Related Articles from Non-Woods Hole Contributors
Permanent URI for this collection
Citations in this collection are to articles authored by researchers not affiliated with a Woods Hole science community. The articles reference data sets from the Biological and Chemical Oceanography Data Management Office. If you are aware of additional citations that should be included here, please contact the WHOAS Project Manger at (WHOAS@whoi.edu)
Browse
Recent Submissions
1 - 9 of 9
-
ArticlePositive feedbacks enhance macroalgal resilience on degraded coral reefs(Public Library of Science, 2016-05-17)Many reefs have shifted from coral and fish dominated habitats to less productive macroalgal dominated habitats, and current research is investigating means of reversing this phase shift. In the tropical Pacific, overfished reefs with inadequate herbivory can become dominated by the brown alga Sargassum polycystum. This alga suppresses recruitment and survival of corals and fishes, thus limiting the potential for reef recovery. Here we investigate the mechanisms that reinforce S. polycystum dominance and show that in addition to negatively affecting other species, this species acts in a self-reinforcing manner, positively promoting survival and growth of conspecifics. We found that survival and growth of both recruit-sized and mature S. polycystum fronds were higher within Sargassum beds than outside the beds and these results were found in both protected and fished reefs. Much of this benefit resulted from reduced herbivory within the Sargassum beds, but adult fronds also grew ~50% more within the beds even when herbivory did not appear to be occurring, suggesting some physiological advantage despite the intraspecific crowding. Thus via positive feedbacks, S. polycystum enhances its own growth and resistance to herbivores, facilitating its dominance (perhaps also expansion) and thus its resilience on degraded reefs. This may be a key feedback mechanism suppressing the recovery of coral communities in reefs dominated by macroalgal beds.
-
Article
-
ArticleOcean acidification as one of multiple stressors : growth response of Thalassiosira weissflogii (diatom) under temperature and light stress(Inter-Research, 2015-12-15)Future shifts in phytoplankton composition and productivity are anticipated given that continuing changes are expected in environmental conditions such as temperature, the partial pressure of CO2 (pCO2) and light climate, all of which regulate phytoplankton communities and their physiology through bottom-up control. Culture experiments revealed that future (elevated) pCO2 had no effect on Thalassiosira weissflogii in the absence of environmental stressors, whereas growth rates drastically decreased under future pCO2 when cells were grown under light and temperature stress. Reduction in growth rates and a smaller decline in cellular photosynthesis under high pCO2 were associated with 2- to 3-fold increases in the production of transparent exopolymer particles (TEP) and in the cell quotas of organic carbon, as well as a similar decrease in the C:chl a ratios. Results suggest that under light- and temperature-stressed growth, elevated pCO2 led to increased energy requirements, which were fulfilled by increased light harvesting capabilities that permitted photosynthesis of acclimatized cells to remain relatively high. This was combined with the inability of these cells to acclimatize their growth rate to sub-optimal temperatures. Consequently, growth rate was low and decoupled from photosynthesis, and this decoupling led to large cell sizes and high excretion rates in future pCO2 treatments compared to ambient treatments when growth temperature and light were sub- optimal. Under optimal growth conditions, the increased energy demands required to re- equilibrate the disturbed acid-base balance in future pCO2 treatments were likely mediated by a variety of physiological acclimatization mechanisms, individually too small to show a statistically detectable response in terms of growth rate, photosynthesis, pigment concentration, or excretion.
-
Article
-
Article
-
ArticleAggregation and Sedimentation of Thalassiosira weissflogii (diatom) in a Warmer and More Acidified Future Ocean(Public Library of Science, 2014-11-06)Increasing Transparent Exopolymer Particle (TEP) formation during diatom blooms as a result of elevated temperature and pCO2 have been suggested to result in enhanced aggregation and carbon flux, therewith potentially increasing the sequestration of carbon by the ocean. We present experimental results on TEP and aggregate formation by Thalassiosira weissflogii (diatom) in the presence or absence of bacteria under two temperature and three pCO2 scenarios. During the aggregation phase of the experiment TEP formation was elevated at the higher temperature (20°C vs. 15°C), as predicted. However, in contrast to expectations based on the established relationship between TEP and aggregation, aggregation rates and sinking velocity of aggregates were depressed in warmer treatments, especially under ocean acidification conditions. If our experimental findings can be extrapolated to natural conditions, they would imply a reduction in carbon flux and potentially reduced carbon sequestration after diatom blooms in the future ocean.
-
ArticleBiogeochemical responses to late-winter storms in the Sargasso Sea, I - Pulses of primary and new production(Elsevier B.V., 2008-09-17)
-
Article
-
ArticleNutrient distributions in baroclinic eddies of the oligotrophic North Atlantic and inferred impacts on biology(Elsevier B.V., 2008-05-07)