No limit to growth? – This is the surprising conclusion from studies on reef ecosystems, where it is found that total productivity continues increasing as the biological diversity on the reef increases. The broader implication for marine conservation management is that it is important to maintain balance across the widest possible diversity of life in the ecosystem.

Otherwise in this issue we see reasons not to be popular – if your a Weddell seal, and your popularity is as a snack for orcas. Also we get a glimpse of the slow lives of deep corals – which have led blameless, if rather uneventful, lives since the times of the Roman emperors, only to be killed by the recent oil spill in the Gulf of Mexico. There are no places left on the planet that can claim to being untouched by human activity. We must understand our impact better, and take responsibility for our actions – our ancestors will be able to read the records of our crimes in the sediments of the deep seas…

Marine science

Life on the Australian shelf: A program compiling existing data sets combined with mapping 1800km² of the seabed with multi-beam sonar, video and sampling has been used to identify environmental factors important in determining the types and amounts of life in various locations around the Australian continental shelf. This data was then extended by statistical modelling over the entire shelf area – some 2000000 km² at 1 km² resolution. ScienceDaily (Mar. 31, 2011)

The slow lives of deep water corals: Born at the time of the Roman Empire, deep water corals growing in the dark at a depth of 300m in the Gulf of Mexico, whilst undeniably long-lived, are perhaps not the most robust ecosystem. Dr. M, in Deep Sea News, April 1st, 2011 (See Wikipedia for more long lived organisms)

Parasite survey: DNA surveys have been used to identify species of gut parasites in crustacea.
Rueckert S, Simdyanov TG, Aleoshin VV, Leander BS (2011) Identification of a Divergent Environmental DNA Sequence Clade Using the Phylogeny of Gregarine Parasites (Apicomplexa) from Crustacean Hosts. PLoS ONE 6(3): e18163. doi:10.1371/journal.pone.0018163

Phytoplankton bloom at altitude: There is increasing evidence of eutrophication even in high altitude lakes, due to deposition of nitrogenous material derived from human activity from the air.
Nelson CE, Carlson CA (2011) Differential Response of High-Elevation Planktonic Bacterial Community Structure and Metabolism to Experimental Nutrient Enrichment. PLoS ONE 6(3): e18320. doi:10.1371/journal.pone.0018320

Seal snacking: The killer whales in Antarctic waters prefer Weddell seals (Leptonychotes weddellii) to other seal species – and snack on them almost exclusively, even though they only make up 15% of the total seal population. Sometimes it is not good to be popular. ScienceDaily (Mar. 30, 2011)

The deep sea recorder: The sediments of the deep sea may be preserving a DNA record of the eukaryotic life that lives both within the sediment, and above it.
Pawlowski J, Christen R, Lecroq B, Bachar D, Shahbazkia HR, et al. (2011) Eukaryotic Richness in the Abyss: Insights from Pyrotag Sequencing. PLoS ONE 6(4): e18169. doi:10.1371/journal.pone.0018169

Improved O₂ sensor? In the early days of electronic sensors a lot of mistakes were made by people who took sensors calibrated in fresh water and used them without re-calibration in the sea. Their measurements reflected a mix of effects as the salt concentration masked or enhanced the reading from the analyte of interest, so the numbers recorded had little absolute value (though often still useful for comparative purposes within a set of samples of similar salinity). A new oxygen sensor is being developed at Michigan State that promises to end these problems (check before use). ScienceDaily (Apr. 4, 2011)

Conservation

No limit to growth? A global survey of reef fish indicates that the larger the number of species present, the higher the total productivity of the ecosystem. This is in contrast to earlier studies that indicated that productivity levels out as diversity increases. The study highlights the problems caused by over-fishing, which reduces biodiversity, and places the entire ecosystem at risk.
Mora C, Aburto-Oropeza O, Ayala Bocos A, Ayotte PM, Banks S, et al. (2011) Global Human Footprint on the Linkage between Biodiversity and Ecosystem Functioning in Reef Fishes. PLoS Biol 9(4): e1000606. doi:10.1371/journal.pbio.1000606

More leatherbacks in Florida: Numbers of nests have increased by 10% per year since 1979. ScienceDaily (Apr. 4, 2011)

Seabird bycatch: A new physical model of the oceans predicts where seabirds are likely to be. The hope is that this can be used to reduce fishing intensity in these areas, and so reduce bycatch of seabirds. ScienceDaily (Apr. 4, 2011)

Can you save a reef? A list of ten ways people can help save coral reefs. Christine, Project Blue Hope, 2nd April 2011

Antarctica being degraded? The introduction of alien species, pollution, over fishing, and a mix of other human activities are said to be having an effect on the marine Antarctic ecosystem, despite the protection provided for the continent by the Antarctic Treaty. ScienceDaily (Mar. 31, 2011)

Dugongs in space and time: 20-years’ of aerial observations of dugong (Dugong dugong) abundance has been used to create spatially-explicit models of their distribution in the coastal waters of northeast Australia. The use of spatial modelling in addition to stock numbers helps inform the development of MPAs.
Grech A, Sheppard J, Marsh H (2011) Informing Species Conservation at Multiple Scales Using Data Collected for Marine Mammal Stock Assessments. PLoS ONE 6(3): e17993. doi:10.1371/journal.pone.0017993

