The oil spill continues to be important to the marine biology community, which is currently chewing over some of the first reports based on data obtained during the slick and in its immediate aftermath. There is still a lot else to consider – climate change is moving back up the agenda, with indications that we need to address this problem now. We will start, however, 2.5 billion years ago (the lengths I go to to find some good news…)

Patchy oxygen concentrations in ancient oceans: Geochemical analysis is gradually putting together a picture of our oceans from 2.5 billion years ago – just after the dawn of life on Earth. This picture shows the first cyanobacteria creating small regions of oxygenated water, probably in the shallows around continental margins, where there was plenty of sunlight and nutrients. Currently scientists estimate that oxygen levels in the atmosphere stayed low for a further 100 million years. ScienceDaily (Aug. 23, 2010)

Life without oxygen: In a related story, scientists have found evidence for multicellular life in the anoxic sediments of the deep Mediterranean. The organisms use hydrogen as fuel and sulphate as the oxidant, the process does not produce a lot of energy, so the organisms are very slow. Nick Lane New Scientist (11 August 2010).

Rock of ages: The age of the oldest known animal fossils has been pushed back to 650 MYA. The fossils are thought to be of sponge-like animals were found in rocks formed from marine sediments in South Australia. They pre-date the Ediacaran fossils (577-542 MYA) and the ‘deep freeze’ event, when the whole earth is though to have been encased in ice about 635 MYA, suggesting that animal life may have survived this event. ScienceDaily (Aug. 17, 2010)

Breathing inside a nudibranch egg: Many marine organisms start lives as eggs, which are left to develop in the open water, or attached to a suitable substrate. WHile the egg can enclose enough food for the young embryo to develop, oxygen needs to diffuse in from the seawater, and carbon dioxide needs to diffuse out. Looking at nudibranch eggs in particular, these are commonly laid in gelatinous masses (commonly colourful coils), within a layer of gelly, which provides protection, but reduces the rate of gas transport. In this study workers find that gas transport is more of a problem for temperate and tropical nudibranch eggs, which are laid in water at higher temperatures than nudibranchs that live in polar regions. The increase in temperature correlates with increased metabollic rate, and a greater need for oxygen. The work predicts that egg masses of warm-water nudibranchs will therefore be laid by preference in faster moving water than eggs laid by polar species.
Measuring current flow rates around eggs looks like a nice challenge for the technically minded diver!
Moran AL, Woods HA (2010) Limits to Diffusive O2 Transport: Flow, Form, and Function in Nudibranch Egg Masses from Temperate and Polar Regions. PLoS ONE 5(8): e12113. doi:10.1371/journal.pone.0012113

University cultures head-banging fish: Many young fish find suitable habitats by the noise of breaking waves and other activity that are associated with them. In this study baby damsel fish were exposed to either natural reef noises or electronic noises, then tested to see which way they swam. The study found that the fish remembered sounds for many hours, and while all fish liked the reef noises, only those fish that had been exposed to the electronic noise would swim towards that. ScienceDaily (Aug. 13, 2010)

Plankton brew up a storm: The colour of the world’s oceans influence how much heat they trap from the sun. Where algae are abundant, they absorb sunlight in the surface waters, and so increase the temperature of the water here. If algae are declining (as recent reports suggest), then oceanic waters will become clearer and sunlight will penetrate to deeper in the water column, but the surface waters will not warm up as much. As storms pick up energy from warm surface waters, it is predicted that algae free waters will (other things being equal) result in reduced storm intensity. In one area of the Pacific this could amount to a 70% decline in hurricane force winds. ScienceDaily (Aug. 14, 2010)

Why do anti-foulants work? Scientists at the University of Gothenburg have discovered the genetic basis for barnacles avoiding certain types of anti-foulant. ScienceDaily (Aug. 15, 2010)

Conservation

Is this reserve working? It is important to be able to assess the effectiveness of any conservation policy, and this can be a problem particularly for marine reserves, where the organisms cannot be ‘fenced in’. This study attempts to separate effects due to the reserve policy and the natural variation that is to be expected due to the heterogeneity of the seascape. A good habitat outside the reseve may bring in more fish than poorer habitats within the reserve. The authors developed a model of the seascape, taken from remote sensing imagery, and used standard sampling techniques to identify the types and numbers of fish in and around the reserve. The two parameters could then be compared like-for-like on a species-by-species basis. Most (though not all) species were shown to have a very much higher biomass in the no-take reserve than outside (typically a 5 fold increase).
Huntington BE, Karnauskas M, Babcock EA, Lirman D (2010) Untangling Natural Seascape Variation from Marine Reserve Effects Using a Landscape Approach. PLoS ONE 5(8): e12327. doi:10.1371/journal.pone.0012327

Frozen coral to wait for the Earth to cool down? Hawaiian corals are being frozen in an effort to prevent their extinction. Trials have shown that cells can be thawed and are still viable for considerable periods. While this is possible, it does beg two questions – first: Who will pay the bills to keep them on ice in perpetuity. Second: If they cannot survive in our current ecosystem, what is going to ‘make things better’ in the future? ScienceDaily (Aug. 17, 2010)

