Hofstra University : GEOL140: Paleoclimatology VOL. 21 doi:1029/2011GEOL1406873, 2011

Proposing the use of a global probe based network of durable

marine “laboratories” to quantify the global flux of

dimethylsulfide across the sea/air interface S. LeoneA

AHofstra University Geology Department, Hempstead New York, USA

Abstract

As it stands now there are <1500 quality scientific papers written regarding the CLAW hypothesis,

many of which confirm the hypothesis. The hypothesis was conceived by four scientists: R.J. Charlson, J.

E. Lovelock, M. O. Andreae & S. G. Warren in a 1987 paper in Nature. The four last names of the

scientists make the acronym CLAW. This hypothesis provides a fascinating concept that there is a

complex interaction between marine organisms and the atmosphere that work together to oppose change in

a particular system through a series of feedback loops. Phytoplankton in the ocean produces

dymethylsulfide and dimethylsulphoniopropionate (DMS/DMSP). These substances act as cloud

condensation nuclei (CCN). When there is an input of sunlight and an output of excessive phytoplankton,

the DMS/DMSP is released into the atmosphere and facilitates the formation of clouds. The clouds

increase albedo and cool the system. There is currently no consistent and unified global network of

sensors to provide real time data regarding the production of DMS/DMSP. Most of the data collected

regarding the concentrations and production of DMS/DMSP are from the Global Surface Sea water DMS

database (http://saga.pmel.noaa.gov/dms), other databases, satellite information, and measurements made

by individual researchers. The current collection of data is fairly accurate and is fit to be used in scientific

writing. The general consensus though among climate scientists specializing in research pertaining to

CLAW is that there needs to be a better data collection protocol and it needs to be implemented in a way

that will facilitate quick and accurate data collection. For this reason I propose that there be a global

network of renewably powered, remotely controlled “DMS laboratories” present in the ocean. The probes

will utilize CalTech’s “lab on a chip” technology to gain accurate real-time data that will quantify the

seawater DMS/DMSP distribution and its global flux across the sea/air interface.

Background

Other planets in this solar system may

have cores, and low-density atmospheres, but to

the best of our knowledge, Earth is the only

planet that demonstrates such complex

interactions between the living organisms and

their inorganic surroundings. This complex

interaction creates sets of self-regulating

phenomenon that sustain the life on Earth.

Similar beliefs have been held by various

indigenous cultures around the world throughout

history. The first western scientific model to

describe this phenomenon was suggested by

James Lovelock. His theory that identifies and

attempts to quantify this global phenomenon is

known as the Gaia Hypothesis (GH).

Lovelock’s theory was inspired by his work with

NASA developing technology to detect life on

other planets. When he published his first paper

on the topic in 1979, the scientific community

attacked his views. The Gaia hypothesis is a

fairly controversial theory and its main critics

purport that it verges on being a quasi religious

belief and that it did not follow the reductionist

approach of modern science. Over the past 20

years the theory has begun to gain much wider

acceptance among the scientific community

(Spowers 2000). Too lovelock though, it made

perfect sense, especially in light of the fact that

he worked with NASA to find life on other

planets. The stark contrast drawn between the

surface of planets like Venus and Mars

compared to the surface of the earth allowed him

to realize just how incredible and unique our

planet actually is.

In a 2000 interview, Lovelock states that

other planets seemed to be in a state of

equilibrium. The atmospheres of planets like

Mars and Venus are composed entirely of

carbon dioxide. This indicates a lifeless state.

Lovelock compares earths atmosphere to the gas

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you put in your car. The rich mixture of oxygen

and hydrocarbons is akin to the fuel going into

the intake manifold of a motor vehicle. The

atmosphere on Mars though is composed of

gasses akin to the exhaust of a car. From this he

believes life on mars and Venus exhausted itself

(Spowers 2000). This lead to the conclusion that

the onset of global warming is a huge problem,

in fact, in Lovelock’s opinion everything else is

secondary to the problems of rising levels of

greenhouse gasses. He asserts that we are now

in a state of “positive feedback” and that instead

of mitigating the harm that is being done, the

system is “actually increasing so that as it

warms, the systems are wiped out and the

process speeds up.”(Spowers 2000). In essence,

treating this planet as a machine has gotten

humans into a lot of trouble. The Gaia

hypothesis helps us to see that nature can indeed

be seen as sacred and that there is still a lot we

don’t know. What we do know, though, is that

it’s important to assess the factors contributing

not only to the Gaia hypothesis but the entire

issue of climate change.

Lovelock’s theory of Gaia is quite broad.

