Themes this week include climate change, and in particular how phytoplankton, some of the smallest plants on the planet, have a vital role in managing the Earth’s carbon dioxide budget. Otherwise, scientists are starting to evaluate how climate change will effect key organisms in the marine ecosystem, and results from these studies are beginning to come in. Fisheries are an important component of many maritime economies, and there are a few interesting papers in this area this week. Historic studies of fisheries are important for understanding how and why they develop, and what economic pressures can lead to collapse. Otherwise, husbandry is becomming important in the marine field, as demonstrated by the breeding of new ‘super prawns’ for the Australian market.

If climate control and resources are two positive things, it is less easy to find good things to say about pollution and the continuing oil spill. The importance of monitoring marine systems for organic mercury compounds is emphasised – while the marine ecosystem dilutes these compounds, the marine food chain concentrates them right back up again, and guess who is at the top of that food chain…

On the oil spill there is a very interesting blog post on how likely the spill was to occur – was it an event so unlikely that (as the US regulators agreed when they licensed the Deepwater Horizon) there was no likelihood of environmental damage? Beyond that, we look at some of the less visible casualties of the spill, and start to quantify just how much of the Gulf marine ecosystem has been wiped out.

First though, Basking sharks are migrating North again, and anyone living on the west coast has a chance of spotting them, as this report in the North Wales Pioneer demonstrates (North Wales Pioneer, 30 June 2010). For more on basking sharks and their migrations, visit the basking shark pages on the MCS National website.

Phytoplankton and climate change

Cocolithophorids need iron: Cocolithophorids are an important group of marine phytoplankton, they are characterised by growing intricate shells formed of calcium carbonate, and so seen as one of the dominant components of the carbon dioxide cycle, helping to remove this from the atmosphere. They commonly form immense blooms in temperate waters, these blooms can be the size of small countries, and are readily visible from space. Here researchers demonstrate that one of the key limiting nutrients for cocolithophorid blooms is iron. ScienceDaily (June 30, 2010)

Better fed phytoplankton absorb more carbon dioxide: This theoretical work suggests that increasing the nutrients available to phytoplankton will reduce their morbidity to viruses in the marine system, and so increase their productivity. ScienceDaily (June 30, 2010)

Climate change effects swimming snails: Pelagic molluscs are an important food source for fish and other zooplankton. In this study scientists looked at their development at elevated both carbon dioxide levels and elevated temperatures. They found that the ability of the mollusc Limacina helicina to deposit shells declined with increasing partial pressure of carbon dioxide in solution.
Comeau S, Jeffree R, Teyssié J-L, Gattuso J-P (2010) Response of the Arctic Pteropod Limacina helicina to Projected Future Environmental Conditions. PLoS ONE 5(6): e11362. doi:10.1371/journal.pone.0011362

Warm fizzy oceans impact sea urchins: Climate change is predicted to result in both warmer and more acidic seawater. An important question here is how will this effect the development of key organisms in the marine ecosystem? Scientists have now looked at the development of the sea urchin Tripneustes gratilla under artificial conditions of elevated temperature and carbon dioxide. Thye found that the increase in temperature gave rise to larger larvae, while the increase in acidity makes it harder for them to lay down carbonate, so resulted in reduced skeletal strength. When exposed to both stresses, the increased acidity won out, with reduced larval size, which may have negative consequences on adult populations.
Sheppard Brennand H, Soars N, Dworjanyn SA, Davis AR, Byrne M (2010) Impact of Ocean Warming and Ocean Acidification on Larval Development and Calcification in the Sea Urchin Tripneustes gratilla. PLoS ONE 5(6): e11372. doi:10.1371/journal.pone.0011372

No ice here… Scientists are predicting the smallest ever amount of sea-ice in the arctic this coming winter. The previous minimum was in 2007 – only three years ago. From ScienceDaily (June 28, 2010)

Arctic ocean monitoring goes wireless: Previously we have monitored the oceans from research vessels on pre-planned cruises. As the only source for much of our information about the world’s oceans, this is clearly not adequate! Looking for a better way to mount a continuous monitoring effort, scientists have developed an array of remote sensors that keep in touch by radio. The system had its first successful test in December in the Arctic ocean. ScienceDaily (June 24, 2010)