Modelling disease in tropical corals: Recently there have been a number of well documented coral beaching events, where tropical hard corals eject their symbiotic algae in response to heat stress. This paper suggests that corals are also more susceptible to a range of diseases on a seasonal basis, reflecting stress induced by both hot and cold weather.
Heron SF, Willis BL, Skirving WJ, Eakin CM, Page CA, et al. (2010) Summer Hot Snaps and Winter Conditions: Modelling White Syndrome Outbreaks on Great Barrier Reef Corals. PLoS ONE 5(8): e12210. doi:10.1371/journal.pone.0012210

Pollution

Floating plastic: Volunteer surveys of floating plastic carried out over the last decade in the Atlantic are now being brought together by Woods Hole Oceanographic Institution and the University of Hawaii. Most plastic peices are about a millimetre in size. While they are found throughout the World’s oceans, current patterns can cause accumulations at certain locations. ScienceDaily (Aug. 20, 2010)

Stopping ocean acidification: Since 1750 the pH of the world’s oceans has fallen from 8.2 to 8.1 (a one pH unit fall is equal to a ten-fold increase in acidity). Predictions indicate that by 2100 this value could be as low as 7.7 if emissions of carbon dioxide are not curbed. Aggressive cuts in emissions with a peak emission date of 2016 and a 5% cut per year thereafter could, however, keep the pH above 8 – still a huge fall since pre-industrial times, but likely to cause a lot less damage to the marine environment. ScienceDaily (Aug. 23, 2010)

Enhancing water quality: Scientists are planning a web-based run-off forecast that will help farmers manage fertilizer application to minimise water-course pollution. The system is being developed for the Chesapeake Bay watershed, one fo the major drainage systems on the US Atlantic seaboard. The forecast is based on the hydrology of the areas concerned, significant factors being soi-moisture content and expected precipitation. As we cannot stop using fertilisers, it is important to develop practical strategies that minimise their impact on waterways and the oceans they drain into. ScienceDaily (Aug. 18, 2010)

Slick paint job: Looks like a few bloggers are less than impressed by the rosey official reports claiming that the oil has gone… Deep Sea News (August 17th, 2010).

Oil in the food chain: Unconfirmed report that of oily droplets, thought to derive from the Gulf oil-spill, have been found in immature blue crabs from around the site of the spill. Bill Sasser, Marine Conservation News, Aug. 24 2010.

Eating the oil spill: New research, sponsored by BP, has been reported in the journal Science that indicates that microbes are attacking the Gulf oil spill. Via Deep-Sea News, August 24th, 2010. Also reported in Science Daily (Aug. 25, 2010).

How toxic are dispersants? More on the debate as to whether or not dispersants helped solve the Gulf Oil slick problem, or increased the toxicity of the oil and caused more damage. This is a difficult issue to get to grips with, without the dispersant more oil will float to the surface, so surface waters will have a higher loading of oil. This has a very visible effect on beaches and bird-life. With the dispersant more oil stops in the water column, where it is spread through a larger volume of water. It will be more toxic, but more heavily diluted – which wins? When kept in the water column the oil does not have a visible impact on wildlife, though in this disaster we have seen large kill-offs of benthic fauna, and now reports of oil entering the food-chain. Deep-Sea News (August 23rd, 2010).

Oil-plume damage to peak in October: As the Gulf oil plume is digested by bacteria, large volumes of water in the Gulf become de-oxygenated, and unable to support other forms of life. This research indicates that these anoxic waters will reach their maximum extent in October 2010. ScienceDaily (Aug. 20, 2010)

Climate change

Sea levels to rise: New research indicates that even with aggressive green policies and climate engineering, sea leavels are likely to rise by between 30 and 70cm by 2010. This will effect approximately 150 Million people living in low-lying areas. ScienceDaily (Aug. 24, 2010)

Mussels range reduced in warm waters: The range of the edible mussel Mytilus edulis along the US seabord is said to have been reduced due to increased water temperatures. ScienceDaily (Aug. 16, 2010)

Indonesian coral die-back: Many corals in the Andaman Sea have died following a prolonged period of increased temperature in late May 2010. Temperatures re reported to be reached 34°C, 4°C warmer than average for the area. ScienceDaily (Aug. 17, 2010)

Wave power down under: Australia’s research council – CSIRO – is evaluating wave power for generating sustainable energy. Estimates indicate that 20% of Australia’s near-shore wave energy along the Southern coastline would need to be harnessed to cover her current energy needs of 130,000 gigawatt hours per year. The current targets for renewables are quite modest, however, and could be achieved through wave power, though this would still require a massive engineering effort, with 100’s of miles of conversion units (my estimate based on figures reported). ScienceDaily (Aug. 17, 2010)

Mediterranean carbon dioxide vents model future oceans: Natural carbon dioxide vents around the island of Ischia in the Mediterranean are providing scientists with a model for how the world’s oceans might look in a future of global warming. The vents increase the acidity of the seawater around the island, just as carbon dioxide from fuel combustion is starting to do to the oceans as a whole. In this study scientists find that the diversity of Foraminifera around the vents is reduced from 24 species to only four. Previous studies on other species indicate a decrease in biodiversity of about 30%, so this is an extreme response from the Foraminifera (they may be especially sensitive as most Foram species live in calcium carbonate shells – which are increasingly soluble and hard to make at lower pH levels). ScienceDaily (Aug. 25, 2010)