One of the main terrestrial phenomenons that

Lovelock and many others have studied in depth

that contributes great insight into Gaia is the

“CLAW Hypothesis.” The letters that spell the

word “CLAW” are taken from the names of the

scientists that wrote a 1987 article in Nature

(Lovelock et. al. 1987). Before the CLAW

hypothesis can be fully explored, it is important

to examine the role of clouds in the atmosphere.

The way that clouds affect the warming and

cooling of the earth is hard enough to quantify.

Understanding the way that clouds affect the

warming and cooling of the earth in a warming

world is an even bigger uncertainty. One of the

main forcing on cloud properties is the existence

and concentration of a cloud condensation nuclei

(CCN). A CCN is a tiny particle present in the

atmosphere that serves as a medium for the

nucleation of a water droplet that makes up a

cloud.

The basis of the CLAW hypothesis is the

prospect that there are oceanic and atmospheric

systems that are coupled in such a way that

opposes changes in climate. In the ocean there

are several thousand species of phytoplankton.

These phytoplankton produce a substance called

dimethylsulfide (DMS). DMS, once released

into the atmosphere, oxidizes to form a sulfate

aerosol. This substance acts as a CCN. The

reflectance or albedo of clouds is responsive to

CCN density. Thus in turn the earth’s radiation

budget is sensitive to the presence of DMS due

to its impact on cloud formation. Regulation of

the climate can be achieved by the feedback that

occurs through the effects of temperature and

sunlight on the populations of phytoplankton

and the production of DMS.

Oceanic phytoplankton, if pushed to

either extreme of their tolerance levels i.e. too

hot and sunny or too cold and dim, will respond

by varying their DMS emissions. This way they

can increase or decrease the insolation hitting

the ocean surface by influencing the marine

cloud reflectivity. By doing this, phytoplankton

effectively drive the system back towards their

tolerance levels.

(Ayers et. al. 2007)

DMS in the atmosphere comes from the

ocean. When DMS is present in the ocean it is the

direct result of biological activity.

Dymethylsulfoniopropionate (DMSP) is the

precursor compound to DMS. DMSP is

synthesized by phytoplankton and the amount of

DMSP present depends on the species of

phytoplankton present. So far, direct emission of

DMS from phytoplankton has been observed in a

laboratory setting. It has not, however, been

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observed in the oceans. It is also likely that the

action of grazing zooplankton and viruses have an

affect on the phytoplankton community that yields

substantial levels of DMSP in the water. It is

typical that the higher levels of DMSP and DMS

usually correlate with the onset of a plankton

bloom.

In light of the fact that there has been no

direct observation of DMS/DMSP production in

phytoplankton in the oceans, it is important to

implement a system that will allow real time

quantification of the levels of DMS/DMSP, the

presence of viruses, the grazing zooplankton, the

temperature and sunlight concentration in a

particular location. A. Lana et. al. in their 2011

paper utilized state of the art climatological

records and interpolation/extrapolation techniques

to carry out their research. They identified several

significant issues with the current state of the

databases and individual measurements used for

their research. There doesn’t seem to be any

quality control in the database and a lack of

unification of the DMS measurement protocol.

This is troubling to many for it retards any

research attempts regarding oceanic DMS/DMSP

concentrations.

In addition to a lack of a unified measurement

protocol, the role of DMSP or DMS in plankton

physiology is still unclear (Ayers et. al. 2007). It

is hypothesized that the conversion of DMSP to

DMS may have something to do with relieving

oxidative stress following exposure to UV

radiation, nutrient limitation, or changes in

surface temperature. It has also been suggested

that DMSP has osmoregulative properties or is a

carrier in organic sulfur cycling. (S. M. Vallina

et. al. 2007)

The fact that the role of DMSP and DMS in

plankton is unclear makes it difficult to

understand how the emission of DMSP or DMS

from plankton would change as the surface water

environment changed in response to climate

change. It would be important to know if

changing certain oceanic conditions would alter

the plankton community in such a way that would

promote species of plankton that were higher

emitters of DMSP or DMS. In addition it would

be of note to determine the extent to which

increasing acidity would have on phytoplankton

communities and their emission of DMSP, for

deformed plankton have been observed. (Norris

2003)

Once the DMSP is in the water, there are

several processes that convert the substance into

DMS. The complexity of the process is what is

important to note for the purposes of this paper.

The early work in understanding the processes

was based in physics and utilized different

variables pertaining to wind speed, solubility of

DMS and other factors. Fully understanding the

complexities of the sea-air interface, knowing

what we already know poses a significant

challenge. A major difficulty in obtaining DMS

measurements from the water is the wind speed

associated with oceans experiencing large blooms.

The safety of scientists and observation platforms

is a main concern and so until Ayers et. al. in

1995 determined certain micrometeorological

techniques to gain a better understanding of this

flux. Still, the techniques are only predictions

based on proxies of eddy accumulation and eddy

covariance.

