[
Sometimes specialized science language can get sooo specialized and/or change so rapidly that even scientists in similar fields can find it a challenge to be sure what is meant, or an interested amateur can end up feeling lost and "out"; the language used isn't meant to exclude any reader, it is used so the *scientists* can communicate what they mean more clearly and (believe it or not ;) ) more quickly! The best thing to do if you're ineterested is ferquently to copy the article and stick the definitions of the words you're not sure of right in to the text so you can become more familiar with the words *in context*. Definitions are given in (= definition)]
by S. Abboud
A bloom is a consequence
(= result) of seasonal life cycles when there
is localized increases in asexual reproduction and growth typical of all
metagenic (
= the reproduction cycle of organisms that alternate between a sexual generation and an asexual generation) organisms that result in normal or abnormal seasonal biomass (Figure 1: an alternate photo of a
bloom has been inserted). Blooms can be influenced by localized anthropogenic
(
= human caused) effects attributed to oceanic sea surface temperature, nutrient inputs (Purcell
et al. 2007, Brodeur et al. 2008), disturbances (Brodeur
et al.
2002) including over-harvesting fisheries and translocations (Purcell 2005,
Howarth
et al. 2002). Apparent sudden jellyfish population increases
(i.e. blooms, Figure 2) are possible due to increased recruitment (
= increase in a natural population as offspring grow and new animals arrive) from local
asexual reproduction (Madin & Deibel 1998), high fecundity (i.e.
enhanced
fertilization success), aggregation (
= gathering) of mature medusae (Strathmann 1990, Purcell
and Madin 1991, and Hamner
et al. 1994), and previously mentioned
ecophysiological (
= adaptation of an organism's physiology/function to environmental conditions) and reproductive versatility (
= adaptive reproductive strategies) (Hadfield & Strathmann 1996,
Lucas 2001, Deibel & Lowen 2011).
Term
|
Description (Lucas & Dawson 2013)
|
bloom
|
A true bloom is a consequence of seasonal life cycles when
there is localized increased asexual reproduction (= producing offspring without a sexual act) and growth typical of all
metagenic organisms, resulting in normal or abnormal seasonal biomass. A true
bloom is categorized as an endemic (= native / to a restricted area) bloom staying in the same location over
time. Though apparent blooms are either transient blooms (blooms that move
spatially over time) or an accumulation within enclosed habitats, not
reflecting true blooms
|
accumulation
|
A long-term summation of fluctuations (= changes/ variability) in relative number
compared on temporal (= time) and spatial (= space) scales without causation
|
mass occurrence
|
Similar to an accumulation but larger in magnitude (= number - like a baby elephant or adult elephant is one elephant) and/or
biomass (= total amount of animal by total mass of animals present rather than by number - a baby elephant is much smaller than an adult, so even though it is also ONE elephant it has a much smaller individual biomass- a group of 12 baby elephants would have a smaller biomass than a group of 12 adult elephants)
|
aggregation
|
Accumulation of individuals likely emigrated (= left) from natural
or apparent blooms due to passive drifting, active behavior, or a combination
of the two
|
swarm
|
A very dense aggregation (= group) of individuals coming together
primarily through individual motion than currents alone
|
outbreak
|
Extraordinary increases in biomass over a short time
period within a reproductive season that is typically associated with anthropogenic
(= human caused) ecosystem changes
|
Due to the pelagic mobility of jellyfish, it is often
difficult to properly describe a mass of jellyfish as a bloom or any of the
other previously described related events. These events similar to jellyfish
blooms differ by location of reproduction, mode of how they came together and
other factors that influence jellyfish distributions (Mills 2001; Graham et
al. 2001; Hamner & Dawson 2009; and Richardson et al. 2009; also
see Lucas & Dawson submitted 2012). It is imperative to consistently use
the following relative terms to facilitate interpretation of scientific
literature and best present cause and consequences (translation of entire section = To make communication between those interested in this topic as clear as possible it is very important that everyone use the same terms, and with the same meaning!) (Lucas & Dawson 2013):
bloom, accumulation, mass occurrence, aggregation, swarm, and outbreak (Table
1).Due to the
pela
et al. 2001; Hamner &
Dawson 2009; and Richardson
et al. 2009; also see Lucas & Dawson
submitted 2012). It is imperative to consistently use the following relative
terms to facilitate interpretation of scientific literature and best present
cause and consequences (Lucas & Dawson 2013): bloom, accumulation, mass
occurrence, aggregation, swarm, and outbreak (Table 1).
The key to
understanding the distributions of jellyfishes is in identifying the original
source of jellyfish blooms. Bloom biology focus is on the meditative medusae
form, which, in large numbers, can have negative economic impacts on commercial
fisheries from fish larvae consumption (Sandlifer et al. 1974), on aquaculture
by destroying equipment and stock (Purcell et al. 1999; Delano 2006),
and on power station operations by impairing equipment (as seen in Brodeur et
al. 2008; Clark 2008).
