasses, which have a patchy distribution. In this study on the Californian coast it was found that while the intra-species diversity of the limpet was dependent upon location, this was driven by local environmental factors, not by problems of dispersal and cross fertilisation between isolated limpet populations.
Begovic E, Lindberg DR (2011) Genetic Population Structure of Tectura paleacea: Implications for the Mechanisms Regulating Population Structure in Patchy Coastal Habitats. PLoS ONE 6(4): e18408. doi:10.1371/journal.pone.0018408

Can’t see to tell the time: Cave fish that live in perpetual darkness spend less time asleep than their cousins that have not adapted to this environment. ScienceDaily (Apr. 8, 2011)

Conservation

Questioning conservation strategy: The common conservation strategy of trying to protect rare and endangered species comes under criticism in the marine environment. Our seas have seen previously common species being wiped out by fisheries mismanagement, causing knock-on damage to the entire ecosystem, and greatly reducing its ability to support any life at all… ScienceDaily (Apr. 18, 2011)

Fisheries recuperation: The importance of studying how areas recover from fisheries activities cannot be underestimated, as this will determine how quickly the world’s oceans can recuperate from centuries of mismanagement. Here the Stellwagen Bank National Marine Sanctuary (designated 1998, Gulf of Maine, US) is followed after designation as a Marine Protected Area, to see how quickly the sea-floor recovers from decades of bottom trawling. This interim report indicates that no firm conclusions can yet be drawn. Full recovery may be a long and drawn out process… ScienceDaily (Apr. 22, 2011)

A serious blow for coastal ecosystems: Hypoxic waters, which have oxygen levels below 2mg/l – which low enough to cause severe stress or death for many marine organisms, are of increasing concern in coastal waters. They occur as the conclusion of a sequence of events: The absence of filter feeding fishes, or the presence of excess nutrients (both of which are usually caused by human activity) stimulates a phytoplankton bloom. When the plankton dies it decays, using up oxygen on the water. Commonly we don’t see the consequences of this, as the dead plankton sinks to the bottom, but in this study it is found that winds can bring the dead water back to the surface, and drive it into normally highly productive estuaries.
Roegner GC, Needoba JA, Baptista AM (2011) Coastal Upwelling Supplies Oxygen-Depleted Water to the Columbia River Estuary. PLoS ONE 6(4): e18672. doi:10.1371/journal.pone.0018672

Engineering fix: Wind operated pumps are being recommended for use in the Baltic, these would pump oxygenated surface water down to replace the deoxygenated water there. ScienceDaily (Apr. 18, 2011)

Scotland’s National Marine Plan (Pre-Consultation Draft): The Scottish Government’s objectives for marine management include wealth creation and protection of a healthy marine ecosystem. In the past these have clearly been mutually exclusive objectives, witnessed by the legally endorsed collapse of most fisheries around the principality. There is an online response form to make your views clear. The Scottish Government, March 21st 2011.

Grass banks protect coral: Vetiver grass banks have a spongy root system that stabilises dune sands close to the coast. This reduces soil erosion, and the plumes of sediment that suffocate corals. ScienceDaily (Apr. 7, 2011)

Toxic turtles: A tracking study combined with taking blood samples of loggerhead turtles showed that the amounts of persistent organic pollutants in their blood was associated with where they foraged. ScienceDaily (Apr. 19, 2011)

Noise kills: Official, noise caused by underwater prospecting and deep penetrating sonar systems can causes fatal damage to squid and octopuses. ScienceDaily (Apr. 11, 2011)

Fisheries and exploitation

Radiation trap: A mix of hemicellulose (from wood) and chitosan (from crustacean shells) traps radioactive iodine, and may help clean up after nuclear accidents. ScienceDaily (Apr. 15, 2011)

Rejected! The rejection of life-giving organ transplants is a serious problem in modern medicine, where many patients die before being found a compatible replacement. An understanding of the rejection response may be gained b looking at the colonial sea squirt Botryllus schlosseri (common around the UK coast), which can sense whether or not a neighboring sea squirt is a clone of itself, or an invader. ScienceDaily (Apr. 15, 2011)

Buddies live longer: Most organisms are subject to senescence – a gradual process of genetic deterioration – that defines their maximum attainable life span. Life is a race to breed and pass on your genes before the inevitable. For organisms that normally reproduce by cloning (or budding), however, when the genetic clock is not rebuilt and reset, senescence poses a serious threat of extinction. Colonial sea squirts get round this by boosting levels of telomerase, an enzyme that protects DNA from damage. Elevated levels of telomerase are also found in unusually long-lived humans. ScienceDaily (Apr. 19, 2011).