Motivation: The anthropogenic influence on the atmosphere

is predicted to lead to significant changes global

climatic conditions. Roughly half of the current carbon

dioxide emissions are being absorbed by the ocean and

by land ecosystems. This absorption is sensitive to

climate as well as to atmospheric carbon dioxide

concentrations. This creates a feedback loop. (Cox et.

al. 2000) The CLAW hypothesis though, has a

counterpart: the Anti-CLAW hypothesis. Lovelock

contends that the constituents of the CLAW hypothesis

will reverse from their current state of negative feedback

and wind up acting as a positive feedback loop

(Lovelock 2007). Considering the evidence of increased

atmospheric carbon presented by Cox et.al. and the fact

that as of now, there is a predicted increase in global

temperature, it is likely that world oceans may

stratify. (Lovelock 2007)

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This would reduce the supply of nutrients that up

well from the deep. These nutrients are key for the

proper functioning of phytoplankton in its euphotic

zone. In a CLAW hypothesis reversal, this would

lead to a decline in phytoplankton activity and thus

less DMS production. If there is less DMS present

in the atmosphere there will be less cloud

formation and so less albedo. The problem with

this is that the lack of cloud cover will potentially

lead to further climate warming. This in turn, will

continue to reduce the global production of DMS.

Having a global network of biosensors can

help keep scientists savvy to the changes occurring

in real time. The radiation balance has a

fundamental effect on Earth's climate. About one

third of the solar radiation that reaches the Earth is

reflected back into space by clouds and from earth

surfaces, such as ice and snow. The atmosphere

absorbs some solar energy, but most of the other

two thirds is absorbed by the land and oceans,

which are warmed by the sunlight (Norris 2003).

The sun's energy is converted into heat, and the

land and oceans then radiate a portion of this

energy back as outgoing long-wave (infrared)

radiation, also known as terrestrial radiation.

Albedo is an important factor in the radiation

balance, and clouds have the major effect on

albedo. The optical properties of a cloud are a key

issue to understanding and therefore predicting

global climate change. A cloud's optical properties

are related to the size distribution and number of its

droplets. The more cloud condensation nuclei, the

smaller the size of its water droplets and the higher

the density of water droplets since the same

amount of water vapor is distributed among a

greater number of CCN. This affects the radiative

properties (reflectance, transmittance and

absorbance) of the cloud. Because of the vast

amount of atmosphere between the sea and space,

there is a lot of room for cloud activity. When the

clouds are low and thick, they act as shields,

blocking and reflecting insolation into space. This

in turn cools the planet. When clouds are high up,

they can also trap the outgoing heat, which is in the

form of longwave radiation. This warms the

planet. On the whole, data suggests that clouds

have a general net cooling effect on the planet

(Norris 2003).

Climate scientists have realized that

current models had a poor ability to accurately

reproduce the effect of clouds. For this reason,

scientists have made it a priority to measure and

understand more about clouds physical properties

and radiative fluxes. Programs like CERES, and

the IRI/LDEO Climate Data Library are observing

clouds from space in order to more accurately

quantify cloud properties and their respective effect

on albedo. If a more accurate model of cloud

physics can be expressed, scientists will be able to

construct more accurate simulations of climate

budget and projections of change. Based on what

we have learned over the years in regard to the

CLAW hypothesis, it is likely that DMS has an

influence on the global heat budget and the

hydrological cycle due to its impact on cloud

formation. In order to understand how any CLAW

related feedback mechanism (positive or negative)

between the plankton population and the

atmosphere might operate, it is vital that the

biological role of DMS/DMSP within the cells of

plankton is clarified. The reason for this is because

the biological role of DMS/DMSP in plankton is

inextricably tied to how the feedback between

biology and atmosphere may respond to

environmental changes. It seems that an

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understanding of this feedback process in the

CLAW hypothesis remains elusive (Ayers et. al.

2007). Being able to accurately quantify the

amount of DMS being produced in real time all

across the globe will be a vital contribution to the

climate science community.

Currently, some of the most recent

research in the field has come from data contained

in the Global Surface Sea water DMS Database.

Simo et. Al. states that there is no quality control in

the database. This was worth stressing because

there doesn’t seem to be unification of the DMS

measurement protocol, and very few

intercalibration exercises have been conducted in

the last 30 years. Furthermore, a number of

sampling and analytical issues have been reported

in recent years. For this reason it is important to

have a definitive, reliable, and long lasting network

of instruments that provide real time analysis of the

DMS/DMSP sea and air measurements. This will

help to assess health of the planet based on the

progression of cloud formation and earths radiation

balance. In addition it will continue to support

James Lovelock’s Gaia hypothesis.