Coral – the next 100 years: Predicted changes to coral populations around Hawaii, assuming a ‘middle-of-the-road’ climate change scenario, factoring in temperature change and acidification.
Hoeke RK, Jokiel PL, Buddemeier RW, Brainard RE (2011) Projected Changes to Growth and Mortality of Hawaiian Corals over the Next 100 Years. PLoS ONE 6(3): e18038. doi:10.1371/journal.pone.0018038

Fisheries and exploitation

World fisheries management: This expert review indicates that 80% of the world’s fish stocks are either fully exploited, overexploited or have collapsed. Despite this only a handful of countries have a robust scientific underpinning fisheries management. Only those countries where scientific advice, rather than political expediency, is used to determine policy have shown any signs of fisheries revival. The UK and Northern Europe has one of the least sustainable fisheries (2004 data).
Mora C, Myers RA, Coll M, Libralato S, Pitcher TJ, et al. (2009) Management Effectiveness of the World’s Marine Fisheries. PLoS Biol 7(6): e1000131. doi:10.1371/journal.pbio.1000131

Take home toxin: Some colonial anemones sold for aquaria are capable of producing palytoxin – the deadliest poison know. The anemones have been associated with severe respiratory reactions and skin irritation in owners.
Deeds JR, Handy SM, White KD, Reimer JD (2011) Palytoxin Found in Palythoa sp. Zoanthids (Anthozoa, Hexacorallia) Sold in the Home Aquarium Trade. PLoS ONE 6(4): e18235. doi:10.1371/journal.pone.0018235

Survival strategy: How do hatchery release strategies impact on the survival of the released smolts? Acoustically tracked Seymour River steelhead (Oncorhynchus mykiss) smolts showed little change in survival with release time or date, though smolts released at sea did appear to survive better. In fact smolts released at sea survived better than smolts that had been vaccinated against common ailments!
Balfry S, Welch DW, Atkinson J, Lill A, Vincent S (2011) The Effect of Hatchery Release Strategy on Marine Migratory Behaviour and Apparent Survival of Seymour River Steelhead Smolts (Oncorhynchus mykiss). PLoS ONE 6(3): e14779. doi:10.1371/journal.pone.0014779

Pollution

Bankers not alone: Transocean executives get 2/3 of their target safety bonuses for their ‘best year in safety performance’. This is despite the Deepwater Horizon incident. Dr. M, Deep Sea News, April 4th, 2011

Japanese reactor leaks: Japan asks Russia for assistance containing future leaks from the Fukushima Daiichi nuclear plant, which is being forced to release radioactive waste water into the sea. Chizu Nomiyama and Shinichi Saoshiro, Reuters, TOKYO | Mon Apr 4, 2011

Simple model for pesticides: The way that pesticides are applied, and their fate in the soil is important in determining how much enters watercourses , estuarine and coastal waters. Pesticide loadings from agriculture are very sensitive to the pesticide’s persistence or stability in the ground, while the peak concentrations of a pesticide in watercourses are mainly related to its mobility. For a particular pesticide its distribution in the natural ecosystem subsequent to application is associated with landscape characteristics, such as the soil sorption coefficient. In practice, however, it is difficult to make reliable estimates of pesticide levels other than for small, enclosed water bodies close to the point of application.
Luo Y, Spurlock F, Deng X, Gill S, Goh K (2011) Use-Exposure Relationships of Pesticides for Aquatic Risk Assessment. PLoS ONE 6(4): e18234. doi:10.1371/journal.pone.0018234

(Under)estimating casualties: The problem with an incident in the sea, such as the Deepwater Horizon oil spill in the Gulf of Mexico, is that it is very difficult to actually quantify the damage done to the marine ecosystem. Whilst birds may make it back to shore, most plants and animals die where they are not seen or recorded. In this report it appears that even cetacean deaths (whales and dolphins, which should be about the easiest casualties to record) were grossly under-reported. In fact they estimate that only 2% of the carcasses were ever counted… ScienceDaily (Mar. 30, 2011)

Climate change

Nitrogen free zone: Denitrification rates in freshwater ecosystems increase rapidly with increased temperature. This appears to be linked to falling levels of dissolved oxygen under the same conditions. Oxygen levels fall due to reduced solubility at higher temperatures, but more importantly because respiration increases faster than photosynthesis, creating an imbalance in supply and demand. The mechanism linking denitrification rates to oxygen concentration is not, however elucidated.
Veraart AJ, de Klein JJM, Scheffer M (2011) Warming Can Boost Denitrification Disproportionately Due to Altered Oxygen Dynamics. PLoS ONE 6(3): e18508. doi:10.1371/journal.pone.0018508

Heat exhaustion: Since 1950 the Fraser River in British Columbia, Canada, has warmed by 2°C. This increase in temperature correlates with increased mortality amongst sockeye salmon swimming upriver to breed. Different populations of salmon breed in different places in the river system, and show differing susceptibility to warming. ScienceDaily (Mar. 31, 2011)

Carbon capture: Coastal plants may have a large role to play in carbon capture – until recently sea grasses and salt marshes were largely ignored in calculations. The degradation of coastal ecosystems may result in the release of large amounts of carbon through the decomposition of buried biomass.
Irving AD, Connell SD, Russell BD (2011) Restoring Coastal Plants to Improve Global Carbon Storage: Reaping What We Sow. PLoS ONE 6(3): e18311. doi:10.1371/journal.pone.0018311