Floating turbines: Offshore wind turbines are an increasingly important component of the UK’s renewable energy budget, but conventional designs require firm foundations, so they are restricted to water depths of 50m. Engineers have recently published a feasibility study for a floating turbine, based on existing gas and oil platform designs. Calculations suggest that conventional platform designs could support 5MW turbines – the largest currently available – and power a small town. A prototype design is being built in collaboration with electricity operator Energias de Portugal, and should be launched in 2012. ScienceDaily (July 1, 2010)

Fisheries

Historic changes in sea cucumber harvests: Sea cucumbers have been an important component of the fisheries of Indonesia, supplying ‘trepang’ principally to the Chinese market. This study follows the commercial development of the trade from documentary sources covering the last three hundred years, up to the collapse of the fisheries in the 20th century through over-exploitation. The pattern of fishing a trading follows a common pattern for the exploitation of marine reserves. The development of a wealthy consumer class in china stimulating demand, which is supplied by local peoples catching and processing trepang, then trading them through a network of small markets an finally through a central market, the port of Makassar, where chinese traders are primarily based. The networks of trade persists after the collapse of the trepang fishery, now focussing on sales of grouper and clown fish (popular for aquaria after the film ‘Finding Nemo’).
Schwerdtner Máñez K, Ferse SCA (2010) The History of Makassan Trepang Fishing and Trade. PLoS ONE 5(6): e11346.doi:10.1371/journal.pone.0011346

The perfect prawn? A new breed of prawns developed by Australia’s CSIRO are reported to produce a crop of 12.8 tonnes per hectare, compared with 5 tonnes from current farmed varieties. The ‘super prawns’ were created by selective breeding from Black Tiger prawns (a local species), and CSIRO hopes that they will be a conpetitive alternative to the import of prawns currently reared in Vietnam and China. From ScienceDaily (June 29, 2010)

Marine pollution

Marine mercury: Older readers will be aware of the devastating consequences of mercury poisoning from the Minamata disaster in Japan in 1956. The mercury that caused this disaster was released into rivers in the form of methylmercury, which is many times more poisonous than metallic mercury. Despite that fact that the concentration levels of this compund in seawater were below detectable limits, it was concentrated in the shellfish in Minamata bay to levels that caused severe toxicity – with 2265 recorded victims (1784 of whome died).
Scientists at Dukes have now reported that the marine ecosystem may be particularly vulnerable to methylmercury contamination. They have found that methylmercury is stabilised by chloride ions – the salt in seawater. With high levels of mercury exposure in the US (8% of all women have above the recommended levels), the researchers are advising more emphasis be placed on monitoring methylmercury in the marine system, which is the most likely source of poinsoning, rather than freshwater systems, which just happen to be easier to monitor. ScienceDaily (June 28, 2010)

Microbial communities reflect environmental fluctuations: This study moves away from the simple bacterial count approach to monitoring water standards on bathing beaches, utilising gene-chips to identify a wide range of bacteria (including common pathogens) in water runoff. The scientists were able to follow how the bacterial community changed as water polluted with fecal matter travelled down river channels to the sea at Santa Barbara. They found that the ratio between different bacterial species was a good indicator of the degree of contamination of the water.
Wu CH, Sercu B, Van De Werfhorst LC, Wong J, DeSantis TZ, et al. (2010) Characterization of Coastal Urban Watershed Bacterial Communities Leads to Alternative Community-Based Indicators. PLoS ONE 5(6): e11285. doi:10.1371/journal.pone.0011285

Oil spill

How probable was the Gulf oil spill? Where BP a bunch of cowboys, or could it have happened to any of the big oil companies working in the deep waters of the Gulf of Mexico? This article looks at how accidents in general happen, with an aim to answering this question. If you are responsible for anything it will make valuable reading, as it compares and contrasts a number of famous catastrophes, and picks out some of the common mistakes that led to them. It also puts the question of broader culpability into better focus. This is perhaps the most interesting post on the oilspill debate so far, and I recommend that everyone reads it! From Culturing Science, by Hannah Waters June 22 2010

How large a dead zone? Scientists at NOAA are now predicting a dead zone of between 6500 and 7900 square miles as a consequence of the Gulf oil spill.From ScienceDaily (June 28, 2010)