Due to the complexity of jellyfish life histories and the
consequences of their blooms, Parsons (1993) and Mills (1995) implored
jellyfish scientists to study the functional role of jellyfish in maintaining
the ecology of the oceans. This call resulted in much of the current
information that we know and highlighted what remains to be known about
jellyfish blooms.
Phylogenetics
(= development and differences within species or structure within species) and population genetics have proven to be useful for understanding jellyfish
biology (Hamner & Dawson 2008; 2009), their geographic distribution (e.g.,
Dawson 2005), and genetic variation between populations. Jellyfish
that aggregate, bloom, or swarm are clustered taxonomically and
phylogenetically (translated section = Jellyfish that "live together" tend to be similar in development and in relatedness to each other), though taxa that bloom and swarm are typically more diverse
than non-accumulating sister taxa (Hamner & Dawson 2008).
Hamner and Dawson (2009)
presents an inventory for species that occur en
masse (= together),
encompassing jellyfish biodiversity (= variety of life), jellyfish molecular
phylogenetics, species richness, and phenotypic diversity on a global scale.
Conclusions include that taxa are not randomly distributed within medusoid
Cnidaria, and there are synergistic (= interconnected) effects of environmental attributes and
organismal traits promoting en masse occurrences. Phylogenetics can be
used to differentiate between aggregations, blooms, and swarms (Hamner &
Dawson 2009), and population genetics can differentiate between evolutionary
significant units at the population level (Waples 1994). The integration of
these molecular analyses with ecology can distinguish endemic (= native) versus transient
blooms and identify putative
environmental and genetic influences. This integration allows for the
previously mentioned knowledge gaps to be addressed, since jellyfish blooms are
characterized by increased biomass ascribed to local conditions (= increase in the amount of jellyfish is impacted by local conditions). Therefore, it
is necessary to know the condition exposure overtime, not just a snap-shot of
present conditions, to fully understand the spatial distribution of jellyfish.
Combining population dynamics and population genetics is essential for tracking
jellyfish blooms throughout the season. Categorizing a bloom as endemic or
transient will provide necessary information to identify putative causes.
Similar to the
development of molecular ecology, using more a evolutionary approach
incorporating molecular techniques and focusing on the mechanisms of evolution
to understand ecology is how best to understand jellyfish blooms. Many
questions in ecology are not framed to include evolution as part of the
question asked or as part of the solution in finding its answer. Though, an
evolutionary context is necessary to find a resolved and robust answer
(Dobzhansky 1964, 1973) through providing a framework allowing for correct
assumptions to be made. Current
jellyfish molecular studies emphasize the macroevolution ('deep' timeline
between taxa, e.g. Gingerich 1987, Benton 2015), but few consider jellyfish
microevolution ('shallow' timeline evident through population genetics, eg.
Dobzhansky 1937, Kothe et al. 2016). Microevolutionary studies typically exist
in the space between ecological and evolutionary processes since their
population dynamics both are influenced by overlapping processes (Lucas &
Dawson 2012). After all, there cannot be ecology without the mechanisms of evolution:
mutation, genetic drift, gene flow, and selection. Therefore it is necessary to integrate
ecology and population genetics in a novel framework (Lucas & Dawson 2012)
to identify types and causes of blooms (Figure 3). This integration can
distinguish endemic versus transient blooms and tease out environmental or
genetic influences on blooms. Beyond using population genetics as a tool to
find (1) what causes jellyfish blooms, and providing the foundation for (2) how
jellyfish affect ecosystems/communities: there are some other necessary
techniques that should be utilized in concert. Some of these techniques rely on
specific methodology. More rigorous sampling is necessary within a jellyfish
season (intra-annual) and also between jellyfish seasons (inter-annual) to
understand if the bloom has normal or abnormal biomass and whether it is
endemic or transient. Additionally, understanding dispersal (a mode of gene
flow) through mathematical and oceanographic modeling will result in more
accurate identification of possible environmental variables that cause blooms,
which would then be empirically tested with laboratory manipulations. The combination of these techniques must be
applied through integrating population genetics and ecology to answer (a) how
frequent is genetic structure between species (phylogenetics) and populations
(within species)? & (b) on what geographic scale does genetic structure
exist (macroevolution or microevolution)? With these answers we can finally
have more substantiated conclusions about the causes of jellyfish blooms and
what actions we can take to minimize them as the oceans continue to change.
Figure. 2. Hypothetical preliminary quantitative
evolutionary-ecological framework (adapted Lucas & Dawson 2013) to define
jellyfish en masse events. The
abscissa shows a single jellyfish season (May-September) and the ordinate axis
shows distance along a northern flowing current. Jellyfish abundance &
biomass increase with diameter. The theoretical blooming event dictated by the
arrows for two separate possible patterns for these blooms due to reproduction
and then subsequent decrease due to mortality or emigration. (A) shows an
endemic bloom that remains at the same location throughout the season. (B)
shows a transient bloom that moves throughout the season.
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