New Caledonian conflicts: New Caledonia’s lagoon (Melanesia) is home to one of the world’s most extensive reef formations, and the world’s third largest nickel mine. The two have cohabited for a century, during which time the reef has been largely protected by a fast flush through of water, clearing turbidity caused by mining operations. The new study should help to improve reef health further. ScienceDaily (Apr. 20, 2011)

Benefits of reserves: Numbers of juvenile scallops in the Arran reserve have been found to be much greater than in surrounding, unprotected, waters. There is also evidence of generally improved biodiversity.
ScienceDaily (Apr. 22, 2011)

Mining the cyanobacterial genome: Reported methodology uncovers a possible apratoxin, a biosynthetic gene cluster, and a cytotoxin with promise for treating cancer.
Grindberg RV, Ishoey T, Brinza D, Esquenazi E, Coates RC, et al. (2011) Single Cell Genome Amplification Accelerates Identification of the Apratoxin Biosynthetic Pathway from a Complex Microbial Assemblage. PLoS ONE 6(4): e18565. doi:10.1371/journal.pone.0018565

Common jellyfish cause gill damage: Caged salmon are unable to escape jellyfish swarms, which can cause injury and death. In this study it is found that macerated common jellyfish Aurelia aurita caused extensive gill damage to Atlantic salmon.
Baxter EJ, Sturt MM, Ruane NM, Doyle TK, McAllen R, et al. (2011) Gill Damage to Atlantic Salmon (Salmo salar) Caused by the Common Jellyfish (Aurelia aurita) under Experimental Challenge. PLoS ONE 6(4): e18529. doi:10.1371/journal.pone.0018529

Shit drifts: Concentrated waste plumes from fish farms can effect coasts a lot further away than would be from by a simple dilution model for waste entering the marine system. ScienceDaily (Apr. 7, 2011)

Immunity in scallops: The enzyme dopa decarboxylase (DDC) is vital to the immune regulatory network of molluscs.
Zhou Z, Yang J, Wang L, Zhang H, Gao Y, et al. (2011) A Dopa Decarboxylase Modulating the Immune Response of Scallop Chlamys farreri. PLoS ONE 6(4): e18596. doi:10.1371/journal.pone.0018596

Pollution

In Deepwater, a blow-out in the first world: This is an interesting and informative review of the Gulf of Mexico oil spill (2010). This review places the disaster within the global environmental context. A context in which the same amount of oil (equivalent to about one day’s supply of petrol for the US) is spilt every year in the Niger delta. Essential reading.
Safina C (2011) The 2010 Gulf of Mexico Oil Well Blowout: A Little Hindsight. PLoS Biol 9(4): e1001049. doi:10.1371/journal.pbio.1001049
There is also a press release from scientists at Cornell. [While very little is understood about the Gulf marine ecosystem, it is one of the better studied ecosystems in the world, both before and after the spill.] ScienceDaily (Apr. 19, 2011)

No smoking gun: Deaths of dolphins in the Gulf of Mexico are not necessarily related to the Deepwater Horizon incident. By para_sight in Deep Sea News, April 10th, 2011 [This, and linked articles in the discussion, look at the NOAA’s published statistics for dolphin deaths over the last decade, and how correlation may not correspond to causation]

Climate change

Sun lovers suffer in the heat: Not all penguins like life in the cold, but even species such as the chinstrap penguin will suffer as a result of global warming, as the base of the antarctic food chain depends upon krill, which in turn depends upon sea ice. ScienceDaily (Apr. 11, 2011)

King of Antarctica: Water temperatures in Antarctica are now high enough to permit king crabs to get established. They pose a threat to indigenous molluscs and other shelled animals, which have not had to protect themselves from shell crushing predators for millennia, and have gone soft as a consequence… ScienceDaily (Apr. 19, 2011)

Old mermaids tales: The tooth enamel of fossil sirenia (related to dugongs and sea cows) has been used to provide historical records of oxygen-18 concentrations, which are indirectly related to climate. ScienceDaily (Apr. 21, 2011)

Old reefs more diverse: Shallow ancient reefs were hardest hit by ocean acidification in previous cycles of climate warming. However, the paleantology of ancient reefs indicate that they were more diverse than their modern day counterparts, and that may have helped them survive climate change. ScienceDaily (Apr. 7, 2011)