Proposal for new research

Using modified “lab on a chip” technology

developed by CalTech (Liu et. al. 2009) to

effectively create a network of interconnected,

centrally linked “microlabs” to measure levels of

DMS and DMSP in phytoplankton on a global

scale. The labs will be encapsulated in a specific

vessel designed for durability and ease of

maintenance and potential retrofitting. The vessel

will also be equipped with a propulsion system,

which draws energy from solar power, tidal

currents, or both. The unit will not only be able to

run real time collection and transmission of DMS

and DMSP data, it will be able to determine the

effects of CO2 concentrations, sunlight, grazing

zooplankton, temperature and viral lysis on the

production, dissemination and oxidation of DMS

and DMSP.

In order to accomplish this, the unit will be

equipped with several sensors, including but not

limited too, a PH sensor, a thermometer, a

photometer, a salt refractometer, a current speed

sensor, and a heavy metal sensor. The unit will

also be able to rise to the surface and extend a

probe into the atmosphere in order to collect data

regarding the concentrations of DMS/DMSP in the

air directly above a particular system.

There will be an onboard computer with

power efficient processors capable of dynamically

adjusting their frequencies to reduce energy

consumption. These chips will likely be akin to the

A5 processing chips at the heart of Apple’s iPad’s

and iPhones. Because accurate location

quantification will be necessary, the units will be

equipped with onboard GPS chips in order to

convey precise global coordinates at any time.

The super computer used for this research

will be a Cray XT system. Similar systems have

been installed at several operational meteorological

and hydrological services and leading climate

research centers worldwide. Examples include but

are not limited too, NOAA, NCAR, Korea

Meteorological Administration (KMA), Brazilian

National Institute for Space Research (INPE) and

Center for Weather Forecasts and Climate Studies

(CPTEC), Danish Meteorological Institute (DMI),

and the U.S. Naval Oceanographic Office

(NAVO). (Nyberg 2010)

In order for the unit to be able to

communicate with the central data collection server

it will utilize very low frequency (VLF)

transmission to land based towers, which will then

be able to route the data to a server linked to a

super computer to analyze the collected data. The

reason VLF transmissions were chosen as the

transmission medium is because they are often

used in Integrated Communication Systems (ICS)

for naval vessels and HF ground-to-air

applications. The technology will likely come from

Hagenuk Marinekommunikation (HMK). The

company has provided solutions for more than 25

navies throughout the world who now rely on the

high level of technical expertise of HMK. Over

540 systems have been delivered for all classes of

ships, including 117 submarine systems.

Moreover, HMK provides a full service package

including feasibility studies, system engineering,

hardware and software design, production, system

integration and setting to work as well as

integrated logistics combined with comprehensive

after sales services over the whole product life

cycle. Lastly, the technology that allows user

interface with the VLF system can be a single

workstation that is expandable to a networking

multi-console client/server configuration that,

according to the contractor, provides sophisticated

automated communications support for naval

applications. The solutions offered by HMK

posses the reliability of a company providing for

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the United States navy, and the customizability

necessary for such a specific application.

The communication ability of the units

will boast two way transmission capabilities for

the obvious purpose of relaying collected

information back to the server, and the less

obvious ability to receive remote course and

speed commands from a controlling computer.

This system would ideally be composed of

several hundred of these units to create a global

network. Ideally a climate scientist would be

able to identify one singular, or several units in

one of the many strategically placed locations

and have full control over the device(s). This

will allow for a level of accurate, real time

climatic data collection never before achieved.

The reason each unit has its own

propulsion system, whether it be a set of

propellers or a series of pumps and jets is so the

units can maintain one fixed position in the sea,

or move about the sea for however long a certain

experiment or research project dictates.

An example of the novel application of

this technology is the fact that so far there is no

system of interconnected, un-tethered, real time

data collecting mechanisms of this scale. There

have been global collaborations of many

different scientists and instrumental records, but

the ingenuity behind this concept is to have one

place for scientists to go to analyze the real time

data of the DMS/DMSP concentrations and a

other measurable factors in the marine climate

system. The information can easily be archived

and made public for all scientists and individuals

who may not have the means to get to the

supercomputer that all the units are linked to.

Furthermore, the main goal of this global

network is to have the ability to monitor the

health of the planet. The possibility of the

oceanic feedback loop reversing and creating

another system that subjects this planet to

unnecessary temperature increases is very real.

James Lovelock is not the only scientist who is

concerned with the future of our climate system.

Although any scientist knows that the planet will

survive long after humans are extinct, the focus

of preventing climate change is to ensure the

prosperity of humans and all other organic life

alike. It is not farfetched that at some point the

earth may shrug humans off its proverbial

shoulder. This is why this proposal is so

important. Although it is serving to quantify but

one phenomenon out of the trillions that exist on

this planet, it is a step in the right direction.

References

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