Don’t drink the water – don’t eat the fish? Some 89% of Americans said they were ‘extremely concerned’ about the safety of seafood sourced in the Gulf. From ScienceDaily (June 28, 2010)

Oil and arsenic: During its prolonged period of burial oil pick up a lot of minerals, which are, of course, also liberated into the seawater when a spill occurs. One of the less desireable elements found in oil is arsenic. Further, sediments that would usually grab onto the arsenic, get clogged by oil, so don’t do an efficient clean-up. ScienceDaily (July 2, 2010)

Unseen casualties: Nematodes are not the most obvious denizens of the deep, but millions of them live in every cubic metre of mud, and thousands even in the deep sea oozes. They have a range of eating habits, and are important in turning over mud, releasing nutrients back into the water column, and taking oxygen down into the mud so other organisms can flourish. Unfortunately, nematodes don’t like oil, and are predicted to suffer badly as a consequence of hte gulf spill, greatly reducing the bio-diversity of large areas of sea-bottom. Deep Sea News 28 June 2010

Pure science

MarBOL collection: A collection of open access papers published by PLoS ONE covering the DNA barcoding of marine organisms. Barcoding has proven a very valuable tool for estimating the actual number of organisms present in our marine ecosystems. This collection promises to be a great aid for anyone interested in coming up to speed in thte subject.

Seaweed ID refresher: The swollen ends of the fronds of many saeweeds are not air bladders… Sea Coast Online, June 30, 2010

Fish (re)emerge from the depths… This study looks at the Pacific leaping blenny (Alticus arnoldorum), that has undergone a series of adaptions resulting in their abandonning the water for most of their life-cycle, forraging and breeding on land! The study looks in particular at this fish’s tail-twisting behaviour, which propells it at great speed across the land. If land based evolution was to start again based on this propulsory innovation, our evolutionary equivalents might end up like Zebedee from the Magic Roundabout!
Hsieh S-TT (2010) A Locomotor Innovation Enables Water-Land Transition in a Marine Fish. PLoS ONE 5(6): e11197. doi:10.1371/journal.pone.0011197

Tracking fish: Radio beacons are a great way to track marine mammals – which periodically surface, allowing the beacon to broadcast information on the last dive – but they are not too useful for tracking fish that remain submerged. To get round this scientists are testing underwater gliders, which dive to collect information from tagged fish, then surface to relay this information back to base. Underwater gliders use very little power, and can operate for up to three months travelling at one mile per hour. ScienceDaily (June 23, 2010)

12 Deep sea biology symposium: The book of abstracts from this meeting is currently available in three parts, lots of stuff here of interest if you like your diving very deep and dark! A number of the research strands have previously been picked up through press releases.

Counting fish in the ocean’s deeps: Estimates of the numbers of fish in the hadal zone (below 6km in depth) have been made by measuring the times taken for fish to arrive at baited camera sites. The studies suggest that fish occur to greater depth than previously thought, and that the deep water species appear to be dominated by the liparids or ‘snailfish’. Snailfish are benthic dwellers, and examples occur at all depths in the world’s oceans. ScienceDaily (July 1, 2010)

What big teeth you have, grandma… Only three animals are known to suffer a menopause – killer whales, pilot whales and humans, and in all three animals this seems to be related to a well developed ‘grandmother’ role. In this older females assist younger females rear and protect their young. Pretty convincing evidence of strongly developed social behaviour in all three animals… ScienceDaily (July 2, 2010)

Leaders and followers: Three spined sticklebacks seem attracted to individuals who move confidently, and will tend to shoal after robotic fish that exhibit these characteristics. BBC 1 July 2010

Conservation

How to restore reefs? Tropical reefs seem to be increasingly at risk from damaging bleaching events, caused by extreme temperatures. As a consequence, conservationists are looking for ways to rehabilitate these damaged ecosystems. ScienceDaily (June 24, 2010)

Cost effective preservation of biodiversity: Can we protect more with less? – Authors here advocate redirecting resources and protection to the highest value sites. My one note of caution here is that in the marine ecosystem, do we know enough to identify these ‘most important’ sites? ScienceDaily (June 30, 2010)